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Animals must learn to ignore stimuli that are irrelevant to survival and attend to ones that enhance survival. When a stimulus regularly fails to be associated with an important consequence, subsequent excitatory learning about that stimulus can be delayed, which is a form of nonassociative conditioning called ‘latent inhibition’. Honey bees show latent inhibition toward an odor they have experienced without association with food reinforcement. Moreover, individual honey bees from the same colony differ in the degree to which they show latent inhibition, and these individual differences have a genetic basis. To investigate the mechanisms that underly individual differences in latent inhibition, we selected two honey bee lines for high and low latent inhibition, respectively. We crossed those lines and mapped a Quantitative Trait Locus for latent inhibition to a region of the genome that contains the tyramine receptor gene Amtyr1 [We use Amtyr1 to denote the gene and AmTYR1 the receptor throughout the text.]. We then show that disruption of Amtyr1 signaling either pharmacologically or through RNAi qualitatively changes the expression of latent inhibition but has little or slight effects on appetitive conditioning, and these results suggest that AmTYR1 modulates inhibitory processing in the CNS. Electrophysiological recordings from the brain during pharmacological blockade are consistent with a model that AmTYR1 indirectly regulates at inhibitory synapses in the CNS. Our results therefore identify a distinct Amtyr1 -based modulatory pathway for this type of nonassociative learning, and we propose a model for how Amtyr1 acts as a gain control to modulate hebbian plasticity at defined synapses in the CNS. We have shown elsewhere how this modulation also underlies potentially adaptive intracolonial learning differences among individuals that benefit colony survival. Finally, our neural model suggests a mechanism for the broad pleiotropy this gene has on several different behaviors. To efficiently navigate their environment, animals must pay attention to cues associated with events important for survival while also dismissing meaningless signals. The difference between relevant and irrelevant stimuli is learned through a range of complex mechanisms that includes latent inhibition. This process allows animals to ignore irrelevant stimuli, which makes it more difficult for them to associate a cue and a reward if that cue has been unrewarded before. For example, bees will take longer to ‘learn’ that a certain floral odor signals a feeding opportunity if they first repeatedly encountered the smell when food was absent. Such a mechanism allows organisms to devote more attention to other stimuli which have the potential to be important for survival. The strength of latent inhibition – as revealed by how quickly and easily an individual can learn to associate a reward with a previously unrewarded stimulus – can differ between individuals. For instance, this is the case in honey bee colonies, where workers have the same mother but may come from different fathers. Such genetic variation can be beneficial for the hive, with high latent inhibition workers being better suited for paying attention to and harvesting known resources, and their low latent inhibition peers for discovering new ones. However, the underlying genetic and neural mechanisms underpinning latent inhibition variability between individuals remained unclear. To investigate this question, Latshaw et al. cross-bred bees from high and low latent inhibition genetic lines. The resulting progeny underwent behavioral tests, and the genome of low and high latent inhibition individuals was screened. These analyses revealed a candidate gene, Amtyr1 , which was associated with individual variations in the learning mechanism. Further experiments showed that blocking or disrupting the production the AMTYR1 protein led to altered latent inhibition behavior as well as dampened attention-related processing in recordings from the central nervous system. Based on these findings, a model was proposed detailing how varying degrees of Amtyr1 activation can tune Hebbian plasticity, the brain mechanism that allows organisms to regulate associations between cues and events. Importantly, because of the way AMTYR1 acts in the nervous system, this modulatory role could go beyond latent inhibition, with the associated gene controlling the activity of a range of foraging-related behaviors. Genetic work in model organisms such as fruit flies would allow a more in-depth understanding of such network modulation.

There has now been an abundance of research conducted to explore genetic bases that underlie learning performance in the honey bee (Apis mellifera). This work has progressed to the point where studies now seek to relate genetic traits that underlie learning ability to learning in field-based foraging problems faced by workers. Accordingly, the focus of our research is to explore the correlation between laboratory-based performance using an established learning paradigm and field-based foraging behavior. To evaluate learning ability, selected lines were established by evaluating queens and drones in a proboscis extension reflex (PER) conditioning procedure to measure learning in a laboratory paradigm-latent inhibition (LI). Hybrid queens were then produced from our lines selected for high and low levels of LI and inseminated with semen from many drones chosen at random. The genetically diverse worker progeny were then evaluated for expression of LI and for preference of pollen and/or nectar during foraging. Foragers from several different queens, and which had resulted from fertilization by any of several different drone fathers, were collected as they returned from foraging flights and analyzed for pollen and nectar contents. They were subsequently evaluated for expression of LI. Our research revealed that pollen foragers exhibited stronger learning, both in the presence (excitatory conditioning) and absence (LI) of reinforcement. The heightened overall learning ability demonstrated by pollen foragers suggests that pollen foragers are in general more sensitive to a large number of environmental stimuli. This mechanism could contribute toward explanations of colony-level regulation of foraging patterns among workers.

