Melittobia australica Girault and M. digitata Dahms (Hymenoptera: Eulophidae) were studied parasitizing blow fly puparia Neobellieria (=Sarcophaga) bullata (Diptera: Calliphoridae) using either one or five foundress females per host. The percentage of puparia parasitized was higher overall for M. digitata than for M. australica. Regardless of foundress numbers, the average total number of descendents produced was significantly higher for M. digitata (66.5 – 158) than for M. australica (10.9 – 55.5). The number of descendents produced per female was inversely proportional to the number of foundresses on a host for both species. Developmental times from parasitism until parasitoid emergence increased for M. australica and decreased for M. digitata as the number of foundresses increased. Life spans of adult progeny of both species, deprived of host and food, were longer for progeny derived from fewer foundresses. Body size as measured by forewing and hind-tibia lengths of descendents showed significant reduction as number of foundresses increased for both species, except for the forewing of M. digitata. Changing foundress number did not affect offspring sex ratios (0.95 – 0.98 for M. australica, and 0.95 – 0.97 for M. digitata).
Species 1: Hymenoptera Eulophidae Melittobia australica
Species 2: Hymenoptera Eulophidae Melittobia digitata
Species 3: Diptera Calliphoridae Neobellieria bullata (blow fly)
Keywords: Host preference, parasitism
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