The biology of Tribolium destructor Uytt. I. Some effects of fertilization and food factors on fecundity and fertility

A brief review of recent papers on Tribolium destructor Uytt. is given, and its potential danger as a pest noted. It is shown that 85 % extraction flour leads to about double the fecundity found on 60 or 75% extraction flour. The pre‐oviposition period is shown to be affected by both larval and adult food. Unfertilized females lay eggs, but these are relatively few in number, and are all sterile. Oviposition appears to be stimulated when males associate with unfertilized females, and also when they are removed from fertilized females: the presence of five males seems to lead to greater oviposition than when only one male is present, but the use of small numbers makes these conclusions rather insecure. Although copulation occurs at frequent intervals, females will lay viable eggs for as long as 250 days after the removal of the male. Fertility remains virtually constant throughout life when males are present, and is not increased by the presence of more than one male. Fertility varies inversely with the number of eggs laid. The oviposition period is long and the average curve has a characteristic form, despite considerable daily and individual fluctuations. Oviposition may continue until death or may end some weeks before. Poor conditions tend to lengthen both the oviposition period and the length of life, the latter being greater for males than for females.