Biology and temperature responses of chelonus kellieae and chelonus phthorimaeae hymenoptera braconidae and their host the potato tuberworm phthorimaea operculella lepidoptera gelechiidae
Powers N.R.; Oatman E.R., 1984: Biology and temperature responses of chelonus kellieae and chelonus phthorimaeae hymenoptera braconidae and their host the potato tuberworm phthorimaea operculella lepidoptera gelechiidae. Hilgardia 52(9): 1-32
Comparative studies of the biologies and host relationships of the indigenous C. phthorimaeae and the introduced C. kellieae were studied at 26.7 .+-. 1.degree. C, 50% .+-. 5% RH and 12-h photoperiod. Comparisons of the population growth potential of both species of parasites and their host, P. operculella, were made at five different temperatures. Both species of parasites are primary, solitary, egg-larval endoparasites of the potato tuberworm. The egg of both species is hymenopteriform. There are three instars, the first being caudate-mandibulate finally becoming vesiculate-mandibulate; the second and third are mandibulate; the third instar possesses spines and setae. The pupa is exarate. Descriptions and measurements of immature stages are given. Superparasitism of the host egg occurred in experimental conditions, but only one parasite larva was found in a host larva. The parasite larva developed in the haemocoel of the still living host. The mature parasite larva emerged from the first instar host and continued feeding externally. it then formed a silver-white cocoon within that of its host. Comparison of the biologies of both C. phthorimaeae and C. kellieae shows that the only significant difference is that the population growth potential of C. phthorimaeae is greater than that of C. kellieae at all temperatures studied, but less than that of its host at 21.1 .+-. 1, 23.9 .+-. 1, and 26.7 .+-. 1.degree. C. This demonstrates the adaptability of C. phthorimaeae at higher temperatures of 29.4 .+-. 1.degree. C and 32.2 .+-. 1.degree. C. C. kellieae produced no female progeny at 32.2 .+-. 1.degree. C. These studies should not be used as the only indication of success or failure of these parasites to regulate their host. Because of their biological similarities, studies of their competitive interactions should be investigated.Other references