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United States Department of Agriculture

Agricultural Research Service

Research Project: INSECT CRYOPRESERVATION, DORMANCY, GENETICS AND BIOCHEMISTRY

Location: Insect Genetics and Biochemistry Research

Title: The long winter: the synergy between fluctuating thermal regime and quiescence physiology in the pollinator, Megachile rotundata

Authors
item Yocum, George
item Rinehart, Joseph
item Torson, Alex -
item Greenlee, Kendra -
item Kemp, William
item Bowsher, Julia -

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 18, 2013
Publication Date: August 12, 2013
Citation: Yocum, G.D., Rinehart, J.P., Torson, A.S., Greenlee, K.J., Kemp, W.P., Bowsher, J.H. 2013. The long winter: the synergy between fluctuating thermal regime and quiescence physiology in the pollinator, Megachile rotundata [abstract]. 5th International Symposium on the Environmental Physiology of Ectotherms and Plants. p. 57.

Interpretive Summary: The alfalfa leafcutting bee Megachile rotundata (F.) is the primary pollinator for alfalfa seed production. Developing a more thorough understanding of M. rotundata low-temperature and diapause physiology is essential for the sustainable management of this key pollinator. We previously demonstrated that a daily high-temperature pulse (fluctuating thermal regime, FTR) significantly increased the survival of M. rotundata exposed to low-temperature storage. Since the longest period of low-temperature storage of M. rotundata occurs during overwintering, we wanted to evaluate whether FTR would improve overwintering survival and overall quality of this alternative pollinator. Using a storage regime employing a base temperature of 6°C and daily pulse for 1 hour at 20°C, survival of post-diapausing M. rotundata was extended through the first post-larval growing season and into the second. Illumina sequencing was carried out to determine the underlying molecular physiology of FTR in this important solitary bee pollinator.

Technical Abstract: The alfalfa leafcutting bee Megachile rotundata (F.) is the primary pollinator for seed production in alfalfa and a number of specialty crops. Developing a more thorough understanding of M. rotundata low-temperature and diapause physiology is essential for the sustainable management of this key pollinator. Under normal managed conditions, brood of the alfalfa leafcutting bee will develop from eggs to diapausing prepupae under field conditions, after which they are moved to constant low-temperature-storage until the following spring, whereupon incubation begins and development resumes. We previously demonstrated that a daily high-temperature pulse (fluctuating thermal regime, FTR) significantly increased the survival of M. rotundata pupae and adults exposed to low-temperature storage during interrupted incubation. Since the longest period of low-temperature storage of M. rotundata occurs during overwintering, we wanted to evaluate whether FTR would improve the survival and overall quality of this alternative pollinator. Using a storage regime employing a base temperature of 6°C and daily pulse for 1 hour at 20°C, economically significant levels of survival of post-diapausing M. rotundata were extended through the first post-larval growing season and into the second. Illumina sequencing was carried out to determine the underlying molecular physiology of FTR in this important solitary bee pollinator. These lines of investigation strengthen a growing body of literature demonstrating that FTR protocols are superior to constant temperature protocols for insect cold storage and will provide molecular biomarkers for optimizing other insect low-temperature storage regimes.

Last Modified: 4/23/2014