Influence of parasitoid-host density on the behaviour ecology of Goniozus nephantidis (Muesebeck) (Hymenoptera: Bethylidae), a parasitoid of Opisina arenosella Walker

摘要

Since Goniozm nephantidis (Muesebeck) is found to have strong parental care for its progeny, the influence of different densities of G. nephantidis and its host, Corcyra cephalonica (Stainton) on the behaviour ecology of the parasitoid was studied. Interaction between different densities of the host and parasitoid revealed that a ratio of 1:1 was significantly superior to all other ratios resulting in maximum parasitism (9.0 larvae / female), fecundity (93.2 / female) and number of progenies (75.2 /female). Exposing more than one C. cephalonica larva did not significantly increase the parasitizing efficiency, fecundity and progeny produced. Conversely, exposing a single C. cephalonica larva to several female parasitoids adversely affected the biological attributes of the parasitoid. Increasing the densities of either host insects or parasitoids had an inverse relationship with oviposition behaviour, parasitism efficiency and progeny production of the parasitoid establishing the important and significant role played by host-parasitoid density.