Interspecific tertiary parasitism between two aphid hyperparasitoids, Dendrocerus carpenteri and Asaphes lucens (Hymenoptera:Megaspilidae and Pteromalidae)
Using the pea aphid, Acryrthosiphon pisum (Harris) as the host and Aphidius ervi (Haliday) as the primary parasitoid, interspecific tertiary parasitism was studied in the aphid hyperparasitoids Dendrocerus carpenteri and Asaphes lucens. Laboratory experiments indicate that the possibility of tertiary parasitism by Asaphes is greatly reduced to an average of 5.0% during the last nine days of the 15-day development of the Dendrocerus within the mummy. It supports earlier reports that Dendrocerus has evolved a defensive behavior which deters tertiary parasitism not only by its own species but by Asaphes lucens as well. The 4th instar larva and the prepupa have developed segmental spines and a conical process at the posterior end which enables it to twitch violently and move about in the mummy when probed by the ovipositor of Asaphes, thus inhibiting oviposition. The behavior of Dendrocerus carpenteri (Curtis) is in contrast to that of Asaphes lucens (Provancher). Dendrocerus oviposits by backing into the mummy, whereas Asaphes oviposits while standing on top of the mummy. Dendrocerus antennates the mummy by using the whole surface of the antenna, while Asaphes taps with the antennal tips. Dendrocerus was never seen to host feed, as was the case with Asaphes. Superparasitism is evident in both species with the emergence of dwarfs and on one occasion, multiple parasitism was observed, with the emergence of dwarf adults of both species. The overall mortality of hyperparasitoids in these experiments was 19.1%, which is similar to other laboratory experimental studies. Diapause was observed in Dendrocerus carpenteri. It may have been caused by some condition of the adult female. No set pattern of sex ratio determination was evident in the hyperparasitoids studied.
Carew, William Patrick B, "Interspecific tertiary parasitism between two aphid hyperparasitoids, Dendrocerus carpenteri and Asaphes lucens (Hymenoptera:Megaspilidae and Pteromalidae)" (1988). ETD Collection for Fordham University. AAI8818454.