FEMALE COMPETITION AND DISPLAY IN KRIBENSIS ( pulcher), A WEST AFRICAN

Lynn Marie Drennan B.S., California State University, Sacramento, 2003

THESIS

Submitted in partial satisfaction of the requirements for the degree of

MASTER OF SCIENCE

m

BIOLOGICAL SCIENCES (Biological Conservation)

at

CALIFORNIA STATE UNIVERSITY, SACRAMENTO

FALL 2006 FEMALE COMPETITION AND DISPLAY IN KRIBENSIS (), A WEST AFRICAN CICHLID

A Thesis

By

Lynn Marie Drennan

Approved by:

, Committee Chair Dr. Ronald Coleman

Dr. Brett Holland

------' Third Reader . J am1e e1te

Date: 2006 ~7.)

11 Student: Lynn Marie Drennan

I certify that this student has met the requirements for the format contained in the CSUS

Thesis Format Guide from Graduate Studies, and fua:t this thesis is suitable for shelving in the Library and credit is to be awarded for this thesis.

/J-)~.,---, Dr. Coordinator . Date.

Department of Biological Sciences

111 Abstract

of

FEMALE COMPETITION AND DISPLAY IN KRIBENSIS (Pelvicachromis pulcher), A WEST AFRICAN CICHLID

by

Lynn Drennan

The field of sexual selection has focused on male-male competition and choice by females. This type ofintrasexual competition and intersexual selection (mate choice) has been well documented experimentally. The opposite situation, female-female competition and choice by males, has only been considered fairly recently and in a few situations, typically those studying so called sex-role reversed systems. By conducting experiments on the biparental cichlid fish, Pelvicachromis pulcher, commonly called the kribensis, my objectives were to determine if a kribensis female will compete against another kribensis female for the attention of a kriben.Sis male and to see if a kribensis male will choose his mate based on the kribensis female's display competition. More specifically, I looked at whether bright females, larger females or albino females . provided longer display times when competing for a male mate. I also looked at whether a male was more likely to choose a bright, a large, or an albino female versus duller or smaller females. I predicted that kribensis females do c~mpete with displays against other kribensis females and that the bright, large, and albino females will compete the most. I also predicted that kribensis males will choose their mates based on the fem.ale's

lV display competition as well as the male choosing a bright, large or albino female. To test my objectives and predictions, research was conducted in the Evolutionary Ecology of

Fishes Laboratory at California State University, Sacramento from Summer 2005 to

Summer 2006. The experiment consisted of putting two females into an experimental and then introducing a male. The females were allowed to use displays to compete for a 30 minute trial. The display times of the females were recorded then they, along with the male, were left for five days so that the male could perhaps choose a female mate. As predicted, the females were found. to compete against each other for the males, with the bright, larger, and albino females competing the longest, and there was a general trend for the male to choose brighter and larger fe~ales. These findings provide evidence that female-female competition does occur outside of sex-reversed and uniparental mating systems and should be considered in understanding the sexual systems of a wider range of .

Committee Chair

v Acknowledgements

I would like to thank Dr. Ronald Coleman for allowing me the excellent opportunity of working on research involving the wonderful fish known as .

Without his help and guidance this research would never have been completed. I am extremely grateful to my supervisory committee (Dr. Ronald Coleman, Dr. Brett Holland, and Dr. Jamie Kneitel) for their unending support, guidance, and patience throughout my research experience. I appreciate the work and guidance provided by the Department

Graduate Committee (Dr. Jim Baxter and Dr. Tom Landerholm) and the Department

Chair, Dr. Nicholas Ewing. I would like to thank all of my instructors at CSU,

Sacramento for their unending love of biology, their various perspectives and their real world knowledge that they willingly shared with me. I thank my lab mates for being there when I needed help or if I needed to talk about classes, problems, etc. I would like to thank the American Cichlid Association (ACA), the Pacific Coast Cichlid Association

(PCCA), and the Aquatic Specialties and Pets (ASAP) for the financial consideration and

fish supply that was provided so that I could complete my thesis work. I thank my

supervisors (Rhonda Rios-Kravitz and Barbara Stephens) at the CSU, Sacramento

Library for being understanding and helpful throughout this whole educational process.

Lastly, but definitely not least, I want to thank my whole family (my parents Brad and

Deb Drennan, my sister Lauri Drennan, and my grandparents Gordon and Judy Muir,

Pam, Danny, Kaleen and Krislyn Patterson, and Dr. Michael Dierker) for their support

and encouragement throughout this whole ordeal because without them I would never vi had the gumption to complete this work. They gave more support then they will ever know. For anyone I may have missed, I thank everyone for what they did for me that allowed me to complete this important goal in my academic career.

vii Table of Contents

Page

Acknowledgements .••••••.••••••••••..•••••••••••..•••••••..••••••••••••..•••••••••••••••••••••••••••..•••••..•••••••••••••• vi

List of Tables ..•••••.•••••••..••..••..•...••...•..••.••••...••.•.•.•••••..••...•.•.••...••.••..••••••••••..•••••••••••••..••••••. ix

List of Figures ••..•.•.•••••..••••••••••...•••••...••••••.••.•..•.•••••.••••••.••••.••••••..••...•..••..••..•••••••••••.•..•..••••• x

INTRODUCTION•••••••.••••••..••••••...•••.••••.•••.••••.••...•..•••••••••.••••••••••••••••••••.••••••.•••••••••••••••••••• 1 Background ...... 2 Mate Choice ...... 7 Sex-role Reversal ...... 12 Monogamy ...... 15 Parental Care ...... 18 Communication in Fish ...... 20 The Kribensis ...... 28 Objectives ...... '...... 32

MATERIALS AN'D METHODS ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 33 Study Animals ...... i··········· ... 33 Care ...... 33 Test Aquaria ...... 34 Experimental Setup for Test Trials ...... 36 Preliminary Experiments ...... 36 Experiment 1 ...... 3 7 Experiment 2 ...... 3 7

RESULTS ••••••••••••••••••••••••••••.•••••••••••••••••••••••••••••••••.••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 39

DISCUSSION ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••..•••••..••••• 43

CONCLUSION •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••.•••••••..••..•••••••••.•••••• 51

LITERATURE CITED ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••.••••••••••• ,••••••••••••••••••••• 52

APPENDIX ••••.•••.••••••••••••••••••••••••.•••••••••••••••••••••••••..••••••..•••.••••••••••.•••••••••••••••••••..•••••..•••.•. 57

Vlll List of Tables

Table Page

Table 1. Sex-role reversed species vs. kribensis. Kribensis is not considered to exhibit a conventional (males compete· and females choose) sex role system because the females compete, but they are also should not be considered a sex-role reversed species. The differences between the sex-role systems and kribensis are shaded...... 31

Table 2. Preliminary data table. a.) Bright vs. Dull and Large vs. Small female - female competition display times. b.) Bright vs. Dull and Large vs. Small male choice chart ...... : ...... 57

Table 3. Final data table. a.) Bright vs. Dull, b.)Large vs. Small, and c.)Normal vs. albino female-female competition display times. d.) Final data- Bright vs. Dull and Large vs. Small male choice charts ...... , ...... 58

Table 4. All final data collected- Bright vs. Dull trials. Weight, Standard and total lengths for females and males, female-female competition times, and male choice results ...... 59

Table 5. All final data collected- Large vs. Small trials. Weight, Standard and total lengths for females and males, female-female competition times, and male choice results ...... - ...... 61

Table 6. All final data collected- Normal vs. Albino trials. Weight, Standard and total lengths for females and males, female-female competition times, and male choice results ...... 63

IX List of Figures

Figure Page

Figure 1. Tank setup for experimental trials. (Just to mention, there is a clear plastic cup placed under the filter to keep the filter off the ground, which is not shown in the diagram) ...... 35

Figure 2. Final data Bright vs. Dull females graph - Female-female competition display times ...... 40

Figure 3. Final data Large vs. Small females graph- Female-female competition display times ...... 41

Figure 4. Final data Albino vs. Normal - Female-female competition display times ...... : ...... 42

x 1

INTRODUCTION

The field of sexual selection has mainly focused on male-male competition and choice by females (Berglund et al. 1992; Swenson 1997). There are many examples of this type of mating system found in the animal kingdom. Although the male-male competition and choice-by-females scenario is very common, there are other types of mating systems that have now been discovered (female-female competition, choice by males) and the evidence for these other systems is growing (Vincent et al. 1992; Eens and Pinxten 2000; Berglund and Rosenqvist 2001 ). There are even mating systems

(female-female competition, choice by males, with conventional sex roles otherwise) that are found that do not fit into the currently defined sexual systems and these species that have unusual mating systems need a new defined category to be placed in

(Swenson 1997; Beeching et al. 1998). The kribensis (Pelvicachromis pulcher) is an example of a species that does not fit into the current conventional (males compete, choice by females) mating system nor the sex-role reversed (females compete, choice by males) mating system. To correctly understand and categorize kribensis and its mating system, I will summarize sexual selection and the comparisons that are involved when looking at and trying to determine the sexual mating system of a species. This will include discussion of the foundation papers in sexual selection, as well as an explanation of mate choice, sex-role reversal, monogamy, parental care, and some details about communication in fish. When one looks at these topics, and the examples 2 of species in these topics, then one can see how a species like kribensis differs and why it needs to be classified as a different mating system.

Background

To determine a sexual system of a species one needs to understand the basics of sexual selection theory which was first proposed by Charles Darwin in 1871. He defined sexual selection as the advantages that certain individuals have over others of the same sex and species relating to reproduction, and their increased chances of passing on those advantages to their offspring. Research has focused on two key areas: intrasexual competition and intersexual selection (often called mate choice). The majority of research in the field of sexual selection has focused on male-male competition and choice of males by females, whereas female-female competition for males and choice by males for females has been understudied as an important selective force (Berglund et al 1992).

Darwin started the theory of sexual selection and other authors expanded the field and the factors that affect the process of sexual selection. Key milestone papers in sexual selection include Darwin (1871), Bateman (1948), Trivers (1972), and Emlen and Oring (1977). Darwin (1871) distinguished between intra- and intersexual selection. Models of intrasexual selection assume that one sex is a limiting factor for the other, resulting in increased competition among members of the non-limiting sex for access to the limiting sex. The outcome of intrasexual competition creates the opportunity for the limiting sex. to be choosy. He writes that males are the more eager 3 sex and will mate with any female, but females are more passive, yet still exert choice.

