Mate Choice by Both Sexes Maintains Reproductive Isolation in a Species Flock of Pupﬁsh (Cyprinodon Spp) in the Bahamas Rhiannon J

ethologyinternational journal of behavioural biology Ethology

Mate Choice by Both Sexes Maintains Reproductive Isolation in a Species Flock of Pupﬁsh (Cyprinodon spp) in the Bahamas Rhiannon J. D. West & Astrid Kodric-Brown

Department of Biology, University of New Mexico, Albuquerque, NM, USA

Correspondence Abstract Rhiannon J. D. West, Department of Biology, University of New Mexico, Albuquerque, NM, Female and male mate choices can reinforce reproductive isolation after USA. sympatric speciation. Using a binary choice design, we examine the E-mail: [email protected] importance of visual cues in female mate choice in all three sympatric species of pupfish on San Salvador Island. We also examine the importance Received: December 2, 2014 of olfactory cues in female choice of the hard-shelled invertebrate special- Initial acceptance: February 2, 2015 ist (Cyprinodon brontotheroides). We examine male mate choice in two of Final acceptance: April 10, 2015 the three species, the scale eater (C. desquamator) and the detritivore (S. Foster) (C. variegatus). Females of all three species use visual cues and prefer conspecific males. C. brontotheroides females do not use olfactory cues to dis- doi: 10.1111/eth.12394 criminate between conspecific and heterospecific males. Males of Keywords: female mate choice, frequency- C. desquamator and C. variegatus also preferentially court conspecific dependent selection, male mate choice, females. Thus, mutual mate choice, where both females and males exhibit olfactory cues, reproductive isolation, mate choice, acts as a strong behavioral pre-mating isolation mechanism sympatric speciation, visual cues in these sympatrically speciated pupfish.

(Gazella marica; Wronski et al. 2012), guppies (Poecilia Introduction reticulata), haplochromine cichlids (Astatotilapia flavii- To date, studies of behavioral pre-mating isolating josephi) and swordtails (Xiphophorus malinche) in all of mechanisms in sympatric species flocks have focused which males preferentially court larger, gravid mostly on female choice (Strecker & Kodric-Brown females (Sargent et al. 1986; Dosen & Montgomerie 1999; Kodric-Brown & Strecker 2001; Elmer et al. 2004; Werner & Lotem 2006; Tudor & Morris 2009). 2009; Kahn et al. 2010; Kekal€ ainen€ et al. 2010; Sexual selection can facilitate sympatric speciation Kodric-Brown & West 2014). However, mutual mate (Ritchie 2007), particularly when the divergence is choice, where both sexes preferentially mate with based upon invasion of a new ecological niche (Maan phenotypically similar individuals, would facilitate & Seehausen 2011) and is a signal of localized adapta- sympatric speciation and reinforce species barriers tion (van Doorn et al. 2009). Generally, sexual selec- afterward. Mate choice by females is the classic tion in conjunction with ecological niche expansion paradigm of sexual selection, and thus, the most results in behavioral pre-zygotic isolation that main- investigated mechanism for maintaining behavioral tains species boundaries (Strecker & Kodric-Brown pre-zygotic reproductive isolation. However, selection 2000; Coyne & Orr 2004; Savolainen et al. 2006; imposed by male preferences for mates also shapes Elmer et al. 2011). the evolution of female traits (Andersson 1994). Male Here, we examine male mate choice in Cyprinodon mate choice is common in breeding systems with variegatus and C. desquamator two members of a three paternal care of offspring (Gwynne 1991; Chen et al. species flock of pupfish in the Bahamas. Male mate 2012; Myhre et al. 2012), but a growing literature has choice would reinforce behavioral pre-mating isola- shown that it can occur in the absence of paternal tion in this species flock as has been seen in some sys- care (Edward & Chapman 2011). Examples include tems (Espinedo et al. 2010; Swenton 2011; Gregorio insects (as reviewed in Bonduriansky 2001), gazelles et al. 2012), but not others (Kozak et al. 2009).

