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Apparent Homosexual Behaviour in an All-female Population of a Lizard, Lepidodactylus lugubris and its Probable Interpretation
Abstract
A case of apparent homosexual behaviour between female lizards is described and photographed in an all-female, parthenogenetic population of Lepidodactylus lugubris (Gekkonidae) in Hawau. Although other hypothetical explanations are offered, it appears most reasonable that this behaviour constitutes a demonstration of social rank. Briefly reviewed are homosexuality in lizards and the status of the L. lugubris population in Hawaii.
Homosexuelles, kopulations-ähnliches Verhalten wurde unter Weibchen einer nur weiblichen, parthenogenetischen Population des tropischen Geckos Lepidodactylus lugubris auf der Insel Oahu, Hawaii, beobachtet. Die beobachtete und photographierte Haltung ähnelte der Kopulationshaltung der bisexuellen Geckos. Dies scheint die erste Mitteilung über Homosexualität weiblicher Echsen in der Natur zu sein.
In diesem Fall scheint der Grund der Homosexualität nicht zu sein (1) das Nicht-Erkennen des Geschlechtes oder (2) Wirkung von männlichen Geschlechtshormonen, die wegen Hermaphroditismus oder teilweisem Geschlechtswechsel vorhanden sind. Anscheinend repräsentiert es auch nicht (1) eine Ersatz-Befriedigung, da das andere Geschlecht nicht vorhanden ist, oder (2) eine wirkliche Bevorzugung von Partnern desselben Geschlechts.
Das homosexuelle Benehmen der “männlichen” Geckoweibchen scheint ihren sozialen Rang oder ihre territoriale Überlegenheit zu demonstrieren, wie bei manchen anderen Vertebraten.
... Same-sex mounting occurs in many species, and many hypotheses have attempted to explain this behavior (e.g. Werner 1980;Shine et al. 2000;Field and Waite 2004;Switzer et al. 2004;Levan et al. 2009;Bailey and Zuk 2009). Adaptive hypotheses attribute same-sex mounts to some adaptive value, such as to establish dominance or hierarchies (intrasexual conflict hypothesis: e.g., Werner 1980;Preston-Mafham 2006), while non-adaptive hypotheses mainly consider same-sex mounts to be caused by failure in sex discrimination (mistaken identity hypothesis: e.g., Barlow 2000;Marco and Lizana 2002), lack of opposite sex, strongly biased sex ratio (opposite-sex deprivation hypothesis: Shine et al. 2003;Field and Waite 2004;Switzer et al. 2004;Poiani 2010), or poor adaptation to an unfamiliar environment, such as captivity (maladaptation hypothesis: Bagemihl 1999). ...
... Werner 1980;Shine et al. 2000;Field and Waite 2004;Switzer et al. 2004;Levan et al. 2009;Bailey and Zuk 2009). Adaptive hypotheses attribute same-sex mounts to some adaptive value, such as to establish dominance or hierarchies (intrasexual conflict hypothesis: e.g., Werner 1980;Preston-Mafham 2006), while non-adaptive hypotheses mainly consider same-sex mounts to be caused by failure in sex discrimination (mistaken identity hypothesis: e.g., Barlow 2000;Marco and Lizana 2002), lack of opposite sex, strongly biased sex ratio (opposite-sex deprivation hypothesis: Shine et al. 2003;Field and Waite 2004;Switzer et al. 2004;Poiani 2010), or poor adaptation to an unfamiliar environment, such as captivity (maladaptation hypothesis: Bagemihl 1999). Although same-sex mounts are well-studied in some animals, such as birds and mammals (MacFarlane et al. 2006;Bailey and Zuk 2009), very little is known on this behavior in turtles and tortoises. ...
