Summer diapause induced by high temperatures in the oriental tobacco budworm: ecological adaptation to hot summers.
Summer diapause in Helicoverpa assulta (Hübner), which prolongs the pupal stage, particularly in males, is induced by high temperatures. In the laboratory, 3(rd)-, 4(th)-, 6(th)-instar and prepupal larvae were exposed to high temperatures - 33 and 35 °C with a photoperiod of LD16:8 - until pupation to induce summer diapause. The results showed that the incidence of summer diapause was influenced by temperature, stage exposed, and sex. The higher the temperature, the more often summer diapause was attained. Sixth-instar and prepupal larvae were the sensitive stages for summer diapause induction. H. assulta summer-diapausing pupae needed diapause development to resume development when temperatures became favorable. Furthermore, both body mass and energy storage capacity (lipid and glycogen) were significantly affected by diapause rather than sex, and were significantly higher in summer-diapausing pupae than in non-diapausing pupae. In addition, the body mass loss and respiration rate showed that the rate of metabolism in the summer-diapausing pupae was consistently lower than in non-diapausing pupae, which were significantly affected by diapause and pupal age. We conclude that summer diapause in H. assulta is a true diapause, and H. assulta has evolved mechanisms to accumulate energy storage and to lower its metabolism to adapt to hot summers.
The State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China.
Zhudong
Z
Liu
The State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China.|Institute of Health Sciences, Anhui University, Hefei 230039, China.
Yucui
Y
Xin
The State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China.|College of Forests and Biology, Agriculture and Forest University of Zhejiang, Hangzhou 310000, China.
Yanan
Y
Zhang
College of Forests and Biology, Agriculture and Forest University of Zhejiang, Hangzhou 310000, China.
Jianting
J
Fan
The State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China.
Jianghua
J
Sun
D000222:Adaptation, Physiological; D000818:Animals; D001834:Body Water; D001835:Body Weight; D000074767:Diapause; D004463:Ecology; D006358:Hot Temperature; D009036:Moths / Q000254:growth & development / Q000502:physiology*; D012119:Respiration; D012621:Seasons