Cannibalism in Amblyseius largoensis (Muma) (Acari: Phytoseiidae), an important natural enemy of coconut mite pests

Abstract

ABSTRACTThe phytoseiid mite Amblyseius largoensis (Muma) is an important natural enemy of two key coconut pests, the red palm mite, Raoiella indica Hirst (Acari: Tenuipalpidae), and the coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae). Amblyseius largoensis is considered a generalist due to its ability to feed on multiple food sources (e.g. phytophagous mites, small insects, plant exudates, nectar, and pollen). Specimens of A. largoensis sometimes attack each other in competitive situations. Thus, we hypothesized that intraspecific interactions, such as cannibalism, may occur when heterospecific prey are scarce. Experiments were conducted to determine whether, and to what extent, the availability of heterospecific prey, eggs of R. indica, influenced the tendencies of A. largoensis to cannibalise. Additionally, the oviposition of A. largoensis was measured in the presence and absence of both conspecific nymphs and R. indica eggs. Overall, in the absence of the heterospecific prey, A. largoensis consumed conspecific nymphs, and few eggs were produced, whereas in the presence of abundant herbivorous prey, cannibalism decreased, and oviposition increased. These results suggest that, similar to other phytoseiid mites, A. largoensis employs cannibalism as an adaptive survival strategy when heterospecific prey is absent or scarce.