The primary focus of this thesis was to examine the correlation between the heightened expression of learning behavior and pollen foraging in honey bees. The first objective was to develop a visual based proboscis extension reflex (PER) assay to evaluate subjects using both a visual and more traditional olfactory learning assay. The availability of two stimulus modalities facilitated the examination of intermodal stimulus interaction. Restrained intact honey bees can be successfully conditioned to discriminate diffuse blue and green light stimuli with recall present after 24 hours. However, subjects did not exhibit intermodal stimulus interaction under these experimental conditions. The second focus area utilized the visual learning paradigm to examine two genetic lines of honey bees, one selected for high and low levels of conditioned stimulus preexposure effect (CSPE) learning and the other for high and low levels of pollen collecting behavior. Earlier work using only the CSPE lines suggested a correlation between the expression of CSPE and the tendency to forage for pollen. Tests showed that while both the pollen and CSPS lines exhibited visual discrimination teaming, there were differences between the sublines in their response to the unreinforced light stimulus. This behavioral comparison revealed that if there is a common genetic basis that it is at least multigenic and only a partial overlap in the expression of learning behavior. The third chapter attempted to explore a potential underlying mechanism for the expression of CSPE learning. The third chapter examined the effect of nitric oxide (NO), a potential regulator in the neurological pathway for the expression of CSPE. Nitric oxide is a broadly functioning neurotransmitter, present in the olfactory learning pathway of honey bees. Reduced NO levels did not attenuate the expression of CSPE. Therefore, it was concluded that NO was not involved in the CSPE pathway. A genetic analysis of subjects provided the last piece of insight into the structural underpinnings of CSPE. The use of single nucleotide polymorphism (SNP) technology was an effort to test the common basis between the two lines in greater detail. Mapping results revealed a significant QTL shared by the pollen and CSPE lines.

Animals must learn to ignore stimuli that are irrelevant to survival and attend to ones that enhance survival. When a stimulus regularly fails to be associated with an important consequence, subsequent excitatory learning about that stimulus can be delayed, which is a form of non-associative conditioning called latent inhibition. Honey bees show latent inhibition toward an odor they have experienced without association with food reinforcement. Moreover, individual honey bees from the same colony differ in the degree to which they show latent inhibition, and these individual differences have a genetic basis. To investigate the mechanisms that underly individual differences in latent inhibition, we selected two honey bee lines for high and low latent inhibition, respectively. We crossed those lines and mapped a Quantitative Trait Locus (QTL) for latent inhibition to a region of the genome that contains the tyramine receptor gene Amtyr1. We then show that disruption of Amtyr1 signaling either pharmacologically or genetically increases expression of latent inhibition without affecting appetitive conditioning. Electrophysiological recordings from the brain during pharmacological blockade are consistent with a model that Amtyr1 regulates inhibition, such that without a functional AmTYR1 protein inhibition becomes strong and suppresses sensory responses in general. Finally, sequencing Amtyr1 and its up and downstream genomic region for high and low line workers suggested that individual differences might arise from variation in transcriptional control rather than structural changes in the coding region. Our results therefore identify a distinct reinforcement pathway for this type of non-associative learning, which we have shown also underlies potentially adaptive intracolonial learning differences among individuals that in combination benefit colony survival. Competing Interest Statement The authors have declared no competing interest. Footnotes * Revised format

In an effort to address the opioid epidemic, a majority of states recently passed some version of a Good Samaritan law (GSL) and/or a naloxone access law (NAL). Good Samaritan laws provide immunity from prosecution for drug possession to anyone who seeks medical assistance in the event of a drug overdose; NALs allow laypersons to administer naloxone, which temporarily counteracts the effects of an opioid overdose. Using data from the National Vital Statistics System multiple-cause-of-death mortality files for 1999–2014, this study is the first to examine the effects of these laws on overdose deaths involving opioids. The estimated effects of GSLs on opioid-related mortality are consistently negative but not statistically significant. Adoption of an NAL is associated with a statistically significant 9–10 percent reduction in opioid-related mortality, although the negative association between NALs and opioid-related mortality appears to be driven by early adopters—states that passed legislation before 2011.

By this point, you may be asking yourself, what is the catch? There has to be a catch as this sounds too good to be true, and it is! The catch is that we are relying on the efforts of Ohio beekeepers to assist with the selection process. Remember how I stated earlier that the OQP has a very limited number or resources? This project has been possible in part by financial support from OSBA, but has largely relied on the generous resources and time donated by all of the regional coordinators.

Working Paper No. 23171 In an effort to address the opioid epidemic, a majority of states have recently passed some version of a Naloxone Access Law (NAL) and/or a Good Samaritan Law (GSL). NALs allow lay persons to administer naloxone, which temporarily counteracts the effects of an opioid overdose; GSLs provide immunity from prosecution for drug possession to anyone who seeks medical assistance in the event of a drug overdose. This study is the first to examine the effect of these laws on opioid-related deaths. Using data from the National Vital Statistics System multiple cause-of-death mortality files for the period 1999-2014, we find that the adoption of a NAL is associated with a 9 to 11 percent reduction in opioid-related deaths. The estimated effect of GLSs on opioid-related deaths is of comparable magnitude, but not statistically significant at conventional levels. Finally, we find that neither NALs nor GSLs increase the recreational use of prescription painkillers.

The photographs indicate the position that we use to introduce the queens into their new colony. Two suggestions that apply to nearly every style of introduction are to always place the candy end up and place the queen cage in an area that is well supplied with bees, preferably between two brood frames. The reason for placing the candy end up is to prevent any dead attendants from sticking to the candy, which may restrict the access of the surviving attendants and the queen to the candy.