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United States Department of Agriculture

Agricultural Research Service

Research Project: INSECT GENOMIC BIODIVERSITY AND MOLECULAR REGULATION OF DIAPAUSE Title: Fluctuating thermal regimes improve survival of the alfalfa leafcutting bee during cold storage

Authors
item Yocum, George
item Rinehart, Joseph
item Kemp, William

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 14, 2010
Publication Date: July 7, 2010
Citation: Yocum, G.D., Rinehart, J.P., Kemp, W.P. 2010. Fluctuating Thermal Regimes Improve Survival of the Alfalfa Leafcutting Bee During Cold Storage [abstract]. 1st International Conference on Pollinator Biology, Health and Policy, July 24-28, 2010, University Park, PA. p. 9.

Interpretive Summary: The alfalfa leafcutting bee, Megachile rotundata is commonly held at low temperatures for overwintering the prepupae or for interrupting spring incubation to synchronize adult emergence with the peak alfalfa bloom. However, static low temperature exposures can be stressful depending on the temperature, duration of exposure, and the developmental stage exposed. Short high-temperature pulses have been demonstrated to alleviate the harmful effects of prolonged low temperature exposure. We first determined percent survival of developing bees held for varying durations at 6, 12 or 18ºC. Next, the effects of a pulse at 20ºC as well as the duration and frequency of the pulse on the survival of developing M. rotundata stored at 6ºC was determined. Finally, we examined the effect of high-temperature pulses on the survival of dormant prepupae to determine the feasibility of multi-year storage. This investigation clearly established that high-temperature pulses increase survival, and that both the duration and the frequency of the high-temperature pulses are important factors affecting survival of developing M. rotundata stored at low temperature. Short high-temperature pulses also increased the survival of dormant prepupae stored at 6ºC. This research contributes to the societal need for improved commercial-scale pollinator health and performance through expanded fundamental knowledge and enabling technologies.

Technical Abstract: The alfalfa leafcutting bee, Megachile rotundata is commonly held at low temperatures for overwintering the prepupae or for interrupting spring incubation to synchronize adult emergence with the peak alfalfa bloom. However, static low temperature exposures can be stressful depending on the temperature, duration of exposure, and the developmental stage exposed. Short high-temperature pulses have been demonstrated to alleviate the harmful effects of prolonged low temperature exposure. We first determined percent survival of developing bees held for varying durations at 6, 12 or 18ºC. Next, the effects of a pulse at 20ºC as well as the duration and frequency of the pulse on the survival of developing M. rotundata stored at 6ºC was determined. Finally, we examined the effect of high-temperature pulses on the survival of dormant prepupae to determine the feasibility of multi-year storage. This investigation clearly established that high-temperature pulses increase survival, and that both the duration and the frequency of the high-temperature pulses are important factors affecting survival of developing M. rotundata stored at low temperature. Short high-temperature pulses also increased the survival of dormant prepupae stored at 6ºC. This research contributes to the societal need for improved commercial-scale pollinator health and performance through expanded fundamental knowledge and enabling technologies.

Last Modified: 11/28/2014
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