We also examine the role of both visual and olfac- and reddish orange fins and belly in C. variegatus, and tory cues in female mate choice in C. desquamator and a pale blue body with clear pectoral fins outlined with C. brontotheroides. Both kinds of cues function in mate black in C. brontotheroides (Martin & Wainwright choice in other pupfish (Kodric-Brown 1983, 1996; 2013a; personal observation). However, as in most Strecker & Kodric-Brown 1999, 2000; Kodric-Brown pupfish studied to date, male breeding coloration is & Stecker 2001; Ludlow et al. 2001; Draud & Itzko- facultative and can be turned on or off almost instan- witz 2004) and play a role in promoting or maintain- taneously (Kodric-Brown 1998; Barton & Barton ing reproductive isolation in a variety of other kinds 2008). Territories provide incidental protection of eggs of organisms (Elmer et al. 2009; Smadja & Butlin from predation, as males chase away females who are 2009; Hohenlohe & Arnold 2010). We focused on attempting to forage on the territory. Territories of female preferences in the scale eater C. desquamator C. desquamator are smaller than those of C. variegatus, and the hard-shelled specialist C. brontotheroides.To are usually located in shallower water, and are con- date, little is known about female preferences in the fined to small, rocky outcrops near the shoreline. scale eater in either the field or the laboratory (Barton Male C. variegatus courtship consists of circling below & Barton 2008; Kodric-Brown & West 2014), and a female and guiding her toward the substrate, while nothing about female preferences in the hard-shelled C. desquamator males approach the female in a series invertebrate specialist. We focused on mate choice of rapid zigzag or darting movements and lead her to because it will not only provide information on the the territory. In sequential trails, male detritivores proximal mechanisms, such as the sensory cues used court female conspecifics and scale eaters equally, in courtship and mating in each species, but it also whereas male scale eaters preferentially court conspe- will provide insights into the evolution of pre-mating cifics (Kodric-Brown & West 2014). Territorial males isolation in a very young species flock. rarely shoal with conspecific females and juveniles. Generally, territorial male detritivores and scale eaters The System only shoal when they are disturbed, for example, by a predator or an ungainly biologist, and quickly return Three sympatric species of pupfish occupy three saline to their territories (personal observation). C. brontot- lakes on San Salvador Island, The Bahamas (Holtme- heroides are very scarce in all three lakes and much of ier 2001; Turner et al. 2008; Martin & Wainwright their behavior is unknown. 2011). The species evolved in the last 6000 yrs, when the lakes formed on the island (Pacheco & Foradas M&M 1986; Hagey & Mylroie 1995; Milliken et al. 2008). The species flock consists of a relatively rare scale Female Mate Choice eater, C. desquamator which preys upon the other two species, a very abundant detritivore, C. variegatus, and We examined the strength of female preferences for a very rare hard-shelled prey specialist, C. brontothero- conspecific males in F1 populations of C. variegatus, ides (Holtmeier 2001; Turner et al. 2008; Martin & C. desquamator, and C. brontotheroides from Crescent Wainwright 2013a). The species differ in morphology, Lake. It is one of the smallest lakes on San Salvador ecology and behavior related to trophic specialization Island with populations of all three species of pupfish (Holtmeier 2001; Barton & Barton 2008; Turner et al. and has the highest densities of C. desquamator. Labo- 2008; Martin & Wainwright 2011, 2013a; Kodric- ratory raised offspring from wild-caught parents were Brown & West 2014; West and Reade in prep). Species used to lessen potential trapping impacts on all three isolation is likely maintained by behavioral pre-zygotic species, but especially on the rare C. brontotheroides. isolation as the three species coexist in sympatry with The parental populations consisted of 15 C. brontother- overlapping habitats but readily hybridize in the labo- oides and 20–30 individuals each of C. variegatus and ratory (Holtmeier 2001). In the field, there are large C. desquamator. The parental fish were housed by spe- fitness costs to hybrids (Martin & Wainwright 2013b). cies and bred in large (1.89 kl) stock tanks with a C. variegatus and C. desquamator have a polygynous 14:10 light:dark schedule and salinity at 35 ppt., con- mating system with males defending contiguous terri- sistent with salinities in Crescent Lake. Under natural tories. Females mate with multiple males and deposit conditions in the lake, fish are exposed to heterospe- several eggs on a male’s territory during a spawning cifics and therefore avoidance may be learned. We sequence. Males defending territories develop breed- raised the fish in separate tanks for several reasons: (i) ing coloration that varies from black on the body and all three species readily hybridize in captivity; (ii) our fins in C. desquamator to blue iridescent on the nape design removes the role of learning and experience of

