Title: The genetic components of extended life expectancy in chilled, post-diapause quiescent Alfalfa Leafcutting Bees, Megachile rotundata Authors
Submitted to: Annual Meeting of Society of Integrative and Comparative Biology
Publication Type: Abstract Only
Publication Acceptance Date: September 6, 2013
Publication Date: January 3, 2014
Citation: Torson, A.S., Yocum, G.D., Rinehart, J.P., Kemp, W.P., Bowsher, J.H. 2014. The genetic components of extended life expectancy in chilled, post-diapause quiescent Alfalfa Leafcutting Bees, Megachile rotundata [abstract]. Annual Meeting of Society of Integrative and Comparative Biology. January 3-7, 2014. Austin, TX. Abstract Book page 345. Interpretive Summary: Seventy percent of crops grown for human food production are dependent on pollinators. The value of this pollination service worldwide is estimated to be over 100 billion dollars annually. This value does not include agriculture products that are not directly consumed by humans such as alfalfa that is used as an input for meat and milk production. The alfalfa leafcutting bee Megachile rotundata is the primary pollinator used in the production of alfalfa seed in North America. There is growing interest in M. rotundata for pollination of various specialty crops. One of the key components making the alfalfa leafcutting bee available for these earlier season crops and to buffer against year-to-year price swings is the development of prolonged storage protocols. A storage protocol employing fluctuating thermal regime (FTR) has dramatically improved long-term survival of the alfalfa leafcutting bee during winter storage. This investigation was undertaken to clarify the physiological mechanisms responsible for this extended life expectancy during storage. Understanding the physiological mechanism of FTR will aid in the development of biomarkers that will be used to further optimize this vital storage technique.
Technical Abstract: The alfalfa leafcutting bee, Megachile rotundata, a solitary bee native to Eurasia, is the world’s most intensively managed solitary bee and has become the primary pollinator for alfalfa seed production. These bees, when commercially managed, are overwintered as diapausing prepupae under static thermal regime (STR) at 6°C until the spring when individuals are moved to 29°C and development resumes. Recent work has shown that individuals overwintered using a fluctuating thermal regime (FTR), consisting of a daily temperature increase to 20°C for one hour, show a dramatic increase in survival when compared to those overwintered in the current management practice. In this study individuals reared under FTR and STR protocols were collected as post-diapausing quiescent prepupae at two different time points and transcriptome profiling was performed using high-throughput mRNA sequencing (RNA-seq). An expression analysis identified differentially regulated transcripts between both treatments and time points. Transcript annotation and functional class analysis were used to identify differentially expressed transcripts. Transcripts belonging to oxidative stress and metabolic pathways predicted to protect against chill-injury were observed. This data provides first description of the genetic components that drive the differences in life expectancy between individuals reared under FTR and STR protocols.