DOCSLIB.ORG

THE EFFECTS of SPERM COMPETITION on TESTES SIZE and INTROMITTENT ORGAN MORPHOLOGY in WATERFOWL by CHRIS R. COKER B.Sc

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
THE EFFECTS of SPERM COMPETITION on TESTES SIZE and INTROMITTENT ORGAN MORPHOLOGY in WATERFOWL by CHRIS R. COKER B.Sc THE EFFECTS OF SPERM COMPETITION ON TESTES SIZE AND INTROMITTENT ORGAN MORPHOLOGY IN WATERFOWL by CHRIS R. COKER B.Sc. (hon.), Trent University, 1993 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES (Department of Animal Science) We accept this thesis as conforming to the required standard THE: UNIVERSITY OF BRITISH COLUMBIA April 1998 © Chris R. Coker, 1998 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department The University of British Columbia Vancouver, Canada DE-6 (2/88) Abstract Waterfowl are one of very few avian taxa that possesses an intromittent organ (10). This thesis examines the adaptive significance of the 10 in waterfowl by determining the relationships between 10 morphology and the intensity of sperm competition (as reflected by frequency of extra-pair copulations (EPCs)). Intromittent organ morphological characteristics, including length and circumference (adjusted for body size), number of ridges and/or knobs (per unit area), ridge/knob height, ridge/knob length, and % area covered by ridges/knobs were measured from scaled museum drawings of freshly killed, sexually mature, specimens of 57 waterfowl species (across 33 genera). Thirty of which were ranked by frequency of EPC (1= monogamous, 2= rare EPC, 3= frequent EPC, 4= promiscuous). Testes sizes were also investigated in relation to EPCs, where testes masses (adjusted for body size) from 47 species (across 24 genera) were obtained (32 species with mating strategies). The size of the testes, the size (length) of the 10, the size (height) of the 10 ridges/knobs and the % area covered by ridges/knobs increased significantly with the frequency of EPC. These relationships exist even after the removal of phylogenetic constraints. These results are consistent with the hypothesis that waterfowl 10s are involved in sperm competition. Further research into the actual mechanism by which the 10 is involved with sperm competition would be worthwile. TABLE OF CONTENTS Page Abstract ii Table of Contents iii List of Tables v List of Figures •. '.. vi Acknowledgements vii Chapter 1 Introduction and Background 1 Intromittent Organs 2 Male Genitalia in Animals 2 Male Genitalia in Birds 4 Why Do Some Birds Possess or Lack an IO? 5 Male Genitalia in Waterfowl 10 Female Genitalia in Birds 11 Extra-Pair Copulation 14 Sperm Competition 16 Chapter 2 The relationship between testes size and mating strategy in waterfowl 21 Avian Testes 21 Materials and Methods 23 Results 29 Discussion 32 Chapter 3 The relationship between intromittent organ morphology and mating strategy in waterfowl 37 Sperm Competition 37 Hypothesis 38 Materials and Methods 39 Results 43 Discussion 55 iii Chapter 4 Conclusions and Future Directions 59 Conclusions 59 Study Limitations 59 Future Directions 61 A Final Thought 62 References 65 Appendix A Intromittent Organ Model 73 iv List of Tables Page Table 2.1 Table of testes masses, body masses, mating strategies, and testes data sources 25 Table 3.1 Principal components analysis 43 Table 3.2 List of species categorized according to mating strategy 46 Table 3.3 Correlation matrix of morphological characteristics 50 Table 3.4 Correlation matrix of morphological characteristics after phylogenetic constraints removed 52 v List of Figures Page Figure 2.1 The relationship between testes mass and mating strategy 29 Figure 2.2 The relationship between body mass and testes mass 30 Figure 2.3 The relationship between testes size and IO size 31 Figure 2.4 The relationship between testes size and IO size (removal of phylogenetic effects) 32 Figure 3.1 Sample of Harlequin duck and Ruddy duck intromittent organ drawings showing various characteristics 40 Figure 3.2 Principal components analysis of morphological measurements......... 45 Figure 3.3 PCA of initial 18 species categorized according to mating strategy 49 Figure 3.4 PCA with newly added species' mating strategies 51 Figure 3.5 The relationship between IO length and mating strategy 53 Figure 3.6 The relationship between the number of ridges and knobs (per unit) and mating strategy 54 Figure 3.7 The relationship between the area covered by ridges and/or knobs and mating strategy 54 Figure 3.8 The relationship between the height of the ridges/knobs and mating strategy... 