Discovery and genetic characterization of single cohort adult colonies with male aggregations, and preliminary evidence for lekking in a Malagasy kite spider (Isoxya, Gasteracanthinae)

We report on a discovery of a kite spider from Madagascar that exhibits unique colonies. We found colonies of the newly described araneid Isoxya manangona n. sp. formed by up to 41 interconnected, single-cohort adult female webs with up to 38 adult males aggregating on a central, single, non-sticky 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. Based on limited field data, the observations we report clearly indicate that Isoxya manangona n. sp. colonies stage mating arenas.