Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: May 1, 2000
Publication Date: N/A
Interpretive Summary: The sunflower leafcutting bee, a native wood-nesting species, has much potential for development as a commercial pollinator of sunflowers. With support from Pioneer Hybrid in Woodland CA, we have been studying the use of this species as a pollinator in hybrid seed cages for the past three years. We are encouraged by our findings. We have learned that for a range of sunflower varieties: 1)visits by relatively few Megapugs produce as much or (usually) more seed per head (weightwise) than many more honeybees; 2)Megapugs spread themselves out across flower heads throughout the cages; 3)females can produce two to three nests and nine to ten progeny over the span of sunflower bloom in cages, and thereby double or triple their numbers; 4) bee activity can be modified by appropriate temperature treatments that made the bee more amenable to synchronization with sunflower bloom.
Technical Abstract: Sunflower hybrids are frequently produced in field cages to prevent contamination of hybrid seed lines by pollen from wild plants or other undesirable varieties. Hybrid production requires that plants in cages be pollinated by insects. Traditionally, the insect of choice has been the honeybee, but honeybees are not especially effective when confined in cages, and they can be intimidating to field workers who must enter the cages during their normal course of duties. We have been experimenting with using a native solitary bee, Megachile pugnata, as a replacement pollinator for honeybees on sunflowers grown in cages. Our results have been promising: bee-for-bee, "Megapugs" are much more effective as sunflower pollinators; they visit flowers throughout the large cages; females successfully produce progeny using sunflower pollen and nectar.