Short Communication Journal of Orthoptera Research 2017, 26(1): 1-5 Same-sex sexual behavior in Xenogryllus marmoratus (Haan, 1844) (Grylloidea: Gryllidae: Eneopterinae): Observation in the wild from YouTube PAOLA OLIVERO!, TONY ROBILLARD 1 Instituto de Diversidad y Ecologia Animal (IDEA), CONICET-UNC and Facultad de Ciencias Exactas Fisicas y Naturales, Universidad Nacional de Cordoba. Av. Vélez Sarsfield 299 CP X5000JJC. Cordoba, Argentina. 2 Institut de Systématique, Evolution et Biodiversité, ISYEB - UMR 7205 CNRS, MNHN, UPMC, EPHE, Muséum national d'Histoire naturelle, Sorbonne Universités, case postale 50, 57 rue Cuvier, F-75231 Paris cedex 05, France. Corresponding author: T. Robillard (tony.robillard@mnhn.fr) Academic editor: Corinna Bazelet | Received 20 April 2017 | Accepted 30 May 2017 | Published 28 June 2017 http://zoobank.org/9864E869-7928-44CB-A93F-903D0DDB3F45 Citation: Olivero P, Robillard T (2017) Same-sex sexual behavior in Xenogryllus marmoratus (Haan, 1844) (Grylloidea: Gryllidae: Eneopterinae): Observation in the wild from YouTube. Journal of Orthoptera Research 26(1): 1-5. https://doi.org/10.3897/jor.26.14569 Abstract Searching on the internet for supplementary information about spe- cies of interest can be helpful when trying to document a quite common but under studied species. While revising the genus Xenogryllus Bolivar, 1890, we used this method to find additional references about the species Xenogryllus marmoratus (Haan, 1844). We were extremely interested in one video showing an interaction between two males of this species. The video shows a small male of X. marmoratus mounting a larger male of the same species, and eating the product of the metanotal glands. Meanwhile, the larger male tries to transfer his spermatophore to the small one. Same- sex matings have been described in other insect species and are frequently observed in many animal groups. Most of the reported cases of same-sex sexual behavior documented in other species of insects are consistent with two causes: mistakes in sexual recognition and lack of experience. How- ever, there are several hypotheses to explain same-sex sexual behavior that vary according to the context in which the behavior occurs. Here, we de- scribe and discuss this video content in terms of reproductive strategies, in a context of evolution and sexual selection. Key words male-male sexual interactions, reproductive strategies, sexual selection Introduction While searching on the internet for additional references about species of interest, one can sometimes find little natural history treasures. Images from websites such as Flickr (https:// www.flickr.com/) or Projectnoah (www.projectnoah.org) can provide rich information about the animal's distribution, in addition to high-quality pictures of our favorite animals. Similarly, sound recordings can be found in online sound libraries, even if orthopterans are usually far less covered by these databases than are birds or frogs and are difficult to identify based on sound only. A good compromise is to look for video files on popular websites such as YouTube (http://www.youtube.com). With video media, it is common to get information about the location where the video was made, along with sounds and images that facilitate identification. Online videos can be particularly helpful when trying to document a species that is relatively common, but under studied. Recently, the study of such under studied species of eneopterine crickets has revealed the existence of a system of communication never reported before in crickets. This new system of communication involves high-frequency calling songs emitted by the male (Robillard and Desutter-Grandcolas 2004), absence of phonotaxis and vibrational response by the female (ter Hoftede et al. 2015). Such findings challenge the stereotyped model of communication of crickets and their mating strategies. It suggests that detailed investigations should focus on biological traits of as many species as possible in a phylogenetic context (Desutter- Grandcolas and Robillard 2004). While revising the tribe Xenogryllini Robillard, 2004 (Jaiswara et al. in prep), we used online videos to find additional information about the species Xenogryllus marmoratus (Haan, 1844). This species is very common in Japan and China, where it is named Matsumushi (Japanese = pine insect) or bao ta ling (Chinese = pagoda bell), re- spectively. Because X. marmoratus is commonly observed in the field by local naturalists, it was likely to occur in the list of species that can benefit from online resources (Robillard and Tan 2013). We found several videos where the species can be