This fundamental difference between the sexes is based initiajly on anisogamy: females make few, big, resource-heavy eggs and males make many, small, 'cheap' sperm. This means that a female usually has more to lose in a reproductive bout and therefore is more choosy when selecting her mates because of the energy that she must use to produce a: clutch of offspring and the limits of how many eggs she can produce at one time. A male usually has more to gain by being able to mate with more than one fomale, because he is not limited by egg production, and therefore he is less choosy about his mates since he does not have to use as much energy to produce sperm for his offspring.

Bateman (1948) expanded upon Darwin's ideas and used these ideas as a guide when he asserted that sexual selection was generally accepted as a basic biological fact, but the evidence for it was circumstantial. To· provide evidence to support sexual · selection, he discussed intrasexual selection, which occurs in the fruit fly Drosophila melanogaster. According to Bateman, intrasexual selection almost always involved male-male competition and choice by females, but it seldom involved the reverse.

Bateman proposed that female-female competition is rare for the following reasons: 1) evidence ofintrasexual selection has been seen to act mainly on males (male-male competition), 2) the contribution of males into the next generation is more variable than females, 3) males experience stronger selection than females due to more intense intrasexual actions, 4) the intensity of intra-masculine selection and frequency of inseminations, and 5) the eagerness in males and the reluctance by females to mate in 4

mating systems which are naturally widespread. However, he mentioned two studies

that found males discriminating among females. In studies by Stalker (1942) and

Dobzhansky and Koller (1938), there was evidence that males can and do discriminate

among females. Although there is an assumption that males are mainly affected by

sexual selection, the selection, according to Bateman, is based on the behavior of the

animals not the gender. Bateman provided another step in understanding sexual

selection although there were other elements missing.

Trivers (1972) expressed confusion about Darwin's treatment of sexual selection

because Darwin· lacked a general framework to relate important variables like sex-

linked inheritance, sex ratio at conception, differential mortality, parental care, and type

of breeding system (monogamy, polygyny, polyandry, or promiscuity). Trivers focused

on the variable of parental investment in his paper to further Darwin's ideas. He

defined parental investment as "any investment by the parent in an individual offspring

that increases the offspring's chance of surviving (and hence reproductive success) at

the cost of the parent's ability to invest in other offspring" (p. 139). This applies to

initial primary sex cell investment as well as any other investment that benefits the

young. He then expanded the theory to show that a sex whose parental investment is

greater than the opposite sex will become a limitjng resource. The individuals of the

sex investing less will compete to breed with the individuals of the sex investing more.

This can be seen to occur in both females and males (depending on the type of mating . I I system) since parental care can be biparental (both parents) or uniparental (male or I female only care). Trivers argued that what governs the operation of sexual selection is I I 5

the relative parental investment of each sex into their offspring, which can affect the

limiting sex. When the parental investment of males is comparable to that of females,

then male and female reproductive success would be similar and choice by females

would be comparable to choice by males. If a male invests less per offspring than a

females does, but still more than one half what she invests, then selection may favor a

male to stay with one female. If the reproductive success for a male investing in the

offspring of one female is greater than if he invests in the offspring of two females, than

the male is selected to only invest in the offspring of one female. But if the parental

investment of a male is more than that of a female (regardless of initial sex cell

contribution) then it is expected that females will compete for males and males will be

,~·, selective in their choice of females. For example, in species with male parental care, males become a limiting resource for females, causing male reproductive success to

vary more than a female's, which makes males the limiting sex and females the

I competing sex. Trivers (1972) listed various ways in which a male may invest in his r

offspring. Providing food, finding and defending a territory for the female to feed, lay

eggs, or raise young, building a nest, defending the female herself, brooding eggs,

feeding the young, as well as protecting the young, are all forms of male parental

investment that increase a male's total investment that counteracts the initial inequality

in size of sex cells. Even though a male invests in his offspring, a female should still

question the ability of the male's genes to promote the survival of her offspring and the

offspring's future reproductive success, as well as, more importantly, the male's ability

and willingness to be a good parent. When a male invests considerable care in his 6 offspring, then the same considerations that apply to choice by females should also apply to choice by males.

Emlen and Oring (1977) argued that sexual selection can vary in intensity for different species or different populations within those species. Their classification system was based on 1) males competing against each other for females, 2) male reproduction is limited by the availability of sexually receptive females, 3) the rarity of receptive females compared to abundant competing males, 4) male characteristics allow males to monopolize their mates, and 5) male monopolization attempts lead to a mating system (Shuster and Wade, 2003). Emlen and Oring (1977) wrote that it is the ability of some of the population to control access of mates from others in the population which causes competition within the members of a population to attract mates. This control can be direct, physically herding mates and physically excluding other rivals, or indirect, controlling critical resources. The greater the control or monopolization of mates the greater variance in mating success. An animal's social organization can also be predicted based on the understanding of environmental variables affecting the animal. To understand the intensity of sexual selection the sexual composition of the overall population is not important but rather the Operational Sex Ratio (OSR) is of greater importance. According to Emlen and Oring (1977), the OSR is defined as the relative number of sexually active males to fertilizable females at any given time. The

OSR is an empirical measurement of mate monopolization and the greater the imbalance of the OSR, the greater variance in reproductive success among individuals of the limited sex. Therefore, the more abundant sex should be the more competitive 7

sex and the limited sex should be more choosy. When the OSR is biased towards

males, then polygyny can occur, and when it is biased towards females, polyandry

should occur. Monogamy occurs when neither sex can monopolize additional members

of the opposite sex directly or through the control of resources. This means the OSR is ili ·~· ...~. not heavily biased towards one sex or the other. Mating systems (monogamy,

polygyny, polyandry) are plastic and variable based on ecological influences ~t can

alter a mating type among species or even among different populations within a species.

After considering the foundation papers in sexual selection, mate choice needs

to be considered. Mate choice is the key mechanism for intersexual selection.

Understanding mate choice is essential to understanding sexual selection.

Mate Choice

There are many reasons why an animal should not mate indiscriminately, but

instead choose its mates based on the potential mate's quality. Mate choice is defined

by Halliday (1983) as patterns of behavior, by one sex, that has them mating with

certain members of the opposite sex rather than others. This is purely at an

observational level and there are many factors that can affect mate choice. Mate choice

can be based on fecundity or fertility, immediate gains and parental abilities, resources

or high status, mate complementarity, good physical condition, or most effective

courtship displays (Halliday 1983). Santangelo and Itzkowitz (2006) tested the mate

choice process of convict cichlids and how the fish are affected by intrasexual selection.

Their results suggested that competition caused the fish to alter their behavior by mate 8 guarding. The primary females spent more time with their accepted male and the males made more efforts towards primary females when competition was involved. Since these fish are monogamous, mate guarding is very important when they find their desired mate so that other competitors do not disrupt the pair.

There are three main types of mate choice typically found in the scientific literature. These include choice by females, mutual mate choice, and choice by males.

Choice by females is the most common system of mate choice found in animals.

Females are usually more choosy about their potential mate(s). Barlow (2000) describes this as the "feminine syndrome" - a female produces relatively few, very expensive eggs and a female usually invests much more into her offspring than a male does. A female also has a limited number of eggs that she can produce in a lifetime therefore she should take caution when she decides on a potential mate. Because of the feminine syndrome, the female is said to be coy and choosy so a female will take time when assessing a potential mate by judging his competitive ability and the resources he offers. In this syndrome, a female does not need to fight with other females for a mate or be brightly colored, so she stays smaller and more dull than the male because bright colors may be physiologically expensive and/or increase her exposure to predators. The reproductive success in this scenario also does not vary as much among females as it does among males, so females choose and males compete.

Choice by females occurs in many fish species and males may be chosen for many reasons. Males may compete for females by fighting for them, holding larger or . better territories, building elaborate nests, courting more vigorously or persistently, 9 bringing food to a female, or by male sexual ornaments. Female wrasses (Pseudolabrus celidotus) choose males based on the territories h~ld by males in deep water; the deeper the water, the more attractive for the female wrasse (Jones 1981 ). Female mottled sculpin ( Cottus bairdi) prefer larger males for an increase in reproductive success

(Brown 1981). Female guppies (Poecilia reticulata) prefer males with more orange coloration be.cause of the instinctual response to carotenoids, which also are used in foraging (Grether 2005). Some female Lake Malawi cichlid fish (Tramitichromis intermedius) choose males based on bower construction and courtship behaviors

(Ripley and Lobel 2005).

Mutual mate choice is a somewhat rare system of mate choice but there are examples of species that choose their mates based on mutual choice. Mutual mate choice is seen where assortative mating of high-quality individuals mate with other high-quality individuals and low-quality individuals mate amongst themselves. This occurs because the preferred individuals are able to be choosy in their mate choices. ·

Through mutual mate choice, sexual selection of an ornament may be used by preferred individuals of the sexually selected sex for high-quality individuals of the opposite sex

(Kraak and Bakker 1998). An example of mutual mate choice occurs in threespine stickleback (Gasterosteus aculeatus) under certain conditions. In this species, males have an attractive red coloration that females choose, while males choose large females for their bigger, heavier eggs. In other words, males are limited by the number of eggs they can oxygenate and care for, the males with brighter red throats are approached and chosen by more ripe females than they can accept, so the males are then able to be 10 choosy for females with higher quality eggs (Kraak and Bakker 1998). Both sexes have something the other sex wants (red coloration/large, higher quality eggs), so choosiness exists in both sexes. Size assortative pairing also occurs in the

(Beeching and Hopp 1999), and mutual mate choice is said to occur in Banggai cardinalfish (Pterapogon kauderni) (Kolm 2004).

Choice by males is the rarest system of mate choice. It is difficult to find this choice system in species exhibiting conventional sex roles (versus a sex-role reversed species) but it is found. Choice by males is thought to occur when females vary in quality (fecundity, egg size, ability to provide parental care) and when males are limited in the number of mates they can mate with, which then allows a male to choose a female that provides him with the highest reproductive success (Sargent et al. 1986).

Servedio and Lande (2006) remarked that male mate choice may be based on a trait related to the female's fertility or on a character that is sex-limited and the males may also prefer traits in females that reflect the male's selected traits. Female-female competition is also a factor affecting male mate choice in species where this type of competition occurs (whether in sex-role reversed or conventional sex role species).

