Abstract:
Selitrichodes neseri (Hymenoptera: Eulophidae) is a parasitoid of the invasive gall-forming wasp Leptocybe invasa (Hymenoptera: Eulophidae), which has caused serious damage to Eucalyptus plantations in many
parts of the world. S. neseri is a recently discovered parasitoid considered to be a potentially important biological control agent of L. invasa. The aim of this study was to provide the first basic data on the biology of
S. neseri, which is essential for its application in biological control. S. neseri was shown to be a biparental
ectoparasitoid. Observation from dissected galls indicated that the parasitoid developed on late larvae,
pupae and callow adults, although development did occur in a range of gall ages. Observed nominal parasitism
in captivity ranged from 9.7% to 71.8%. Adult S. neseri specimens, fed with honey-water and galled
Eucalyptus leaves, survived an average of 26 days at 26 C. The average developmental time from oviposition
to emergence was 19.3 days ± 0.2 days. There was no pre-oviposition period. A single female produced a
maximum of thirty-nine offspring, with a maximum of ten per day. Dissection of the ovaries showed that
twelve ovarioles were present. The sex ratio of S. neseri observed in this study was 1:3.43 males:females.
Galls of native insects most closely related to L. invasa and to galls of similar morphology to L. invasa-induced
galls, were not suitable for S. neseri oviposition. S. neseri showed considerable potential as a biological control
agent of L. invasa due to its relatively short developmental time, long adult life span when supplemented
with carbohydrates, ability to utilize a range of gall ages and the fact that it has a high level of host specificity.
