Jumping spider invades an orb web to prey on a resident male

While surveying operational sex ratios of the giant golden orb weaver Nephila pilipes (Fabricius, 1793) in Singapore, we documented a stunning case of predatory behavior of a jumping spider Viciria pavesii Thorell, 1877. A female V. pavesii invaded a N. pilipes orb web that was occupied by the resident female and four males, and successfully captured, killed, and removed one of the Nephila males. Whether araneophagy in V. pavesii is opportunistic or a predatory ritual remains to be tested more precisely, but because the observed predatory event triggered an aggressive response by the N. pilipes alpha male, it is plausible that V. pavesii may engage in aggressive mimicry. We place our observation into the context of jumping spider cognition and behavioral tactics that are so far well understood only in a few spartaeine genera, notably Portia Karsch, 1878. Viciria Thorell, 1877, we argue, is another such jumping spider taxon worthy of behavioral scrutiny.

Automated summary

While studying the sex ratios of Nephila pilipes in Singapore, researchers observed a fascinating case of predatory behavior by Viciria pavesii, a jumping spider. The V. pavesii female invaded a N. pilipes orb web occupied by a female and four males, successfully capturing and killing one of the Nephila males. The aggressive response of the N. pilipes alpha male suggests that V. pavesii may engage in aggressive mimicry.