Discovery and Genetic Characterization of Single Cohort Adult Colonies With Male Aggregations, and Preliminary Evidence for Lekking in a Malagasy Kite Spider (Isoxya, Gasteracanthinae)

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.

Genitalic morphology and phylogenomic placement of the Australian spider Paraplectanoides crassipes Keyserling, 1886 (Araneae, Araneidae) with a discussion on the classification of the family Araneidae

“…2020). For example, in Agnarsson et al (2023), the same authors state that ‘The circumscription of the family Araneidae follows Kuntner et al (2019) and not the World Spider Catalogue [ sic. ]’.…”

“…Turk et al 2020). For example, in Agnarsson et al (2023), the same authors state that 'The circumscription of the family Araneidae follows Kuntner et al (2019) and not the World Spider Catalogue [sic.]'. As another example of the utility of the family rank, Kuntner et al (2023) state that 'Nephilidae is the only spider family for which all species have been scored for IUCN threat status (https://www.iucnredlist.…”