Calorespirometric determination of the effects of temperature on metabolism of Harmonia axyridis (Col: Coccinellidae) from second instars to adults

`The multicolored Asian lady beetle, Harmonia axyridis (Pallas), is displacing native coccinellid species in North America. To elucidate the mechanisms underlying this phenomenon, it is important to understand its physiological ecology. Hence, this study examined the temperature dependence of the respiratory physiology of this species. Calorespirometry was used to measure metabolic heat and CO2 production rates from second, third, and fourth instars; pupae; and adult beetles at temperatures from 0 to 40degreesC at 5degreesC intervals. Mass-specific respiration rates, in terms of either CO2 or heat production, increased with temperature, and, with the exception of pupae, decreased with increasing development. For all developmental stages, the results showed that below 10degreesC, CO2 was produced primarily from nonoxygen-consuming reactions. CO2 production gradually shifts more to oxygen-consuming reactions with increasing temperature, the fraction of CO2 from oxygen-consuming reactions reaching 0.5-0.7 at 40degreesC. Adults and second instars were stressed at 35degreesC and showed high mortality at 40degreesC, but these conditions were tolerated by all other stages studied. These data agree with field observations of the success of the multicolored Asian lady beetle in the temperature range from 15 to 25degreesC.