Same-sex mounting is an aspect of animal behavior that has received increased attention in recent years in an attempt to improve our limited understanding of the possible causal mechanisms. Here, to our knowledge, we review for the first time same-sex mounting in turtles and tortoises. To this end, we have compiled data on same-sex mounts in 13 chelonian species and discuss the data together with those hypotheses most commonly raised in turtle studies, namely, the intrasexual conflict, maladaptation, mistaken identify, and opposite-sex deprivation hypotheses. Compilation of the data revealed that in almost every species with reports of same-sex mounting there were dominance relationships mediated by aggressive/submissive interactions; most of these cases occurred in captivity, and the sex ratios were not skewed. We discuss future research directions, providing initial ideas of experimental testing on each hypothesis, in the hope of directing more research effort to this field.
... Aaron Bauer and Dan Scantlebury. All agreed that the lizards in question were Mourning Geckos, Lepidodactylus lugubris (Duméril and Bibron 1836), a non-native parthenogenetic gekkonid native to the tropical Pacific (e.g., Werner 1980;Krysko and Krysko 2016). ...
... E mpirical observations of SSB (that is, any attempted sexual activity between two or more members of the same sex) in animals are widespread 1-4 , with evidence of SSB in mammals 5-9 , birds 10-14 , arthropods 15-19 , molluscs 20-22 , echinoderms 23-25 and other animals [26][27][28][29][30] . Since SSB is traditionally thought to be deleterious, as same-sex matings require energy expenditure but cannot produce offspring, there has been much interest in understanding its origin and maintenance 1-5 . ...
The widespread presence of same-sex sexual behaviour (SSB) has long been thought to pose an evolutionary conundrum, as participants in SSB suffer the cost of failing to reproduce after expending the time and energy to find a mate. The potential for SSB to occur as part of an optimal strategy has received less attention, although indiscriminate sexual behaviour may be the ancestral mode of sexual reproduction. Here, we build a simple model of sexual reproduction and create a theoretical framework for the evolution of indiscriminate sexual behaviour. We provide strong support for the hypothesis that SSB can be maintained by selection for indiscriminate sexual behaviour, by showing that indiscriminate mating is the optimal strategy under a wide range of conditions. Further, our model suggests that the conditions that most strongly favour indiscriminate mating were probably present at the origin of sexual behaviour. These findings have implications not only for the evolutionary origins of SSB, but also for the evolution of discriminate sexual behaviour across the animal kingdom.
... Este gecko puede emitir llamados de múltiples clics durante contextos sociales (Hunsaker y Breese 1967, Frankenberg 1982b; Petren y Case 1998). Estos llamados son emitidos en interacciones entre hembras durante el cortejo homosexual, el cual puede ir acompañado de pseudocópulas (Werner 1980, Frankenberg 1982b. Cabe recordar que L. lugubris es una especie partenogenética que presenta poblaciones que casi en su totalidad son hembras (Cuéllar y Kluge 1972, Yamashiro et al. 2000. ...
Lizards mainly depend on chemical and visual signals to communicate and, to a lesser extent, on acoustic signals, so generally it has been considered that these reptiles do not emit sounds. However, representatives of different lizard families can emit sounds through their mouths and in different contexts. In Chile, the reports on the emission of sounds in lizards are scarce and anecdotal, and in very few cases, these acoustic signals have been studied in detail. However, the knowledge about sound emissions of some species of native lizards from Chile has increased during the last few years. The goal of this review is to define the state of the art on the emission of sounds in native lizards of Chile as well as to encourage the development of research related to this particular communication modality. For this, we made an exhaustive compilation of the existing information on this topic. Of the 121 species of native lizards in Chile, there are reports of sound emission for only 13 species (10.7%) of the genus Diplolaemus, Garthia, Lepidodactylus, Liolaemus, Phyllodactylus, Phymaturus and Pristidactylus. Most of these species emit sounds in predation contexts, probably for the purpose of deterring the attack of a predator. We discuss several aspects that should be considered for the future studies about lizard sounds.
... data). Pseudocopulation between two L. lugubris has been reported (Werner 1980; McCoid and Hensley 1991), although it was not witnessed in a total of 37 h of experimentally staged interactions (Bolger and Case 1992;Hanley et al. 1994). One way to determine whether a gecko's genotype influences its susceptibility would be to examine rates of mite infestation of formerly heavily and lightly infested individuals under common conditions and then test the rate of mite infestation in their offspring (BulI pers. ...
