Table Of Content

Acta Arachnologica, 69 (1): 17–21, June 20, 2020 The first report of matriphagy in Stegodyphus pacificus Pocock 1900 Rishikesh Tripathi, Ashish Kumar Jangid*, Manju Siliwal, Sutirtha Dutta Department of Animal Ecology and Conservation Biology, Wildlife Institute of India, Dehradun- 248001, Uttarakhand, India E-mail: [email protected]; [email protected] *Corresponding author Abstract ― Here we report and describe matriphagy (maternal self-sacrifice) phenomenon in Stegodyphus pacificus Pocock 1900, observed in Thar Desert of Rajasthan, India. All 57 nests observed during the study ex- hibited matriphagy. Typically, a female laid a cluster of about 100 eggs and spiderlings hatched nearly 33 days after the egg-laying. Around 17 days after hatching, spiderlings started feeding on their mother. Spiderlings dispersed from the nest after the death of the mother, roughly 84 days since egg-laying. While matriphagy has been known in some spider species, this phenomenon has not been reported or described in S. pacificus. Key words ― Eresidae, maternal care, mother suicide, Pacific social spider, Thar Desert surveys, we came across 57 nests of S. pacificus. It is one of Introduction the big-sized spiders in the landscape, with females averag- Some of the group of spiders have evolved to become ing more than 19mm in length (Dyal 1935). The nests were the first source of food for their offspring. One such phe- monitored between 73–95 days as total effort, where three nomenon is known as matriphagy, wherein the female gets out of the 57 nests were observed in one-hour interval for cannibalized by her offspring (Kim & Horel 1998). Such partially overlapping “74–78 (75.67 ± 2.08)” days, and rest behavior has been recorded in many species of spiders, such 54 nests were monitored within 24 hours interval for “73–95 as Amaurobius ferox (Walckenaer 1830), Stegodyphus linea- (84.87 ± 4.63)” days upon bushes of Ziziphus spp. and some tus (Latreille 1817), S. mimosarum Pavesi 1883, S. dumicola grass species. Pocock 1898, S. sarasinorum Karsch 1892, Cheiracan- Results and Discussion thium japonicum Bösenberg & Strand 1906 and Coelotes terrestris (Wider 1834) (Ori 1976; Seibt & Wickler 1987; In all the cases, spiderlings fed on their mother during Gundermann et al. 1988; Evans et al. 1995; Schneider & their secondary development stage. Some insect remains Lubin 1997; Kim & Horel 1998; Toyama 1999; Salomon et (exuvia) of the species of Orthoptera and Coleoptera were al. 2005; Deshmukh 2017), and as a result of matriphagy, fe- also found in the nest. Based on 57 observed field incidents, males breed once in their life and such species are common- a sequence of matriphagy is as follows (Fig. 3). ly referred as semelparous species (Young & Augspurger *days are mentioned in the cumulative pattern after eggs 1991). being laid by the female “lower limit – upper limit (mean ± We carried out spider documentation surveys in the Des- standard deviation)”. ert National Park Jaisalmer, Rajasthan, between November 1.　 Initially, female laid a cluster of around 80–120 2017 and February 2018 (Fig. 1). During surveys, we ob- (99.88±11.09) eggs covered by her silky sheet web served for the first time the phenomenon of matriphagy in (Fig. 2B). Stegodyphus pacificus Pocock 1900, and here, we report 2.　Female collected sufficient prey kept for her survival detailed process of matriphagy and compares it with similar during the egg-guarding period of 6–11 (7.89 ± 1.08) observations in other species. days after laying the eggs. 3.　 Female closed entrances of the nest with silk and Materials and Methods spent most of the time guarding eggs instead of cap- The study area consists of grasslands with an arid type turing new prey. of forest system (Fig. 2A; Champion & Seth 1968). The 4.　Eggs hatched between 29–38 (33.21 ± 1.99) days. Spid- observations were recorded in winter during arachnid diver- erlings emerged from the eggs and initially for few days sity assessment within time zone GMT +5:30. During the they fed on the regurgitated food by female (Fig. 2C). 18 R. Tripathi, A. K. Jangid, M. Siliwal & S. Dutta Fig. 1. Observation sites in the Thar Desert of Rajasthan India (Mapped using open source software QGIS version 2.14 Essen with the base-map type of OSM landscape). 5.　Spiderlings started feeding on liquefied tissues of trophic eggs in the nest of Amoraubius ferox, which is for the abdomen of female until only her exoskeleton providing additional nutrition to the spiderlings. However, remained. Duration for feeding was in between the no trophic eggs were observed during the present study in range of 43–59 (50.37 ± 3.31) days. Usually, spider- the nests of S. pacificus. lings consume around 20–30% of the female’s body. Interestingly, in Cheiracanthium japonicum, most adult However, the carapace of females remained intact, females are eaten by their spiderlings, but sometimes not but the internal muscles were digested by enzymes (Ori 1976). On the other hand, in the present study, all the and sucked by spiderlings. After about 53–70 (62.02 females of S. pacificus were killed by their spiderlings. ± 4.16) days, the abdomen of females shrunk, and fe- Similar behavior was also observed in other species of this males died (Fig. 2D) and spiderlings stopped feeding genus viz., S. lineatus, S. dumicola, S. mimosarum, and S. on female. sarasinorum, in which mother die during the matriphagy 6.　