The Proboscis Extension Reflex Not Elicited in Megachilid Bees

Abstract

A honey bee will reflexively extend its proboscis in response to antennal stimulation with sucrose solution (Bitterman et al, 1983). For decades the proboscis extension reflex (PER) of honey bees {Apis mellifera L., Hymenoptera: Apidae) has been used as a tool to further the understanding of their cognitive processes, such as learning and memory (Takeda, 1961; Bitterman et al, 1983), and revealing their neural and molecular foundations (reviewed in Giurfa, 2007). The PER has also been used to demonstrate learning abilities of bumble bees (Hymenoptera: Bombus spp.) (Laloi et al, 1999; Laloi and PhamDelegue, 2004) and stingless bees (Hymenoptera: Apidae) (Abramson et al, 1999; McCabe et al, 2007). We were interested in using the PER to answer questions about the cognitive processes of solitary bees, especially Osmia lignaria Say (blue orchard bee) and Megachile rotundata Fabricius (alfalfa leafcutting bee) (Hymenoptera: Megachildae). Our initial attempts to use simple PER elicitation procedures with O. lignaria failed, although honey bees readily responded. The lack of response in O. lignaria could have been due to procedural factors, such as method of bee restraint (Robin L. Foster, pers. comm.), or speciesspecific factors, such as level of social complexity. To determine whether the technique used to elicit the PER from honey bees can be adapted for use with other bees, we tested variations of the traditional PER elicitation technique on several species of Hymenoptera.