What advantage do sexually reproducing organisms gain from their mode of reproduction that compensates for their twofold loss in reproductive rate relative to their asexual counterparts? One version of the Red Queen hypothesis suggests that selective pressure from parasites is strongest on the most common genotype in a population, and thus genetically identical clonal lineages are more vulnerable to parasitism over time than genetically diverse sexual lineages. Our surveys of the ectoparasites of an asexual gecko and its two sexual ancestral species show that the sexuals have a higher prevalence, abundance, and mean intensity of mites than asexuals sharing the same habitat. Our experimental data indicate that in one sexual/asexual pair this pattern is at least partly attributable to higher attachment rates of mites to sexuals. Such a difference may occur as a result of exceptionally high susceptibility of the sexuals to mites because of their low genetic diversity (relative to other more-outbred sexual species) and their potentially high stress levels, or as a result of exceptionally low susceptibility of the asexuals to mites because of their high levels of heterozygosity.
Q: How do geckos walk across ceilings? A: Millions of hair-like setae on each foot. Q: Where do geckos come from? A: Throughout the world. Usually where it's warm. Q: How many species of geckos are there? A: Close to 1,500 and counting! Q: What do they eat? A: Insects mostly. Discover the biology, natural history, and diversity of geckos-the acrobatic little lizards made famous by a car insurance ad campaign. Lizard biologist and gecko expert Aaron Bauer answers deceptively simple questions with surprising and little-known facts. Readers can explore color photographs that reveal the natural wonder and beauty of the gecko form and are further informed by images of how geckos live in their natural habitats. Although written for nonexperts, Geckos also provides a carefully selected bibliography and a new list of all known species that will be of interest to herpetologists. Anyone who owns a gecko, has seen them in the wild, or has wondered about them will appreciate this gem of a book. © 2013 The Johns Hopkins University Press. All rights reserved.
In this innovative celebration of diversity and affirmation of individuality in animals and humans, Joan Roughgarden challenges accepted wisdom about gender identity and sexual orientation. A distinguished evolutionary biologist, Roughgarden takes on the medical establishment, the Bible, social science-and even Darwin himself. She leads the reader through a fascinating discussion of diversity in gender and sexuality among fish, reptiles, amphibians, birds, and mammals, including primates. Evolution's Rainbow explains how this diversity develops from the action of genes and hormones and how people come to differ from each other in all aspects of body and behavior. Roughgarden reconstructs primary science in light of feminist, gay, and transgender criticism and redefines our understanding of sex, gender, and sexuality. This is a witty, playful, and daring book that has revolutionized our understanding of sexuality.
In captivity, females of parthenogenetic species of whiptail lizards (Cnemidophorus) occasionally mount other females and behave as if attempting to mate. This occurs under crowded conditions, and probably is not related to reproduction.
Vocal and visual displays, territorial contests and spacing of individual geckos were studied in captivity. The geckos had only one vocalization, emitted in attack, tail wave and tail rattle. They were spaced but with no territoriality and exhibited no social hierarchy. Contests between individuals were uncorrelated asymmetric, the approached individual always attacked and won.
Bei gefangen gehaltenen parthenogenetischen Hausgeckos Hemidactylus garnotii wurden drei verschiedene agonistische Signale festgestellt; ein lautes Quieken während des Angriffes, ein Wedeln des Schwanzes bei Annäherung und ein Schütteln des Schwanzes vor dem Angriff. Alle Geckos interagierten miteinander ohne eine Rangordnung. Die Geckos verteilten sich auf Vorzugsplätze, aber nicht dauerhaft. Ein sich nähernder Gecko wurde immer durch den angegriffen, dem er sich näherte, und verlor dabei stets, wie bei einer nichtkorrelierten Asymmetrie.