55 Figure 3.9 Intromittent organ of the Ruddy duck, Oxyurini jamaicensis (left), and it's features compared to the Mealworm beetle, . Tenebrio molitor (right) 58 vi Acknowledgements This thesis could not have been completed without the efforts of Helen Hays from the American Museum of Natural History (New York). The unpublished illustrations of waterfowl intromittent organs were drawn and are owned by her; she kindly let me use them for the purpose of this study. I would like to thank my supervisory committee, Kim Cheng, Frank McKinney (University of Minnesota), Wayne Vogl, Harold Kasinsky, and Raja Rajamahendran for their support and tutelage. There are also many people who were involved in helping me on certain aspects of my thesis. I would like to express gratitude to Kevin Johnson at the University of Utah, for his help on the phylogenetic analysis; Wayne Vogl for assisting in the dissections and model casting, and Gary Bradfield for his guidance on the statistical analysis. I would also like to acknowledge Frank McKinney, Dan Brooks (Texas A & M University), and Peggi Rodgers (Wildlife Rehabilitator) who provided information on mating behaviours; and Sue Briggs (CSIRO, Canberra), Brad Millen (Royal Ontario Museum), Maryanne Hughes (UBC), and Trevor Pitcher (York University), who helped supply testes data, I would also like to thank my family and friends who showed their love and support (and tried not to snicker at my topic of research). Finally, I would like to thank my wife, Anne Hepplewhite, who was there all the way and never doubted my ability to achieve excellence. vii Chapter 1 Introduction and Background Rapid and divergent evolution in male genital morphology is expected in animals with internal fertilization (Eberhard 1985). This is due to a variety of adaptive pathways that enhance the success of self's ejaculate relative to rival ejaculates (i.e. to ensure paternity). The theory that the evolution of male genitalia results from sexual selection has been examined in the book, Sexual Selection and Animal Genitalia (Eberhard 1985), which extensively reviewed numerous studies of male genitalia in a vast array of vertebrates and invertebrates. The class Aves, however, is seldom mentioned in this book. Except for general descriptions of anatomy and physiology (e.g. Barkow 1829, Eckhard 1876, Muller 1908, Liebe 1914, Lake 1981, King 1981), studies on the function or adaptive significance of the intromittent organ (IO) are extremely rare in birds. Perhaps this is due to the fact that the majority of avian species do not have an IO, and consequently there has been little interest in carrying out research in this area. The majority of IO studies that have been carried out are on mammals, or insects. Mammals have external lOs and domestic and farm mammals are abundant and easily accessible for research. IO studies began in insects in association with sperm competition studies (e.g. Waage 1979, Michiels 1989, Miller 1991). Though most avian species lack an IO, some species do have one. This study attempts to examine the evolution and adaptive significance of the IO in waterfowl. I Intromittent Organs It has long been recognized that among closely related species with internal fertilization, the genitalia often show clear morphological differences (Eberhard 1985). This is particularly accentuated in the male of the species and is widespread throughout numerous animal groups. For example, species-specific IO are found in flatworms, nematodes, oligochaete worms, insects, spiders, millipedes, sharks and rays, some lizards, snakes, mites, opilionids, crustaceans, molluscs, and mammals (including rodents, bats, armadillos, and primates) (Eberhard 1990). In contrast, animals that have external fertilization, such as most fish, do not have species-specific genital morphology. External fertilizing groups of animals include echinoderms, most polychaete worms, hemichordates, brachiopods, sipunculid worms, frogs, few insects, and most fish (Eberhard 1990). Even as recently as 1990, birds have been categorized as not having an IO, and in fact, have even been classified as having external fertilization! (Eberhard 1990, pp. 134). Any structure that has evolved both rapidly and divergently (i.e. it acquires a new form in each new species) is a useful taxonomic character at the species level (Eberhard 1985). The universality of this pattern can be demonstrated below with a review of the genitalia from a variety of animal groups together with an examination of the complexity of many genitalia. Male Genitalia in Animals When fertilization is internal, the male, with few exceptions, develops intromittent 2 or copulatory organs for introducing sperm into the female reproductive tract. For example, the 10 of elasmobranchs are grooved, finger-like appendages of the pelvic fins known as claspers (Kent 1987) and in the anuran genus Ascaphus, the IO is a permanent tubular tail-like extension of the cloaca (Taylor & Guttman 1977). Male turtles, crocodilians, a few birds and mammals exhibit an unpaired erectile penis. In its simplest form, the penis is a thickening of the floor of the cloaca that consists chiefly of spongy erectile tissue, the corpus spongiosum, which bears a urethral groove on its dorsal surface and ends in a glans penis (Fox 1977).
