Effects and tissue pathology of an unidentified microsporidium from the convergent lady beetle, Hippodamia convergens Guerin-Meneville (Coleoptera: Coccinellidae), on three non-target coccinellids By

A microsporidium from H. convergens was transmitted horizontally to three non-target coccinellids (Adalia bipunctata L., Coccinella septempunctata L. and Harmonia axyridis Pallas) under laboratory conditions. The effects of microsporidiosis on larval development, larval mortality, sex ratio, fecundity and adult longevity were examined. For all beetle species, larval development was prolonged as a result of infection. Fecundity and longevity was adversely affected only for the natural host, H. convergens. Spore counts were similar for A. bipunctata and H. convergens but fewer spores were observed in C. septempunctata and H. axyridis. Vertical transmission of the pathogen was observed in all host species. Three eugregarines were found and described from two adult A. bipunctata. In H. convergens, the microsporidium infected muscles surrounding the midgut and within the fat body, Malpighian tubules, pyloric valve epithelium, colon epithelium, nerves, muscles, connective tissues, and ovaries. Tissue pathology differed for C. septempunctata and H. axyridis.