794 Ethology 121 (2015) 793–800 © 2015 Blackwell Verlag GmbH R. J. D. West & A. Kodric-Brown Mate Choice Maintains Reproductive Isolation heterospecifics from potentially influencing mate The males were then replaced with a novel combina- choice, and (iii) prevents harassment and excessive tion of males and the tests were repeated. fin damage of C. variegatus and C. brontotheroides by C. desquamator. The stock tanks were enriched with Olfactory Cues plants and rocks to provide a natural environment. Fish were fed freeze dried brine shrimp (San Francisco The olfactory experiments were performed to test â â Bay ) and tropical fish flakes (TetraMin ) twice daily. whether C. brontotheroides females discriminated Handling was minimized as much as possible. No between the odors of conspecific and heterospecific mortalities resulted from the behavioral trials per- males. We additionally tested whether females of each formed in this study. Offspring were raised to matu- species responded differently to heterospecific males. rity and used in all trials. For the visual trials, we used Thus, we tested whether C. brontotheroides and C. var- 20 females of each species, for the olfactory trials, we iegatus females differed in their response to C. desqua- used 20 female C. brontotheroides. In both visual and mator males and similarly, whether C. brontotheroides olfactory trials, we used 20 males of each species in and C. desquamator females differed in their response novel combinations. No male pairs were used more to C. variegatus males. Due to a small sample size of than once. The female and male choice experiments C. brontotheroides males, we were unable to test the were conducted from April 14 to June 4, 2012, and responses of C. variegatus and C. desquamator females the olfactory trials were conducted from June 4 to to the olfactory cues from C. brontotheroides males. September 1, 2012, during the peak of the breeding We used a binary choice design to measure female season of these populations in the Bahamas. Fish responses to olfactory cues. To obtain olfactory cues were raised in environmentally enriched 20-g tanks from each species, two conspecific males were housed with no more than 10 conspecific juveniles to a tank. in a 4-l-holding tank for 24 h. They were separated by All adults were housed with two territorial males and a clear divider with small perforations that allow for 3–5 females to a tank. All females were gravid and water to flow through. They were removed for feed- males were in breeding coloration and were courting ing twice a day but otherwise were undisturbed. The females in the holding tanks. Thus, all fish used in the water from these males was then used in the subse- study were socially experienced. Conspecifics used in quent female choice experiments. Following Kodric- the same trials were taken from different tanks to Brown & West (2014), female C. brontotheroides were avoid familiarity effects. placed in a 22-l aquarium (PETCO Bookshelf aquarium, 60 cm long 9 20.65 cm wide) filled with 20 l of Visual Cues water at 35 ppt. Two lines were drawn on the front of the aquarium to delineate three ‘compartments’. The A small pool (91 cm in diameter) was filled to a depth two outside compartments were 17 cm wide and the of 10 cm with water at 35 ppt. salinity. Three clear middle one was 26 cm wide. Intravenous bags of 1-l Lee’s Kritter Keeperâ (30.23 9 19.81 9 20.57 cm) capacity (Tyco Healthcare ‘Kendall Kangaroo’ IV) tanks were placed in the pool and spaced roughly were suspended from the ceiling over each end of the equidistant from each other and from the pool wall. aquarium. One intravenous bag was filled with water Two males of each species were size matched within from conspecific males, and the other was filled with 5 mm of each other, and each pair was placed in one one of the two heterospecific species’ male water. The of the three tanks. A limited sample size prevented us water was dripped into each end of the aquarium at from matching pairs for size and shape. However, size 1 drip/s. The amount of time the female spent in each differences within this range do not appear to affect of the end compartments was recorded for 10 min. female or male mate choice (unpublished data from The female was then moved into a new aquarium, Kodric-Brown & West 2014). A female of one of the and the procedure was repeated with male water from three species was then introduced into the center of the other species. We randomized both the side the the pool. Ten-min tests began once she had started to male conspecific water was dripped into and the order explore the pool and visited each set of males. The the heterospecific male water was presented. time the female spent within 5 cm of each tank, either facing or swimming parallel to the tank was recorded. Male Mate Choice The female was removed and replaced with a female of one of the other species, until females from all three To determine whether C. variegatus and C. desquamator species had been used. One trial consisted of one set males from Crescent Lake discriminated between of males and three sequential females of each species. conspecific and heterospecific females, we used a

Ethology 121 (2015) 793–800 © 2015 Blackwell Verlag GmbH 795 Mate Choice Maintains Reproductive Isolation R. J. D. West & A. Kodric-Brown binary-choice design. Because of insufﬁcient numbers Johnson transformation would be appropriate of C. brontotheroides males, their preference could not (AD = 0.261, p = 0.703). Transformed data were be determined. A 75.7-l aquarium was equally then analyzed with a general linear model with divided into three 20 9 30 cm compartments with male and female species, male by female species two clear plastic dividers. Two female C. variegatus interaction terms, and trial number as a blocking were placed into one outside compartment of the factor. All analyses were performed with Minitab 16 tank, and two female C. desquamator were placed into software. the other outside compartment of the tank. To mini- mize potential effects of size, females were matched in Results size within 5 mm of standard length, although small sample sizes limited a better size matching. A male of Female Mate Choice one species was placed in the center compartment.

