Honey bees begin life working in the hive. At Ϸ3 weeks of age, they shift to visiting flowers to forage for pollen and nectar. Foraging is a complex task associated with enlargement of the mushroom bodies, a brain region important in insects for certain forms of learning and memory. We report here that foraging bees had a larger volume of mushroom body neuropil than did agematched bees confined to the hive. This result indicates that direct experience of the world outside the hive causes mushroom body neuropil growth in bees. We also show that oral treatment of caged bees with pilocarpine, a muscarinic agonist, induced an increase in the volume of the neuropil similar to that seen after a week of foraging experience. Effects of pilocarpine were blocked by scopolamine, a muscarinic antagonist. Our results suggest that signaling in cholinergic pathways couples experience to structural brain plasticity.acetylcholine ͉ Apis mellifera ͉ foraging ͉ mushroom body

Transcription is slow relative to many post-transcriptional processes in the brain. Using the rich system of division of labor in the honeybee (Apis mellifera), we found extreme differences in the extent to which behavioral occupations of different durations were associated with geneexpression differences in the brain. Nursing and foraging, occupations lasting >1 week, were associated with significant expression differences for nearly one-quarter of the genes tested (1208 of 5563 cDNAs tested; P < 0.01, ANOVA), consistent with previous results. In contrast, transitional occupations, performed for 1-2 days after nursing and before the onset of foraging, were associated with either no differences (guards vs. undertakers; 19 cDNAs, fewer than the expectation of 56 false-positives) or few differences (comb builders vs. guards and undertakers; 248 cDNAs), but extensive differences relative to both nursing and foraging (>500 cDNAs, all contrasts). Statistical power analysis indicated that expression differences of two-, 1.5-and 1.25-fold should have been detected in 100, 92 and 37% of cases, respectively. Replication of previous results at these magnitudes was 95, 71 and 51%, with no genes showing differences in the opposite direction. These results indicate that behavioral plasticity over different time-scales may be associated with substantial differences in the extent of genomic plasticity in the brain.Keywords: Apis mellifera, behavior, brain, gene expression, honeybee, microarray, power analysis, replication Long-term behavioral differences between individuals involve differences in gene expression in the brain (Lim et al. 2004). In contrast, short-term changes are mediated by post-translational neurobiological processes acting over minutes, seconds and milliseconds. The extent to which transcriptional changes are associated with behavioral phenotype at 'intermediate' time-scales is not well understood. This knowledge is important for understanding the extent of genomic plasticity in brain function.We explored this issue by taking advantage of the rich system of division of labor in the honeybee (Robinson 2002). Bees feed and care for brood (nurse) during the first 2 weeks of adult life and shift to foraging at about 3 weeks of age. These occupations are 'long-duration', lasting >1 week. Between nursing and foraging, bees engage in one or more 'intermediate-duration' occupations, e.g. nest construction (comb building), guarding the nest entrance or removing corpses from the nest (undertaking). These tasks are performed by distinct groups of individuals usually for 1-2 days (Trumbo et al. 1997).Task specialization in honeybees represents a form of behavioral plasticity. All bees greater than approximately 5 days of age are capable of performing any of these behaviors. Moreover, bees live in densely populated colonies and are simultaneously exposed to the stimuli that elicit the performance of many different tasks. Task specialization involves differential responsiveness to stimuli in the same general hive environm...

This study underscores the need for heightened awareness of upper arm venous variations and advocates the regular use of preoperative ultrasound imaging. We propose that recognition of Type 3 anatomy may have implications in access algorithm and planning.

Animals use a variety of cue types to locate and discriminate objects. The ease with which particular cue types are learned varies across species and context. An enormous literature contains comparisons of spatial cue use to use of other cue types, but few experiments examine the ease with which various nonspatial cues are learned. In addition, few studies have examined cue use in reptiles. Thus, the authors compared whiptail lizards' (Cnemidophorus inornatus) ability to learn and reverse a discrimination using either position (left or right) or visual feature cues. Lizards learned and reversed the task using position cues faster and with greater accuracy than using feature cues.