Load more

Recommended publications
  • Needham Notes
    Lesson 26 Lesson Outline: Exercise #1 - Basic Functions Exercise #2 - Phylogenetic Trends Exercise #3 - Case Studies to Compare • Reproductive Strategies- Energy Partitioning • External versus Internal Fertilization • Sexual Dimorphism o Functional Characteristics o Aids to Identification o Copulatory Organs • Timing - Copulation, Ovulation, Fertilization, Development Objectives: Throughout the course what you need to master is an understanding of: 1) the form and function of structures, 2) the phylogenetic and ontogenetic origins of structures, and 3) the extend to which various structures are homologous, analogous and/or homoplastic. At the end of this lesson you should be able to: Describe the advantages and disadvantages of internal and external fertilization Describe sexual dimorphism and the selection pressures that lead to it Describe the trends seen in the design of copulatory organs Describe the various forms of reproductive strategy for delaying development of the fertilized egg and the selective advantage of them References: Chapter 15: 351-386 Reading for Next Lesson: Chapter 16: 387- 428 Exercise #1 List the basic functions of the urogenital system: The urinary system excretes the waste products of cellular digestion, ions, amino acids, salts, etc. It also plays a key role in water balance along with numerous other structures in different species living in different environments (i.e. gills, skin, salt glands). The primary function of the system is to give rise to offspring, - to reproduce. Exercise #2 Describe the evolutionary trends that we see in the urogenital systems of the different vertebrate groups: The phylogenetic trends that we see throughout the chordates were covered in detail in lectures (lecture 31 and 32) and are summarized schematically in the next figures: Exercise #3 – Comparisons – Case 1 Reproductive Strategies - Energy Partitioning Some would argue that the primary reason that organisms exist is to reproduce and make more organisms.
    [Show full text]
  • A Biological Switching Valve Evolved in the Female of a Sex-Role Reversed
    RESEARCH ARTICLE A biological switching valve evolved in the female of a sex-role reversed cave insect to receive multiple seminal packages Kazunori Yoshizawa1*, Yoshitaka Kamimura2, Charles Lienhard3, Rodrigo L Ferreira4, Alexander Blanke5,6 1Laboratory of Systematic Entomology, School of Agriculture, Hokkaido University, Sapporo, Japan; 2Department of Biology, Keio University, Yokohama, Japan; 3Natural History Museum of Geneva, Geneva, Switzerland; 4Biology Department, Federal University of Lavras, Lavras, Brazil; 5Institute for Zoology, University of Cologne, Zu¨ lpicher, Ko¨ ln; 6Medical and Biological Engineering Research Group, School of Engineering and Computer Science, University of Hull, Hull, United Kingdom Abstract We report a functional switching valve within the female genitalia of the Brazilian cave insect Neotrogla. The valve complex is composed of two plate-like sclerites, a closure element, and in-and-outflow canals. Females have a penis-like intromittent organ to coercively anchor males and obtain voluminous semen. The semen is packed in a capsule, whose formation is initiated by seminal injection. It is not only used for fertilization but also consumed by the female as nutrition. The valve complex has two slots for insemination so that Neotrogla can continue mating while the first slot is occupied. In conjunction with the female penis, this switching valve is a morphological novelty enabling females to compete for seminal gifts in their nutrient-poor cave habitats through long copulation times and multiple seminal injections. The evolution of this switching valve may *For correspondence: have been a prerequisite for the reversal of the intromittent organ in Neotrogla. [email protected] DOI: https://doi.org/10.7554/eLife.39563.001 Competing interests: The authors declare that no competing interests exist.
