Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/20/2002
Publication Date: 11/20/2002
Citation: PANKIW,T., RUBINK,W.L., POLLEN FORAGING RESPONSE TO BROOD PHEROMONE BY AFRICANIZED AND EUROPEAN HONEY BEES (APIS MELLIFERA L.), ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA, . Interpretive Summary: Africanized honey bees have now infiltrated much of the SW United States and displaced their European honey bee counterparts in the wild. Their defensive behavior is well-documented, but an understanding of other aspects of their biology, especially foraging, are essential in order to fully assess their impact in both management agriculture and the natural environment. In this experiment we sought to compare the pollen collection behavior of European and Africanized bees when exposed to artificially supplanted chemical cues, brood pheromones, known to be present on growing bee larvae. It was found that European honey bees responded more strongly to the pheromone as shown by an increased ration of pollen foragers in treated colonies. In addition, we were able to show through other studies that Africanized honey bees responded to lower sucrose concentrations than European honey bees. The different responses of the two bee races suggested that the response to sugar concentrations was not a good predictor for comparative foraging behavior. Part of this is attributed to the more defensive nature of the Africanized bee.
Technical Abstract: We examined the pollen foraging responses of Africanized and European honey bee colonies to hexane extractable compounds of Africanized and European larvae (brood pheromone). Brood pheromone was presented to broodless Africanized and European colonies equalized for numbers of bees, food stores, and empty comb space. The pheromone significantly increased the ratio of pollen to nonpollen foragers returning to colonies. There was no differential pollen foraging response to pheromone racial origin. European colonies in this study had significantly increased the ratio of pollen to nonpollen foragers entering coloniies than did Africanized colonies for pheromone and control treatments. The proboscis extension response to sucrose was used to test the sensitivity to sucrose of eight Africanized (most similar to Apis mellifera scutellata Lepeletier) and six European colonies (most similar to Apis mellifera ligustica L.). Individual sensitivity to sucrose has been demonstrated as a neuro-sensory correlate of foraging behavior in European bees such that individuals that forage for pollen have lower response thresholds to sucrose than bees that forage for nectar. Africanized bees were significantly more likely to respond to lower concentrations of sucrose than European bees. We concluded that sucrose response threshold was a poor predictor for comparative foraging behavior of these races because the neuro-sensory systems of the two races may be differentially "tuned" by thresholds to defensive cues.