Inhibiting DNA methylation alters olfactory extinction but not acquisition learning in Apis cerana and Apis mellifera.
DNA methylation plays a key role in invertebrate acquisition and extinction memory. Honey bees have excellent olfactory learning, but the role of DNA methylation in memory formation has, to date, only been studied in Apis mellifera. We inhibited DNA methylation by inhibiting DNA methyltransferase (DNMT) with zebularine (zeb) and studied the resulting effects upon olfactory acquisition and extinction memory in two honey bee species, Apis cerana and A. mellifera. We used the proboscis extension reflex (PER) assay to measure memory. We provide the first demonstration that DNA methylation is also important in the olfactory extinction learning of A. cerana. DNMT did not reduce acquisition learning in either species. However, zeb bidirectionally and differentially altered extinction learning in both species. In particular, zeb provided 1h before acquisition learning improved extinction memory retention in A. mellifera, but reduced extinction memory retention in A. cerana. The reasons for these differences are unclear, but provide a basis for future studies to explore species-specific differences in the effects of methylation on memory formation.
Eastern Bee Research Institute of Yunnan Agricultural University, Kunming, Yunnan Province, China; Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Science, Kunming, Yunnan Province, China.
Zhiwen
Z
Gong
Eastern Bee Research Institute of Yunnan Agricultural University, Kunming, Yunnan Province, China.
Chao
C
Wang
Division of Biological Sciences, Section of Ecology, Behavior, and Evolution, University of California, San Diego, La Jolla, CA, USA.
James C
JC
Nieh
Eastern Bee Research Institute of Yunnan Agricultural University, Kunming, Yunnan Province, China; Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Science, Kunming, Yunnan Province, China. Electronic address: kentan@xtbg.ac.cn.
Ken
K
Tan
D000818:Animals; D001516:Bees / Q000502:physiology*; D019175:DNA Methylation; D005108:Extinction, Psychological; D007858:Learning; D012903:Smell; D013045:Species Specificity
Acquisition learning and memory; Apis cerana; Apis mellifera; DNA methylation; Extinction learning and memory