heard and/or seen, mostly from Japan, and sometimes recorded with high-quality equipment allowing us to document the details of wing movements during sound production (for example see the videos of “naturalistempus”: https://www.youtube.com/ watch?v=TxXIWDRbWh2Y, or “kiokuima”: https://www.youtube. com/watch?v=kGlj7m9L7ys). Among these interesting data, we were intrigued by one particular video showing a very uncommon interaction in the wild between two males of this species. The mating behavior of X. marmoratus has not been studied in detail yet, but basic observations made in the laboratory (T. Robil- lard pers. obs.) suggest that its basic structure is similar to the mat- ing behavior documented in other species of crickets (Alexander JOURNAL OF ORTHOPTERA RESEARCH 2017, 26(1) 2 P. OLIVERO AND T. ROBILLARD and Otte 1967), including the eneopterine Nisitrus sp. (Preston- Mafham 2000): when the first spermatophore is ready to transfer, the male turns his back while raising his forewings perpendicularly to the body, which exposes the glandular structures located on the metanotum below the base of the forewings. Dorsal glands are com- mon in males of ensiferan insects, in which the female mounts the male’s back during mating (Alexander and Brown 1963, Gwynne 1984, Vahed 1998). In many species of crickets, the female feeds on the secretions from the male’s metanotal glands before, during and after copulation (Boldyrev 1915, Hohorst 1937, Alexander and Otte 1967, Walker 1978, Funk 1989, Brown 1997). These kinds of nuptial feeding include the transfer of any form of nutrient from the male to the female during, or directly after, mating. The nutri- tional gifts are attractive for females and could represent a paternal investment: nutrients from the nuptial gift are used by the female to increase the fitness of the male's offspring (Trivers 1972, Thornhill 1976, Gwynne 1984, Vahed 1998). Also, it is known that the nup- tial feeding can increase the duration of copulation to maximize ejaculate transfer (Hohorst 1937, Bidochka and Snedden 1985). As mentioned above, the video content studied here shows an interaction between two males of the same species, and includes glandular feeding by one of the males. Same-sex sexual behavior is widespread among animals and it has been reported in most in- sect orders (Bagemihl 1999). In many cases, this sexual behavior is a by-product of other reproductive strategies, which are positively correlated to fitness (Bailey and Zuk 2009, Han and Brooks 2015). However, the causes, consequences and evolution of this behavior are still unknown in most groups. In this short communication, we describe the video content and discuss the implications of the ob- served behavioral interactions in terms of reproductive strategies. Materials and methods The video content analyzed here was recorded in Japan, in the prefecture of Yamaguchi in Hofu, by the YouTube user “kiokuima”, and added on the public website YouTube on 20 October 2014, under the address https://www.youtube.com/ watch?v=C9hFOFu5A64 (Kiokuima 2014). It was retrieved by typ- ing the key word Xenogryllus in the search window. The author of the video is an experienced naturalist who has been posting videos of Japanese fauna since 2011. The video content is cited here as a reference and remains the property of its author. The video was extracted for study using the online application Fluvore (http://www.fluvore.com/). Screenshots of the behavioral interactions were extracted from the video using Windows Movie Maker Version 2012 (Microsoft) (Fig. 1). Results The video lasts 6:08 min and consists of several takes fused together. It was recorded at night in the field. The songs of several species of orthopterans can be heard in the background noise, in- cluding calls of X. marmoratus (at least two distinct males). Behavioral description.— 0:00-0:54 min. — A male of X. marmoratus is sitting on dry herbaceous vegetation (Fig. 1A). It turns around, stops, then walks left out of the frame, while moving the antennae. 0:54-1:12 min. - Same male, seen from above, motionless on plant stems. 1:12 min. - Male raises its wings perpendicularly to the body, adopting the usual mating position and exhibiting the metanotal glands (Fig. 1B). 1:20 min. — Another cricket's antennae clearly appear at the male’s back (Fig. 1B, red circle). Both individuals’ antennae briefly touch each other, causing a subtle startle of the first male’s body (1:26), but it keeps its forewings raised. The second cricket slowly approaches from behind (Fig. 1C). 