Heat tolerance of developmental and seasonal stages of Chilo suppressalis. Issue 2 (24th June 2014)

• Record Type: Journal Article
• Authors: Lu, M.X.; Cao, S.S.; Liu, Z.X.; Wang, X.; Du, Y.Z.
• Is Part Of: Entomologia experimentalis et applicata. Volume 152:Issue 2(2014:Aug.)
• Page Start: 91
• Page End: 99
• Publication Date: 2014-06-24
• Subjects: Entomology -- Periodicals; 595.7
• DOI: 10.1111/eea.12203
• Languages: English
• ISSNs: 0013-8703

Abstract

<abstract abstract-type="main" id="eea12203-abs-0001"> <title>Abstract</title> <p>Global warming means that the ability to withstand heat stress is of crucial importance to insects' survival and reproduction. Insects have various ways of achieving thermal tolerance, which can be affected by thermal history, physiological state, and seasonal cycles. In this study, we compared the thermal tolerance of life stages and seasons of a wild population of the striped stem borer, <italic>Chilo suppressalis</italic> (Walker) (Lepidoptera: Pyralidae), an economically significant pest of rice crops in Asia. Our results demonstrate that the eggs, larvae, and adults of <italic>C. suppressalis</italic> collected in rice fields in Yangzhou, China, are able to tolerate extremely high temperatures, in excess of those this species encounters in nature. We found that egg masses had a survival rate of 75% after being kept at 42 °C for 8 h. Egg masses exposed to 39 °C for 8 h had the longest hatching time (3.3 days). LTemp<sub>50</sub> and LTemp<sub>90</sub> (i.e., the temperatures at which 50 or 90% of individuals died within 2 h) of larvae collected in late summer were 45.4 and 47.3 °C, respectively. LTime<sub>50</sub> and LTime<sub>90</sub> (i.e., the time required to kill 50 or 90% of individuals) at 44 °C were 6.2 and 9.6 h, respectively. The corresponding values for 46 °C were 1.5 and 2.6 h. We also found that the heat tolerance of adults collected in late summer was lower than that of larvae. For example, LTemp<sub>50</sub> of male and female adults was 43.8 and 43.6 °C, respectively. Other measures of the heat tolerance of adults, such as LTime<sub>50</sub> at 42 °C, also differed between the sexes, being 5.9 h for males and 7.2 h for females. Although adult survival was robust to heat stress, adult fertility was more sensitive. Our results also indicate that although the second generation of adults (i.e., the summer generation) typically encountered higher temperatures than the overwintering generation, survival of the second generation adults was lower.</p> </abstract>