We examined the hypothesis that pseudosexual behaviour facilitates reproduction in the unisexual gecko, Lepidodactylus luguhris. Thirty-eight hatchlings were housed in isolated or social conditions. Age at initial egg development, days between egg development and laying for the geckos’first three clutches of eggs, inter-clutch intervals and dominance behaviours were recorded. Lepidodactylus lugubris developed their first clutch of eggs at about 9·5 months of age after their endolymphatic sacs became externally visible. The geckos laid their eggs about 28–30 days later with smaller geckos requiring more time between egg development and laying than larger geckos. Grouped geckos formed dominance hierarchies. In the triad and quadrad groups, the subordinate geckos’growth rates were slowed and their fecundity was suppressed. Pseudosexual behaviour was not observed in the geckos and was unrelated to fecundity because isolated geckos developed and laid three clutches of eggs at the same rate as grouped geckos. Dominance behaviour, not pseudosexual behaviour, was related to fecundity in L. lugubris. Dominance behaviour may facilitate dispersal in this colonizing species because subordinate geckos could increase their fecundity by moving to less populated areas.
The recent reptiles include representatives of four orders: Testudinata (turtles and tortoises; ca. 335 species survive); Crocodilia (crocodiles and their allies; ca. two dozen species survive); Rhynchocephalia (only Sphenodon punotatus of New Zealand survives); and Squamata (lizards, amphisbaenids and snakes; ca. 5,700 species survive).
The main features of the hybrid theory can best be summarized by some of its principal exponents: "The hypothesis entails two to three major steps. The initial step is the same as in all cases--the hybridization of diploid bisexual species to produce a diploid parthenoform, Second, if this diploid parthenoform is adequately adapted and an available habitat is present, it colonizes the habitat as a diploid parthenospecies .... The diploid parthenoform backcrosses to one or the other, or both, of the generating diploid bisexual species... to form an allotriploid parthenoform. Again, if this form is able to invade and capture a habitat, then the result is an allotriploid parthenogenetie species" (Wright and Lowe 1968). Thus: "Hybridization diploid unisexuality and then polyploidy are the natural sequence of events, with unisexual populations sustaining themselves by one of the three types of clonal reproduction" (hultz 1969). Finally: "It is further speculated that the formation of unreduced eggs in a diploi...
Conclusion The original hypothesis thatLepidodactylus lugubris is parthenogenetic is strongly supported by the following data: disparate sex ratio (only 4 individuals with mae characteristics
among a total of 673 examined), absence of courtship in reproductively mature females, and acceptance of skin homografts.
The chromosome number ofL. lugubris is about 44, and very likely a diploid complement. It seems very unlikely that gynogenesis is the mode of parthenogenesis
inL. lugubris owing to the absence of congeners and even species in closely related genera throughout much of its geographic range. The
meiotic mechanism and the origin of the males is being further investigated by us.
The present paper is the introductory part of a series of studies made on the habits, anatomy and life-history of the Indian
house-gecko,Hemidactylus flaviviridis Rüel. The more important points dealt with herein are as follows :
(1)
The systematic position of this lizard is reviewed, and the generally recognised definition of theSquamata criticised in the light of the more recent anatomical work.
(2)
The history of the institution of the genusHemidactylus and the speciesH. flaviviridis is concisely dealt with.
(3)
A résumé of our knowledge of fossil lacertilians and Gekkonids is given.
(4)
A suitable cage devised for the keeping and rearing of geckoes has been described, and the method of incubating the eggs also
dealt with.
(5)
An account of its general habits, food and feeding, sloughing, fidelity to particular sites in the house, caudal autotomy,
regeneration, hibernation, age, etc., is given.
(6)
The breeding season is observed to commence generally in March and to continue for several months.
(7)
External differences between the two sexes are noted. It is found that two swellings on the ventral aspect of the tail make
their appearance in the male during the breeding season.
(8)
The method of courtship and copulation has been described.
(9)
Observations are made on the size and nature of eggs, their fertilisation, intra-uterine development, incubation, hatching
and many other related questions.