Location: Weed and Insect Biology Research
2021 Annual Report
Accomplishments
1. Cryopreservation of bumble bee sperm. Bumble bees are not only critical pollinators of agriculturally important crops, but they also include approximately 54 species native to North America, many of which are in decline. Despite this importance, there has been no procedure to cryopreserve their germplasm. ARS researchers in Fargo, North Dakota, reported on the first successful cryopreservation and revival of bumble bee sperm cells, resulting in 55% survival, which is expected to be sufficient to artificially inseminate a queen bumble bee and obtain progeny. These results will serve as a foundation for the development of protocols that will be essential to safeguard important traits in domesticated pollinator species and to preserve the diversity of declining ones.
2. Ultra-low temperature storage of larval mosquitoes. Mosquitos are one of the world’s most dangerous disease vectors, causing significant negative impacts to society. A key limiting factor to the study of mosquito species is that rearing them is a costly and labor-intensive endeavor. Researchers at the ARS laboratories in Fargo, North Dakota, collaborating with scientists at the Centers for Disease Control in Atlanta, Georgia, have been working to develop low-temperature storage protocols to reduce the burden of mosquito rearing. With a goal of developing a cryopreservation protocol, they have determined the extent to which multiple cryoprotectants in over 20 different combinations could be used to successfully store mosquito larvae with minimal damage. The discovery of several combinations showing low toxicity will provide new opportunities for preserving and studying mosquitos.
3. Improved low-temperature storage of the alfalfa leafcutting bee. When managed for pollination services, the alfalfa leafcutting bee is commonly stored at constant low temperatures in the spring to slow their development so that peak nesting activity coincides with peak crop bloom. Interrupting the low temperature storage with a short daily high-temperature pulse (fluctuating thermal regime, FTR) significantly increases bees’ survival. However, commercial rearing chambers are not capable of rapidly changing the temperature as required for a FTR protocol, due to the large mass of bees commonly found in production agricultural settings. ARS researchers in Fargo, North Dakota, have developed new FTR protocols requiring significantly smaller temperature changes that don’t jeopardize the bees’ survival. These novel storge protocols will decrease energy use and stress on the chamber’s refrigeration system and ensure high quality bees.
Review Publications
Yocum, G.D., Rajamohan, A., Rinehart, J.P. 2021. Comparison of fluctuating thermal regimes and commercially achievable constant-temperature regimes for short-term storage of the alfalfa leafcutting bee (Hymenoptera: Megachilidae). Journal of Economic Entomology. https://doi.org/10.1093/jee/toab019.
Campbell, J.B., Dosch, A., Hunt, C.M., Dotson, E.M., Benedict, M.Q., Rajamohan, A., Rinehart, J.P. 2021. Physiological responses to cryoprotectant treatment in an early larval stage of the malaria mosquito, Anopheles gambiae. Journal of Cryobiology. https://doi.org/10.1016/j.cryobiol.2020.12.001.
Campion, C.C., Rajamohan, A., Rinehart, J.P. 2021. Comparative analysis of cryopreservation of seminal vesicle derived spermatozoa from Bombus impatiens and Apis mellifera - Implications for artificial insemination of bumble bees. Journal of Cryobiology. 102:136-139. https://doi.org/10.1016/j.cryobiol.2021.06.002.
