Fecundity of wild Tribolium castaneum (Herbst) from southeast Queensland, Australia

Fecundity was investigated in wild Tribolium castaneum (Herbst) from southeast Queensland, Australia. Although the fecundity of T. castaneum has been investigated in laboratory studies, the reproductive potential of wild females may be less than that of females reared and tested under favourable laboratory conditions. Adult T. castaneum were trapped using corrugated cardboard traps baited with whole wheat flour on four occasions during May-July 1997 in a grain-growing area of southeast Queensland. After each trapping period, fecundity of individual wild females was assessed on whole wheat flour at 30°C and 55% erh. In addition, F1 adults were pooled, a sample was taken and fecundity of individual females was assessed similarly. Almost 90% of the adults were trapped on four of the 10 grain storage sites, and these sites yielded females on all four trapping occasions. There was no systematic effect of trapping period on fecundity of wild females, and in three of these four sites there was no effect at all. There were no significant differences between numbers of progeny produced by F1 females derived from different trapping periods, so the data were pooled for comparison with the results from wild females. Generally, fecundity of wild females was high relative to that of F1 females which had been reared under uniformly favourable conditions in the laboratory. Despite the trapping occurring during some of the coldest months of the year, females were clearly active and capable of reproducing, demonstrating the importance of maintaining high levels of grain hygiene throughout the year.