Characterisation of an anaerobic symbiont and the associated aerobic bacterial flora ofPyrrhocoris apterus(Heteroptera: Pyrrhocoridae)

A Gram-positive anaerobic bacterium was regularly found in great numbers in histological sections and anaerobic cultures of the third bulbous mid-gut portion of Pyrrhocoris apterus (Linné 1758). It formed long chains of irregular pear-shaped cells with large spherical involutions. The fermentation products were L-lactic acid, ethanol and acetic acid, CO2 and H2. The peptidoglycan belongs to the Lys-Asp type. The G + C content was determined to be around 61 mol%. The organism is supposed to be a symbiont of P. apterus and to be a species of a new genus. In the aerobic cultures Streptococcus lactis, an as yet not classified Streptococcus of the serological group D and Hafnia alvei were isolated from the third part of the mid-gut.