Fast acrobatic maneuvers enable arboreal spiders to hunt dangerous prey

Abstract

Spiders, the most specious taxon of predators, have evolved an astounding range of predatory strategies, including group hunting, specialized silk traps, pheromone-loaded bolas, and aggressive mimicry. Spiders that hunt prey defended with behavioral, mechanical, or chemical means are under additional selection pressure to avoid injury and death. Ants are considered dangerous because they can harm or kill their predators, but some groups of spiders, such as the Theridiidae, have a very high diversification of ant-hunting species and strategies [J. Liu et al., Mol. Phylogenet. Evol . 94, 658–675 (2016)]. Here, we provide detailed behavioral analyses of the highly acrobatic Australian ant-slayer spider, Euryopis umbilicata (Theridiidae), that captures much larger and defended Camponotus ants on vertical tree trunks. The hunting sequence consists of ritualized steps performed within split seconds, resulting in an exceptionally high prey capture success rate.

Insectivorous birds and bats outperform ants in the top-down regulation of arthropods across strata of a Japanese temperate forest

“…This could be because ants were classified as mesopredators in our study, and their removal may impact the overall mesopredator pattern. Additionally, ants can serve as an important food source for other predatory arthropods through myrmecophagy, such as spiders (Aranea), bugs (Heteroptera; Brandt & Mahsberg, 2002), net-winged insects (Neuroptera), or flies (Diptera; Aceves-Aparicio et al, 2022; Wilson, 2000).…”

Webless spiders reverse bungee jump to catch prey

“…In PNAS, Aceves-Aparicio et al. describe the hunting sequence of the webless spider Euryopis umbilicata that hunts a large and dangerous prey, Camponotus ants ( 1 ). The E. umbilicata attaches a single silk line to the bark of a eucalyptus tree and waits for a wandering ant to come its way ( Fig.…”

“…Tracking a spider moments before and at the initial launch of an attack would help us understand how the Euryopis spiders achieve these rapid and yet highly precise directional jumps ( 14 ). Kinematic measurements will also help us understand the energetic considerations of the attacks, especially as the spiders target and are equally successful at catching the ants in all directions ( 1 ).…”

“…Although not as fast as Drosophila , ants are also wandering, and this raises the question whether spiders are predicting the direction of movement of ants. Indeed, one out of the five unsuccessful encounters occurred when the ant changed it heading direction ( 1 ). Another curious observation in this paper is that the spider attack was often initiated upon the direct contact between the ants and spider’s legs or its silk thread ( 1 ).…”

“…Indeed, one out of the five unsuccessful encounters occurred when the ant changed it heading direction ( 1 ). Another curious observation in this paper is that the spider attack was often initiated upon the direct contact between the ants and spider’s legs or its silk thread ( 1 ). Like the spider trichobothria, insects also possess hair sensors which are extremely sensitive and are used for escape ( 5 , 18 ).…”