In this review, we provide a current reference on disease resistance in insect societies. We start with the genetics of immunity in the context of behavioral and physiological processes and scale up levels of biological organization until we reach populations. A significant component of this review focuses on Apis mellifera and its role as a model system for studies on social immunity. We additionally review the models that have been applied to disease transmission in social insects and elucidate areas for future study in the field of social immunity.

/pdf/genetic-individual-and-group-facilitation-of-disease-46dak5jyj3.pdf

Genetic, individual, and group facilitation of disease resistance in insect societies.

https://www.bijenhouders.nl/files/Bijengezondheid/Evans%20&%20Spivak%20socialized%20medicine%202010.pdf

Socialized medicine: individual and communal disease barriers in honey bees.

Animal personalities or behavioural syndromes are consistent and/or correlated behaviours across two or more situations within a population. Social insect biologists have measured consistent individual variation in behaviour within and across colonies for decades. The goal of this review is to illustrate the ways in which both the study of social insects and of behavioural syndromes has overlapped, and to highlight ways in which both fields can move forward through the synergy of knowledge from each. Here we, (i) review work to date on behavioural syndromes (though not always referred to as such) in social insects, and discuss mechanisms and fitness effects of maintaining individual behavioural variation within and between colonies; (ii) summarise approaches and principles from studies of behavioural syndromes, such as trade-offs, feedback, and statistical methods developed specifically to study behavioural consistencies and correlations, and discuss how they might be applied specifically to the study of social insects; (iii) discuss how the study of social insects can enhance our understanding of behavioural syndromes—research in behavioural syndromes is beginning to explore the role of sociality in maintaining or developing behavioural types, and work on social insects can provide new insights in this area; and (iv) suggest future directions for study, with an emphasis on examining behavioural types at multiple levels of organisation (genes, individuals, colonies, or groups of individuals).

http://biocircuits.ucsd.edu/nmpinter/Jandt%20et%20al%202014%20BR.pdf

Behavioural syndromes and social insects: personality at multiple levels

Summary 1. When the parasitic mite Varroa jumped species from the eastern to the western honey bee, millions of infested bee colonies died. Recent work has revealed that the probable cause of this collapse is that mites provide a new route of transmission, by acting as a vector, for certain bee viruses. 2. Using a mathematical model parameterized by recently collected data on bee viruses, we investigate the relationship between the mite load in a colony and the possibility of a virus epidemic occurring within a bee colony. 3. The model suggests that the balance of coexistence between mite, virus and bee in the eastern honey bee, has been lost in the western bee host, not simply because of the new transmission route, but also because mite populations in western honey bee colonies has exceeded a critical epidemic threshold. We quantify the critical epidemic mite load for two well-studied bee viruses, acute paralysis virus and deformed wing virus, through the colony’s yearly life cycle. 4. As well as providing practical insights into mite control strategies, the model allows us to disentangle the relative importance of different bee and mite behaviours in virus spread. We consider the evolutionary aspects of the new route of virus transmission, looking in particular at how changes to social organization might bring about collective resistance.

/pdf/the-dynamics-of-virus-epidemics-in-varroa-infested-honey-bee-1p0n3dnycb.pdf

The dynamics of virus epidemics in Varroa -infested honey bee colonies

Honey bees, Apis mellifera, which perform hygienic behavior, quickly detect, uncap and remove diseased brood from the nest. This behavior, performed by bees 15-20 days old and prior to foraging, is likely mediated by olfactory cues. Because the neuromodulator octopamine (OA) plays a pivotal role in olfactory-based behaviors of honey bees, we examined whether bees bred for hygienic and nonhygienic behavior differed with regard to their OA expression and physiology. We compared the staining intensity of octopamine-immunoreactive (OA-ir) neurons in the deutocerebral region of the brain, medial to the antennal lobes, between hygienic and nonhygienic bees (based on genotype and phenotype). We also tested how the olfactory responses of the two lines, based on electroantennograms (EAGs), were affected by oral administration of OA and of epinastine, a highly specific OA antagonist. Our results revealed that bees expressing hygienic behavior (irrespective of genotype) possessed OA-ir neurons that exhibited more intense labeling than same-aged bees not performing the behavior. In bees bred for nonhygienic behavior, OA significantly increased the EAG response to low concentrations of diseased brood odor. Conversely, in bees bred for hygienic behavior, epinastine significantly reduced the magnitude of the EAG response, a reduction not observed in nonhygienic bees. Our results provide two lines of evidence that OA has the potential to facilitate the detection and response of honey bees to diseased brood. We discuss the contributions of OA for behavioral shaping and its ability to bias the nervous system to express one form of behavior over another.

Hygienic behavior in the honey bee (Apis mellifera L.) and the modulatory role of octopamine.

Hygienic behaviour performed by middle-aged worker bees is an important intranidal task in colonies of the honey bee Apis mellifera (L.). It comprises detecting diseased brood in the larval and pupal stages and removing all such infected brood, thereby decreasing the incidence of infection. Hygienic behaviour consists of two task-components: uncapping cells and removing the cell contents. The aim of this study was to observe bees performing hygienic behaviour to determine their age at performance of the behaviour and to describe their behavioural repertoire. The bees performing hygienic behaviour were middle-aged bees, younger than foragers. In the colonies where the behaviours of individual bees were observed, all bees performing the hygienic behaviour were seen to exhibit both the components, though at different frequencies. One behavioural class performed the task of uncapping cells at higher frequencies than the task of removing cell contents, while another class performed both tasks to the same extent. While these two classes had higher frequencies of the tasks comprising the hygienic behaviour but lower frequencies of other common behaviours in their repertoire, a third class of bees included those that performed all behaviours in their repertoire at similar frequencies. There was no difference in the ages of the bees in these three behavioural classes. These results suggest that there is no evidence of task partitioning among bees performing the hygienic behaviour. The segregation observed could, however, be based on their response thresholds to the stimulus and/or on their ability to discriminate the various cues emanating from the dead brood.

I Burns

Papers

Ethology of hygienic behaviour in the honey bee Apis mellifera L. (Hymenoptera: Apidae): behavioural repertoire of hygienic bees.