Comparative growth and development in vitro of Eucelatoria bryani Sab. and Palexorista laxa (Curran) (Diptera Tachinidae) fed a meridic diet and a diet of Helicoverpa zea (Boddie) (Lepidoptera Noctuidae) pupae

Yields of adults were lowest for first instars and highest for third instars of both Eucelatoria bryani Sabrosky and Palexorista laxa (Curran)(Diptera:Tachinidae) collected from the host Helicoverpa zea (Boddie) and reared in vitro on the meridic diet devoid of insect components. When placed on the artificial diet as first and second instars, yields of adults of E. bryani were superior to those of P. laxa; however, for adult yields there was no significant difference between P. laxa and E. bryani when third instars were used. In experiments begun with one-day-old maggots of E. bryani and P. laxa obtained from hosts, P. laxa performed better on the H. zea pupal homogenate (HZPH) diet than on the meridic diet. For E. bryani there was no significant difference between diets for most criteria, demonstrating that this species grew and developed surprisingly well on the meridic diet. The maximal mean adult yield (80%) for P. laxa fed HZPH is the highest ever reported for tachinids reared in vitro. The results demonstrate the excellent potential of in vitro rearing when tachinids are fed superior artificial media and the likely importance of the identification of host chemicals for the development of improved artificial media.