Males are said to become more choosy when energetic and temporal constraints limit the opportunity for a male to mate. So, as with females, male choosiness will vary based on costs that are associated with the discrimination among females (Wong and

Jennions, 2003). Servedio and Lande (2006) examined population genetic models to look at the dynamics of male mate choice. They found that male preference will be lost unless males with a preference can increase their overall courtship output. The loss can 11 be counteracted ifthe males pick females based on traits that indicate high fertility or viability. Amundsen and Forsgren (2001) found that choice by males occurs in the two­ spotted goby (Gobiusculusjlavescens). They tested whether males prefer more colorful females by giving the male a choice between two females that varied in their coloration.

They found that a male spent more time with a colorful female than a drab female as well as performing more courtship displays towards the colorful female. Wong and

Jennions (2003) found that choice by males was found in the pacific blue-eye ,. (Pseudomugil signifier), where the males preferred larger females and the males were consistent in these choices only when the costs of association with possible mates were equal. They suggest that males respond adaptively to the changes that can come when choosing a mate, so that male choosiness will vary depending on the costs that accrue with mate discrimination. McLennon (1995) found that in brook stickleback ( Culaea inconstans ), discriminating males had a selective advantage that allowed them to court receptive females instead of wasting time courting a non-receptive partner. The males preferred nuptially colored females to gravid, inter-spawning females and this preference will increase as the male acquires more clutches to guard. Choice by a male has influenced female coloration in the stickleback and from a male's perspective being able to distinguish a ready-to-spawn female versus an interim spawning female saves him time and energy as well as decreasing the likelihood that his nest will be cannibalized. It is interesting as well that a female Brook stickleback will become less selective in her spawning partner as she invests more search time and energy since she will lose her eggs if she does not spawn within a given time after ovulation. Sargent et 12

al. (1986) provide evidence for choice by males in threespine stickleback and coho

salmon ( Oncorhynchus kisutch ). In the sticklebacks, males may spawn with more than

one female and care for several clutches of eggs at a time so they have to be choosy

when they are approached by several receptive females simultaneously. The male in

: t this species will usually court the larger females first and with the most effort. In the

salmon, the female competes for a territory, makes a nest, spawns, and then takes care

of the eggs. A larger female will be able to provide better parental care and therefore

have higher reproductive success, so the males will then choose the 'best' female and

compete against each other to spawn with her. Lastly, Simcox et al. (2005) examined

male mate choice in a livebearing fish, the Panamanian bishop (Brachyrhaphis

episcopi). In this species, the operational sex ratio is highly skewed towards females

which gives reason for the male choice shown. The study found that the males also

prefer unfamiliar females rather than familiar females. In all of these examples, the

species have different criteria for allowing choice by males, but choice by males does

occur.

Sex-role Reversal

As sexual selection evidence started to build it was found that not all species

followed the scenario characterized by male competition and choice by females. In

some species, females were found to compete. Most evidence for female-female

competition for males is, by definition, found in sex-role reversed species. Sex-role

reversed species are species in which females compete more intensely then males for 13 access to mates (Eens and Pinxten 2000). In addition to the females competing more, the males will become more choosy. Sex-role reversal also can occur when male care exceeds the time needed for a female to produce another clutch of eggs, therefore the male becomes the limiting sex and sex role reversal can occur (Barlow, 1991). In Eens and Pinxten (2000) they state that the idea of sex-role reversal predicts that 1) competition is stronger in females than males, 2) males are more critical in their choices, 3) there is higher variance in female than male mating success, and 4) there are more pronounced female secondary sex traits and mate-attracting displays. This has been found in various species where the females act like males and the males act like females. The idea of sex-role reversed species has its roots in studies of mammals. The typical mammalian mating system consists of the males competing for the females and not helping at all with their children (with some exceptions) and the females being choosy and providing all the care. So a sex-role reversed species would do the exact opposite of this scenario (females compete and males, not females, provide care). But, for fish, the 'norm' is the opposite of mamma~s when looking at sex roles, the male usually provides care and the females do not, so the sex-role reversed rules do not correctly define fish mating systems (Gross and Sargent 1985). Therefore, this sex-role reversal idea needs to be reviewed and remodeled to apply to a wider perspective of animal species and their various mating systems. ·

Pipefish are model organisms for sex-role reversed species. Berglund and

Rosenqvist (2001) studied the deep-snouted pipefish (Syngn.athus typhle). In this species, males tend to be choosy and females compete for access to males. The female 14 also has a temporary ornament consisting of a striped pattern on her flank. These qualifications make the species sex-role reversed by definition. The straightnose pipefish (Nerophis ophidion) is another example of sex-role reversal (Rosenqvist,

1990). Vincent et al. (1992) suggest that there is a correlation between the mating system and the sex roles in the Syngnathid family: mainly polygamous species show sex-role reversals whereas monogamous species show conventional sex roles. This · could be true for other species of animals, but there is not enough data present on the subject; it is something to keep in mind when reviewing the sexual systems of animals.

Sex-role reversal has been suggested or documented in three other species offish, including the Cardinalfish (Apogon notatus), a related cardinalfish (Apogon doederleini), and the Black-chinned (Sarotherodon melanotheron) (Bens and

Pinxten 2000). Sex-role reversal occurs in a variety of birds and amphibians (although no mammals), as well as fish, but in this paper I am focusing solely on fish species.

There are also examples of species that are considered sex-role reversed but they do not follow the rules as they are currently applied. Jn.anemonefishes (Amphiprion), the females do not compete against other females but are considered sex-role reversed because the females are the larger more aggressive member of the pair. There are also numerous harem groups where the females are territorial towards each other, which are considered as having conventional sex roles but there are reservations about their classification (Barlow 2005).

There are also examples of moderately sex-role reversed species like the tidewater goby (Eucyclogobius newberryi). Swenson (1997) found this species to be 15

moderately sex-role reversed because many aspects of male behavior (nest construction

and defense, courtship, and parental care) were typical, but the female behavior (black

nuptial coloration and intense female-female competition) was unusual. The females

were found to compete for males more than vice versa, so although moderate, this

species is still considered a sex-role reversed species in present literature. But is this

really sex-role reversed or is it just another example of a sexual system? Is this a mid- i,. point between sex-role reversed species and another, new type of sexual system? What .I'fl~ about situations, like this, where males act like males and females act like females

except that the females compete with each other?

Monogamy

Sexual mating systems are determined by the actions of the animals involved. If

animals have a mating system where one male mates with many females or vice versa

the mating system is affected. Even more unusual, if a species will -pair up with a 1: 1

ratio then the mating system is also affected and this type of system is more unique.

Monogamy has drawn attention as an unusual concept of animal sexual systems

according to Wickler and Seibt (1983). Monogamy, from an evolutionary standpoint

for males should be counter-selective because of the anisogamy of virtually all animals.

From a sociological standpoint, monogamy refers to two individuals who spend a lot of

time together as a pair, not in a group, or those who share activities disproportionately

(Wickler and Seibt 1983 ). According to Barlow (2000), monogamy is defined as a male

and female forming an enduring exclusive pair, with the subsets 1) courtship - where 16 the male and female will pair up and court each other for a prolonged time and then separate after the eggs are laid, or 2) parent - the male and female will form a pair that continues until the young reach independence. In animal behavior it seems that a monogamous pair is a pair that will stay with each other through a whole brood cycle, and not desert nor stray to find other mates. Biparental care is affected by monogamy since the father and mother are needed to raise a brood and stay together long enough to promote survival of the young but not so long that future reproduction is excessively affected. Parental care may occur in monogamy but it does not guarantee a monogamous situation. There are also monogamous fish that do not show any parental care (Barlow 1984).

In substratum spawning cichlids, firm pair-bonding with a prolonged association, forms a strictly monogamous couple, compared to mouthbrooding cichlids which are more often polygamous. The substrate brooders establish a territory where both sexes defend and sometimes construct their nest, which includes another prolonged association before courtship and parental care even begin. In most species, both sexes become colorful at this time (Fryer and Iles 1972). So monogamy is thought to occur when polygynous opportunities are affected by intrasexual competition, or when biparental feeding and defense are needed (Morley and Balshine 2002). Barlow (2005) remarks that among monogamous cichlids the males are larger in size and dominant but the females compete for males which is not found in the feminine syndrome. Two · species examples include the orange chromide (Etroplus maculatus), and the midas cichlid ( citrinellus). 17

Monogamy is very unusual and rare which can be realized when comparing

monogamy to other types of mating systems which are more common. Barlow (2000)

lists general definitions and subsets for the other types of cichlid mating systems which

include: polygyny, polygynandry, polyandry, and the extended family. He used these

classifications for cichlid mating systems, but they apply to animals as a whole, with

possible exceptions in any group. Polygyny occurs when one male fertilizes the eggs of

more than one female (example-the shell-brooding cichlid, Lamprologus callipteros).

The subsets include, 1) male territory - where a male has control of a territory and the

females visit to spawn (the females spawn with only one male each reproductive cycle),

2) Bigamy- two females hold a territory within a male's territory, and the male may

help take care of the young, and 3) Harem-like bigamy, but this subset usually

includes more then two females and little or no male care'Ofthe young. Polygynandry I is defined as every individual mating with more than one individual of the opposite sex; J each male fertilizes the eggs of more than one female and each female has eggs '.=;

fertilized by more than one male (e.g. the zebra cichlid, Pseudotropheus zebra) . .The

subsets in this category are 1) male territory - males have territories that they control

continuously and the males receive more than one female, and females spawn with

more than one male in a given territory, and 2) lekking - males are scattered over a

certain area that is not constant, and the females visit multiple males. Polyandry occurs ·

when females mate with more than one male, but a male only mates· with one female

(e.g. the checkeredjulie cichlid, Julidochromis marlieri). Lastly, the extended family.

consists of two or more group members of both sexes that are reproducing, and some of 18

the offspring remain in the family (e.g. the daffodil cichlid, Neolamprologus pulcher).

These mating systems help explain why some animals act, look, and behave as they do,

and why they have evolved to reproduce as they do.

Compared to the other mating systems discussed above, monogamy is still a

system that raises many questions on how it persists. But as a sexual system it allows

for many new, unusual behavioral adaptations and new evolutionary consequences.

Parental Care

Parental care is a very important factor in sexual selection which causes a

~- limiting sex and therefore affects mating systems. Parental care consists ofparent(s)

caring for their young to help them survive better than they could on their own.

