Offensive and Defensive Exploitation of Ants by Termitophagous Spiders (Araneae: Zodariidae).

Abstract

Myrmecophagy is one of the most common types of dietary specialization among predators. It can include exploitation of ants, termites, or both. Although ants and termites share a few traits, they are distantly related and possess different defensive mechanisms. Therefore, adaptations to ants and termites should differ, especially in arthropod predators of similar body size as their prey. We investigate offensive and defensive adaptations in Zodariidae spider genus Diores, reported to feed on termites. The ancestral state reconstruction of the diet favored termitophagy for the genus, but metabarcoding analyses revealed that only one of the four studied Diores species fed exclusively on termites. The remaining three species captured both ants and termites. Interestingly, the laboratory observations of a single species, Diores poweri, revealed a similar attack-and-retreat strategy to catch both termites and ants. Three ant species and one termite were successfully captured with a similar frequency, but the capture of Hodotermes termites was more efficient. The paralysis of Hodotermes by D. poweri was approximately 20 times faster than by an ant-eating spider Zodarion nitidum, which correspond to venom composition differences between the species. The habitus of D. poweri resembles the size, shape, movement, and the coloration of its predominant prey, Camponotus maculatus ants, suggesting Batesian mimicry. However, the modeling of the visual discrimination of coloration by potential lizard and bird predators revealed that Diores might be distinguished from Camponotus. Our results suggest that Diores spiders are specialized myrmeco-termitophagous predators, possessing effective adaptations and exploiting ants for defense.