Ten-min tests began once all five fish were active. We The species of female (F2,104 = 9.43, p < 0.000), male recorded the time the male spent swimming parallel (F2,104 = 4.38 p = 0.015), and their interaction to or directly facing a compartment while performing (F4,104 = 41.07 p < 0.000) were all significant predic- male courtship behaviors. Under the constraints of tors of the time females spent investigating visual cues the experimental design, male courtship behavior of males. The blocking factor, trial number, had no consisted of sinusoidal lateral movements with effect on the model (F13,104 = 0.94 p = 0.518). extended pectoral fins, or movement up and down Females of all three species responded to visual cues the partition next to the female, following her move- of males and spent significantly more time with males ments on the other side of the partition. After 10 min, of their own species (Fig. 1). The time females spent the male was replaced with a male of the other spe- with heterospecific males did not differ between species. These experiments only tested male preference, cies (Fig. 1). and as the compartments were not sealed, did not Females of all three species failed to discriminate exclude olfactory cues. A total of 24 males and 24 between conspecific and heterospecific males based females of each species were used in novel combina- on olfactory cues (Table 1; and see Kodric-Brown tions. No female pairs were used more than once. & West 2014). Female C. brontotheroides and female C. variegatus did not differ in the time spent Statistical Analyses associating with the chemical cues of male C. desquamator (H = 0.01, p = 0.918); nor did female Female Mate Choice C. brontotheroides and female C. desquamator differ in A normality test on the residuals of the visual prefer- their responses to male C. variegatus (H = 0.00, ence times indicated they were not normally distrib- p = 1.000). uted. Normality assumptions on an Anderson–Darling test were met with a transformation raising female preference times to the 0.2 power (p = 0.08 AD = 0.667). A general linear model with female and male species, female by male interaction terms, and trial number as a blocking factor was performed on the transformed time data. A post hoc Tukey’s HSD examined significant differences between groups. Olfactory preference residuals were not normally distributed and did not match any particular distribution; thus, we used Bonferroni adjusted Kruskal– Wallis tests. We examined differences in female preferences between conspecific and heterospecific males and between females of different species for males of the same heterospecific species.

Male Mate Choice Fig. 1: Mean (ÆSE) association time of C. variegatus, C. brontotheroides, and C. desquamator females. Females prefer visual cues from Residuals of male preference times were not nor- males of their own species. Means that share letters are not signiﬁcantly mally distributed. A distribution test indicated a different from each other at a = 0.05 level.

Table 1: Association times (s) of C. brontotheroides females with conspeciﬁc and heterospeci- Female Male n Mean SD Median Statistic p ﬁc males in olfactory trials C. brontotheroides C. brontotheroides 20 321.4 282.8 258.0 H = 0.39 0.543 C. desquamator 265.5 284.7 213.5 C. brontotheroides C. brontotheroides 20 302.0 296.4 259.5 H = 0.40 0.539 C. variegatus 249.9 265.2 192.0

Females showed no preference for conspeciﬁc males (p > 0.5).

