Note to readers, attached is the complete final report for FNE97-175
This project was a continuation of Mr. Kelley’s earlier project, FNE96-138. Both involved efforts to attract native bumble bees and leafcutter bees as alternatives to renting hives for pollination of blueberries and cranberries.
Nesting boxes and bales of straw for the bumble bees, and wooden nesting blocks for the leafcutters, had been placed around Mr. Kelley’s farm and that of his neighbor for the earlier project. Monitoring of these nesting sites continued, and more were added. Crocuses and hyacinths were planted to provide the bees with pollen and nectar during the period before the blueberries and cranberries come into bloom. Observations were made from time to time to estimate bee densities and determine species.
Results: Mr. Kelley reports increases in the numbers of leafcutters and bumble bees during the two years that he has been involved in this work. Bumble bees are more numerous, but in a sense the increase in the population of leafcutters is more dramatic, since these were scarcely observed at all, initially. The bumble bee species observed were Bombus ternarius, B. impatiens, B. affinis, and B. vagans. Two genera of leafcutters were observed—Megachile and Osmia.
The bumble bees continued, as before, to eschew the straw bales and nesting boxes prepared for them; the leafcutters continued to occupy about the same fraction of the nesting blocks that had been put out for them, i.e. one-tenth to one-third of the total, depending on the field. It seems likely, then, that the increased bee population had more to do with availability of food than of shelter, particularly considering that the largest increase in bumble bee population was observed in a blueberry field that had a sizeable population of leatherleaf weeds– leatherleaf provides bees with forage before the blueberries begin to bloom.
Mr. Kelley believes emplacement of nesting sites for leafcutter bees is worthwhile, and he intends to continue the practice. Provision of nesting sites for bumble bees would not, however, appear to be worth the effort.