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Title: Entombed pollen: A new condition in honey bee colonies associated with increased risk of colony mortality

item Evans, Jay
item Pettis, Jeffery

Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2009
Publication Date: 6/10/2009
Citation: Vanengelsdorp, D., Evans, J.D., Donovall, L., Mullin, C., Frazier, M., Frazier, J., Pettis, J.S., Hayes, J. 2009. Entombed pollen: A new condition in honey bee colonies associated with increased risk of colony mortality. Journal of Invertebrate Pathology. 101:147-149.

Interpretive Summary: Colony collapse disorder and other factors are impacting honey bee health worldwide, with 30-40% winter colony mortality in the U.S. alone. As part of an extensive search for causes of honey bee losses we recognized an undescribed phenomenom,’entombed pollen’. This syndrome occurs in declining colonies and might reflect unsuitable pollens, pathogens or chemicals collected from the environment. Larvae raised on entombed pollen tended to do more poorly than larvae raised on normal pollen. Entombed pollen was more frequent in honey bee frames that had been used previously. These results point to another possible correlate with collapsing colonies and to a risk factor that beekeepers could use to minimize colony declines.

Technical Abstract: Here we describe a new phenomenon, entombed pollen, which is highly associated with increased colony mortality. Entombed pollen appears as sunken, wax-covered cells amidst “normal”, uncapped cells of stored pollen, and the pollen contained within these cells is brick red in color. There appears to be a lack of microbial agents in the pollen, and larvae and adult bees do not have an increased rate of mortality when they are fed diets supplemented with entombed pollen in vitro, suggesting that the pollen itself is not directly responsible for increased colony mortality. However, the increased incidence of entombed pollen in reused wax comb suggests that there is a transmittable factor common to the phenomenon and colony mortality. In addition, there were elevated pesticide levels, notably of the fungicide chlorothalonil, in entombed pollen. Additional studies are needed to determine if there is a causal relationship between entombed pollen, chemical residues, and colony mortality.