Does conopid parasitism cause bumblebees to collect less pollen and stay out overnight?

Bumblebees are important pollinator species for wild and economically valuable agricultural plants. While bumblebees are subject to many types of parasites, fairly little is known about behavioral changes caused by conopid fly (Diptera: Conopidae) parasites prior to the host’s death about 12 days after infection. In order to determine if conopid infections reduce pollen return in Bombus impatiens individuals, bee pollen collection will be compared with the presence and stage of parasite infection and overnight trip status in commercial colonies allowed to forage in the wild. Bombus impatiens individuals were affixed with RFID tags to provide data on foraging trip length and total time spent outside the colony while video monitoring provided a visual index of pollen return. Conopid parasite status was then determined after a foraging period by monitoring these same individuals in captivity. The timing of infection was then determined at the conclusion of the study before video data is overlaid to look for behavioral changes associated with parasite status and overnighting. We found that parasitism is marginally related to decreasing pollen returns. We also found that overnighting behavior is not associated with conopid parasitism but rather trip day and also results in reduced pollen returns. Finally, we determined that conopid infections to reduce the lifespan of bumblebees quite drastically. These findings contradict previous studies that suggested that overnighting and conopid parasitism were related and we believe both have possible long-term implications for overall colony success.