Insect species with broad geographic distributions can phenologically adjust their life cycles to adapt to different habitats, for example by altering their growth, development, and reproduction periods to better match their emergence times with local conditions, such as food availability, optimum temperature, rainfall, etc.). These adjustments are very important for such widespread species to be able to reproduce in different habitats. The Asian corn borer, Ostrinia furnacalis (Guen佴e) (Lepidoptera: Crambidae) is a major pest insect of Zea mays L., that poses a serious economic threat to corn production in China. Its distribution ranges from north to south in China, through Southeast Asia, and into Australia, and the pest has recently been found in isolated regions of the United States. Because of its wide distribution, the Asian corn borer encounters great variation in climatic conditions across its range and exhibits considerable diversity in its life鄄history parameters among geographic populations. Populations differ distinctly in voltinism, critical photoperiod, post鄄diapause

No abstract

No abstract

Photoperiodic time measurement in insects can be affected by interrupting the dark phase of the light dark cycle with short supplementary light pulses. All the photoperiodic responses tested are highly sensitive to night interruption, and the long night effect is reversed by a light break. Most past studies revealed two points of apparent light sensitivity (the so鄄 called A and B peaks) , but the response pattern varied considerably among different species. Some species had only one peak (or trough) , either A or B. Even the same species may have different patterns of response depending on the experimental conditions. However, it is still not clear whether differences exist in the effect of night鄄interruption on diapause鄄averting among different geographic populations. The cotton bollworm, Helicoverpa armigera (H俟bner) is one of the most serious crop pests in Asia, Australia, Africa and Europe. The species is distributed across much of China and