Male Mate Choice to females. In the current study, males were simultaneously presented with a conspecific and heterospeci- The blocking term, trial number, had no effect on the fic female in a binary choice design, and both model (F23,69 = 0.44, p = 0.985). Neither the species C. desquamator and C. variegatus males preferentially of male (F1,69 = 0.31, p = 0.577) nor the species of courted conspecific females. However, in trials with female (F1,69 = 0.11, p = 0.737) were significant pre- field-caught fish, where males encountered females dictors of time males spent with females. However, sequentially rather than simultaneously, C. variegatus the interaction between male and female species was males indiscriminately courted females of both significant (F1,69 = 10.55, p = 0.002). Post hoc analyses species, while C. desquamator males preferentially show that males of both species preferentially courted courted conspecific females (Kodric-Brown & West conspecific females (Fig. 2: one-way ANOVAs: C. var- 2014). These results suggest that male choice in iegatus males: F1,46 = 7.37, p = 0.009; Cohen’s d = C. variegatus is stronger when females are encoun- 0.784; r = 0.365; C. desquamator males: F1,46 = 4.99 tered simultaneously. Another explanation for this p = 0.030, Cohen’s d = 0.644; r=0.307). discrepancy in the results is that the current study used laboratory-bred, na€ıve fish that were maintained in single species tanks. Thus, familiarity with Discussion conspecific females may have affected preferences of Our results suggest that pre-zygotic isolation is, at laboratory-reared C. variegatus males. Multiple studies least partially, maintained by female choice in suggest that early experience with predators or het- C. brontotheroides, and mutual mate choice in erospecifics as well as familiarity with conspecifics, C. desquamator and C. variegatus from Crescent Lake, can influence female mate choice (as reviewed in one of the localities of the sympatric species flock of Brown & Laland 2003; Verzijden et al. 2012). To Bahamian pupfish on San Salvador Island. The determine the extent of sexual selection in this results of this study are consistent with those by system, studies examining shoaling preferences (sensu Kodric-Brown & West (2014) on female preferences Gabor 1999) and mate choice (sensu Strecker & for conspecific males in wild-caught C. variegatus and Kodric-Brown 2000) need to be conducted. C. desquamator females, but differ in male responses Unlike the only other sympatric species flock of pupfish in Lago Chichancanab, Mexico (Kodric- Brown & Stecker 2001), the Bahamian female pupfish used visual but not olfactory cues in their mate choice. Although the specific visually perceived traits have yet to be identified, the females exhibit strong conspecific association in our experimental aquaria. Differences in coloration (e.g., Seehousen et al. 2008), body size (Nagel and Schluter 1998), and body shape (Langerhans et al. 2007; Langerhans & Mak- owicz 2013) are visually based cues that function in female mate choice which, in turn, creates behavioral pre-mating isolation barriers to reproduction. The three species differ in jaw structure (Martin & Wain- Fig. 2: Mean (ÆSE) courtship time for C. variegatus and C. desquamator males with C. variegatus and C. desquamator females. Males of wright 2011), lateral barring pattern (Martin & Wain- each species prefer to associate with conspecific females (C. variegatus wright 2013a), and body shape. C. desquamator are males: F1,46 = 7.37, p = 0.009; C. desquamator males: F1,46 = 4.99 much more fusiform than C. variegatus and C. brontot- 0.030). heroides (West and Reade, in prep). Males differ in the

Ethology 121 (2015) 793–800 © 2015 Blackwell Verlag GmbH 797 Mate Choice Maintains Reproductive Isolation R. J. D. West & A. Kodric-Brown height of the nuchal hump (West and Reade, in prep), for the less abundant species, C. brontotheroides and breeding coloration (Martin & Wainwright 2013a), C. desquamator, than for the more abundant C. variega- and courtship behavior (Kodric-Brown & West 2014). tus (Kodric-Brown & West 2014). Both of these selec- Some combination of coloration, morphology, and tive pressures would reinforce mutual assortative courtship likely function as visual cues in female pref- mating and, as a result, strengthen pre-mating isola- erence