Facultative symbiont virulence determines horizontal transmission rate without host specificity in social amoebas.

In facultative symbioses, only a fraction of hosts are associated with symbionts. Specific host and symbiont pairings may be the result of host-symbiont coevolution driven by reciprocal selection or priority effects pertaining to which potential symbiont is associated with a host first. Distinguishing between these possibilities is important for understanding the evolutionary forces that affect facultative symbioses.

Seasonally increasing parasite load is associated with microbiome dysbiosis in wild bumblebees.

The microbiome is increasingly recognized for its complex relationship with host fitness. Bumblebees are host to a characteristic gut microbiome community that is derived and reinforced through social contact between individuals. The bumblebee microbiome is species-poor, and primarily composed from a small number of core taxa that are associated with the greater tribe of corbiculate bees.

Facultative symbiont virulence determines horizontal transmission rate without host strain specificity.

In facultative symbioses, only a fraction of hosts are associated with a symbiont. Understanding why specific host and symbiont strains are associated can inform us of the evolutionary forces affecting facultative symbioses. Possibilities include ongoing host-symbiont coevolution driven by reciprocal selection, or priority effects that are neutral in respect to the host-symbiont interaction.

Reduced and Nonreduced Genomes in Symbionts of Social Amoebas.

The social amoeba Dictyostelium discoideum is a predatory soil protist frequently used for studying host-pathogen interactions. A subset of D. discoideum strains isolated from soil persistently carry symbiotic , recently formally described as , , and .

Endosymbiotic adaptations in three new bacterial species associated with : sp. nov., sp. nov., and sp. nov.

Here we give names to three new species of that can remain in symbiosis indefinitely in the spores of a soil dwelling eukaryote, . The new species sp. nov.

Wild social amoebae show plastic responses to the presence of nonrelatives during multicellular development.

When multiple strains of microbes form social groups, such as the multicellular fruiting bodies of , conflict can arise regarding cell fate. Both fixed and plastic differences among strains can contribute to cell fate, and plastic responses may be particularly important if social environments frequently change. We used RNA-sequencing and photographic time series analysis to detect possible conflict-induced plastic differences between wild .

Genetic signatures of microbial altruism and cheating in social amoebas in the wild.

Many microbes engage in social interactions. Some of these have come to play an important role in the study of cooperation and conflict, largely because, unlike most animals, they can be genetically manipulated and experimentally evolved. However, whereas animal social behavior can be observed and assessed in natural environments, microbes usually cannot, so we know little about microbial social adaptations in nature.

Seasonal variation in basal and plastic cold tolerance: Adaptation is influenced by both long- and short-term phenotypic plasticity.

Understanding how thermal selection affects phenotypic distributions across different time scales will allow us to predict the effect of climate change on the fitness of ectotherms. We tested how seasonal temperature variation affects basal levels of cold tolerance and two types of phenotypic plasticity in . Developmental acclimation occurs as developmental stages of an organism are exposed to seasonal changes in temperature and its effect is irreversible, while reversible short-term acclimation occurs daily in response to diurnal changes in temperature.

Sorted gene genealogies and species-specific nonsynonymous substitutions point to putative postmating prezygotic isolation genes in Allonemobius crickets.

In the Allonemobius socius complex of crickets, reproductive isolation is primarily accomplished via postmating prezygotic barriers. We tested seven protein-coding genes expressed in the male ejaculate for patterns of evolution consistent with a putative role as postmating prezygotic isolation genes. Our recently diverged species generally lacked sequence variation.

Comparative proteomics uncovers the signature of natural selection acting on the ejaculate proteomes of two cricket species isolated by postmating, prezygotic phenotypes.

Two of the most well-supported patterns to have emerged over the past two decades of research in evolutionary biology are the occurrence of divergent natural selection acting on many male and female reproductive tract proteins and the importance of postmating, prezygotic phenotypes in reproductively isolating closely related species. Although these patterns appear to be common across a wide variety of taxa, the link between them remains poorly documented. Here, we utilize comparative proteomic techniques to determine whether or not there is evidence for natural selection acting on the ejaculate proteomes of two cricket species (Allonemobius fasciatus and A.

Sexually monomorphic mating preferences contribute to premating isolation based on song in European green lacewings.

When species are in intermediate stages of divergence, complicated patterns of reproductive isolation can arise among males and females of the incipient species. The Chrysoperla carnea group of green lacewings (Neuroptera: Chrysopidae) has recently experienced rapid speciation. They possess sexually monomorphic mating signals that were assumed to be important in mate recognition.