Host vibration - A cue to host location by the parasite, Biosteres longicaudatus

Abstract

Biosteres longicaudatus Ashmead (Hymenoptera: Bracon dae) is a solitary endoparasite of Anastrepha suspensa larvae (Diptera: Tephritidae), which live in fruit tissue. Larvae make andible noises within macerated fruit or larval medium in which they are reared. Parasite females readily located normal, mobile larvae and spent a mean of 16.5±4.7 min/visit to parasitize these hosts. In contrast, females were unable to locate etherized or dead hosts and abandoned them after only 1.9±0.9 and 2.3±0.8 min, respectively. Females of all ages, with and without oviposition experience, exhibited non-random search and ovipositor probe behaviors in response to artifically created vibration. This response was influenced primarily by the number of mature eggs in the ovaries. These findings suggest that 1) an accumulation of mature eggs in the ovaries increase the appetitive drive of females to find and oviposit in hosts and 2) host sound/vibration produced either by movement of hosts through the medium and/or by the rasping mouth hooks during feeding. is used by parasites as a releaser for host finding behavior as well as a cue to the location of the host within the substrate.