as they do in other pupfish (Kodric-Brown tion. Mutual sexual selection (Almeida & deAbreu 1983). Males may also use differences in jaw mor- 2003; Pierotti et al. 2008; Puebla et al. 2011), phology body shape and barring pattern to discrimi- together with ecological niche invasion (Nosil 2012) nate among females. Further studies of intraspecific and predation (Albert & Schluter 2004) by a closely variation in preferences based on some combination related sister species (C. desquamator), is powerful of shape and color may provide insight into what selective pressures that have led to pre-mating isola- visual cues are important in species discrimination tion and effective barriers to interspecific mating in and mate choice in these pupfishes. this system. We focused on the two sensory modalities that operate in mate recognition and species discrimina- Conclusion tion in the only other known sympatric species flock of pupfishes (Strecker & Kodric-Brown 1999), Selection has likely maintained species barriers in this although there may be others. As territorial male system through both divergent selection and rein- C. variegatus produce sounds (Nicoletto & Linscomb forcement selection (sensu Langerhans & Riesch 2008), auditory cues could also contribute to species 2013). Specifically, pre-mating isolation in this system recognition and female choice. So far, little is known has probably been maintained by two selective pres- about the function of these sounds in female choice or sures: (i) divergent selection on ecological niche inva- species recognition in pupfish. In other taxa, females sion in the specialists and predation avoidance in the use multiple sensory modalities in mate choice (Can- ancestral generalists and by (ii) frequency-dependent dolin 2003; Kekal€ ainen€ et al. 2011; van Staaden & reinforcement selection to choose mates that mini- Smith 2011). In East African cichlids, visual cues, mize hybridization. such as male colors and patterns, as well as chemical and auditory cues are used by females to identify and Acknowledgements mate with conspecific males (Verzijden et al. 2010; Maruska et al. 2012). Thanks to S. Levya and A. Reade for assistance in the Finally, pre-mating isolating mechanisms in C. var- laboratory. D. Bolnick, R. Thornhill, P Watson, J.H. iegatus males from Crescent Lake are likely reinforced Brown and two anonymous reviewers provided help- by competition for limited breeding ground, which ful comments on the manuscript. M. Barton provided causes substantial overlapping with male C. desquama- some specimens and invaluable discussions. Research tor territories. Territorial C. variegatus males in Cres- was performed under the University of New Mexico’s cent Lake continuously encounter females of both IACUC permit no. 10-100586-MCC. RJDW was species (pers. observ.), and may be forced to choose funded through a Doctoral Dissertation Improvement between courting conspecific versus heterospecific Grant from Gerace Research Centre. We thank the females although C. variegatus females are more com- Bahamian government for permission to collect and mon. This has likely directly selected for choosey export specimens, and Thomas Rothfus and the Ge- males in Crescent Lake. Comparisons with male mate race Research Centre for logistic support. We have no preferences in the other lakes will reveal the general- conflict of interest to declare. ity of choosiness documented here in Crescent Lake. An unusual aspect of the Bahamian pupfish flock is Literature Cited that one of the sympatric species is a scale-eating predator (C. desquamator). Consequently, there are Albert, A. Y. K. & Schluter, D. 2004: Reproductive charac- two types of selective pressures (i) predation by ter displacement of male stickleback mate p: reinforce- C. desquamator on C. variegatus and C. brontotheroides, ment or direct selection? Evolution 58, 1099—1107. which reinforces assortative mating in these species Almeida, C. R. & deAbreu, F. V. 2003: Dynamical instabili- (Kodric-Brown & West 2014) and (ii) the cost of ran- ties lead to sympatric speciation. Evol. Ecol. Res. 5, 739 dom mating, which produces less fit hybrid offspring —757. (Martin & Wainwright 2013b). The cost of random Andersson, M. 1994: Sexual selection. Princeton Univer- mating would be frequency dependent, thus greater sity Press, Princeton, pp. 624.

