Diverse communication strategies in bees as a window into adaptations to an unpredictable world.

Communication is a fundamental feature of animal societies and helps their members to solve the challenges they encounter, from exploiting food sources to fighting enemies or finding a new home. Eusocial bees inhabit a wide range of environments and they have evolved a multitude of communication signals that help them exploit resources in their environment efficiently. We highlight recent advances in our understanding of bee communication strategies and discuss how variation in social biology, such as colony size or nesting habits, and ecological conditions are important drivers of variation in communication strategies. Anthropogenic factors, such as habitat conversion, climate change, or the use of agrochemicals, are changing the world bees inhabit, and it is becoming clear that this affects communication both directly and indirectly, for example by affecting food source availability, social interactions among nestmates, and cognitive functions. Whether and how bees adapt their foraging and communication strategies to these changes represents a new frontier in bee behavioral and conservation research.

Higher infection probability of haemosporidian parasites in Blue-black Grassquits (Volatinia jacarina) inhabiting native vegetation across Brazil.

Human induced changes on landscape can alter the biotic and abiotic factors that influence the transmission of vector-borne parasites. To examine how infection rates of vector-transmitted parasites respond to changes on natural landscapes, we captured 330 Blue-black Grassquits (Volatinia jacarina) in Brazilian biomes and assessed the prevalence and diversity of avian haemosporidian parasites (Plasmodium and Haemoproteus) across avian host populations inhabiting environment under different disturbance and climatic conditions. Overall prevalence in Blue-black Grassquits was low (11%) and infection rates exhibited considerable spatial variation, ranging from zero to 39%. Based on genetic divergence of cytochrome b gene, we found two lineages of Haemoproteus (Parahaemoproteus) and 10 of Plasmodium. We showed that Blue-black Grassquit populations inhabiting sites with higher proportion of native vegetation cover were more infected across Brazil. Other landscape metrics (number of water bodies and distance to urban areas) and climatic condition (temperature and precipitation) known to influence vector activity and promote avian malaria transmission did not explain infection probability in Blue-black Grassquit populations. Moreover, breeding season did not explain prevalence across avian host populations. Our findings suggest that avian haemosporidian prevalence and diversity in Blue-black Grassquit populations are determined by recent anthropogenic changes in vegetation cover that may alter microclimate, thus influencing vector activity and parasite transmission.

Rapid morphological change in multiple cichlid ecotypes following the damming of a major clearwater river in Brazil.

While anthropogenic disturbances can have damaging effects on biodiversity, they also offer an opportunity to understand how species adapt to new environments and may even provide insights into the earliest stages of evolutionary diversification. With these topics in mind, we explored the morphological changes that have occurred across several cichlid species following the damming of the Tocantins River, Brazil. The Tocantins was once a large (2,450 km), contiguous river system; however, upon closure of the Tucuruí Hydroelectric Dam in 1984, a large (~2,850 km2), permanent reservoir was established. We used geometric morphometrics to evaluate changes in native cichlids, comparing historical museum specimens collected from the Tocantins to contemporary specimens collected from the Tucuruí reservoir. Six species across five genera were included to represent distinct ecomorphs, from large piscivores to relatively small opportunistic omnivores. Notably, statistically significant changes in shape and morphological disparity were observed in all species. Moreover, the documented changes tended to be associated with functionally relevant aspects of anatomy, including head, fin, and body shape. Our data offer insights into the ways cichlids have responded, morphologically, to a novel lake environment and provide a robust foundation for exploring the mechanisms through which these changes have occurred.

Deforestation-driven food-web collapse linked to emerging tropical infectious disease, Mycobacterium ulcerans.

Generalist microorganisms are the agents of many emerging infectious diseases (EIDs), but their natural life cycles are difficult to predict due to the multiplicity of potential hosts and environmental reservoirs. Among 250 known human EIDs, many have been traced to tropical rain forests and specifically freshwater aquatic systems, which act as an interface between microbe-rich sediments or substrates and terrestrial habitats. Along with the rapid urbanization of developing countries, population encroachment, deforestation, and land-use modifications are expected to increase the risk of EID outbreaks. We show that the freshwater food-web collapse driven by land-use change has a nonlinear effect on the abundance of preferential hosts of a generalist bacterial pathogen, Mycobacterium ulcerans. This leads to an increase of the pathogen within systems at certain levels of environmental disturbance. The complex link between aquatic, terrestrial, and EID processes highlights the potential importance of species community composition and structure and species life history traits in disease risk estimation and mapping. Mechanisms such as the one shown here are also central in predicting how human-induced environmental change, for example, deforestation and changes in land use, may drive emergence.