Effect of temperature on the development, oviposition, and mortality of Tribolium audax Halstead and Tribolium madens (Charpentier) (Coleoptera: Tenebrionidae)
The effect of temperature on development time, oviposition, and mortality of the sibling species Tribolium audax Halstead and Tribolium madens (Charpentier) was investigated in the laboratory. The mean development times of T. madens, not including slow-developing larvae, ranged from 54 days at 25 °C and 75% RH to 24 days at 35 °C and 75% RH. The corresponding mean development times for T. audax were 50.5–27.4 days. At 25 °C and below, the larvae of each species separated into two groups, one continuing to the adult stage and the other entering a resting stage. The resting stage could not be broken by a period of 2 weeks at −5 °C. The slow-developing larvae required 4 to 5 times as long to complete their development as those that developed rapidly. Slow-developing larvae of T. madens that had been at 17.5 °C and 75% RH for 658 days, and of T. audax that had been in the same conditions for 908 days, could complete development when placed at 27.5 °C and 75% RH. Peak oviposition for T. madens occurred at 17 weeks after adult emergence at both 27.5 and 30 °C; the total oviposition period was 47 weeks at 30 °C and 60 weeks at 27.5 °C. Peak oviposition for T. audax occurred at 6 weeks at both 27.5 and 30 °C; the total oviposition period was 36 weeks at 30 °C and 59 weeks at 27.5 °C. Larval and pupal mortality was low at 25 °C or above in T. madens and T. audax. Below 25 °C the survival rate of T. madens was somewhat higher than that for T. audax.