Barton, M. & Barton, C. 2008: Pupfishes of the Bahamas. Hohenlohe, P. A. & Arnold, S. J. 2010: Dimensionality of J. Am. Killifish Assoc. 41, 161—171. mate choice, sexual isolation, and speciation. PNAS 107, Bonduriansky, R. 2001: The evolution of male mate choice 16583—16588. in insects: a synthesis of ideas and evidence. Biol. Rev. Holtmeier, C. L. 2001: Heterochrony, maternal effects, and 76, 305—339. phenotypic variation among sympatric pupfishes. Evo- Brown, C. & Laland, K. N. 2003: Social learning in fishes: a lution 55, 330—338. review. Fish Fish. 4, 280—288. Kahn, A. T., Mautz, B. & Jennions, M. D. 2010: Females Candolin, U. 2003: The use of multiple cues in mate prefer to associate with males with longer intromittent choice. Biol. Rev. 78, 575—595. organs in mosquitofish. Biol. Lett. 6,55—58. Chen, H., Salcedo, C. & Sun, J. 2012: Male mate choice by Kekal€ ainen,€ J., Valkama, H., Huuskonen, H. & Taskinen, J. chemical cues leads to higher reproductive success in a 2010: Multiple sexual ornamentation signals male qual- bark beetle. Anim. Behav. 83, 421—427. ity and predicts female preference in minnows. Ethol- Coyne, J. A. & Orr, H. A. 2004: Speciation. Sinauer Assoc. ogy 116, 895—903. Inc, Sunderland, MA. Kekal€ ainen,€ J., Leppanen,€ H.-R., Huuskonen, H., Lai, van Doorn, G. S., Edelaar, P. & Weissing, F. J. 2009: On Y.T., Valkama, H. & Taskinen, J. 2011. The informa- the origin of species by natural and sexual selection. Sci- tion content of odour, colour and tactile cues in the ence 326, 1704—1707. mate choice of minnows. Behaviour 148, 909—925. Dosen, L. D. & Montgomerie, R. 2004: Female size influ- Kodric-Brown, A. 1983: Determinants of male reproduc- ences mate preferences of male guppies. Ethology 110, tive success in pupfish (Cyprinodon pecosensis). Anim. 245—255. Behav. 31, 128—137. Draud, M. J. & Itzkowitz, M. 2004: Mate numbers or mate Kodric-Brown, A. 1996: Role of male-male competition quality: female mate choice in the polygynandrous var- and female choice in the development of breeding col- iegated pupfish (Cyprinodon variegatus). Ethol. Ecol. oration in pupfish (Cyprinodon pecosensis). Behav. Ecol. Evol. 16,1—13. 7, 431—437. Edward, D. A. & Chapman, T. 2011: The evolution and sig- Kodric-Brown, A. 1998: Sexual dichromatism and tempo- nificance of male mate choice. Trends Ecol. Evol. 26, rary color changes in the reproduction of fishes. Amer. 647—654. Zool. 38,70—81. Elmer, K. R., Lehtonen, T. K. & Meyer, A. 2009: Color Kodric-Brown, A. & Strecker, U. 2001: Responses of Cyp- assortative mating contributes to sympatric divergence rinodon maya and C. labiosus females to visual and olfac- of Neotropical cichlid fish. Evolution 63, 2750—2757. tory cues of conspecific and heterospecific males. Biol. Elmer, K. R., Kusche, H., Lehtonen, T. K. & Meyer, A. J. Linn. Soc. 74, 541—548. 2011: Local variation and parallel evolution: morpho- Kodric-Brown, A. & West, R. J. D. 2014: Asymmetries logical and genetic diversity across a species complex of in premating isolating mechanisms in a sympatric neotropical crater lake cichlid fishes. Philos. Trans. R species flock of pupfish (Cyprinodon). Behav. Ecol. Soc. Lond. B Biol. Sci. 365, 1763—1782. 25,69—75. Espinedo, C. M., Gabor, C. R. & Aspbury, A. S. 2010: Kozak, G. M., Reisland, M. & Boughmann, J. W. 2009: Males, but not females, contribute to sexual isolation Sex differences in mate recognition and conspecific between two sympatric species of Gambusia. Evol. Ecol. preference in species with mutual mate choice. Evolu- 24, 865—878. tion 63, 353—365. Gabor, C. R. 1999: Association patterns of sailfin mollies Langerhans, R. B. & Makowicz, A. M. 2013: Sexual selec- (Poecilia latipinna). Behav. Ecol. Sociobiol. 46, 333— tion paves the road to sexual isolation during ecological 340. speciation. Evol. Ecol. Res. 15, 633—651. Gregorio, O., Berdan, E. L., Kozak, G. M. & Fuller, R. C. Langerhans, R. B. & Riesch, R. 2013: Speciation by selec- 2012: Reinforcement of male mate preferences in sym- tion: a framework for understanding ecology’s role in patric killifish species Lucania goodei and Lucania parva. speciation. Curr. Zool. 59,31—52. Behav. Ecol. Sociobiol. 66, 1429—1436. Langerhans, R. B., Gifford, M. E. & Joseph, O. 2007: Eco- Gwynne, D. T. 1991: Sexual competition among females – logical speciation in Gambusia fishes. Evolution 61, what causes courtship-role reversal? Trends Ecol. Evol. 2056—2074. 6, 118—121. Ludlow, A. M., Itzkowitz, M. & Baird, D. R. 2001: Male Hagey, F. M. & Mylroie, J. E. 1995: Pleistocene lake and mating success and female preference for multiple traits lagoon deposits, San Salvador island, Bahamas. In: Ter- in the twoline pupfish. Behaviour 138, 1303—1318. restrial and Shallow Marine Geology of the Bahamas Maan, M. E. & Seehausen, O. 2011: Ecology, sexual selec- and Bermuda (Curran, H. A. & White, B., eds). Geologi- tion and speciation. Ecol. Lett. 14, 591—602. cal Society of America (Special Paper 300), Boulder, Martin, C. H. & Wainwright, P. C. 2011: Trophic novelty is CO, pp. 77—90. linked to exceptional rates of morphological diversification

