Environmental Entomology (1985) 14, 507-511
Robert A. Kistler (1985)
Host-age structure and parasitism in a laboratory system of two hymenopterous parasitoids and larvae of Zabrotes subfasciatus (Coleoptera: Bruchidae)
Environmental Entomology 14 (4), 507-511
Abstract: Host-age structure of Zabrotes subfasciatus (Boheman) on larval parasitism by two hymenopterous parasitoids, Heterospilus prosopidis Viereck (Braconidae) and Anisopteromalus calandrae (Howard) (Pteromalidae), were examined in a series of laboratory experiments. Ages of the hosts offered to the parasitoids were varied and the number of host larvae successfully parasitized was monitored. The sex ratio of the resulting parasitoids was also monitored. A life-history refuge from parasitism by both parasitoids was found, consisting of the egg stage and the small, young larvae. The refuge length differed for both parasitoids. Host individuals were not parasitized efficiently by A. calandrae for the first 14-16 days, whereas they were not parasitized at all by H. prosopidis for the first 12 days. Host individuals were protected from attack during these refuge periods for up to 60% of their larval period. Host-age refuges were important in the stability of these two hostparasitoid systems. Stability increased with increasing length of the refuge period. The shorter refuge period in the H. prosopidis-host system may lead to further instability by creating asynchrony between the host and parasitoid life cycles. The age of the larval host also determined the sex ratio of the parasitoid populations. This factor may further destabilize the H. prosopidis populations, while having a lesser effect on A. calandrae.
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Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Zabrotes subfasciatus | ||||
| Anisopteromalus calandrae (parasitoid) | Zabrotes subfasciatus | |||
| Heterospilus prosopidis (parasitoid) | Zabrotes subfasciatus |
