Biology and Development of Lespesia aletiae (Diptera: Tachinidae) in Two Lepidoptera Species in the Laboratory

Abstract

The tachinid Lespesia aletiae (Riley) was obtained from parasitized larvae of Syntomeida epilais (Walker), which is an arctiid pest of oleander, Nerium oleander (L.). Development of L. aletiae in fifth and sixth instars of S. epilais and of a noctuid, the fall armyworm, Spodoptera frugiperda (Smith) was determined in laboratory studies. Female L. aletiae flies lived an average of approximately 24 d, 14 days longer than males, and were observed to oviposit membranous eggs directly on the host body. First instars cut their way out of the egg and into the host within 2 min of oviposition. The percent of successful parasitism in laboratory assays ranged from 36% in fifth instar S. epilais to 65% in sixth instar fall armyworms. Puparial size was found to increase with increasing host instar and to decrease with increasing number of maggots per host. The time between exposure to parasitoids and host death was longer in fifth than sixth instars of the same host, and was significantly longer in fifth instar S. epilais than in any other combination of host instar and species tested. The parasitoid puparial stage was approximately one day longer for females than it was for males. Both the fifth and sixth instars of the fall armyworm and S. epilais were suitable for the parasitoid's development, however, parasitism levels and parasitoid survival were higher in fall armyworms.