Olfactory learning of fruit odors in the eastern yellow jacket, Vespula maculifrons (Hymenoptera : Vespidae)

Food-seaching workers of eastern yellow jackets, Vespula maculifrons, are a ttracted by the natural odors of a wide variety of succulent fruits; partic ularly effective was pear. The only part of a fruit that repelled was the l eathery epicarp of oranges. After rewarding with sugar water, odors of six fruits, including the pulpy mesocarp of oranges and, in addition, the leave s of catmint Nepeta cataria all become highly attractive. To learn the dist inctive odors of any one of three fruits (pear, apple, quince), nondiscrimi nation training with a rewarded fruit was sufficient for the subsequent olf actory preference of the training fruit over the control fruit. In the othe r cases [banana, hawthorn (Crataegus crus-galli), grape] simultaneous discr imination training with a rewarded and an unrewarded fruit was necessary an d effective for obtaining differential responses to the odors of the traini ng fruits. As far as current evidence goes, olfactory learning plays simila r roles in the fruit foraging of this wasp and in the nectar foraging of th e honey bee (Apis mellifera).