After the death of female, spiderlings started dispers- process (Jackson & Joseph 1973). On the other hand, in S. ing as the source of food (regurgitated food and fe- sarasinorum, spiderlings keep feeding on female body even male body) started depleting and nest was abandoned after female dies (Bradoo 1972). Interestingly, in nests of after 73-95 (84.39 ± 4.97) days since the egg-laying S. dumicola and S. mimosarum, it was observed that apart process by the female (Fig. 2E). from egg-laying female, there were additional few adult or Though matriphagy behavior is also observed in other spi- subadult females, which were not involved in laying the ders, the process varies amongst these spiders We found this eggs but these females were mainly a food provision to spi- behavior in S. pacificus, similar to S. lineatus. For example derlings, showing allomaternal behavior towards raising of of variations, Kim & Horel (1998) reported the presence of spiderlings (Seibt & Wickler 1987). On the other hand, in S. Acta Arachnologica, 69 (1), June 2020 ⒸArachnological Society of Japan Matriphagy in Stegodyphus pacificus 19 Fig. 2. Depiction of ideal habitat of S. pacificus in Thar Desert Rajasthan India, where the matriphagy observations took place (A). Steps of matriphagy in S. pacificus (B-E); Eggs before the hatching and care by mother spider with funnel-shaped nest (B); When the spiderlings start feeding on the female abdomen (C); Spiderlings fed on the abdomen of female until only exoskeleton of carapace remains (D); The nest became abandoned, after the death of mother spider and initiation of the dispersal of the spiderlings (E). Acta Arachnologica, 69 (1), June 2020 ⒸArachnological Society of Japan 20 R. Tripathi, A. K. Jangid, M. Siliwal & S. Dutta Fig. 3. Lateral line chart depicting the phases of matriphagy by Stegodyphus pacificus. pacificus only single female was present in each nest. After Department for the field permissions and logistical assistance. We are the death of female, spiderlings of S. pacificus disperse from thankful to Sohanlal Genwa, who supported us during field activi- ties in Desert National Park, Rajasthan. We are indebted to Dr. Sujit the nest, whereas in S. dumicola spiderlings remained in Narwade, Nafin KS, and Dr. John T.D. Caleb for their suggestions to the nest even after the death of the female (Seibt & Wickler improve the manuscript. 1987). Though there are several similarities and dissimilarities References in the behavior shown by various species of genus Stegody- phus, there is a scope of detailed further research to quantify Bradoo, B. L. 1972. Some observations on the ecology of social spider Stegodyphus sarasinorum Karsch (Araneae: Eresidae) from India. all the phenomena. This study also supports the inevitability Orient. Ins., 6: 193–204. of the matriphagy behavior in some of the species of genus Champion, H. G. & Seth, S. K. 1968. A revised survey of forest types Stegodyphus. Further, other groups of spiders need to be ex- of India. Government of India, New Delhi. plored for the matriphagy phenomenon in India, as it is very Deshmukh, U. S. 2017. Suicidal maternal care in spider Stegodyphus least studied behavior. sarasinorum (family Eresidae). Int. J. Fauna Biol. Stud., 4: 114–116. Dyal, S. 1935. Fauna of Lahore (4- Spiders of Lahore). Bul. Dept. Acknowledgements Zool. Panjab Univ., 1: 119–252. Evans, T. A., Wallis, E. J. & Elgar, M. A. 1995. Making a meal of We express our gratitude to the Director and Dean (Faculty of mother. Nature, 376: 299. Wildlife Science) of the Wildlife Institute of India. We acknowledge Gundermann, J. L., Horel, A. & Krafft, B. 1988. Maternal food-supply the CAMPA-GIB project of Wildlife Institute of India for the financial and its regulation in Coelotes terrestris (Araneae, Agelenidae). Be- and logistic support. We are grateful to the Rajasthan State Forest haviour, 107: 278–296. Acta Arachnologica, 69 (1), June 2020 ⒸArachnological Society of Japan Matriphagy in Stegodyphus pacificus 21 Jacson, C. C. & Joseph, K. J. 1973. Life-history, bionomics and be- Schneider, J. M. & Lubin, Y. 1997. Infanticide by males in a spider haviour of the social spider Stegodyphus sarasinorum Karsch. Ins. with suicidal maternal care, Stegodyphus lineatus (Eresidae). Anim Soc., 20: 189–204. Behav, 54: 305–312. Kim, K. W. & Horel, A. 1998. Matriphagy in the spider Amaurobius Seibt, U. & Wickler, W. 1987. Gerontophagy versus cannibalism in the ferox (Araneidae, Amaurobiidae): an example of mother-offspring social spiders Stegodypahus mimosarum Pavesi and Stegodyphus interactions. Ethology, 104: 1021–1037. dumicola Pocock. Anim. Behav. 35: 1903–1905. Ori, M. 1976. Studies on the disease and ecology of the poisonous spi- Toyama, M. 1999. Adaptive advantages of maternal care and matriph- der Chiracanthium japonicum Bosenberg et Strand, 1906 In Japan: agy in a foliage spider Chiracanthium japonicum (Araneae: Clubi- 2- The ecology of the Japanese spider. Jpn. Soc. Med. Entomol. onidae). J. Ethol., 17: 33–39. Zool., 27: 181–188. Young, T. P. & Augspurger, C.K. 1991. Ecology and evolution of long- Salomon, M., Schneider, J. & Lubin, Y. 2005. Maternal investment in lived semelparous plants. Trends Ecol. Evol., 6: 285–289. a spider with suicidal maternal care, Stegodyphus lineatus (Araneae, Eresidae). Oikos, 109: 614–622. Received September 1, 2019 / Accepted February 20, 2020 Acta Arachnologica, 69 (1), June 2020 ⒸArachnological Society of Japan