Real-time PCR reveals endosymbiont titer fluctuations in Metaseiulus occidentalis (Acari: Phytoseiidae) colonies held at different temperatures

Abstract

Real-time PCR amplification of 16S rRNA sequences from 4 M. occidentalis endosymbionts; Cardinium, Wolbachia, Enterobacter, and Bacteroidetes, provided an estimate of their titer in colonies reared under 3 temperatures. This work also revealed, for the first time, that the Wolbachia and Cardinium titer were reduced in heat-treated COS colonies, but not completely eliminated. However, feeding M. occidentalis colonies the Wolbachia-free two-spotted spider mite diet did eliminate Wolbachia from this predator. No cytoplasmic incompatibility was detected when crosses were made between males reared at room-temperature (23-25C) containing Cardinium (and lacking Wolbachia) and females reared at 34C containing a much lower titer of Cardinium (and lacking Wolbachia), indicating that Wolbachia may be involved in causing previously observed incompatibilities rather than Cardinium.