Parental care can vary in its duration and the amount or type of care given (Gross 2005).

There are three types of parental care, female only parental care, male only parental ·

care, and biparental care. With these forms of parental care, there are significant

patterns (taxonomically) that arise where one sex otthe other will show more care for

the young or in some cases both parents will work together to raise their young. For

vertebrate species, mammals have primarily female-only care (90% of families) and

biparental care (10%), but no known cases of male-only care (except humans); birds

have mainly biparental care (90%), with female-care being uncommon (8%), and male~

only care being very rare (2%); and in fishes the majority of the species provide no

parental care, but out of the species that do provide parental care, male-only care is seen

most (50%) followed by female-only care (20%) and some biparental care (20%) (Gross

2005). With a focus on fish, although they have evolved all forms of parental care, they 19

are particularly noteworthy for their male investment. This predominance is thought to

have evolved not because males received better benefits from caregiving, but because

there was a lower future cost to males for the same benefits as females (Gross 2005).

It has been realized-that parental care behavior is not an adaptation that benefits r ·~. a species as originally thought, but one that maximizes the selfish genetic inte:r;ests of

the parent(s). When natural selection favors parental care, the dynamics of sexual conflict change (Barlow 2000). Parental care is not an all-or-nothing behavior, it can be .. adjusted by an individual's circumstances. Gross (2005) lists four factors that can affect

the amount of parental care given to an individual parent's offspring, these include a)

brood size - the number of offspring that need care, b) past investment - energy given

for each clutch laid and energy spent for past, present and future broods, c) genetic

relatedness-individuals don't want to be cuckolded and care for another's genes, and

d) future mating possibilities - number of future mates that may or may not be

available. Karino and Arai (2006) gave a species example that supports Gross' factors.

In the marine goby (Eviota prasina) males provide parental care for their nests, which

includes egg fanning. Male care is affected by the number of eggs in the nest, the more

eggs the more parental care the male provides. The males do not need to worry about

genetic relatedness since the males only allow the eggs they fertilized into their nests,

although there may be more than one female's clutch within a nest. For future mating

possibilities there are females who will still need nests to lay their eggs in, so th~ males

can give appropriate care for current eggs and then have opportunities for the future.

The male because of his efforts will increase his reproductive success. 20

Communication in Fish

Along with the factors that affect sexual selection subconsciously, communication is needed to advertise sexual selection qualities that affect mating systems and how they operate. Communication is used for all important aspects of a fish's lifestyle. Communication is needed when breeding, feeding, fighting, or peacemaking. When breeding, the courtship stage includes communication that leads to mating. In courtship, communication is used for a) attraction and identification- so the same species of sexually active males and females are together at a time and place appropriate for breeding, b) arousal, appeasement and synchrony - motivational attitudes of male and females are parallel so that the correct breeding patterns are in synch and successful mating occurs, and c) longer-term effects- establishment and maintenance of a pair bond that work together and care for their young (does not occur in all fish) (Keenleyside 1979). Communication in fish occurs mostly as visual communication, although vocal and chemical communication may occur in some species.

Visual communication occurs either by c~lor patterns, body movements, or

competitive displays. In cichlids, particularly, color pattern is a very important mode of

communication in mate choice with respect to competition and displays. The color

patterns can communicate a fish's health, fecundity, or readiness in a mating situation

or competitive display. The colors in these color patterns originate in skin cells called

chromatophores. In certain species, chromatophores can vary in appearance therefore

,..:__::-.::.______21 transforming the appearance of the fish. Chromatophores can vary in color from dark melanin, to bright hues of yellow, orange, or red carotenoid pigments, to others that produce iridescence of blues and greens (Barlow 2000). The changing of color patterns occurs from the simultaneous action of the chromatophores. The chromatophores are branched out in a cell like a spider web. The color pigments can be withdrawn from the branches into a collective spot in the middle of a cell therefore making the color disappear from a fish. When the pigments spread out into the branches, and depending on the expansion of the pigments, the intensity of the color that is shown varies. When spread out, the collective cells overlap in their colors causing coloring in that area on a fish's skin to be continuous (Barlow 2000).

The chromatophores allow a species a distinct pattern affected by internal motivational factors indirectly by neural or hormonal signals or by external environmental conditions directly (Voss 1980). Expansion can be controlled by hormones that are released by the posterior pituitary gland or expansion and contraction can be activated by nerve fibers through the nervous system (Fryer and Iles 1972). This then allows certain species of fish, like cichlids, the capability to change their color patterns rapidly when the need arises. During courtship and mating, the male, less often the female, will intensify his/her non-breeding coloration resulting in sexual dichromatism. The 'ripe' males are beautifully and brilliantly colored to attract females. The breeding 'dress' is markedly different from the non-breeding coloration.

Females can also become more brightly colored than males during periods of courtship and reproduction resulting in reversed sexual dichromatism, although this is more rare. 22

When reversed sexual dichromatism occurs, sexual selection theory predicts reversed traits like female-female competition for males and/or resources, male mate choice, or both (Beeching et al. 1998). Brighter females are found in cichlid species like the (Tilapia zillii) and Guenther's mouthbrooder ( gu.entheri) (Fryer and Iles 1972), kribensis, convict cichlid, Rams cichlid

(Microgeophagus ramirez), dwarf pike cichlid ( Crenicichla regani), and the cichlid species Nanochromis transvestitus (Stewart and Roberts 1984), which are a few examples. Because these color patterns are evolutionary advanced in certain cichlid species, the colors are extremely good indicators of the internal state of the fish and are useful in communicating a fish's desire or intention. It is thought that prolonged association (when pair-bonding has been established) and the bright colors of both sexes

(when both are colored) are for mutual stimulation during the extended period of courtship and mating. The evolution of preferred color ornament systems is a benefit to both the signaler and the receiver in communicating important information (Svensson et al. 2006). External environmental conditions also affect a fish's change of color. The physical and biotic environment can influence how coloration evolves. Water and substrates that are background for displays help select colors that enhance conspicuousness and contrast with the background. The light of shallow, freshwater environments is green, so red provides the maximum contrast (Lythgoe 1979), which is exemplified by fishes with elements· of reds and oranges (e.g. kribensis). In clear water with intermediate depth, blues and yellows are the most visible (Barlow 1974). In turbid water, all colors are represented, but red, yellow, and orange are common 23

(Barlow 1974). Environments that include many hiding places favor conspicuous fish

because of reduced predator risk, whereas species living in sandy substrates or benthic

areas have conditionally reduced coloring because of a higher risk of exposure to

predators (Kodric-Brown 1998).

Based on the importance of visual communication and the use of colors in fish

like cichlids the dynamics of vision in fish is very important. The vision in fish is

strong at least at a short range. This is realized by their ability to catch small items C?f

food when the food is not stationary. There is also good evidence that cichlids possess

good color vision (Fryer and Iles 1972). According to Nelissen (1991), cichlids belong

to a group that have high sensitivity to violet, blue-green, and yellow-green but they can

see a range through those colors. Without the necessary vision dynamics, the colors and

movements used by fish would be ineffective and the colors presented would be a waste

of time and energy used to maintain the colors that other fish could not see. ;.'.·< "":; The colors used in mating situations and competitive displays are highlighted by

signal movements that communicate an individual's intentions and/or mood Baerends

and Baerends-Van Roon (1950) list signal movements that include lateral display,

frontal display, mouth-fighting, and jerking and quivering, which are commonly seen in

mating and competitive bouts. The lateral display is shown when the dorsal and anal

fins are fully erected and the pelvic and caudal fins are fully spread out. The pectorals

are used for movement so they move accordingly. In this display, the fish are

comparing sides and overall body quality, to look bigger and better. This display can be

used to intimidate, to show superiority, or it can be used when a fish is frightened. The 24 frontal display includes two fish approaching one another frontally with their gill covers erect. The fish usually have their mouths open for this display. This is a competitive display against a same sex opponent. The mouth-fighting movement is an extension of the frontal display. The two fish will approach each other frontally with their mouths wide open and they will then try to grab another's jaws and they will tussle. The opponents will push and pull each other using heavy beating of the caudal, pectoral, and anal fins. This is a competitive display used by two males or two females competing.

Jerking and quivering are signals that are also used in fish communication. With the jerking motion, one fish will display to ap.other horizontally with the pelvic fins laid against the body, the pectorals beating alternatively, and the other fins half-spread, maintaining a stationary position. The fish bends its head sideways and brings it back to its original position, usually repeating the motion numerous times and alternating left to right. This is used in a mating display of a male to a female (or vice versa). Jerking gradually becomes quivering. When quivering, the position of the fish is more vertical and the body waves are much stronger. This is an excited motion that is used in a mating display between a female and.a male (or vice versa) as well as a functional display (for example to build a nest when courting). Color along with signal- movements help fish communicate with another individual in mating and competitive situations. By using different degrees of color, or lack thereof, and using known movements, fish can 'talk' to each other and make themselves understood.

When put together, colors and movements help a fish compete. Fish compete in many different ways for many different things. A fish may compete for food, for a 25 territory, or for a mate. In all of these competitions, each species has their own way of handling things. There are many examples of various types of displays include penciling, or a back-and-forth face-off, seen in Orange Chromides; a frontal display with an open mouth seen in lekking Tilapias, or spitting sand at a neighbor and raising territorial parapets also seen in lekking Tilapias (Barlow 2000). Other general displays that occur in many species of fish include: lip-locking, nipping, flaring, tailbeating, bending, charging, brightening their colors, shivering, u-bending, presenting sides to another fish, and there are many more. These displays are mostly seen in aggressive, competitive displays, but are seen often in mating displays, and peaceful, soothing displays.

