Biology of trichogramma brevicapillum
1982
PAK, G.A. | OATMAN, E.R.
The biology of Trichogramma brevicapillum Pinto & Platner (Hymenoptera, Trichogrammatidae) reared on eggs of Trichoplusia ni (Hübner) (Lepidoptera), and the influence of some abiotic and biotic conditions on the parasitization strategy of the adults were studied. Egg, larva, prepupa, and pupa are described. Development of these stages lasted ca. 1,3, 1, and 5 days, respectively, at 25°. Reproduction is biparental, arrhenotokous. The preoviposition period lasts ca. 3 hr, and oviposition activity was maximal in the 3rd and 4th hr of the photophase and was minimal in the scotophase. The suitability of T. ni eggs as a host was maximal in the blastula stage of the embryo, decreased sharply in the early stages of differentiation, and increased rapidly in the later stages of embryological differentiation. A single ♀ reared from a host egg was larger and more fecund than 2 2 from eggs yielding 2 or 3 parasites. Oviposition by individual ♀♀ was restrained when the host egg density was limited, thus preventing superparasitization. The number of progeny per host egg and the ♂ proportion of the sex ratio were inversely related to the host egg density over a range of limited host densities.
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