Complementary Specializations of the Left and Right Sides of the Honeybee Brain

Abstract

Honeybees show lateral asymmetry in both learning about odors associated with reward and recalling memory of these associations. We have extended this research to show that bees exhibit lateral biases in their initial response to odors: viz., turning toward the source of an odor presented on their right side and turning away from it when presented on their left side. The odors we presented were the main component of the alarm pheromone, isoamyl acetate (IAA), and four floral scents. The significant bias to turn toward IAA odor on the right and away from it on the left is, we argue, a lateralization of the fight-flight response elicited by this pheromone. It contrasts to an absence of any asymmetry in the turning response to an odor of the flowers on which the bees had been feeding prior to testing: to this odor they turned toward when it was presented on either the left or right side. Lemon and orange odors were responded to differently on the left and right sides (toward on the right, away on the left), but no asymmetry was found in responses to rose odor. Our results show that side biases are present even in the initial, orienting response of bees to certain odors.

Lateralization of short- and long-term visual memories in an insect

“…Conversely, cockroaches (Cooper et al, 2011) and giant water bugs (Kight et al, 2008) show a consistent bias among most individuals within a population (population-level lateralisation). However, the majority of evidence for population-level lateralisation comes from eusocial insects such as leaf cutting ants (Jasmin and Devaux, 2015), bumble bees (Kells and Goulson, 2001) and honeybees (Rogers & Vallortigara, 2019).…”

Specialized neurons in the right habenula mediate response to aversive olfactory cues

“…Elaboration of this pathway may also help explain the advantage of lateralization in the processing of aversive information. It has been argued, for instance, that the antennal specialization to aversive odors in bees is correlated with directed turning away from the stimulus and escape ( Rogers and Vallortigara, 2019 ). Directional turning has also been observed in larval zebrafish ( Horstick et al, 2020 ), but whether it is correlated with laterality of the Hb-IPN pathway is unclear.…”

Specialized neurons in the right habenula mediate response to aversive olfactory cues

“…Elaboration of this pathway may also help explain the advantage of lateralization in the processing of aversive information. It has been argued, for instance, that the antennal specialization to aversive odors in bees is correlated with directed turning away from the stimulus and escape (Rogers and Vallortigara, 2019). Beyond olfaction, left-right asymmetry appears to be a more general feature of stress-inducing, aversive responses as demonstrated for the rat ventral hippocampus (Sakaguchi and Sakurai, 2017) and human pre-frontal cortex, where heightened anxiety also activates more neurons on the right than on the left (Avram et al, 2010;Ocklenburg et al, 2016).…”