Color and movements also communicate a female's fecundity (capability to produce eggs = offspring) to males as well as other females of a species. Massironi et al. (2005), found the lagoon go by (Knipowitschia parizzae) as an example of a fish that uses color and movement to advertise its fecundity. During the breeding season the female goby displays a conspicuous bright yellow-orange coloration on her belly. The female will display her yellow belly to a male to gain his attention. The color is evident when a female is ready to spawn (evident by her round belly and swollen genital papilla) and disappeared after her eggs were laid. The yellow coloration was present in defined margins and the yellow patch was positively correlated with the number of eggs laid. The color is variable in size among females and for this species is a reliable indicator of female quality for the number of released eggs relative to body size. The

coloration and its correlation of readiness to spawn gives advantages to males to ..i ' 26 recognize a receptive female with respect to energy used for courtship displays and avoidance of female cannibalism of eggs already in the nest. Amundsen and Forsgren

(2003) discussed the two-spotted goby which has a conspicuous yellow-orange belly that breeding females display to males during courtship. A female will bend her body extending her belly towards the male using the color and movement to highlight her belly area (i.e., showing how fecund the female is). Svensson et al. (2006) found that the more colorful female gobies laid significantly larger clutches than females that were drab. Beeching et al. (1998) reported on convict cichlids that have a conspicuous orange ventral coloration used in female-female competition and perhaps male mate choice. Again, the color highlights the fecundity of a female and her fullness of eggs.

Vocal and chemical communications are also known to occur in fish communication although not as strongly as visual communication (most fish are found to be visual breeders, hence the extreme colors, displays, etc.). Vocal communication has been found in cichlids, but to what extent is not yet known. Sound production was first reported in the nile tilapia (Tilapia nilotica), which produces a deep-pitched crack made by courting males (Fryer and Iles 1972). The (Hemichromis bimaculatus) is also known to produce sounds that consist of a 'Br-r-r' sound made by brooding females. Males of this species produce the same sounds although in a deeper tone and longer duration, as well as a 'thump' sound (Fryer and Iles 1972). The thump sound seems to accompany the frontal threat display. Barlow (2000) states that there are now sixteen known cases of acoustic communication in cichlids, mostly low- frequency grunts produced during hostile displays and sometimes during courtship. He 27

discusses the (Herotilapia multispinosa) which produces 'volleys and

thumps or purrs' and the Mozambique mouthbrooder (Oreochromis mossambicus),

which has a large repertoire of sounds made by grinding its pharyngeal teeth .. He also

mentions the species of platinum acaras (Aequidens latifrons ), the pearl cichlids

(Geophagus brasiliensis), and the checkeredjulie cichlid as possible vocalizers as well. ~ ~ ' Chemical communication is a possibility in fish since fish release chemicals into

the water. Fryer and Iles (1972) list three examples. The first example is a species that

releases a 'fright substance' (Schreckstoff) when a fish is injured. This substance is

recognized by other member of the species and warns them of danger. Schreckstojfis

found more often (primarily?) to be released in young Tilapia (Tilapia macrophala)

fish. Secondly, chemical communication is used in cichlids for parent's recognition of

their offspring when the offspring are not visible. This has been shown to occur in the

jewel cichlid (Fryer and Iles 1972). Thirdly, there is evidence that blind fishes use·

chemical perception in species recognition (although not the only method). Chemical

communication, in ways other than what is presently known, are possible since fish .. possess highly sensitive olfactory apparatuses and they are able to detect odors in low

concentrations, as well as tasting the chemicals. This subject needs much more

investigation before we can determine the extent of chemical communication in fish

species. 28

The Kribensis

With the explanations of sexual selection mentioned beforehand one can now take a species and use that information to evaluate a species and how its mating system may differ from a conventional (male competition and choice by females) system or a sex-role reversed (females compete and choice by males) system. The cichlid fish, kribensis, is one such species that needs to be observed since the species has a unique system that does not allow it to fit in the current mating system categories of conventional or sex-role reversed. The kribensis (Pelvica =belly, chromis =color, and pulcher = beautiful) is a cichlid fish from West African rivers. It is known by many common names including: kribensis, krib; Purple cichlid, dwarf rainbow cichlid, and the Niger cichlid. The males can grow to 10 cm and the females usually grow up to 7

cm. These fish are monogamous and show a substrate brooding lifestyle (they prefer enclosed spaces like caves (or flowerpots) where they will lay 10-250 eggs on the roof of a cave or a flat surface). This pattern probably evolved from an earlier pattern of male only care (Keenleyside 1991), which could help explain why female kribensis compete for males and their help in parental care. Both parents attend, care for, and protect their eggs and fry carefully, as well as herding their offspring when they swim.

This fish species practices· biparental care long after the fry are hatched. Kribensis show strong biparental care and a Matriarch/Patriarch system where the female watches the fry and the male defends the female and the.fry. These fish are very territorial and aggressive during breeding and raising their offspring. These fish are highly visual mate selectors, which means color and size are very important. This species shows 29 accentuated by their coloration, where both sexes are brightly colored, but the female is more brightly colored than the male (Voss 1980). Both sexes have brightly colored dorsal and ventral fins and striped frontals. The males and especially the females have one to many ocelli (black spots) on their dorsal and caudal fins. Heiligenberg (1965) suggests these spots could be used as intimidation of intruding fish, especially in the lateral displays. In both males and females there is a wide longitudinal black band down the side of the fish body. In females that are

'coloring up' this black band will fade away and be replaced by the abdomen color spot

(personal observation). When kribensis are scared or threatened their colors disappear and they are bland colored (personal observation). This has been observed i.n other species as well (e.g. Chromidotilapia gu.entheri (Fryer and Iles 1972)).

The females show the most intense coloring (pink, red, or purple) in their abdomen area. The color is concentrated mostly on the abdomen of the female to draw attention to her belly region. The females seem to use their bright coloration to compete for males, as well as a threat display to other females. The abdomen color emph1:1.sizes the part of her body that swells as she fills up with eggs (Barlow 2000). Because of this, she shows the male and other females that she is the best female because she is so full of eggs (Barlow 1974). She then uses this ornament to compete and win the male she is competing for. In female kribensis, the pelvic fins are also brightly colored and rounded (in males they are pointed), and the fins are used in the integration of the female's movements to make her abdomen look more plump by blending the abdomen with the fins as a continuum. It seems that kribensis females are the only cichlids that 30 appear to have the same colored pelvic fins as their abdomens (Voss 1980). This

species shows each color marking very brightly, but they have few permanent patterns.

The colored markings therefore seem associated with expressive movements (Voss

1980).

The kribensis is an excellent fish species for an experiment for several reasons.

It is a coinmon aquarium fish making it easy to find, it is thought by hobbyists to show

female competition, and their displays can be monitored and easily observed. They also

show biparental care and are monogamous so they will stay together for at least the

brood cycle, therefore not adding complications of switching partners. Finally, they

hold separate territories for each male-female pair which leaves each individual able to

choose his/her mate and not switch partners, therefore allowing them to raise their fry

undistracted. Kribensis are not considered to have a conventional sex role system

because the females compete, but they are also not sex-role reversed (Table 1), so they

need a category that they will fit into.

But can female-female competition occur in a species that has males with male

tendencies and females with female tendencies, monogamy, and true parental care?

Can competition occur in systems other than sex-role reversed systems, or is this female .

competition always the result of a sex-role reversed system? Competition can occur

among females if you have a female who is aggressive with other females, if you have

monogamy, if you have biparental care, and ifthe females are not protectively colored

but marked to catch the eye of a potential partner. This is the case of the cichlid fish

kribensis. 31

Table 1. Sex-role reversed species vs. kribensis. Kribensis is not considered to exhibit a conventional (males compete and females choose) sex role system because the females compete, but they are also should not be considered a sex-role reversed species. The differences between the sex-role systems and kribensis are shaded. r

i:

Females brighter than males x x

Parental care uniparental (male) bi parental

Monogamous x

Polyandrous x

Guarding fry male female

Guarding partner n/a male 32

Objectives I proposed that female kribensis compete against other female kribensis for the attention of kribensis males and that a male will choose his mate based on that competition. My objectives for this thesis were to test:

- If female kribensis use competitive displays to compete against other

female kribensis for a male kribensis mate,

- If brighter females will display longer than dull females,

- If larger females will display longer than smaller females,

- If albino females will display longer than normal colored females, and

- If males will choose bright or large females more often than dull or small

females.

The significance of the anticipated findings would be to present the case and provide evidence that female-female competition does occur outside the sex-reversed and uniparental systems. This would open the door to more studies of this nature; for example, other cichlid species, which could further support female-female competition.

But most importantly, if this hypothesis proves to be true, then the inclusion of female­ female competition would change the way sexual selection is viewed. It could also bring another perspective to the understanding of the sexual systems of animals, those that may have been overlooked or wrongly identified because of current views relating to all male­ male competition or sex-role reversed scenario. 33

MATERIALS AND METHODS

The focus of this study is to observe if kribensis females compete against each other to win a male mate and if a male will choose a female based on the female's competition. Physical appearance and physical actions will be used to test if and how females are competing for their mates. Male mate choice will be determined by the male choosing a female and the pair being found in close association (e.g. sharing of the same flowerpot) or by spawning.

Study Animals

Kribensis were obtained from a stock tank at the California State University,

Sacramento campus as well as the Aquatic Specialties and Pets and Pacific Coast Cichlid

Association fish suppliers. The males and females CSUS were young, juvenile fish and resided together prior to the experiment. The other fish obtained were varying ages and sizes. After the experiment was initiated the sexes were separated into separate holding tanks.

Animal Care

The fish were fed TetraCichlid flakes daily when not in a running experiment. If the fish were in a timed experiment, the fish were fed when the timed trial was finished.

Each tank was illuminated by fluorescent lighting above the tanks that were run on 13/11 34 hour day/night cycle. Temperatures were kept at 78-82 degrees C. The tanks were supported by sponge air filters and heated by rod heaters.

Test Aquaria

The test aquaria were constructed identically (see fig. 1), but varied in the number of test tanks used at certain times because of space restrictions (three during the semester and ten during the summer breaks). The test aquaria were square glass tanks that measure

60.96 cm x 60.96 cm x 30.48 cm. Each tank was covered with two panes of glass to keep the fish from jumping from the tank. The floors of the tanks were covered with pebble- sized gravel that appeared a dark gray or black collectively, but were actually a mixture of colors separately (gray, green, purple, white, and black). This gravel color helped highlight the display colors of the fish. In each test tank there were two clay pot halves

(8.26 cm diameter and 8.89 cm height), which allowed the fish cover and the opportunity to develop a territory or possible spawning site. There also were seven green

Hygrophelia plastic in each tank setup that provided cover for the fish. In each tank there was also one clear plastic cup (8.89 cm diameter, 6.99 cm height) that kept the plus-shaped sponge filter off the substrate and therefore kept the fish from hiding behind the filter and staying out of sight. The sponge air filters and heaters were also included in the tank setups. White plastic covering was used to surround the two sides and back of the test tanks to keep the fish from seeing other conspecifics in other test aquaria. 35

hAAtAr filter !;; JC )/ / / / / I • I •• 12' l/C) / CX1 / / Q ( / - 2' / gravel l plants I fl ovverr::::ots

Figure 1. Tank setup for experimental trials. (Just to mention, there is a clear plastic cup placed under the filter to keep the filter off the ground, which is not shown in the diagram) 36

Experimental Setup for Test Trials

The experimental setup for test trials occurred in a square aquarium. Two females were randomly caught from the female stock tank and were placed into the aquarium.