    [Show full text]
  • Reproductive System Further Information: Fish Reproduction and Spawn (Biology)
    Reproductive system Further information: Fish reproduction and Spawn (biology) Organs: 1. Liver, 2. Gas bladder, 3. Roe, 4. Pyloric caeca, 5. Stomach, 6. Intestine Fish reproductive organs include testicles and ovaries. In most species, gonads are paired organs oF similar size, which can be partially or totally Fused.[52] There may also be a range oF secondary organs that increase reproductive Fitness. In terms oF spermatogonia distribution, the structure oF teleosts testes has two types: in the most common, spermatogonia occur all along the seminiFerous tubules, while in atherinomorph fish they are confined to the distal portion oF these structures. Fish can present cystic or semi- cystic spermatogenesis in relation to the release phase oF germ cells in cysts to the seminiFerous tubules lumen.[52] Fish ovaries may be oF three types: gymnovarian, secondary gymnovarian or cystovarian. In the First type, the oocytes are released directly into the coelomic cavity and then enter the ostium, then through the oviduct and are eliminated. Secondary gymnovarian ovaries shed ova into the coelom From which they go directly into the oviduct. In the third type, the oocytes are conveyed to the exterior through the oviduct.[53] Gymnovaries are the primitive condition Found in lungFish, sturgeon, and bowFin. Cystovaries characterize most teleosts, where the ovary lumen has continuity with the oviduct.[52] Secondary gymnovaries are Found in salmonids and a Few other teleosts. Oogonia development in teleosts Fish varies according to the group, and the determination oF oogenesis dynamics allows the understanding oF maturation and Fertilization processes. Changes in the nucleus, ooplasm, and the surrounding layers characterize the oocyte maturation process.[52] Postovulatory follicles are structures Formed aFter oocyte release; they do not have endocrine Function, present a wide irregular lumen, and are rapidly reabsorbed in a process involving the apoptosis oF Follicular cells.
    [Show full text]
  • Female Penis, Male Vagina, and Their Correlated Evolution in a Cave Insect
    Please cite this article in press as: Yoshizawa et al., Female Penis, Male Vagina, and Their Correlated Evolution in a Cave Insect, Cur- rent Biology (2014), http://dx.doi.org/10.1016/j.cub.2014.03.022 Current Biology 24, 1–5, May 5, 2014 ª2014 Elsevier Ltd All rights reserved http://dx.doi.org/10.1016/j.cub.2014.03.022 Report Female Penis, Male Vagina, and Their Correlated Evolution in a Cave Insect Kazunori Yoshizawa,1,* Rodrigo L. Ferreira,2 We observed coupling in all Neotrogla species and found that Yoshitaka Kamimura,3 and Charles Lienhard4 the gynosome acts as an intromittent organ to receive volumi- 1Systematic Entomology, School of Agriculture, Hokkaido nous spermatophores from the male. As in most related taxa, University, Sapporo 060-8589, Japan including those having well-developed male genitalia (Fig- 2Biology Department, Federal University of Lavras, ure 1C) [8], the male is positioned under the female during copu- 37200-000 Lavras, MG, Brazil lation (Figure 1A). The apical sclerotized part of the gynosome, 3Department of Biology, Keio University, Yokohama 223-8521, bearing the opening of the spermathecal duct, deeply pene- Japan trates the male (Figures 2, 3, S2, and S3), and its tip fits the open- 4Natural History Museum of the City of Geneva, CP 6434, ing of the seminal duct (Figures 2D and 3C). The membranous 1211 Geneva 6, Switzerland part inflates within the male genital chamber, and numerous spines on the membrane internally anchor the female to the male (Figures 2B, 2E, 3A, 3D, and S2). In this position, the Summary male sternum is gripped between the female paraprocts and inflated gynosome (Figures 2B and 2C).
    [Show full text]
  • Reproductive Cycle and Spatiotemporal Variation in Abundance of the One-Sided Livebearer Jenynsia Multidentata, in Patos Lagoon, Brazil
    Hydrobiologia 515: 39–48, 2004. 39 © 2004 Kluwer Academic Publishers. Printed in the Netherlands. Reproductive cycle and spatiotemporal variation in abundance of the one-sided livebearer Jenynsia multidentata, in Patos Lagoon, Brazil Alexandre M. Garcia1, João P. Vieira1, Kirk O. Winemiller2 & Marcelo B. Raseira1 1Fundação Universidade Federal de Rio Grande, Departamento de Oceanografia, Laborat´orio de Ictiologia, C. P. 474, Rio Grande, RS, Brazil E-mail: [email protected] 2Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843-2258, U.S.A. Received 17 June 2003; in revised form 25 August 2003; accepted 27 August 2003 Key words: Anablepidae, life-history, livebearing fishes, Patos Lagoon estuary Abstract Jenynsia multidentata is an important component of the fish assemblage of the Patos Lagoon estuary in southern South Brazil. In order to investigate its reproductive cycle and abundance patterns, standardized sampling was conducted over large spatial (marine, estuary and lagoon) and temporal (1996–2003) scales. Both females and males were significantly more abundant during summer (December–March) than winter (June–August). Total abundance was significantly positively correlated with water temperature (R = 0.91), but not with salinity and Secchi depth. Females achieved higher average (49.1 mm LT) and maximum size (91 mm) than males (37.7 mm; 66 mm), and average sex ratio was female-biased (3.2:1) across all months. An annual reproductive cycle composed of two cohorts was proposed: individuals born from December to March started reproducing during late winter and spring and individuals born from September to November started reproducing during late summer and fall.
