Specific metabolic heat rates (Rq) and respiration rates (RCO2) of adult Harmonia axyridis Pallas, the multicolored Asian lady beetle, and Hippodamia convergens Guerrin-Manaville, the convergent lady beetle, were measured in isothermal calorimeters at 5°C intervals from 0 to 40°C. Anabolic rates and Rq/RCO2 ratios were calculated as functions of temperature from the calorespirometric data. The two species have similar heat and CO2 rates from 0 to 10°C, but both rates are higher for H. convergens at all other temperatures. Anabolic rates and Rq/RCO2 ratios indicated high-temperature stress in H. convergens at 40°C and at 35 and 40°C in H. axyridis. Anabolic rates and Rq/RCO2 ratios for the two species differed markedly from 15 to 30°C, where H. convergens had a higher anabolic rate and lower Rq/RCO2 ratio (i.e., greater metabolic efficiency) than H. axyridis. The data show that H. axyridis maximizes the anabolic rate, and therefore the biosynthesis rate, at low temperatures around 5°C and maximizes the catabolic rate at 25–30°C to support movement. In H. convergens, the optimum temperature range is the same for both biosynthesis (anabolic rate) and movement (catabolic rate), i.e., from 15 to 30°C. The ability of H. axyridis to more efficiently use periods of low temperature for development and reproduction and periods of mid-range environmental temperatures for searching for prey and feeding probably contribute to its competitive displacement of native North American coccinellid species.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.