The tendency for organisms to be larger in cooler climates (Bergmann's rule) is widely observed in endotherms, and has been reputed to apply to some ectotherms including amphibians. However, recent reports provide conflicting support for the pattern,

Global loss of honey bee colonies is threatening the human food supply. Diverse pathogens reduce honey bee hardiness needed to sustain colonies, especially in winter. We isolated a free-living Gram negative bacillus from hemolymph of worker honey bees (Apis mellifera) found separated from winter clusters. In some hives, greater than 90% of the dying bees detached from the winter cluster were found to contain this bacterium in their hemolymph. Throughout the year, the same organism was rarely found in bees engaged in normal hive activities, but was detected in about half of Varroa destructor mites obtained from colonies that housed the septic bees. Flow cytometry of hemolymph from septic bees showed a significant reduction of plasmatocytes and other types of hemocytes. Interpretation of the16S rRNA sequence of the bacterium indicated that it belongs to the Serratia genus of Gram-negative Gammaproteobacteria, which has not previously been implicated as a pathogen of adult honey bees. Complete genome sequence analysis of the bacterium supported its classification as a novel strain of Serratia marcescens, which was designated as S. marcescens strain sicaria (Ss1). When compared with other strains of S. marcescens, Ss1 demonstrated several phenotypic and genetic differences, including 65 genes not previously found in other Serratia genomes. Some of the unique genes we identified in Ss1 were related to those from bacterial insect pathogens and commensals. Recovery of this organism extends a complex pathosphere of agents which may contribute to failure of honey bee colonies.

A major goal in macroecology is to determine how body size varies geographically, and explain why such patterns exist. Recently, a grid‐cell assemblage analysis found significant body size trends with latitude and temperature in Plethodon salamanders, and support for the heat‐balance hypothesis as a possible explanation for these trends. Here we demonstrate that the heat‐balance hypothesis is unlikely to have generated this pattern, and that there is no overall body size trend with temperature in Plethodon. Using data from 3155 local Plethodon assemblages, we find no support for body size clines with latitude, and no relationship between body size and temperature. We also found that body size did not covary with elevation, in contrast to what was predicted by heat‐balance. We then examined the various scenarios under which body size clines across grid‐cell assemblages could evolve via heat‐balance, and found that none were tenable in light of the existing data. Instead, a single, widely distributed species was responsible for the pattern across grid‐cell assemblages. Finally, we examined why phylogenetic eigenvector regression does not account for phylogenetic non‐independence among taxa, and should not be used to account for shared evolutionary history in assembly‐level analyses. Assemblage‐level patterns are a useful means of assessing biogeographic trends, and are an important complement to within‐species and cross‐species patterns. However, while the use of grid‐cell assemblage approaches from digital databases is expedient, their results must be examined critically, and whenever possible, compared with data obtained from local species assemblages (particularly for ecological mechanisms that operate at the level of individuals). Finally, our results emphasize the importance of using corroborative data to evaluate alternative hypotheses, so that potential mechanisms that explain bioegeographic patterns are properly assigned.

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We assessed community responses of aquatic invertebrates in 16 small, seasonal ponds in a forested region of north central Minnesota, USA, to evaluate potential influences of timber harvest and efficacy of uncut forested buffers in adjacent uplands. Invertebrate data gathered before (2000) and during the first 4 years following clearcut timber harvest (2001)(2002)(2003)(2004) indicated that tree removal was followed by shifts in aquatic invertebrate communities in adjacent seasonal ponds. Retention of forested buffers appeared to partially mitigate influences of tree removal, but benefits of buffers may be limited by wind throw or other factors. Additional research is needed to clarify relationships between ecological characteristics of seasonal ponds and upland silviculture activities, and to better document efficacy and longevity of forested buffers.