Bacteria in the Bacillus cereus group encompasses diverse niches and include causative agents of anthrax and food poisoning, specialized invertebrate pathogens and psychrotolerant species. Understanding whether natural selection has led to divergence between phylogenetic clades can help understanding the processes shaping speciation, and has important implications for understanding the distribution and biological safety of this group. We tested whether the three most common terrestrial species in this group (B. cereus, Bacillus thuringiensis and Bacillus mycoides) are ecologically specialized in terms of resource use, thermal adaptation and fitness in different environmental conditions. All isolates tested grew vigorously in protein rich media and insect cadavers, but exploitation of soil or plant derived nutrients was similarly weak for all species. Psychrotolerance rather than clade predicted growth patterns in artificial media, while psychrotolerant isolates could outcompete B. thuringiensis in insect cadavers at low temperature. Nevertheless, for B. thuringiensis and B. mycoides, clade and taxonomic species were important predictors of growth and relative fitness in live insect infections. The common ecological niche in these terrestrial B. cereus species is the ability to exploit protein rich resources such as cadavers. However, selection has led to different phylogenetic groups developing different strategies for accessing this resource. Thus, clades, as well as traditional taxonomic phenotypes, predict biologically important traits.

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The acquisition of antibiotic resistance commonly imposes fitness costs, a reduction in the fitness of bacteria in the absence of drugs. These costs have been primarily quantified using in vitro experiments and a small number of in vivo studies in mice, and it is commonly assumed that these diverse methods are consistent. Here, we used an insect model of infection to compare the fitness costs of antibiotic resistance in vivo relative to in vitro conditions. Experiments explored diverse mechanisms of resistance in a Gram-positive pathogen, Bacillus thuringiensis, and a Gram-negative intestinal symbiont, Enterobacter cloacae. Rifampicin resistance in B. thuringiensis showed fitness costs that were typically elevated in vivo, although these were modulated by genotype-environment interactions. In contrast, resistance to cefotaxime via de-repression of AmpC β-lactamase in E. cloacae resulted in undetectable costs in vivo or in vitro, while spontaneous resistance to nalidixic acid, and carriage of the IncP plasmid RP4, imposed costs that increased in vivo. Overall, fitness costs in vitro were a poor predictor of fitness costs in vivo because of strong genotype environment interactions throughout this study. Insect infections provide a cheap and accessible means of assessing fitness consequences of resistance mutations, data that is important to understand the evolution and spread of resistance. This study emphasizes that the fitness costs imposed by particular mutations or different modes of resistance are extremely variable, and that only a subset of these mutations are likely to be prevalent outside of the laboratory.

This paper uses a material semiotic approach to explore how the ontological multiplicity of climate affects the communication of seasonal climate outlooks (SCO). The analysis is based on an ethnography of the UK Meteorological Office's (Met Office) 3‐month outlook, which predicts seasonal climate variability for the whole of the UK over the next 3 months. I advance geographical knowledge by critiquing a tendency among SCO providers to assume that stakeholders only treat the climate as a descriptive index of weather trends. Instead, I propose that the idea of a normal climate, which is central to this mode of communication, is an effect of materially diverse professional practices, such as running seasonal climate models, making contingency plans, or writing and publishing newspaper articles. These socio‐material practices enact multiple understandings, or ontologies, of what the climate is, which then shape how SCO are understood and used. The analysis identifies moments where ontologies of climate converge and diverge and discusses the effect that these moments have on the communication of the Met Office's 3‐month outlook. The paper concludes by assessing the theoretical significance of material semiotic approaches for geographical research into the multiplicity of climate, as well as the practical significance of this work for scientists who are involved in communicating climate information.