Host makes the difference: the effect of two planthopper host species on host-feeding and parasitism activities of the pincer wasp Gonatopus bonaerensis

Females of Gonatopus bonaerensis Virla (Hym.: Dryinidae), a parasitoid of Delphacidae (Hemiptera), practices host-feeding. It was demonstrated for several species of Dryinidae that host mortality caused by host-feeding is greater than that caused by parasitism. Here we investigated the effect of host species, host age, and the age of female parasitoids on both parasitism and host-feeding rates throughout the female lifetime. Experiments were done exposing the planthoppers Delphacodes sitarea Remes Lenicov & Teson, the most common host, and Peregrinus maidis (Ashmead), an occasional host. The hosts have a very strong influence on biological traits and on the behavior of this pincer wasp. Females of G. bonaerensis lived longer in presence of D. sitarea. Faced with its usual host, the parasitoid killed more planthoppers by parasitism than by host-feeding, but in front of its occasional host, predation prevailed. Regardless of the host, younger nymphs were the most attacked both for host-feeding and oviposition.