1:37 min. — The second individual puts one leg on the back of the first one (red circle on Fig. 1D). At this point, the viewer is prepared to observe a mating sequence, but when the second in- dividual moves forward on the first individual's back, it becomes clear that this is not a female, but a second male of X. marmoratus (Fig. 1E) (hereafter male 2). 1:37-1:48 min. — Male 2 mounts the back of male 1 up to the exposed metanotal glands (Fig. 1F). 1:48-3:07 min. — Male 2 feeds on the glands of male 1 (Fig. 1F- G), even pushing forward male 1's forewings with its head. 3:08 min. — Male 1 reacts by moving the whole body, then becomes still again while male 2 continues feeding on its glands. 4:10 min. — Slightly different angle, probably shortly after. Male 2 is still eating from male 1’s glands but the latter moves, as if trying to remove male 2 from its back (Fig. 1H). 4:24 min. — The intentions of male 1 become clearer as the apex of its abdomen enters the frame of the video: its genitalia are raised and a spermatophore is ready to be transferred (Fig. 11). Male 1 attempts mating with male 2. 4:45 min. — Slightly different angle, probably shortly after. This angle shows that male 2 is clearly shorter than male 1, as it is en- tirely sitting on the abdomen of male 1 (Fig. 1J). Both males are motionless, but male 2 continues feeding on male 1’s glands. 5:20-6:08 min. - Multiple new attempts at mating. Male 1 re- peatedly bends its abdomen apex dorsally, but fails to reach male 2, which calmly continues feeding on the other's glands (Fig. 1)). Discussion The video clearly shows a small male of X. marmoratus mount- ing a larger male of the same species, and eating the product of the metanotal glands. Meanwhile, the larger male tries to transfer his spermatophore to the small one. The hypothesis that males of two sympatric species, a large one and a smaller, may be interacting in the video can be discarded for several reasons: first, the acoustic background of the video lets us hear only the song of X. marmo- ratus and no other song that could be due to another species of this genus. Second, we believe that, if there was a new species of large cricket in Japan, it would have been described long ago by local taxonomists. Third, the ongoing revision of Xenogryllus led us to examine many Xenogryllus specimens from Japan from several collections of natural history museums; this study suggests that X. marmoratus is the only species of the genus distributed in Japan (T. Robillard pers. obs.; Jaiswara et al. in prep.). The fact that the video content was obtained from YouTube might call into question its authenticity. It is obviously the result of video editing from several video takes, which means that the overall timing could not be completely trusted. However, it is clear that the same insects have been filmed in the wild more or less continuously, according to the acoustic background and the simi- larity of the vegetation visible during the whole sequence. The lon- gevity and high-quality of activity of the author on his YouTube channel (ca. 650 followers) dedicated to the fauna of Japan attests to the reliability of his videos and precludes the possibility that this video could be faked. Consequently, even if this video should be treated with caution, the rarity of observations of same-sex mat- ing in the wild deems this video worthy of discussion here. JOURNAL OF ORTHOPTERA RESEARCH 2017, 26(1) P. OLIVERO AND T. ROBILLARD 3 , ee Figure 1. Screenshots of the video showing same-sex sexual behavior between males of Xenogryllus marmoratus (Haan, 1844). For details, see the results section. JOURNAL OF ORTHOPTERA RESEARCH 2017, 26(1) 4 P. OLIVERO AND T. ROBILLARD Same-sex matings are frequently observed in many animal groups (Thornhill and Alcock 1983, Maklakov and Bonduriansky 2009) and have been described in other insect species, for exam- ple in Drosophila melanogaster (McRobert and Tompkins 1988), the weevil Diaprepes abbreviates (Harari et al. 2000), the damselfly Ischnura elegans (van Gossum et al. 2005), the seed beetle Acan- thoscelides obtectus, the flour beetle Tribolium castaneum (Castro et al. 1994), and also in field crickets (Bailey and French 2012). However, in most cases, same-sex mating function is difficult to define (Vasey and Sommer 2006). Same-sex sexual behavior is treated differently according to the context and the social environment where it occurs, such as sex- ratio, competition between males for females, mating experience of the males, etc. (Burgevin et al. 2013, Han and Brooks 2015). Therefore, there are a variety of hypotheses to explain its evolu- tion in male insects. Genetic studies in model organisms have demonstrated that there are common patterns in the evolution