MODELING HOST ATTACKS AND PROGENY PRODUCTION OF SPALANGIA-GEMINA, SPALANGIA-CAMERONI, AND MUSCIDIFURAX-RAPTOR (HYMENOPTERA, PTEROMALIDAE) AT CONSTANT AND VARIABLE TEMPERATURES

In assays at constant temperatures, Spalangia gemina Boucek, Spalangia cameroni Perkins, and Muscidifurax raptor Girault and Sanders females killed more house fly (Musca domestica L.) pupae at 30 degrees C than at 15, 20, 25, or 35 degrees C, with attack rates for the three speci es of 11.2, 12.6, and 21.1 pupae killed per parasitoid per day, respec tively. Progeny production followed a similar pattern, with maximum ra tes of 6.8, 7.5, and 9.2 progeny per day at 30 degrees C for S. gemina , S. cameroni, and M. raptor, respectively. Both Spalangia species pro duced proportionally fewer males at higher temperatures than at lower temperatures; sex allocation by M. raptor was relatively unaffected by temperature except for a trend to produce fewer females at 15 degrees C (29.6% females) than at higher temperatures (43-47%). The four-para meter thermodynamic model of Sharpe and DeMichele with high temperatur e inhibition fit the attack rate and progeny production rate data well . These models were very effective at predicting host attacks and para sitism at high, variable temperatures typical of outdoor mid summer co nditions in many regions, provided that 1-h time steps were used in ra te summation algorithms. Assays for long-term net rates of fly destruc tion revealed that S. gemina and S. cameroni would be most effective f or fly control at 25 degrees C and substantially less effective at eit her low (15 degrees C) or high (35 degrees C) temperatures. M. raptor was equally effective at killing house fly pupae over the 15-30 degree s C range, but was significantly less effective at 35 degrees C. (C) 1 996 Academic Press, Inc.