Ant-mimicking spider, Myrmarachne species (Araneae : Salticidae), distinguishes its model, the green ant, Oecophylla smaragdina, from a sympatric Batesian O. smaragdina mimic, Riptortus serripes (Hemiptera : Alydidae)

Abstract

In north Queensland, Australia, the alydid bug Riptortus serripes and the undescribed salticid spider Myrmarachne sp. F are co-occurring visual Batesian mimics of the green tree ant Oecophylla smaragdina. Myrmarachne sp. F lives near ant nests and avoids contact with aggressive worker ants, suggesting that, like other salticids, it can distinguish visually between prey, mates and rivals. An experiment was conducted to test the hypothesis that Myrmarachne sp. F can distinguish O. smaragdina from its visual mimic, R. serripes. Individual spiders were exposed to individuals of O. smaragdina, R. serripes or a control hemipteran and their interactions video-recorded. For each encounter, the animals’ initial motion and distance apart were recorded, and the spider’s response was categorised. These experiments revealed that Myrmarachne sp. F responded differently to the various species, ‘avoiding’ the ant more frequently than the bug. Further tests are needed to determine whether the spider’s differing reactions to the two species are due to visual or other cues.