of these behaviors (Bailey and Zuk 2009) and most of the reported cases of same-sex sexual behavior documented in other species of insects are consistent with two causes: 1) mistakes in sexual rec- ognition and 2) lack of experience (Scharf and Martin 2013). The first hypothesis posits that mistakes in sexual recognition could come from errors in processing the sensorial information com- monly involved in courtship (e.g. visual, acoustic, chemical sig- nals) or because individuals resemble the opposite sex in some way (Bailey and French 2012). In some cases, males use body size to distinguish between the sexes. For example, in species of but- terflies or grasshoppers in which females are larger than males, larger individuals are mounted more often, independent of their sex (Bland 1991, Solensky 2004). On the other hand, immature males of some species show absence of sex-specific characteristics (McRobert and Tompkins 1988) or phenotypes more typical of females (Ruther and Steiner 2008), which may cause interacting partners to confuse their identity (McRobert and Tompkins 1988, Bailey and French 2012). In crickets, it is known that during mat- ing, males deposit sexual pheromones on the body of the females. These pheromones can be detected by other individuals in sub- sequent sexual interactions (Thomas and Simmons 2009). In the same way, in other groups of insects, female pheromones are at- tached to the male’s cuticle during mating and those males con- sequently become attractive for other males (Barrows and Gordh 1978, Wendelken and Barth 1985). This could result in cases of same-sex sexual behavior by the receptive males (Wendelken and Barth 1985). On the other hand, the second hypothesis posits that the need to recognize mates successfully could cause immature individuals to attempt to mate with same-sex individuals. In this way, they would learn from unsuccessful matings to identify the opposite sex correctly (Dukas 2006). Mistaken identification was suggested in 80% of the cases as the mechanism responsible for same-sex sexual behavior in insects (Scharf and Martin 2013). In the video, we can observe how the larger male lifts the forewings to expose its metanotal gland to the smaller male and then tries to transfer the spermatophore. From the point of view of the larger male, there is a possibility that it confuses the smaller one with a female, making plausible the hypothesis of a recognition mistake. This explanation, however, is not possible if males distinguish females based on body size, since the dimor- phism is usually the contrary in crickets (females are commonly larger than males), including in Xenogryllus species (TR, pers. obs.). Nevertheless, we have only one observation of the behavior in the species and we do not know the conditions or the environ- ment in which the individuals were found. If the males here are experiencing a male-biased sex ratio and strong scramble competi- tion, it would be important for males to find females rapidly be- fore another male does (Han and Brooks 2013a, b). Consequently, males could benefit from increasing the rate of mating attempts, even if they sometimes choose the wrong partners. This strategy would be less costly than missing a chance to mate with an avail- able female (Han and Brooks 2015). Finally, another possible explanation for this observation could be that the males are isolated and have no possibility of interacting with females. Long-term exposure to individuals of the same sex or absence of mating opportunities can be the cause of another mechanism leading to these sexual behaviors. The lack of potential mates could increase the occurrence of same-sex sexual behaviors due to learned changes in preferences. In some species, the preferences for same-sex partners after isolation from opposite sex partners can even persist after opposite sex partners are avail- able (Field and Waite 2004, Bailey and French 2012). From the point of view of the smaller male, which deliberately feeds on the larger male’s metanotal glands, the hypothesis of rec- ognition mistake is not permitted. This behavior could however be compared to satellite male strategy documented in field crickets (e.g. Cade 1979, Bailey 1991). Here, the smaller male would not only act as a satellite male waiting to silently intercept potential fe- males, but could also use nutritive resources produced by the larg- er male and destined for females, to benefit its own reproduction. In conclusion, we document a case of same-sex sexual behavior in the cricket species Xenogryllus marmoratus based on one wild ob- servation, including courtship behaviors and even the production