in two adaptive radiations of Cyprinodon pupfishes. Evo- Sargent, R. C., Gross, M. & Van Den Berghe, E. P. 1986: lution 65, 2197—2212. Male mate choice in fishes. Anim. Behav. 34, 545—550. Martin, C. H. & Wainwright, P. C. 2013a: A remarkable Savolainen, V., Anstett, M.-C., Lexer, C., Hutton, I., Clark- species flock of Cyprinodon pupfishes endemic to San son, J. J., Norup, M. V., Powell, M. P., Springate, D., Salvador Island, Bahamas. Bull. Peabody Mus. Nat. Hist. Salamin, N. & Baker, W. J. 2006: Sympatric speciation 54, 231—240. in palms on an oceanic island. Nature 441, 210—213. Martin, C. H. & Wainwright, P. C. 2013b: Multiple fitness Seehousen, O., Terai, Y., Magalhaes, I. S., Carleton, K. L., peaks on the adaptive landscape drive adaptive radia- Mrosso, H. D. J., Miyagi, R., van der Sluijs, I., Schneider, tion in the wild. Science 339, 208—211. M. V., Maan, M. E., Tachida, H., Imai, H. & Okada, N. Maruska, K. P., Ung, J. S. & Fernald, R. D. 2012: The Afri- 2008: Speciation through sensory drive in cichlid fish. can cichlid fish Astatotilapia burtoni uses acoustic com- Nature 455, 620—626. munication for reproduction: sound production, Smadja, C. & Butlin, R. K. 2009: On the scent of specia- hearing, and behavioral significance. PLoS ONE 7, tion: the chemosensory system and its role in premating e37612. isolation. Heredity 102,77—97. Milliken, K. T., Anderson, J. B. & Rodriguez, A. B.. 2008: van Staaden, M. J. & Smith, A. R. 2011: Cutting the Gor- A new composite Holocene sea-level curve for the dian knot: complex signaling in African cichlids is more northern Gulf of Mexico. In: Response of Upper Gulf than multimodal. Curr. Zool. 57, 237—252. Coast Estuaries to Holocene Climate Change and Sea- Strecker, U. & Kodric-Brown, A. 1999: Mate recognition Level Rise (Anderson, J. B. & Rodriguez, A. B., eds). systems in a species flock of Mexican pupfish. J. Evol. Geological Society of America, Boulder, CO (Special Biol. 12, 927—935. Paper 443). pp. 1—11. Strecker, U. & Kodric-Brown, A. 2000: Mating preferences Minitab 16 Statistical Software. 2010. [Computer soft- in a species flock of Mexican pupfishes (Cyprinodon, Te- ware]. State College, PA: Minitab, Inc. (www.mini- leostei). Biol. J. Linn. Soc. 71, 677—687. tab.com) Swenton, D. M. 2011: Sex differences in mate preference Myhre, L. C., de Jong, K., Forsgren, E. & Amundsen, T. between two hybridizing species of poeciliid fish. Ethol- 2012: Sex roles and mutual mate choice matter during ogy 117, 208—216. mate sampling. Am. Nat. 179, 741—755. Tudor, M. S. & Morris, M. R. 2009: Variation in male mate Nagel, L. & Schluter, D. 1998: Body size, natural selec- preference for female size in the sword tail Xiphophorus tion, and speciation in sticklebacks. Evolution 52, malinche. Behaviour 146, 727—740. 209—218. Turner, B. J., Duvernell, D. D., Bunt, T. M. & Barton, M. Nicoletto, P. F. & Linscomb, S. H. 2008: Sound production G. 2008: Reproductive isolation among endemic pupf- by the sheepshead minnow Cyprinodon variegatus. Envi- ishes (Cyprinodon) on San Salvador Island, Bahamas: mi- ron. Biol. Fish 81,15—20. crosatellite evidence. Biol. J. Linn. Soc. 95, 566—582. Nosil, P. 2012: Ecological Speciation. Oxford University Verzijden, M. N., van Heusden, J., Bouton, N., Witte, F., Press, Oxford, UK, pp. 304. ten Cate, C., et al. 2010: Sounds of Lake Victoria cichlids Pacheco, P. J. & Foradas, J. G. 1986: Holocene environ- vary within and between species and affect female mate mental changes in the interior karst region of San Salva- preferences. Behav. Ecol. 21, 548—555. dor, Bahamas; the Granny Lake pollen record. Proc. Verzijden, M. N., ten Cate, C., Servidio, M. R., Kozak, M., Symp. Geol. Bahamas 3, 115—122. Boughman, J., et al. 2012: The impact of learning on Pierotti, M. E. R., Knight, M. E., Immler, S., Barson, N. J., sexual selection and speciation. Trends Ecol. Evol. 27, Turner, G. F. & Seehausen, O. 2008: Individual varia- 511—519. tion in male mating preferences for female coloration in Werner, N. Y. & Lotem, A. 2006: Experimental evidence a polymorphic cichlid fish. Behav. Ecol. 19, 483—488. for male sequential mate preference in a lekking species. Puebla, O., Bermingham, E. & Guichard, F. 2011: Perspec- Ethology 112, 657—663. tive: matching, mate choice and speciation. Integr. Wronski, T., Bierbach, D., Czupalla, L.-M., Lerp, H., Ziege, Comp. Biol. 51, 485—491. M., Cunningham, P. L. & Plath, M. 2012: Rival presence Ritchie, M. G. 2007: Sexual selection and speciation. leads to reversible changes in male mate choice of a des- Annu. Rev. Ecol. Evol. Syst. 38,79—102. ert dwelling ungulate. Behav. Ecol. 23, 551—558.