One male was then introduced into the square aquarium. Three timers were used in the experimental setup. One timer was used as the trial timer which was set for thirty minutes for each trial. The other two timers were used to time the displays of each female separately.

To record the female competition, six categories were determined for the experimental setup that included bright versus dull, large versus small females, and albino versus normal colored females.

Preliminary Experiments

Preliminary experiments were conducted during the summer of 2005 in Humboldt

124 on the California State University, Sacramento campus, to work out the details of the experimental apparatus and protocol. These data (Appendix 1, Table 2) strongly suggest that the experiments are feasible and that females that differ in color display distinctively different amounts of competition and displays, i.e., brighter females displayed more than duller females. Similarly, larger females displayed more than smaller females. The data strongly suggest the expected results but these data suffer from pseudo-replication.

The final experiments were conducted beginning in December 2005 through

Summer 2006 in the Evolutionary Ecology of Fishes Laboratory and Humboldt 124 at

California State University, Sacramento campus. 37

Experiment 1

The goal of this experiment was to test the hypothesis that female kribensis compete against each other with colors and displays to attract a male mate. This general hypothesis is broken down further to include 1) there is a difference in display time to a male by a bright bellied female compared to a dull bellied female, 2) there is a difference in display time to a male by a large female compared to a small female, and 3) there is a difference in display time to a male by an albino female compared to a normal colored female. Therefore two females were placed in a trial tank and then placed into a category

(bright/dull, large/small, albino/normal). The male was then introduced I timed the duration (to the nearest second) of the competitive displays of each female, by using a separate digital timer for each female. The trial was run for thirty minutes. The data was recorded in a minute, second (mm:ss) format and later transfigured to be a minute and fraction of seconds (m.ss/60) to allow for easier analysis calculations. The data was then analyzed by a one-tailed paired t-test.

Experiment 2

The goal of this experiment was to test the hypothesis that a male will choose a female mate based on displays, colors, and size of a female. This general hypothesis is broken down further to include 1) there is a difference in male preference for a bright­ bellied female compared to a dull-bellied female, 2) there is a difference in male preference for a large female compared to a small female, and 3) there is a difference in male preference for an albino female compared to a normal colored female. To show 38 this, after the experiment 1 trial was completed in a trial tank, the two females and the male were able to socialize allowing the male to have an opportunity to choose a female.

After 5 days, close association, spawning, or no choice by the male was observed and recorded for analysis. The data was recorded by a tally mark of which female the male chose. The marks were then summed for. each category and then analyzed by a Chi­ square test.

The sample sizes were 15 trials for each set of characteristics (bright vs. dull, large vs. small, albino vs. normal), if possible. Also, all fish were weighed (in grams) and measured for SL (standard length, from nose to base of caudal fin) and TL (total length, from nose to tip of tail) (in millimeters). 39

RESULTS

The preliminary data provided enough evidence for the experiment's validity and after working out tiny quirks (managing timers, available fish stocks, and avoiding pseudo-replication) further studies were undertaken. The continued results that were found suggest that there was a significant difference among the females that competed to win a male mate. Between bright and dull females, bright females were found to compete longer and more vigorously for the male that was offered (p < .001, 15 trials)

(table 3a, figure 2). Between large and small females, the large females were shown to compete longer and more vigorously than the small females (p = .001, 15 trials) (Table

3b, figure 3). Between normal and albino females, albino females were found to compete longer and more vigorously than the normal females (p = .004, 8 trials) (Table 3c, figure

4). The continued results that were found in Experiment 2 presented a significant difference in the females that a male fish chose. Between bright and dull females, bright females were always chosen over the dull females by the male (5 bright: I dull) (Table

3d). Between large and small females, large females were almost always chosen over the small females by the male (6 large: I small) (Table 3d). Between normal and albino females, neither the albino nor the normal females were chosen over the other (0 albino: 0 normal) by the male fish. Competition and Display Time for Bright vs. Dull Females

18.00 16.00 -·= 14.00 .§. 12.00 Cl) E 10.00 D Bright ·-1- >. 8.00 • Dull co Q. 6.00 c"' 4.00 2.00

0.00 I ' - I I 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Trial

~ Figure 2. Final data Bright vs. Dull females graph - Female-female competition display times. 0 Competition and Display for Large vs. Small Females

14.00 -

12.00 - - -

-.5 10.00 - E I: - - -Cl) E 8.00 - D Large ·-..... - >. 6.00 _ I ..., - • Small ns -c. - - 4.00 - - ·-c"' I - - - 2.00 ~ - -

..__ llJ_ - llJ_ '-- '-- '-- ..__ ..__ - 0.00 I' - ,· I 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Trial

+:>. Figure 3. Final data Large vs. Small females graph - Female-female competition display times ...... Competition and Display for Albino vs. Normal Females

12.00

c 10.00 ·-E 8.00 -Cl) E I I I n 1 • I DAlbino ·-I- 6.00 I ~ I I I : I 1 • I• Normal ca -Q. 4.00 ·- c"' 2.00

0.00 1 2 3 4 5 6 7 8 Trial

+:-. Figure 4. Final data Albino vs. Normal females graph - Female-female competition display times. N . j I l

43 I' i f "ii i; '' DISCUSSION

I have shown in these experiments that kribensis females do compete against each

other with colors and other displays to win a male mate. The brighter females, larger

females and albino females all competed with displays significantly longer than the dull,

small and normal females which coincides with what males would hypothetically choose

(fecundity, size, roundness, health) when there is choice by ma.Jes involved in a mating

system. The choice by males was not significant because there was not a large enough

sample size with which to gather significant data. The trend shown by the data gathered

is the choice by males includes choosing females that are brighter and larger, but more

data is needed to come to a significant conclusion. With their life history that includes a

monogamous, biparental care, non-sex-role reversed situation the females have obtained

the characteristics to compete for a male and for a male to choose the best female for him

to mate with. Because of their social and sexual system kribensis females are

evolutionarily programmed to compete with specific behaviors and displays and for

males to choose based on female competition.

When Darwin (1871) described his theory on sexual selection, he focused on the

male-male competition and choice by female scenario. Authors after Darwin also

focused on the male-male competition and choice by female scenario. In all of these

writings there are hints or wording used that suggest systems other than male.competition

and choice by females can occur. Darwin writes that 1.) sexual selection usually meant

males competing and females choosing, 2.) male appearance is more often affected by 44 ! ' I sexual selection, with some exceptions, and females are more dull, and 3.) the female is usually less eager than males in their reproductive efforts. In each of these statements there are exceptions implied, even if at the time he did not know what they were, and these statements lend evidence that male competition and choice by females is not the only system in the animal world. One of Darwin's arguments for sexual selection is that it leads to the development of secondary sexual characteristics, which does not specify a sex showing these characteristics, just that if they are present then sexual selection is present and evolving. So if females have more developed and obvious characteristics, then in those females, sexual selection is acting more on the females than the males of a species and therefore it should, and does, result in a system other than male competition and choice by females.

Bateman (1948) remarks that males are mainly affected by sexual selection, which is based on the behavior of the animals not the gender. This means that if an animal behaves a certain way to affect sexual selection then it does not matter if it is ~ male or female exhibiting this behavior. Bateman proposed that female-female competition is rare for five reasons that can be argued against within certain situations.

The reasons and counterarguments are 1.) intrasexual selection seems to affect mainly males (mainly, not only, males), 2.) male contribution of the next generation is more variable than a females contribution (not so in the case of biparental care with both sexes staying until the fry have hatched and often times longer), 3.) males are affected by stronger selection pressures than females because of more intense intrasexual actions (not ifthe female-female competition is more than the male-male competition), 4.) the 45 intensity of intra-masculine and frequency of inseminations (what if intra-feminine selection actually occurs and females mate more than the males), and 5.) eager males and reluctant females (eager females are possible if they show competition and males are choosy). In point one he writes that the evidence so far indicated that males are mainly acted upon in sexual selection, but the evidence gives no adequate explanation of why this should be so. This hints that total proof is not available for strictly all male competition and choice by females, so it cannot be exclusive.

Trivers ( 1972 emphasizes the statement that the operation of sexual selection is governed relative to the parental investment of the sexes in their offspring. This means that depending on the amount of parental care or investment that males provide, males can invest more in their offspring than the female invests (sex-role reversed species as well as conventional sex role species), resulting in systems other than just male competition and choice by females.

Emlen and Oring (1977) add that the operational sex ratio (OSR), which is the relative number of sexually active males to females, show that the more abundant sex should be the more competitive sex and the other less comp-etitive and more choosy, and that environmental variables affect an animal's social system resulting in various.mating systems. This works in populations where the OSR is greatly female biased (polyandry) or when it is greatly male biased (polygyny), but not necessarily including other sex role factors. The OSR has little or no significance in a monogamous population where the ratio is 1: 1. This means that populations should not be solely judged by the OSR alone since if you add other important sex role factors, the system used by a population can 46

! I change. So, if the OSR is 1: 1 and the environment and other sex role variables allow a ' species opportunities to alter from the 'norm', then a species, or population of a species,

can form a system different from a male competition and choice by females system.

Others like Kokko and Johnstone (2002) believe that the OSR is not the primary indicator of sex roles but parental investment is more important as an indicator. They also remark that choosiness is determined by high species-specific mate encounter rates, high sex-

specific mate encounter rates, high breeding costs (parental investments), low costs of mate searching, and the variability in quality of the opposite sex, not just how the OSR is biased. It seems that there are many factors that are needed to decide a mating system.