of the spermatophore. More data and experiments are obviously necessary to test the hypotheses raised by this observation and to understand the conditions in which these sexual behaviors occur. However, this video content offers valuable information about a sexual behavior that had not been reported before for this species, and rarely for crickets in general. This can demonstrate that casual observational data could offer important information for the analy- sis of unaddressed aspects of the biology. The information obtained in this work will help provide a more complete knowledge of this behavior in crickets, in the context of evolution and sexual selection. Acknowledgements We thank Laurel Symes (Dartmouth College, USA) for helpful suggestions, three anonymous reviewers and the editor for their constructive comments on the manuscript. References Alexander RD, Brown WL (1963) Mating behaviour and the origin of in- sect wings. Miscellaneous Publications of the Museum of Zoology, University of Michigan 628: 1-19. Alexander RD, Otte D (1967) The evolution of genitalia and mating behav- iour in crickets (Gryllidae) and other Orthoptera. Miscellaneous Publi- cations of the Museum of Zoology, University of Michigan 133: 1-62. Bailey WJ (1991) Acoustic behaviour of insects. An evolutionary perspective. Chapman and Hall, London, 225 pp. Bailey NW, Zuk M (2009) Same-sex sexual behavior and evolution. Trends in Ecology & Evolution 24: 439-446. https://doi.org/10.1016/j. tree.2009.03.014 Bailey NW, French N (2012) Same-sex sexual behaviour and mistaken identity in male field crickets, Teleogryllus oceanicus. Animal Behaviour 84: 1031-1038. https://doi.org/10.1016/j.anbehav.2012.08.001 Bagemihl B (1999) Biological exuberance: animal homosexuality and natural diversity. St. Martin, New York. JOURNAL OF ORTHOPTERA RESEARCH 2017, 26(1) P. OLIVERO AND T. ROBILLARD 5 Barrows EM, Gordh G (1978) Sexual behavior in the Japanese beetle Popillia japonica, and comparative notes on sexual behavior of other scarabs (Coleoptera: Scarabaeidae). Behavioral Biology 23: 341-354. https://doi.org/10.1016/S0091-6773(78)91365-2 Bidochka MJ, Snedden WA (1985) Effect of nuptial feeding on the mating behaviour of female ground crickets. Canadian Journal of Zoology 63: 207-208. https://doi.org/10.1139/z85-032 Bland RG (1991) Mating behavior of Phaulacridium vittatum Sjéstedt (Or- thoptera: Acrididae). Journal of Australian Entomology Society 30: 221-229. https://doi.org/10.1111/j.1440-6055.1991.tb00417.x Boldyrev BT (1915) Contributions a l’etude de la structure des spermato- phores et des particularites de la copulation chez Locustidae et Gryl- lodea. Horae Societatis Entomologicae Rossicae 41: 1-245. Brown WD (1997) Female re-mating and the intensity of female choice in black-horned tree crickets, Oecanthus nigricornis. Behavioral Ecology 8: 66-74. https://doi.org/10.1093/beheco/8.1.66 Burgevin L, Friberg U, Maklakov AA (2013) Intersexual correlation for same- sex sexual behaviour in an insect. Animal Behaviour 85: 759-762. https://doi.org/10.1016/j.anbehav.2013.01.017 Cade WH (1979) The evolution of alternative male reproduction strategies in field crickets, in: Blum MS, Blum NA (Eds) Sexual selection and re- productive competition in Insects. Academic Press, New York, 343-380. Castro L, Toro MA, Lopezfanjul C (1994) The genetic properties of ho- mosexual copulation behaviour in Tribolium castaneum: artificial selection. Genetics Selection Evolution 26: 361-367. https://doi. org/10.1186/1297-9686-26-4-361 Desutter-Grandcolas L, Robillard T (2004) Acoustic evolution in crickets: need for phylogenetic study and a reappraisal of signal effectiveness. Anais da Academia Brasileira de Ciéncias 76: 301-315. https://doi. org/10.1590/S0001-37652004000200019 Dukas R(2006) Learning in the context ofsexual behaviour in insects. Animal Biology 56: 125-141. https://doi.org/10.1163/157075606777304258 Field KL, Waite TA (2004) Absence of female conspecifics induces homo- sexual behaviour in male guppies. Animal Behaviour 68: 1381-1389. https://doi.org/10.1016/j.anbehav.2003.12.022 Funk DH (1989) The mating of tree crickets. Scientic American 1989(August): 42-49, Gwynne DT (1984) Courtship feeding increases female reproduc- tive success in bushcrickets. Nature 307: 361-363. https://doi. org/10.1038/307361a0 Han CS, Brooks RC (2013a) Correlational selection does not explain the evolution of a behavioral syndrome. Journal of Evolutionary Biology 26: 2260-2270. https://doi.org/10.1111/jeb.12223 Han CS, Brooks RC (2013b) Evolution of individual variation in behaviour and behavioural plasticity under scramble competition. Animal Be- haviour 86: 435-442. https://doi.org/10.1016/j.anbehav.2013.05.039 Han CS, Brooks RC (2015) Same-sex sexual behaviour as a by-product of re- productive strategy under male-male scramble competition. Animal Be- haviour 108: 193-197. https://doi.org/10.1016/j.anbehav.2015.07.035 Harari AR, Brockmann HJ, Landolt PJ (2000) Intrasexual mounting in the beetle Diaprepes abbreviatus (L). Proceedings of the Royal Soci- ety B: Biological Sciences. 