    [Show full text]
  • Female Bed Bugs (Cimex Lectularius L) Anticipate the Immunological Consequences of Traumatic Insemination Via Feeding Cues
    Female bed bugs (Cimex lectularius L) anticipate the immunological consequences of traumatic insemination via feeding cues Michael T. Siva-Jothya,1, Weihao Zhonga,2, Richard Naylora, Louise Heatona, William Hentleya, and Ewan Harneya,1,3 aDepartment of Animal & Plant Sciences, University of Sheffield, S10 2TN Sheffield, United Kingdom Edited by Joan E. Strassmann, Washington University in St. Louis, St. Louis, MO, and approved May 30, 2019 (received for review March 15, 2019) Not all encounters with pathogens are stochastic and insects can likelihood of immune insult across generations (11) and during adjust their immune management in relation to cues associated ontogeny (12). Recent work on Drosophila melanogaster has shown with the likelihood of infection within a life cycle as well as across that females can use male courtship song as a cue to up-regulate generations. In this study we show that female insects (bed bugs) immunity in anticipation of mating (13) which improves female fit- up-regulate immune function in their copulatory organ in antici- ness (14) over relatively short time frames. It therefore seems possible pation of mating by using feeding cues. Male bed bugs only mate that in the presence of reliable cues, and predictable behavioral with recently fed females and do so by traumatic insemination (TI). cascades, immune anticipation of mating-induced infection may be Consequently, there is a tight temporal correlation between female particularly important in female bed bugs (15) because of TI. feeding and the likelihood of her being infected via TI. Females that In this study we examine anticipatory immune system man- received predictable access to food (and therefore predictable agement over a 7 d feeding cycle that is associated with TI.
    [Show full text]
  • Reduction of Female Copulatory Damage by Resilin Represents Evidence for Rsif.Royalsocietypublishing.Org Tolerance in Sexual Conflict
    Downloaded from http://rsif.royalsocietypublishing.org/ on March 4, 2015 Reduction of female copulatory damage by resilin represents evidence for rsif.royalsocietypublishing.org tolerance in sexual conflict Jan Michels1,2, Stanislav N. Gorb1 and Klaus Reinhardt3,4 Research 1Department of Functional Morphology and Biomechanics, Institute of Zoology, Christian-Albrechts-Universita¨t zu Kiel, Am Botanischen Garten 1–9, 24118 Kiel, Germany Cite this article: Michels J, Gorb SN, 2Biological Oceanography, GEOMAR Helmholtz Centre for Ocean Research Kiel, Du¨sternbrooker Weg 20, Reinhardt K. 2015 Reduction of female 24105 Kiel, Germany 3 copulatory damage by resilin represents Applied Zoology, Department of Biology, Technische Universita¨tDresden,Helmholtzstraße10,01217Dresden,Germany 4Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK evidence for tolerance in sexual conflict. J. R. Soc. Interface 12: 20141107. Intergenomic evolutionary conflicts increase biological diversity. In sexual http://dx.doi.org/10.1098/rsif.2014.1107 conflict, female defence against males is generally assumed to be resistance, which, however, often leads to trait exaggeration but not diversification. Here, we address whether tolerance, a female defence mechanism known from interspecific conflicts, exists in sexual conflict. We examined the traumatic Received: 8 October 2014 insemination of female bed bugs via cuticle penetration by males, a textbook Accepted: 16 January 2015 example of sexual conflict. Confocal laser scanning microscopy revealed large proportions of the soft and elastic protein resilin in the cuticle of the spermalege, the female defence organ. Reduced tissue damage and haemolymph loss were identified as adaptive female benefits from resilin. These did not arise from resistance because microindentation showed that the penetration force necess- Subject Areas: ary to breach the cuticle was significantly lower at the resilin-rich spermalege biomechanics, biophysics than at other cuticle sites.
