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| Isoxya manangona Agnarsson, Starrett, Babbitz, Bond, Gregorič, Raberahona, Williams & Kuntner, 2023 DOI: 10.1093/isd/ixac029 |
Abstract
Spiders are notoriously solitary and cannibalistic, with instances of colonial or social lifestyles in only about 50-60, or ~0.1% of 50,000 described species. Population analyses indicate that most colonies consist of multiple cohorts formed by close relatives. Territorial social spiders facultatively form colonies by interlinking individual webs, but further cooperation is infrequent, and only among juveniles or (rarely) females. In spiders therefore, aggregations of males outside of the male-male competition context has been unknown. Here, we report on a discovery of a kite spider from Madagascar that exhibits unique colonies. We found colonies of the newly described araneid Isoxya manangonan. sp. formed by up to 41 interconnected, single-cohort adult female webs with up to 38 adult males aggregating on a central, single, nonsticky line. With males resting tightly together, we found no evidence for male-male aggression. Genetic analyses from RAD sequencing suggest that most colonies consist of unrelated individuals. Furthermore, genetic variability of males was somewhat less than that of females. Single cohort colonies made up purely of adults, and peaceful male aggregations, have not previously been observed in spiders. Although direct behavioral observations are preliminary, we speculate based on the available evidence that these colonies may represent a novel and first case of lekking in spiders.
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| Colonial Isoxya manangona n. sp. from Andasibe, Madagascar. (a) A part of a colony with 79 spiders in 41 webs (image shows 23 webs). (b) A detail from another colony where females are in their individual webs (image shows 14 of the 16 webs in the colony) while males hang on line in between webs (image shows 12 males). (c) A detail of another colony showing male leks. These males showed no overt intrasexual aggression that would be typical of solitary spiders. |
Taxonomy
Family Araneidae Clerck, 1757
Genus Isoxya Simon, 1885
Isoxya manangona sp. n.
Etymology: The specific epithet is a noun in apposition and refers to the Malagasy verb ‘to gather/aggregate’, referring to the species unusual mating aggregations.
Ingi Agnarsson, James Starrett, Zachary Babbitz, Jason E Bond, Matjaž Gregorič, Onjaherizo Christian Raberahona, Steven Williams and Matjaž Kuntner. 2023. Discovery and Genetic Characterization of Single Cohort Adult Colonies With Male Aggregations, and Preliminary Evidence for Lekking in a Malagasy Kite Spider (Isoxya, Gasteracanthinae). Insect Systematics and Diversity. 7(1); DOI: 10.1093/isd/ixac029
www.ezlab.si/post/evidence-for-lekking-in-a-new-kite-spider
