Effects of an unidentified microsporidium on the convergent lady beetle, Hippodamia convergens Guérin-Méneville (Coleoptera: Coccinellidae), used for biological control

Convergent lady beetles, Hippodamia convergens Guérin-Méneville, are collected from overwintering sites in California and redistributed for aphid control in home gardens and agroecosystems. The effects of an unidentified microsporidium on the life history characteristics of commercially available H. convergens were examined. Mean development for microsporidia-infected and uninfected H. convergens was 15.40 ± 0.14 and 14.76 ± 0.16 days, respectively (P = 0.01). Larval mortality did not differ significantly. Cumulative mean egg production for microsporidia-infected and uninfected females was 545.8 ± 92.6 and 928.3 ± 86.4 eggs, respectively (P = 0.004) and mean survival was 64.5 ± 5.6 and 77.1 ± 4.5 days, respectively (P = 0.04). Microsporidian spores (3.6 × 2.4 μm) are similar in size to those of Nosema hippodamiae.