The regulation of division of labor in social insects, particularly in the honey bee (Apis mellifera L.), has received considerable attention from a number of biological subdisciplines, including quantitative and behavioral genetics, because of the high complexity of the behavioral traits involved. The foraging choices of honey bee workers can be accurately quantified, and previous studies have made the foraging behavior of honey bees one of the best studied naturally occurring behavioral phenotypes. Three quantitative trait loci (QTL) have been identified that influence a set of foraging variables, including the concentration of nectar collected and the amount of pollen and nectar brought back to the hive. This study extends previous genetic investigations and represents the most comprehensive investigation of the genetic architecture of these foraging variables. We examined the effects of markers for the three established QTL and for one further candidate gene (Amfor), in two reciprocal backcross populations. These populations were also used to carry out two new QTL mapping studies, with over 400 Amplified Fragment Length Polymorphism (AFLP) markers in each. We detected a variety of effects of the genetic markers for the established QTL and the candidate gene, which were mostly epistatic in nature. A few new QTL could be detected with a variety of mapping techniques. Our results add complexity to the genetic architecture of the foraging behavior of the honey bee. Specifically, we support the hypotheses that pln1, pln2, pln3, and Amfor are involved in the regulation of foraging behavior in the honey bee and add some new factors that deserve further study in the future.

Alternative reproductive tactics are common in males but rather rare in females. In this respect, ants are apparently an interesting exception. Ant queens can either start a new colony on their own or utilize the work force of existing colonies for dependent colony founding. As the success of these different options depends on body reserves of the queens, the finding of two different classes of alate queens in some ant species that differ only in size strongly suggests alternative modes of reproduction. Studies of queen size polymorphism from a number of ant species differ in scope and also in their results. Nevertheless, across taxa evidence exists that small queens found dependently while their larger conspecifics found colonies on their own. However, in most cases it is not clear whether the small queens exploit unrelated colonies (intraspecific "social parasitism") or return to their natal colonies. In some ant species the queen size polymorphism might constitute an evolutionary transition to either interspecific social parasitism or a morphologically more pronounced queen polymorphism linked to dispersal. In others, queen size polymorphism might be a stable phenomenon. Although it is important in this context whether queen size polymorphism is caused by a genetic polymorphism or phenotypic plasticity, so far no conclusive evidence about proximate mechanisms of size determination has been presented. Some considerations are made about the question why female alternative reproductive tactics correlated with morphological adaptations are comparatively widespread in ants.

With recent findings of an unexpected variability in the reproductive behaviour of ant sexuals, their morphology has become an area of major evolutionary interest (Heinze and Tsuji, 1995). Here we report on the occurrence of two queen morphs in Leptothorax rugatulus (Hym., Formicidae): Microgynes (small queens), exceeding worker-size only marginally, and macrogynes, which are, typically for the subgenus Myrafant, about twice as big as their workers. The frequency distribution of queen-size is clearly bimodal, in contrast to worker-and male-size. The average size of queens is highly correlated with the size of daughters in field-collected colonies, whereas within colonies no correlation between the average queen-size and the size of workers or males exists. This gives additional support that size-dimorphism is due to a specific, transmissible size reduction of the microgynes which could be based on genetics, the environment or both. This reduction is quasi-isometric, with a slightly smaller thorax-to-head ratio in microgynes, and scanning electron microscopy does not reveal any significant degeneration of the pterothorax, ocelli or number of ommatidia. The frequency of microgynes at different sample sites is highly variable, correlating well with the prevailing social structure in the respective subpopulations. Indeed, the majority of macrogynes is found in monogynous colonies, while microgynes abound in polygynous ones, which is strong evidence for an alternative dispersal tactic. However, the expected correlation to altitude or latitude was not found and further investigations are needed to reveal proximate and ultimate causes of this prevalent polymorphism between two types of female ant reproductives.