Bacterial Communities in Central European Bumblebees: Low Diversity and High Specificity

Recent studies on the microbial flora of the honeybee gut have revealed an apparently highly specific community of resident bacteria that might play a role in immune defence and food preservation for their hosts. However, at present, very little is known about the diversity and ecology of bacteria occurring in non-domesticated bees like bumblebees, which are of similar importance as honeybees for the pollination of agricultural and wild flowers. To fill this gap in knowledge, we examined six of the most common bumblebee species in Central Europe from three locations in Germany and Switzerland for their bacterial communities. We used a culture-independent molecular approach based on sequencing the 16S rRNA gene from a selection of individuals and examining a larger number of samples by terminal restriction fragment length polymorphism profiles. The gut flora was dominated by very few and mostly undescribed groups of bacteria belonging to the Proteobacteria, Bacteroidetes, Firmicutes and Actinobacteria. This core set of bacteria was present in all of the examined bumblebee species. These bacteria are similar to, but distinct from, bacteria previously described from the honeybee gut. Significant differences were observed between the communities of bacteria in the different bumblebee species; the effect of sampling location was less strong. A novel group of Betaproteobacteria additionally shows evidence for host species-specific genotypes. The gut flora of bumblebees therefore is apparently composed of relatively few highly specialized bacteria, indicating a strong interaction and possibly important functions with their host

Sperm reduces female longevity and increases melanization of the spermatheca in the bumblebee Bombus terrestris L

Abstract.: Here we present evidence that the male mating products (sperm and gland products) reduce survival during hibernation of queens of the bumblebee B. terrestris. Most remarkably, the inseminated queens are significantly more likely to have melanized spermathecae than their virgin sisters. Although we could not detect a direct relationship between these two findings they are quite remarkable since B. terrestris is a monandrous and comparably long-lived insect where sexual conflict is unlikely to evolve. The reduced survival can probably be attributed to a general cost of maintaining the sperm, whereas the presence of melanized spermathecae in the inseminated queens may indicate a pathogen transferred during mating or genetic incompatibilities between males and queen

The genetic architecture of susceptibility to parasites

<p>Abstract</p> <p>Background</p> <p>The antagonistic co-evolution of hosts and their parasites is considered to be a potential driving force in maintaining host genetic variation including sexual reproduction and recombination. The examination of this hypothesis calls for information about the genetic basis of host-parasite interactions – such as how many genes are involved, how big an effect these genes have and whether there is epistasis between loci. We here examine the genetic architecture of quantitative resistance in animal and plant hosts by concatenating published studies that have identified quantitative trait loci (QTL) for host resistance in animals and plants.</p> <p>Results</p> <p>Collectively, these studies show that host resistance is affected by few loci. We particularly show that additional epistatic interactions, especially between loci on different chromosomes, explain a majority of the effects. Furthermore, we find that when experiments are repeated using different host or parasite genotypes under otherwise identical conditions, the underlying genetic architecture of host resistance can vary dramatically – that is, involves different QTLs and epistatic interactions. QTLs and epistatic loci vary much less when host and parasite types remain the same but experiments are repeated in different environments.</p> <p>Conclusion</p> <p>This pattern of variability of the genetic architecture is predicted by strong interactions between genotypes and corroborates the prevalence of varying host-parasite combinations over varying environmental conditions. Moreover, epistasis is a major determinant of phenotypic variance for host resistance. Because epistasis seems to occur predominantly between, rather than within, chromosomes, segregation and chromosome number rather than recombination via cross-over should be the major elements affecting adaptive change in host resistance.</p

Experimentally evolved trypanosome: infection success and virulence in the bumblebee

In this paper, Beer's Viable System Model (VSM) is applied to knowledge management. Based on the VSM, domains of knowledge are identified that an organization should possess to maintain its viability. The logic of the VSM is also used to support the diagnosis, design and implementation of the knowledge processes that should make and keep organizationally viable knowledge available

Time and energy constraints and the relationships between currencies in foraging theory

Measured foraging strategies often cluster around values that maximize the ratio of energy gained over energy spent while foraging (efficiency), rather than values that would maximize the long-term net rate of energy gain (rate). The reasons for this are not understood. This paper focuses on time and energy constraints while foraging to illustrate the relationship between efficiency and rate-maximizing strategies and develops models that provide a simple framework to analyze foraging strategies in two distinct foraging contexts. We assume that while capturing and ingesting food for their own use (which we term feeding), foragers behave so as to maximize the total net daily energetic gain. When gathering food for others or for storage (which we term provisioning), we assume that foragers behave so as to maximize the total daily delivery, subject to meeting their own energetic requirements. In feeding contexts, the behavior maximizing total net daily gain also maximizes efficiency when daily intake is limited by the assimilation capacity. In contrast, when time available to forage sets the limit to gross intake, the behavior maximizing total net daily gain also maximizes rate. In provisioning contexts, when daily delivery is constrained by the energy needed to power self-feeding, maximizing efficiency ensures the highest total daily delivery. When time needed to recoup energetic expenditure limits total delivery, a low self-feeding rate relative to the rate of energy expenditure favors efficient strategies. However, as the rate of self-feeding increases, foraging behavior deviates from efficiency maximization in the direction predicted by rate maximization. Experimental manipulations of the rate of self-feeding in provisioning contexts could be a powerful tool to explore the relationship between rate and efficiency-maximizing behavio

Construction and characterization of a BAC-library for a key pollinator, the bumblebee Bombus terrestris L

Abstract.: The primitively social bumblebee Bombus terrestris is an ecological model species as well as an important agricultural pollinator. As part of the ongoing development of genomic resources for this model organism, we have constructed a publicly available bacterial artificial chromosome (BAC) library from males of a field-derived colony. We have shown that this library has a high coverage, which allows any particular sequence to be retrieved from at least one clone with a probability of 99.7%. We have further demonstrated the library's usefulness by successfully screening it with probes derived both from previously described B. terrestris genes and candidate genes from another bumblebee species and the honeybee. This library will facilitate genomic studies in B. terrestris and will allow for novel comparative studies in the social Hymenopter