267: 2071-2079. https://doi.org/10.1098/ rspb.2000.1251 Hohorst W (1937) Die Begattungsbiologie der grylle Oecanthus pellucens Scolpi. Zeitschrift fuXr Morphologie und Okologie der Tiere 32: 227-275. https://doi.org/10.1007/BF00403075 Kiokuima [Screen name] (2014) Xenogryllus marmoratus [Video file]. https:// www. youtube.com/watch?v=C9hFOFu5A64 [2014, October 20] Maklakov AA, Bonduriansky R (2009) Sex differences in survival costs of homosexual and heterosexual interactions: evidence from a fly and a beetle. Animal Behaviour 77: 1375-1379. https://doi.org/10.1016/j. anbehav.2009.03.005 McRobert SP, Tompkins L (1988) Two consequences of homosexual courtship performed by Drosophila melanogaster and Drosophila affinis males. Evolution 42: 1093-1097. https://doi.org/10.2307/2408925 Preston-Mafham K (2000) Diurnal mating behaviour of a Nisitrus sp. cricket (Orthoptera: Gryllidae) from Sumatra. Journal of Natural His- tory 34: 2241-2250. Robillard T, Desutter-Grandcolas L (2004) High-frequency calling in Ene- opterinae crickets (Orthoptera, Grylloidea, Eneopteridae): an adap- tive radiation revealed by phylogenetic analysis. Biological Journal of the Linnean Society 83: 577-584. https://doi.org/10.1111/j.1095- 8312.2004.00417.x Robillard T, Tan MK (2013) A taxonomic review of common but little known crickets from Singapore and the Philippines (Insecta: Orthop- tera: Eneopterinae). The Raffles Bulletin of Zoology 61: 705-725. Ruther J, Steiner S (2008) Costs of female odour in males of the para- sitic wasp Lariophagus distinguendus (Hymenoptera: Pteromalidae). Naturwissenschaften 95: 547-552. https://doi.org/10.1007/s00114- 008-0357-0 Scharf I, Martin OY (2013) Same-sex sexual behavior in insects and arach- nids: prevalence, causes, and consequences. Behavioral Ecology and Sociobiology 67: 1719-1730. https://doi.org/10.1007/s00265-013- 1610-x Solensky MJ (2004) The effect of behavior and ecology on male mating success in over wintering Monarch butterflies (Danaus plexippus). Journal of Insect Behaviour 17: 723-743. https://doi.org/10.1023/ B:JOIR.0000048985.58159.0d Stojkoviae B, Jovanoviae DS, Tuciae B & Tuciae N (2010) Homosexual be- haviour and its longevity cost in females and males of the seed beetle Acanthoscelides obtectus. Physiological Entomology, 35: 308-316. ter Hofstede HM, Schéneich S, Robillard T, Hedwig B (2015) Evolu- tion of a communication system by sensory exploitation of star- tle behavior. Current Biology 25: 1-8. https://doi.org/10.1016/j. cub.2015.10.064 Thomas ML, Simmons LW (2009) Male-derived cuticular hydrocarbons signal sperm competition intensity and affect ejaculate expenditure in crickets. Proceedings of the Royal Society B 276: 383-388. https:// doi.org/10.1098/rspb.2008.1206 Thornhill R (1976) Sexual selection and paternal investment in insects. American Naturalist 110: 153-163. https://doi.org/10.1086/283055 Thornhill R, Alcock J (1983) The Evolution of Insect Mating Systems. Harvard University Press, Cambridge, Massachusetts. https://doi. org/10.4159/harvard.9780674433960 Trivers RL (1972) Parental investment and sexual selection. In: B Campbell (Ed.) Sexual Selection and the Descent of Man, 1871-1971. Aldine Publishing Company, Chicago, 136-179. Vahed K (1998) The function of nuptial feeding in insects: a review of em- pirical studies. Biological Reviews 73: 43-78. https://doi.org/10.1017/ $0006323197005112 Van Gossum H, De Bruyn L, Stoks R (2005) Reversible switches be- tween male-male and male-female mating behaviour by male damselflies. Biology Letters 1: 268-270. https://doi.org/10.1098/ rsbl.2005.0315 Vasey PL, Sommer V (2006) Homosexual behaviour in animals: topics, hypotheses and research trajectories. In: Sommer V, Vasey PL (Eds) Homosexual behaviour in animals: an evolutionary perspective. Cambridge University Press, Cambridge, 3-42. Walker TJ (1978) Post-copulatory behavior of the twospotted tree cricket, Neoxabea bipunctata. Florida Entomologist 61: 39-40. https://doi. org/10.2307/3494433 Wendelken PW, Barth RH (1985) On the significance of pseudofemale be- havior in the neotropical cockroach genera Blaberus, Archimandrita and Byrsotria. Psyche 92: 493-504. https://doi.org/10.1155/1985/97012 JOURNAL OF ORTHOPTERA RESEARCH 2017, 26(1)