Cannibalism of brood

Signs or indications

Difficult to diagnose. CappedCapping:
the covering that bees add over comb cells containing fully ripened honey or to cap brood that has reached the pupal stage; bee bread cells are not capped
cells opened and pupae showing evidence of being removed and eaten. Imbalance of brood from the normal ratio of roughly 1 egg to 2 larvae to 4 capped brood is evidence that larvae are not being properly fed.

Description

Bees on occasion will cannibalize brood. It is a normal means by which adult population can regulate their resources during spring, during times of disease (European foulbrood and American foulbrood, for example), and is a major means that hygienic bees use to control varroa mites. This is fairly common during spring buildup, when pollen income is disrupted by poor weather.

Cannibalism is also seen in instances of diseased brood and starvation. Instead of a solid pattern of capped brood, the pattern is spotty. Hygienic bees remove brood that is infested with varroa mites, especially in the fall months. Partially eaten pupae may be especially evident in parasitic mite syndrome (PMS) colonies. New evidence suggests cannibalism of pupae might spread deformed wing virus, leading to colony collapse.

Drone brood is heavily cannibalized in the fall.

Most closely resembles

weak spring colonies; disease conditions; PMS

Resources

Posada-Florez F, et al. 2021. Pupal cannibalism by worker honey bees contributes to the spread of deformed wing virus. Scientific Reports 11:8989. https://www.nature.com/articles/s41598-021-88649-y

Seifert P, Buling N and Grunewald B. 2021. Honey bee behaviours within the hive: insights from long-term video analysis. PLoS ONE. https//doe.org/10.1371/journal pone 0247323

Oliver R. 2015. Understanding colony buildup and decline: Part 6. Scientific Beekeeping. Accessed 2023. https://scientificbeekeeping.com/tag/rainy-weather/

“Honey bee hygiene: Cannibalism”. YouTube, uploaded by ApisProtect, 15 April 2021. https://www.youtube.com/watch?v=m_PPDFMgQV8

 Spotty brood pattern due to bees removing developing pupae in cells where mites are reproducing; photo by Ana Heck
Spotty brood pattern due to bees removing developing pupae in cells where mites are reproducing; photo by Ana Heck
 Spotty pattern. Bees opening pupal cells where mites occur to halt mite reproduction; photo by Meghan Milbrath
Spotty pattern. Bees opening pupal cells where mites occur to halt mite reproduction; photo by Meghan Milbrath
 Cannibalism exhibited by hygienic bees uncapping and removing worker pupae; photo by The BeeMD photo collection
Cannibalism exhibited by hygienic bees uncapping and removing worker pupae; photo by The BeeMD photo collection
 Cannibalized brood in deadout; photo by Dewey M. Caron
Cannibalized brood in deadout; photo by Dewey M. Caron