The appetitive form of associative learning plays a major role in honey bee (Apis mellifera) foraging. In Southeast Asia the native honey bee species Apis cerana is often attacked by hornets (Vespa velutina), mainly in the period from April to November. During the co-evolution of those two species, honey bees have developed several strategies to defend themselves such as learning the odors of hornets and releasing alarm components to inform other mate. However, little is known about whether and how honey bees modulate their olfactory learning the presence of the hornet predator and alarm components of honey bee itself.
  Prof. TAN Ken and his team of Xishaungbanna Tropical Botanical Garden (XTBG) conduct a study to investigate learning of A. cerana under predation risk. They asked whether worker bees could detect live hornet odor. They then tested whether associate hornet odors and honey bee main alarm pheromone isopentyl acetate (IPA) with sucrose rewarded. Finally they asked whether bees responded differently to predator odor and IPA and whether the predator odors modulated olfactory learning of flower odors.
  In the experiments, eastern honey bee, A. cerana, could detect the odor of live hornets, and associate odor signaling a potential risk with the sucrose reward. Compared to a floral odor, both risk-signaling odors were less well learned as predictors of reward. Combinations of the risk-signaling odor with the floral odor reduce appetitive learning of the floral odor
 Their results showed that learning of floral odors was not blocked under risk conditions, and no indication for aversive or aggressive responses was seen (e.g. sting extension). It appeared, therefore, that two opposing behaviors may compete and lead to a lower level of appetitive responsiveness to the learned floral odor.
  The study entitled “Honey Bees Modulate Their Olfactory Learning in the Presence of Hornet Predators and Alarm Component” has been published in PLoS ONE.

Contact
TAN Ken, Ph.D Principal Investigator
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
Tel: 86-871-65227717
Fax: 86-871-65227358
E-mail: kentan@xtbg.ac.cn