Author
 |
STANLEY, CORY - Utah State University |
|
Pitts Singer, Theresa |
|
Submitted to: Journal of Apicultural Research
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/18/2011 Publication Date: 7/12/2011 Citation: Stanley, C., Pitts Singer, T. 2011. Attraction to Old Nest Cues During Nest Selection by the Solitary Bee Megachile rotundata (Hymenoptera: Megachilidae). Journal of Apicultural Research. 50(3)227-234. Interpretive Summary: The alfalfa leafcutting bee is an important pollinator for the commercial production of alfalfa seed. However, many of the bees released for pollination do not remain at the commercial nesting sites and, therefore, an overall loss of bee production occurs in the field. Alfalfa leafcutting bees are solitary, yet gregarious, and they nest in pre-existing cavities. When selecting nest cavities, the female bees are attracted to previously used nests. Nests consist of a row of cells, each containing several components that may serve as odor cues for nesting females. In this study, we sought to: a) determine if there is a preference for cells that previously held male or female alfalfa leafcutting bees, b) verify attraction to whole nest cells from old alfalfa leafcutting bee nests, and c) determine which individual nest components of a cell are attractive to females. In a series of cage and open field experiments, females were allowed to start nests in nesting blocks containing whole cells or individual cell components from old nests. Statistical analyses were used to compare the choices made by the female bees. Females were attracted to whole cells from old nests in both cage and open field studies. They were equally attracted to male and female cells. Also, they were equally attracted to whole cells from old alfalfa leafcutting bee nests and from another related bee species, Osmia lignaria. In cages, they were equally attracted to all cell components. However, in the open field, females preferred some cell components over others. These results provide a foundation for future studies to identify potential chemical lures to aid in the retention of bee populations at commercial nest sites. Technical Abstract: The alfalfa leafcutting bee, Megachile rotundata F. (Hymenoptera: Megachilidae), is an important pollinator for the commercial production of alfalfa seed. However, poor nest establishment is an ongoing problem for bee managers. Megachile rotundata are solitary, yet gregarious bees that nest in pre-existing cavities. When selecting nest cavities, M. rotundata are attracted to previously used nests. Nests consist of a linear series of cells, each containing several components that may serve as cues for nesting females. In the current study, we sought to: a) determine if there is a preference for cells that previously held male or female conspecific bees, b) verify attraction to conspecific whole nest cells, and c) determine which individual nest components of a cell are attractive to nesting females. In a series of cage and open field experiments, M. rotundata females were allowed to initiate nests in blocks containing whole cells or individual cell components from old nests. Their nest choices were compared using ANOVA and REGWQ. Females were attracted to whole cells from old nests in both cage and open field studies. They were equally attracted to male and female cells. Also, they were equally attracted to whole cells from conspecifics and from another megachilid bee, Osmia lignaria. In cages, they were equally attracted to all cell components. However, in the open field, females preferred some cell components over others. These results provide a foundation for future studies to identify potential chemical lures to aid in the retention of bee populations at commercial nest sites. |