    [Show full text]
  • The Evolution of Sexually Antagonistic Phenotypes
    The Evolution of Sexually Antagonistic Phenotypes Jennifer C. Perry1,2 and Locke Rowe3 1Jesus College, University of Oxford, Oxford OX1 3DW, United Kingdom 2Edward Grey Institute, Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom 3Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S 3B2, Canada Correspondence: [email protected] Sexual conflict occurs whenever there is sexually antagonistic selection on shared traits. When shared traits result from interactions (e.g., mating rate) and have a different genetic basis in each sex (i.e., interlocus conflict), then sex-specific traits that shift the value of these interaction traits toward the sex-specific optimum will be favored. Male traits can be favored that increase the fitness of their male bearers, but decrease the fitness of interacting females. Likewise, female traits that reduce the costs of interacting with harmful males may simulta- neously impose costs on males. If the evolution of these antagonistic traits changes the nature of selection acting on the opposite sex, interesting coevolutionary dynamics will result. Here we examine three current issues in the study of sexually antagonistic interactions: the female side of sexual conflict, the ecological context of sexual conflict, and the strength of evidence for sexually antagonistic coevolution. Conflict requires some interaction or common activity locus conflict. Examples of the second include between males and females ... which generates the most traits that are expressed in both sexes with constraint that the ideal optima for each sex cannot a common genetic architecture between the be achieved simultaneously. sexes, such as human height or pelvis shape.
    [Show full text]
  • Reproduction in Fishes Semelparity — Spawn Once Why? I
    I. Lifetime spawning frequency Reproduction in Fishes Semelparity — spawn once Why? I. Lifetime spawning frequency Iteroparity — spawn multiple times II. Spawning cycles semelparous iteroparous III. Modes of spawning IV. Sex change and mating systems II. Spawning cycles III. Modes of reproduction • semelparous — annual (or multiples thereof) • oviparity — egg laying • iteroparous — annual, lunar, daily; & cycles within cycles • ovoviviparity — livebearing, no maternal nourishment daily • viviparity — livebearing with maternal nourishment monthly yearly Tradeoff: number vs. size of eggs/offspring Oviparity • external fertilization — gametes shed into water Number of offspring (eggs or young) and degree of parental care - most common mode Species Relative Egg or Mean # of Eggs Degree of Offspring Size or Offspring Parental Care - ancestral condition Mola mola very small 28,000,000 none, free floating pelagic eggs - simple cod very small 9,000,000 haddock very small 2,000,000 - small, but numerous eggs sturgeon medium 200,000 eggs buried, no • internal fertilization — eggs fertilized internally, but other care salmon medium 5,000 later released into water sculpin medium 140 - uncommon stickleback medium 60 high medaka medium 30 - many elasmobranchs sand shark very large 1-2 extreme: uterus w/ cannibalism - often very large eggs in cases 1 Internal Fertilization in Oviparous species Ovoviviparity • internal fertilization — eggs fertilized internally & hatch internally, but no direct maternal nourishment advantage - young are generally larger and more advanced disadvantages - low dispersal of offspring - few offspring produced - if mother dies while pregnant, offspring die, too examples: - most sharks and rays - coelacanth - rockfishes copulation: white tip reef sharks Viviparity • internal fertilization & direct maternal nourishment - ovarian fluids - placenta (some sharks) advantage - young are very large and advanced disadvantages - same as for ovoviviparity - energetic cost to mother 2 Internal Fertilization: males have an intromittent organ 1.
