Eb. White et al., FACULTATIVE HYPERPARASITISM IN BRACHYMERIA-POMONAE (HYMENOPTERA, CHALCIDIDAE), European journal of entomology, 95(3), 1998, pp. 359-366
This report summarizes a study designed to uncover any tendency toward
s hyperparasitic behavior in Brachymeria pomonae (Cameron), a parasito
id of pink bollworm (PBW) (Pectinophora gossypiella Saunders) imported
from Australia to California for biological control of the latter pes
t species. Brachymeria pomonae hyperparasitized both Apanteles oenone
Nixon (ca. 10% of pupae exposed) and Cardiochiles nigriceps Viereck (c
a. 23% of pupae exposed), and all hyperparasitic offspring of B. pomon
ae were males. However, B. pomonae's aggressive primary parasitism of
several lepidopterous hosts, together with the low hyperparasitism rat
es and the failure to produce hyperparasitic female offspring suggeste
d that hyperparasitism is a facultative behavior in this parasitoid. B
rachymeria pomonae caused substantial mortality in A. oenone and C. ni
griceps as a result of ovipositional probing. Finally, it did not atta
ck PBW nor A. oenone pupae if they were not enclosed in a PBW cocoon,
but aggressively attacked the pupae of both when enclosed in PBW cocoo
ns. The results are of significance because B. pomonae was a candidate
for release against PBW in California. Because of its facultative hyp
erparasitic habit, no effort was made to release it from quarantine. T
he basis for this decision, including the uncertain impact that hyperp
arasitoids may have on biological control programs, is discussed.