Biological assessment in quarantine of Asecodes hispinarum Bouček (Hymenoptera: Eulophidae) as an imported biological control agent of Brontispa longissima (Gestro) (Coleoptera: Hispidae) in Hainan, China

The biology of Asecodes hispinarum Bouček (Hymenoptera: Eulophidae), a larva parasitoid imported from Vietnam as a classical biological control agent of coconut leaf beetle, Brontispa longissima (Gestro) (Coleoptera: Hispidae), was studied in quarantine in Hainan, China. The developmental stages of A. hispinarum were characterized from material reared at 22–26 °C and 70–80% RH. Development time (egg to adult) was 17.5 ± 2.1 days under these conditions. This study evaluated the life table parameters of A. hispinarum in a climate chamber at 16–30 °C, 80% RH and 12 h photo phase. Temperature had no effect on the sex ratio of parasitoid offspring. Mean adult longevity was inversely related to temperature with a maximum of 3.7 days at 16 °C and a minimum of 1.3 days at 30 °C. The lower developmental threshold estimated by the linear regression was 10.7 °C and 261.3 degree days. Most of the total lifetime complement of eggs of A. hispinarum was produced within 12 h of emergence. A. hispinarum that fed on 10% honey (w/v) lived significantly longer (2.98 days) than those fed on other energy sources, but showed no effects on parasitism, fecundity, emergence rate or sex ratio. A. hispinarum females parasitized all instars of larvae of B. longissima, but parasitism varied with host instar stage. Development of the parasitoid was not affected by the instar of the beetle host.