    [Show full text]
  • The Innervation of the Male Copulatory Organ of Spiders (Araneae) – a Comparative Analysis Tim M
    Dederichs et al. Frontiers in Zoology (2019) 16:39 https://doi.org/10.1186/s12983-019-0337-6 RESEARCH Open Access The innervation of the male copulatory organ of spiders (Araneae) – a comparative analysis Tim M. Dederichs1*, Carsten H. G. Müller1, Lenka Sentenská2, Elisabeth Lipke3, Gabriele Uhl1* and Peter Michalik1* Abstract Background: Nervous tissue is an inherent component of the many specialized genital structures for transferring sperm directly into the female’s body. However, the male copulatory organ of spiders was considered a puzzling exception. Based on the recent discovery of nervous tissue in the pedipalps of two distantly related spider species, we investigated representatives of all major groups across the spider tree of life for the presence of palpal nerves. We used a correlative approach that combined histology, micro-computed tomography and electron microscopy. Results: We show that the copulatory organ is innervated in all species investigated. There is a sensory organ at the base of the sperm transferring sclerite in several taxa and nervous tissue occurs close to the glandular tissue of the spermophor, where sperm are stored before transfer. Conclusions: The innervation of the copulatory organ by the bulb nerve and associated efferent fibers is part of the ground pattern of spiders. Our findings pave the way for unraveling the sensory interaction of genitalia during mating and for the still enigmatic mode of uptake and release of sperm from the male copulatory organ. Keywords: Copulation, Intromittent organ, Sexual selection, Bulb nerve, Sensory organ, Pedipalp, Palpal organ, Copulatory mechanism, Spiders Background spiders, however, was considered a puzzling exception Animals with internal fertilization have evolved highly since no muscles, nerves and sense organs had been specialized and diverse genital structures for transfer- found in it [11–15].
    [Show full text]
  • The Arachnida
    THE ARACHNIDA THE arachnids are more easily recognized than defined. They have so many features in common with Limulus that some zoologists have classed Limulus in the Arachnida. The essential differences between the Xiphosurida and the Arachnida are in the feeding organs and the organs of respiration. The arachnids feed on liquids extracted from their prey, which are ingested by a pharyngeal sucking pump; the xiphosurids feed on solid food, which is ground up in a pro­ ventricular grist mill. The arachnids are terrestrial and breathe by means of lungs or tracheae; the xiphosurids, being aquatic, have abdominal gills, and theoretical attempts to derive the arachnid lungs from gills are not convincing. The most primitive of modern arachnids, the Palpigradi, are more generalized than Limulus. The Xiphosurida and the Arachnida, therefore, are two branches of the subphylum Chelicerata, but their common ancestors are not known. While there are paleontological reasons for believing that the xiphosurids and the trilobites had a com­ mon progenitor, the actual origin of the arachnids is obscure. How­ ever, as was noted in the last chapter, the pycnogonids have some surprisingly arachnoid characters. The scorpions have a superficial resemblance to the Eurypterida, but the scorpion, as compared with the Palpigradi, is not a primitive arachnid. However, it is not an ob­ ject of the present text to discuss theoretical arthropod phylogeny. The student may learn the essentials of arachnid anatomy from a study of the scorpion, the spiders, and a tick, which are the principal subjects of this chapter. 59 ARTHROPOD AN A TOMY THE SCORPION The scorpion in appearance (fig.
    [Show full text]
  • Reproduction Biology and Embryonic Development PAUL JIVOFF, ANSON H
    Copyright © 2007 Maryland Sea Grant College. The Blue Crab: Callinectes Sapidus, Victor S. Kennedy and L. Eugene Cronin, editors All rights reserved. No part of this publication maybe reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage or retrieval system, without permission in writing from Maryland Sea Grant. Chapter 7 Reproduction Biology and Embryonic Development PAUL JIVOFF, ANSON H. HINES, AND L. SCOTT QUACKENBUSH INTRODUCTION changes in population structure that reduce the reproductive success of individuals as well as removal Reproduction in the blue crab Callinectes sapidus of individuals before they have had a chance to is a complex process requiring precise coordination reproduce. The blue crab reproductive cycle of of physiological, behavioral, and ecological processes molting, maturation, mating, and brood production to ensure reproductive success. Mating is timed to differs from other fished crabs such that blue crab the female's maturity molt, which occurs once in reproduction may respond differently to intense the female's life (Van Engel 1958). It involves intri- fishing pressure. Developing a better understanding cate interactions between males and females, and of blue crab reproduction will not only lead to between competing males before, during, and after improved management of harvested populations but mating (Teytaud 1971; Gleeson 1980; JivofF 1997a; can also provide a good model for the evolution of Jivoff and Hines 1998b). Environmental conditions, life history strategies and mating systems. such as temperature and salinity, can modify aspects In this chapter, we review what is known about of blue crab mating (and other aspects of reproduc- the reproductive biology of the blue crab and discuss tion) because they influence the timing of molting, potentially important aspects that are known in as well as the structure of local populations, includ- other crustaceans but still unknown in this species.
    [Show full text]