Archytas marmoratus (Diptera: Tachinidae): Advances in Large-scale Rearing and Associated Biological Studies

Abstract

Archytas marmoratus (Townsend) was successfully reared on a large scale using maggots that were mechanically extracted from fecund females in a homogenizer (Virtis). In selected biological studies, extracted maggots were evaluated in a solution of hydroxyethyl cellulose against larvae of Heliothis zea (Boddie) and Spodoptera frugiperda (J. E. Smith) in diet cups. Maggots dispensed on the inner lid of diet cups yielded significantly higher rates of parasitization of H. zea larvae than did maggots dispensed on the surface of semisynthetic diets. No significant differences in percentage parasitization of H. zea larvae were obtained when maggots were dispensed at 5.9, 10.5, or 15.2 per cup lid. Significant reduction in yield of parasitized H. zea larvae, however, did occur when maggot numbers were reduced to 2.7 per cup lid. Percentage parasitization of H. zea larvae was significantly higher when diet cups containing 6.8 maggots per lid were held on their sides during larva-maggot development than when placed upright or inverted. Rates of parasitization of S. frugiperda larvae were significantly lower on multiple larvae per diet cup than on single larvae similarly confined. No significant differences in the mortality of A. marmoratus adult females were detected when 20, 30, or 40 pairs were held in plyboard cages (33 by 33 by 18 cm) during the prelarviposition period. Maggots extracted from A. marmoratus females held for 14 and 21 days at 13°C yielded 89.0 and 51.3% parasitization of H. zea larvae, respectively. In standardized rearing procedures, extracted maggots of A. marmoratus yielded 86.9% parasitization of H. zea larvae when maggots were applied at a mean 10.4 per diet cup lid.