When you look at the various factors that can affect a species' reproductive

system, along with environmental conditions, it easy to see that there are more possibilities that can occur than just male competition and choice by females. By looking

at and accounting for OSRs, mate choice, sex role reve~al, amounts of parental investment and care and which parent is providing the care, potential reproductive rates, mating systems, and sexual dichromatism, it is reasonable to assess that female-female competition and choice by males can occur, as well as sex-role reversed systems, mutual choice systems, or no choice systems. It is also clear how different populations in a

species can have alternate systems depending on the different levels of these factors or lack there of in their specific environments.

In the literature, mate choice, sex role reversal, monogamy, parental care, and communication are all important elements of sexual selection. Mate choice, being an important part of sexual selection, can be seen to occur differently when observing i·: ~ . !• I, 47 !: r •t ~ animals of different species. It has been found that not only choice by females occurs but ~ i that mutual mate choice and more importantly choice by males have been found in ~ : j. various species. This is an important element that can alter normal mating systems and !· l [:I 1:: produce alternative sexual systems or life histories of animals. Without a choice by r·I I' males element existing in animal species then sex-role reversed systems as well as !'''',. conventional sex-role species could not evolve from the male competition and choice by females type of system. Choice by males allows for new possibilities in animal mating l: systems. ~

Sex-role reversed systems are an important advancement away from the normal male competition and choice by females scenario, by providing an alternative to the normal model. It is important to see that females are not the weak, coy creatures that

Darwin and others described. Although this system is not the same as a male competition and choice by females system, it does parallel the normal model and most scientists tend to view the females carrying the "male" tendencies and acting male and the males carrying the "female" tendencies and acting female, therefore the genders may be . switched, which is interesting; but this does not truly provide a new model system so to speak (i.e. female with female tendencies that also happen to compete for males and males with male tendencies that choose females-a new type of model). Sex role reversal systems can also have the error of including any species that shows female competition.

Other factors need to be considered (mate choice, parental care; and OSR ratios) to conclude ifthe species is truly sex-role reversed or if the species should belong to a different model. The species of tidewater goby, kribensis, slender kribensis (P. 48 taeniatus), and lagoon goby (Knipowitschia panizzae) all have female-female competition but exhibit conventional sex roles and therefore should not be included in the sex role reversal system but they still need to be recognized as being different when compared to the normal male competition and choice by females system. So far it seems that scientists have thrqwn female competition into the sex-role reversal category because of a lack of another category as well as a lack of evidence and knowledge of female competing species.

Monogamy as a mating system changes sexual situations dramatically. It can affect a species' OSR, mate choice requirements, parental care tendencies, and a species coloration and communication. When ·a species is monogamous there is a I : I ratio that allows a species to be specific in what their mate will bring.to the pair. Requirements of a healthy, strong mate are looked for, or parenting skills or territory defense and/or food procurement which are all ways an individual could be selective about their mate.

Monogamy also affects parental care tendencies· (if a species shows parental care) in allowing the pair to both provide more energy into their offspring without the worry that their mate has another mate to divide labors with (although desertion can occur in monogamy). Monogamy can also affect species in their coloration and its communication. In a species, both male and female can be dull instead of a bright male, dull female or both can be brightly colored. One sex being bright and the other dull is not necessary because the male or female are not trying to attract multiple mates at one time.

All in all, monogamy allows for new opportunities in sexual selection and the sexual systems animals exhibit. I I l I 49 l 1 · Parental care directly affects a species' mating system. From female-only or 1 · male-only care to biparental care, sexual systems are changed to help a parent in his/her reproductive quest to have more surviving offspring than other individuals in that species gene pool. Parental care can affect if a system is polygynous (female only care), polyandrous (male-only care), or monogamous (biparental care). It can affect if a system is sex-role reversed or not. Parental care can affect mate choice in various ways such as the coloring of a parent, or the requirements that an individual selects in a mate. Parental care is extremely important in sexual systems and evolving sexual selection as well as being an interesting phenomenon.

Communication in its various forms provides the delivering of information from one individual to another or others. Color provides clues to fecundity, health, readiness to court or readiness to fight. Competitive displays can show a mates 'worthiness' in various aspects related to mating, parental care, and guarding abilities, or it can tell others he/she is already taken. Vocal or chemical communication can, with more information and examples, show that these types of communications are important in sexual selection as well. Without proper communication mating systems could not exist or function properly.

Pelvicachromis pulcher was shown to have female-female competition for their male mates. Males were seen to execute a choice in the female he would pair. Except for female competition and choice by males, the species otherwise shows conventional sex roles and is an example of a species that alters the variables affecting their reproductive system with an outcome that is not the norm. This species differs and should not be 50 included in the category of sex-role reversed species because of 1) a 1: 1 OSR instead of being female-biased because of polyandry, 2) biparental care instead of male only care,

3) females providing fry care and males providing defense whereas in sex-role reversed species only the male cares and there is no mate defense, and 4) the female remains for the whole cycle instead of leaving the male to cope alone. By having the characteristics that include: 1) an OSR that is normally 1: 1 in a population (Nwadiaro 1985), 2) a · monogamous system resulting in equal reproductive success, 3) biparental care long after the fry have hatched, 4) the females competing more than the males and being more sexually dichromatic, and 5) choice by males being observed, the species Pelvicachromis pulcher has provided evidence for an alternate mating category, other than the conventional (male competition and choice by females) or the sex-role reversed system

(female competition and choice by males), that is important in expanding the knowledge needed to correctly categorize animals when dealing with their reproductive and social structures and life histories. 51

CONCLUSION f .~ , In conclusion, based on the data that I have collected, female kribensis do f compete against one another for a male mate and there is a choice exhibited by a

kribensis male for a female mate. So moving from beginning thoughts on this subject

from Darwin, Bateman, Trivers, and Emlen and Oring, through mate choice, sex-role

reversed theory, mating systems, parental care, and fish communication, there seems to

be another sexual mating system, other than male competition and choice by females, that

is not accounted for except by a few scientists. Even then there are characteristics that

kribensis show that give evidence for further study to provide, without question, that

female-female competition and choice by males is occurring and should be considered for

another type of mating system (not conventional or sex-role reversed). Testing other sex

role variables (for example, numerical amounts of parental care and who is providing

what and when, mortality rates, true monogamy or extra matings, amount of choice by

males, etc.) for this species specifically would give a clearer idea if this species' mating

system is indeed one not covered by traditional male competition/choice by females

system or sex-role reversed systems. 52

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APPENDIX

This appendix consists of raw data tables from the experiments that were run for this thesis.

Table 2. Preliminary data. a.) Bright vs. Dull and Large vs. Small female-female competition display times. b.) Bright vs. Dull and Large vs. Small male choice chart. a.)

Bright vs. Dull Large vs. Small

Tank Bright Dull Tank Large Small # # 1 17m 16s ·14m 46s 4 1m54s OmOOs 4 5m3s 3m20s 2 4m6s 1m 56s. 5 10m 39s 5m26s 6 4m06s 1m46s 3 3m 11s 1m 34s 1 6m48s Om45s 2 4m 01s 1m 11s 1 1m20s 2m OOs 2 Sm 13s Om29s 5 6m 17s 3m 32s 3 13m 05s 5m 53s 7 6m 02s. 2m20s 1 6m29s 1m 29s 2 4m35s 2m4as 7 4m28s 1m43s 3 13m 20s am 19s 5 9m55s 3m31s 4 am 19s 5m 19s 1 6m33s 1m 10s 2 11m 40s 5m31s 3 11m 55s 6m05s 5 02m OOs OOm 27s 3 ?m 53s 2m29s 1 6m23s OOm 29s

b.)

Bright vs. Dull Large vs .. Small

Tank# Bright Dull Tank# Large Small 5 x 2 x 5 x 6 x 1 x 7 x 2 x 4 x 58

Table 3. Final data table. a.) Bright vs. Dull, b.) Large vs. Small, and c.)Normal vs. albino female-female competition display times. d.) Final data- Bright vs. Dull and Large vs. Small male choice charts. a.) b.) c.)

Trial B Q Trial .b .§ Trial A N 1 8.85 3.20 1 6.18 4.08 1 1.62 0.00 2 7.73 3.63 2 4.97 1.67 2 2.60 0.83 3 11.57 7.97 3 12.47 4.30 3 7.18 3.98 4 4.47 0.58 4 2.07 1.50 4 1.67 1.10 5 1.70 0.88 5 9.90 7.85 5 2.03 1.62 6 1.15 1.78 6 7.02 3.80 6 6.75 4.75 7 16.05 13.28 7 12.47 2.05 7 10.28 7.55 8 6.38 3.72 8 3.27 1.07 8 2.75 3.08 9 5.42 2.83 9 2.20 3.30 10 6.70 6.07 10 4.92 2.20 11 4.02 3.15 11 6.18 3.95 12 2.48 1.57 12 9.52 6.75 13 5.28 2.55 13 4.50 2.87. 14 8.62 6.07 14 3.73 2.27 15 3.83 2.35 15 2.20 1.63

d.)

§ D .b .§ x x x x x x x x x x x x x

5 1 6 1 59

Table 4. All final data collected- Bright vs. Dull trials. Weight, Standard and total lengths for females and males, female-female competition times, and male choice results.

