Abstract:
Our goal in this chapter is to determine whether particular behavioral traits represent actual adaptations in the context of foraging. Social bees are our chosen study system because they provide a convenient and tractable biological system with which to study the potential adaptiveness of a wide range of foraging traits such as flower constancy, floral color preference, learning to associate floral color as a predictor of reward, traplining, and communication about food sources. This variety of behavioral traits allows us to demonstrate the strengths and weaknesses of applying five approaches (four experimental and one theoretical) to the study of foraging at the species, population, and colony level. (1) The comparative approach allows us to contrast behavioral traits of extant species with those of their common ancestor. We correlated differences in floral color preference between closely related species (and populations), with a known phylogeny, with features in each bee's respective environment. (2) Reciprocal transplant experiments allowed us to test for local adaptation. We compared the relative foraging performance of distinct bee populations in both of their respective native environments. (3) Manipulating the foraging environment to eliminate specific behavioral traits permitted a direct comparison of animals' foraging performance in their normal and experimentally manipulated environment, allowing us to quantify the effect of the trait in question (traplining) on foraging performance. (4) Manipulating the foraging phenotype to eliminate specific behavioral traits is another valuable approach. Unless suitable behavioral mutants, knockouts, or molecular techniques to selectively block gene expression are available, creating such artificial foraging phenotypes is only possible for a very small number of specific traits, for example, the honeybee dance language. (5) Integrating biologically realistic modeling with experimental studies allows us to test predictions about the adaptive significance of foraging-related traits not amenable to experimental manipulation and to identify the ranges over which these traits might affect fitness. Do these approaches provide evidence that foraging behaviors are adaptive? In some cases, we show that forager behavior has indeed been tuned to function adaptively in a given niche, although the adaptive benefits of such behavioral traits are often strongly context dependent. However, in other cases, the observed patterns of behavior were more parsimoniously explained by chance evolutionary processes, or by the historical conditions under which bees operated in their evolutionary past. © 2006 Elsevier Inc. All rights reserved.
Abstract:
Division of labor is common across social groups. In social insects, many studies focus on the differentiation of in-nest and foraging workers and/or the division of foraging tasks. Few studies have specifically examined how workers divide in-nest tasks. In the bumble bee, Bombus impatiens, we have shown previously that smaller workers are more likely to feed larvae and incubate brood, whereas larger workers are more likely to fan or guard the nest. Here, we show that in spite of this, B. impatiens workers generally perform multiple tasks throughout their life. The size of this task repertoire size does not depend on body size, nor does it change with age. Further, individuals were more likely to perform the task they had been performing on the previous day than any other task, a pattern most pronounced among individuals who guarded the nest. On the other hand, there was no predictable sequence of task switching. Because workers tend to remain in the same region of the nest over time, in-nest workers may concentrate on a particular task, or subset of tasks, inside that region. This division of space, then, may be an important mechanism that leads to this weak specialization among in-nest bumble bee workers. © 2009 Springer-Verlag.
Abstract:
Honey bees (Apis mellifera) use the dance language to symbolically convey information about the location of floral resources from within the nest. To figure out why this unique ability evolved, we need to understand the benefits it offers to the colony. Previous studies have shown that, in fact, the location information in the dance is not always beneficial. We ask, in which ecological habitats do honey bee colonies actually benefit from the dance language, and what is it about those habitats that makes communication useful? In this study, we examine the effects of floral distribution patterns on the benefits of dance communication across five different habitats. In each habitat, we manipulated colonies' ability to communicate and measured their foraging success, while simultaneously characterizing the naturally occurring floral distribution. We find that communication is most beneficial when floral species richness is high and patches contain many flowers. These are ecological features that could have helped shape the evolution of the honey bee dance language. © 2012 Springer-Verlag.
Abstract:
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). © 2013 Cambridge Philosophical Society.
