Canibalismo em Amblyseius largoensis (Muma) (Acari: Phytoseiidae), um importante inimigo natural de ácaros praga do coqueiro, (Cocos nucifera L.).

Abstract

The mites of the Phytoseiidae family concentrate the main species of predatory mites used as biological control agents in various crops. Some of these species have general food habit and occur naturally on the plants, as is the case of the species Amblyseius largoensis that is found in coconut leaflets. For these species, the behavior of cannibalism may represent a survival strategy in conditions of low food availability, and this was the hypothesis of the present study. Initially, A. largoensis creations were established from individuals collected in coconut leaflets, after establishment of the creations the tests were started. A pregnant female was used as a repetition in all treatments that consisted of combinations between presence or absence of the extra-guild prey (60 Raoiella indica eggs) and immature presence or absence of A. largoensis (10 immature). The cannibalism of A. largoensis on its immature was affected by the presence of the extra-guild prey (R. indica eggs), which is greater in the absence of the extra-guild prey. This behavior of cannibalism of the A. largoensis females provided enough energy for their survival and oviposition in the absence of food. A higher number of deposited eggs were observed when females fed exclusively on the extra-guild prey whereas a lower oviposition was observed when the food was immature of the species itself. Intermediate values were observed in the presence of both immature and pre-guild prey. The results suggest that a limited supply of food may lead to the cannibalism behavior of A. largoensis, thus representing a survival strategy of the species. However, this is a behavior that should occur sporadically since A. largoensis is a general species, feeding not only other species of mites but also pollen and sugary exudates of plants.