TRIAL BID Weight SL TL Spots TIME MALE PICK - (Q) (mm) (mm)

1 F1 B 3.2 43.5 55.3 O*O am 51s (8.85) y Tank4 F2 D 2.8 38.6 49.2 1*1 3m 12s (3.20) -- --· ------.~~~---- - ~-{'!' •. 1"-;., 41~ ,,±::;$ Dec29 -_ .. ,..., -r; ·-·;:;::- ·-~~}~-· 05 M 5.4 57.0 74.0 ·_., ;.;: 2 F1 B 3.2 42.4 51.4 1*1 7m 44s (7.73) -- Tank 6 F2 D 3.0 39.5 50.0 0*1 3m 38s (3.63) --.'l:' -- --..,.~... ~-"" Dec29 .. - - - = ·" rf · o,. ··, 05 M 5.0 58.6 78.0 '""I '.H~ .li,...._ . ·-···~ 11m 34s 3 F1 B 2.7 42.1 54.0 1*0 (11.57) -- Tank 7 F2 D 2.9 40.0 53.0 2*1 7m 58s (7.97} • . .___,.., .""J'r -- Dec29 . . "'": ·'•:i:, 11·•. ~ ~~ ".'" i!. ;,:,.-:;"l ~t •, ~ .. ' •• {! oi;; ~-. 05 M 8.1 63.6 85.5 ·.'"" ' .·"~' " 4 F1 B 2.8 39.4 48.5 2*1 4m 28s (4.47) y Tank 8 F2 D 1.5 41 .0 50.8 1*1 Om 35s (0.58) ~i-- .~-- !"' ·- - -~~ ' ~ Dec29 -. ··... 11. .. h ii· -~~ ;-·".<...II -· ;;~;~~-; ~ 05 M 6.2 57.4 76.5 ' 5 F1 B 2.7 40.7 53.0 3*1.5 1m 42s (1.70) -- Tank 1 F2 D 2.5 39.6 50.2 1*0 Om 53s (O. ~~ ) -- '; - ~ Jan 13 - ...,- ·i;,'!' .. 06 M 8.1 53.8 73.3 ;: ' '· ' 6 F1 B 3.0 42.1 53.6 2*1 1m 09s (1.15) -- Tank 2 F2 D 2.6 40.0 49.4 1.5*0 1m 47s (1 .78) - .... ·-..;-;·-'"', --...-~- .. - - ~:· - - ~ ~; - .. Jan 13 ;:a.. ~ :::: _..._ ·' - 06 M 9.9 57.8 75.0 ...... "" 16m 03s 7 F1 B 2.8 41 .0 52.9 2*1 (16.05) -- 13m 17s Tank4 F2 D 3.0 42.3 52.2 1*0 r.--(13.281 - y ~· .,,.-n-~,,.,.- r;: ;r-"J"r'-~ Jan 13 ;I; ~;_·_,, :;: ',., . - ·- ,. i,. .J. ~-~ •1.;, :;, 06 M 5.4 57.0 74.0 ~.·i ~-; 8 F1 B 2.7 42.7 52.7 2*0 6m 23s (6.38) -- Tank 7 F2 D 2.2 43.8 50.1 2*0 ~ 3m 43~ (3.72) -- ~ T - June 2 - . ...., 06 M 7.8 64.1 83.9 ~ ,, 60

Table 4 continued ...

TRIAL BID Weiaht SL TL Soots TIME MALE PICK Sm2Ss 9 F1 B 1.8 3S.4 4S.4 2*0 (S.42) y 2m SOs

Tank4 F2 D 2.1 34.2 4S.2 1*0 . ...,.,,., .,.,.,_ "!31>" ....----:: _( ?. B3 L _~ __-- __ June 6 ' .. •• ' .~· "':I:'· - 8' ,. 06 M 6.1 S7.9 76.4 ., ;. •:; ,., ... '" 6m42s 10 F1 B 1.4 34.6 42.3 2*0 (6.70) -- 6m 04s Tank S F2 D 1.4 32.3 40.7 1*0 (6.07) ?- ... .-...- --.... "";: .• J June 7 -~, ·1:., . ' '7 ,_ -;__,;: 06 M 4.3 46.2 S9.3 ~ .. } ~ :· ;,..·· 4m 01s 11 F1 B 4.0 43.4 S6.3 3*0 (4.02) -- 3m 09s Tank 9 F2 D 2.9 4S.7 S7.8 2*0 . r-ti"· ·-,\...... • ~- J~ .1 .S) ~~ -- ~-----.'... ..i.• •: ;_ June 7 . - !{ ··-· - •• ;.i; ~' ~:~· ? . - 06 M 4.4 S6.1 76.2 ... • ·'

TRIAL - us Weight SL TL Spots TIME MALE PICK (a) (mm) (mm)

1 F1 L 3.0 43.0 52.5 1*1 6m 11s (6.18) y Tank 1 F2 s 2.1 41.5 50.7 1*0 4m 5s (4.08) -- ' ..., -£7"' Dec29 . ~; I'< - ,.,,:··a. 05 M 8.1 53.8 73.3 '":." 2 F1 L 2.4 44.6 59.5 2*0 4m 58s (4.97) -- Tank 2 F2 s 2.0 40.0 50.1 1*0 1m 40s (1 .67) -- • - !;';_ ,__ ...... ~ . --· Dec29 . " ., ll'' 05 M 9.9 57.8 75.0 I>• 12m 28s 3 F1 L 4.0 43.6 56.1 1*0 (12.47) -- Tank 3 F2 s 2.3 40.7 50.1 1*1 4m 18s (4.30) -- .... ·, .,,,. .. Jan 13 ' < .... ~:;;·, /'fr. ,;< 06 M 6.6 59.5 83.0 ~ .. 4 F1 L 4.3 40.1 49.8 1*1 2m 28s (2.07) -- Tank 5 F2 s 2.7 41.8 51.6 O*O 1 m 30s (_1.50) y t ~n ,_ .. Jan 13 " -- w ';' ' "· '·'"""' 06 M 7.4 63.5 80.3 - . '::Cp

5 F1 L 5.1 39.3 51.7 3*1 9m 54s (9.90) Y (s)

Tank 1 F2 s 4.4 30.4 38.8 2*0 7m 51~ (7.85) ,__ -- May24 -~ " ,"· ",. 06 M 9.7 62.6 78.0 - 6 F1 L 4.1 42.4 53.9 2*0 7m 01s (7.02) -- Tank 10 F2 s 1.6 33.2 43.4 2*0 3m 48s (3.80) ~ . -- - . :·. - May31 - .. ' t ); .· 06 M 5.6 60.8 75.4 ,~,. .c,,'.'"·" . 12m 28s 7 F1 L 3.6 44.3 54.0 2*1 (12.47) y Tank6 F2 s 2.8 42.7 54.3 1*0 } m 03s {2.05) -- 1- ; •.....-r June 2 - - .'.'Y '\r 06 M 8.8 64.5 88.1 ~ .· 8 F1 L 3.1 36.8 47.2 3*0 3m 16s (3.27) -- Tank 2 F2 s 2.2 35.5 43.5 2*0 1m 04s (1.07) -- ~ ·. June 6 - . -~- 06 M 8.1 62.1 83.7 ,. - _, 62

Table 5 continued ...

TRIAL I I BID I Weiaht I SL I TL I Soots TIME MALE PICK 2m 125 9 I F1 I L I 4.1 I 41.7 I 53.6 I 3*1 (2.20) I y 3m 185 Tank 3 F2 s 2.1 41.1 49.2 2·0 k <3.30) I~~ ------~ 1 June 6 -·- - · ·', :!';! -· ·'· - ,;. e,., f - -:i 06 M 6.2 57.9 74.5 4m 555 10 I F1 I L I 2.8 35.3 44.6 2*0 (4.92) 2m 125 Tank 10 F2 I §__I 1.9 I 35.8 I 44.1 L 2:g_ .... L (21Q)_ June 7 06 M 4.4 48.6 60.3 11 F1 L 1.7 31 .9 44.0 I 2*0 Tank 2 F2 s 2.1 30.0 37.9 June 20 06 M I . J 2.4 I 45.8 57.9 9m 315 12 I F1 I L I 2.3 I 32.1 I 40.2 I 2*0 I (9.52) 6m455 Tank4 F2 s 1.4 27.7 35.5 3*0 ... - (6.75) .,,.... ""':.... June 20 'l: - . ', ~~ --I; 06 M 3.4 46.8 63.7 N 4m 305 13 I F1 I L I 4.1 I 45.0 I 56.5 2*1 (4.50) I y 2m 525 Tank 6 F2 s 3.9 I 41.6 I 54.3 I_ t'O_ l__ J :Z.§?) June 21 ~- 06 M 7.5 58.0 79.3 3m445 14 I F1 I L I 3.5 I 39.3 I 50.8 I 2*0 1 (3.73) 2m 165 Tank 9 I F2 l__ § _J 2.3 I 36.4 I 48.2 l~o_ J_ J?. 2 ~1 June 22 06 I M I ·~ ~ 1 5.0 58.6 75.5 2m 125 15 I F1 I L I 4.1 I 44.1 I 56.9 I 2*0 I (2.20) 1m 385 Tank 10 I F2 I_s I 3.3 I 42.6 I 53.0 I 1*0 L_ c1 .63) June 22

. I ~ 06 I M I 7.7 I 63.1 I 79.7 I . - f· " ·~· j. ·- . ' I "!l. ~-~·- .:r·-:.Jt 63

Table 6. All Final data collected - Normal vs. Albino trials. Weight, Standard and total lengths for females and males, female-female competition times, and male choice results.

TRIAL AIN Weight SL TL Spots TIME MALE - PICK (g) (mm) (mm) m:s (m:s/60) 1 F1 A 3 33 .9 45.8 1*0 1 m 37s (1.62) -- Tank 8 F2 N 3.8 34.9 45.3 4*0 Om Os (0.00) -- May23 M 3.9 39.7 54.6 - ·- 06 2 F1 A 2.1 35.1 44.7 1*0 2m 36s (2.60) -- Tank 8 F2 N 2.2 33.3 43.8 O*O Om 50s (0.83) -- June 2 M 6.1 64.7 79.9 06 ·• 3 F1 A 1.4 34.1 42.7 O*O 7m 11s (7.18) -- Tank 8 F2 N 2.6 35.2 44.1 3*0 3m 59s (3.98) -- _,_ June 12 M 3.4 4.03 52.9 I' -- -.I 06 . 4 F1 A 2.5 33.3 42.5 O*O 1m 40s (1 .67) -- Tank6 F2 N 3.2 34 43.5 2*1 1m 06s (1.10) -- June 27 M 4.3 42.5 55.2 - ·- ·- 06 5 F1 A 2.6 35.5 43.3 O*O 2m 02s (2.03) -- Tank 7 F2 N 2.9 32.4 43.5 O*O 1m 37s (1.62) -- , __ ·: June 28 M 10 65.8 89.1 I• 06 6 F1 A 1.8 32.3 41 .1 O*O 6m 45s (6.75) -- Tank 8 F2 N 2.7 35.5 47 1*1 4m 45s (4.75) --

June 28 M 6.1 59 75.5 ,,."•·"' I ··• 06 7 F1 A 2.2 33 43.4 O*O 10m 17s -- (10.28) Tank 9 F2 N 2.9 33 44.7 2*1 7m 33s (7.55) --

June 28 M 7.2 57.8 74.7 1 ~ 06 8 F1 A 2.1 33.6 41.9 O*O 2m 45s (2. 75) -- Tank 10 F2 N 2.2 34 45.4 1*1 3m 05s (3.08) -- >lL. ~- June 28 M ------11' if' ., 06 ~ •r.'1·