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United States Department of Agriculture

Agricultural Research Service

Title: Studies for Improving Health and Management of Alfalfa Leafcutting Bees in the Northwestern U.S.

Authors
item Pitts Singer, Theresa
item James, Rosalind

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 19, 2004
Publication Date: N/A

Interpretive Summary: To assist alfalfa seed producers throughout the Northwestern U.S. in the management of healthy alfalfa leafcutting bee populations, we initiated a regional 'Bee Health' survey. We are working with up to three bee managers in seven states. We sample at four intervals throughout the annual alfalfa leafcutting bee management cycle, as well as gathering information on individual management practices via questionnaires. The four 'stages' of bee management we identified are: 1) Pre-Incubation; 2) Post-Emergence; 3) Post-Harvest; and 4) Wintering of Prepupae (pre- and post-punching or stripping). We obtain samples from managers at each of these stages, and also have them fill out a survey containing questions about their management practices (for both bee and seed production) that are pertinent to each stage. We passively collect temperature and humidity using small dataloggers that stay with the bees through the different stages. Generally, we found that for some growers, the percent of bees emerging from their overwintering stock was very low. However, a few local stocks and stocks from Canada had fair to good emergence. Also, sex ratios were usually less than two males for each female. We will continue the survey for a few years in order to gather enough data for scientific analyses. Our results so far have given us new ideas and perspectives for investigations.

Technical Abstract: To assist alfalfa seed producers throughout the Northwestern U.S. in the management of healthy alfalfa leafcutting bee populations, we initiated a regional 'Bee Health' survey. We are working with up to three bee managers in seven states. We sample at four intervals throughout the annual alfalfa leafcutting bee management cycle, as well as gathering information on individual management practices via questionnaires. The four 'stages' of bee management we identified are: 1) Pre-Incubation; 2) Post-Emergence; 3) Post-Harvest; and 4) Wintering of Prepupae (pre- and post-punching or stripping). We obtain samples from managers at each of these stages, and also have them fill out a survey containing questions about their management practices (for both bee and seed production) that are pertinent to each stage. We passively collect temperature and humidity using small dataloggers that stay with the bees through the different stages. Generally, we found that for some growers, the percent of bees emerging from their overwintering stock was very low. However, a few local stocks and stocks from Canada had fair to good emergence. Also, sex ratios were usually less than two males for each female. We will continue the survey for a few years in order to gather enough data for scientific analyses. Our results so far have given us new ideas and perspectives for investigations.

Last Modified: 11/1/2014
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