Rove beetle species and their pitfall trap abundance were studied in red spruce (Picea rubens Sarg.; Pinaceae) stands in the Acadia Research Forest, New Brunswick, Canada, in 1999. The study yielded over 5000 specimens representing 134 species in 11 subfamilies of Staphylinidae. Of these, 58 species represent new distribution records for New Brunswick (NPR), including 15 new distribution records for Canada (NCR), 6 new species, and 4 synonyms, as follows: Omaliinae, 3 species; Proteininae, Proteinus pseudothomasi Klimaszewski sp. nov. (NCR, NPR) and P. acadiensis Klimaszewski sp. nov. (NCR, NPR); Tachyporinae, 3 species; Trichophyinae, 1 species; Aleocharinae, 33 species, including Atheta capsularis Klimaszewski sp. nov., A. brunswickensis Klimaszewski sp. nov., A. pseudocrenuliventris Klimaszewski sp. nov., Oxypoda lacustris Casey (NPR) [= O. bradorensis Lohse syn. nov., O. egestosa Casey syn. nov., O. lassula Casey syn. nov., and O. optiva Casey syn. nov.], and Pella gesneri Klimaszewski sp. nov.; Oxytelinae, 3 species; Paederinae, 3 species; and Staphylininae, 10 species. The new species or known species representing new records for Canada are presented here with a short diagnosis, habitus images, and genital illustrations to help with identification. The habitus images and most genital illustrations are presented here for the first time for these species.

Theory and empirical results suggest that high biodiversity should often cause lower temporal variability in aggregate community properties such as total community biomass. We assembled microbial communities containing 2 to 8 species of competitors in aquatic microcosms and found that the temporal change in total community biomass was positively but insignificantly associated with diversity in a constant temperature environment. There was no evidence of any trend in variable temperature environments. Three non‐exclusive mechanisms might explain the lack of a net stabilising effect of species richness on temporal change. (1) A direct destabilising effect of diversity on population level variances caused some populations to vary more when embedded in more diverse communities. (2) Similar responses of the different species to environmental variability might have limited any insurance effect of increased species richness. (3) Large differences in the population level variability of different species (i.e., unevenness) could weaken the relation between species richness and community level stability. These three mechanisms may outweigh the stabilising effects of increases in total community biomass with diversity, statistical averaging, and slightly more negative covariance in more diverse communities. Our experiment and analyses advocate for further experimental investigations of diversity‐variability relations.

(E)-6,10-dimethyl-5,9-undecadien-2-ol (geranyl acetol), termed here fuscol, was identified as a male-produced pheromone emitted by Tetropium fuscum (F.) and Tetropium cinnamopterum Kirby. In field experiments, traps baited with synthetic fuscol alone were not significantly attractive, but the combination of fuscol plus host volatiles (a synthetic blend of monoterpenes plus ethanol) attracted significantly more male and female T. fuscum and female T. cinnamopterum than did host volatiles alone. This is the first homoterpenoid alcohol to be described in the Cerambycidae, and the first pheromone reported from the sub-family Spondylidinae.

Several recent studies suggest that community composition can take on alternate, apparently stable, states. For the most part, these studies are observational in nature and have not shown that alternate states arise from the order of species arrival during community assembly. Previous studies also provide little insight into the mechanisms that create alternate states, especially when direct species interactions, rather than environmental feedback, control their formation. We conducted experiments in identical physical environments to show that differences in the sequence of community assembly can create alternate species compositions that persist for many generations. Assembly sequence determined whether experimental food webs contained a single intraguild predator, or two intraguild predators. When the intraguild predator, Blepharisma americanum, became established in communities before the introduction of Tetrahymena vorax, combined effects of resource depletion and intraguild predation prevented the establishment of Tetrahymena. In contrast, when Tetrahymena preceded Blepharisma, both species frequently coexisted. Supporting experiments describe the exploitative competitive abilities of both intraguild predators, document the population dynamics of each species in less complex community modules, and determine the ability of Tetrahymena to invade Blepharisma cultures in the absence of competing prey. These results show that both competition and predation contribute to the formation of two alternate community states and confirm that one stable state resists transformation to the other.

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The Clinch River, in eastern United States, supports a diverse freshwater fauna including endangered mussels. Although mussel populations are stable in the Clinch's northeastern Tennessee segment, long-term declines have been documented upstream in Virginia. We analyzed water and sediment quality data collected by government agencies from the 1960s through 2013 in an effort to inform current management. The river was divided into sections considering data availability and major tributaries. We tested for spatial differences among river sections and for temporal trends, and compared measured values to potentially protective levels if available. Ammonia concentrations approaching and exceeding protective levels were recorded, most often during the 1970s and 1980s in upstream sections. Sediment metals occurred at levels potentially causing biological effects, mainly during the 1980s and 1990s. In the 2000s, water-column metals have been well below protective levels for general aquatic life. Dissolved solids (DS) increased in most river sections over the study period but mussel-specific protective levels are not known. Analysis of water pH, total N, and total P did not generate conservation concern. Enhanced monitoring for sediment metals, water-column metals, and ionic composition of DS; closer alignment of agency water monitoring practices in the two states; and research to determine biological effects of DS at current and anticipated levels can aid future conservation management.(KEY TERMS: rivers/streams; water quality; metals; nutrients; dissolved solids; freshwater mussels.) Price, Jennifer E.

Summary1. Food web theory hypothesizes that trophic interaction strengths of consumers should vary with consumer metabolic body mass (mass 0AE75 ) rather than simply with consumer body mass (mass 1AE0 ) owing to constraints on consumption imposed by metabolic demand for and metabolic capacity to process nutrients and energy. Accordingly, species with similar metabolic body masses should have similar trophic interaction strengths. 2. We experimentally tested this hypothesis by assembling food webs comprised of species of arthropod predators, small sap-feeding and large leaf-chewing insect herbivores and herbaceous plants in a New England, USA meadow grassland. The experiment comprised of a density-matching treatment where herbivore species were stocked into field mesocosms at equal densities to quantify baseline species identity and metabolic body mass effects. The experiment also comprised of a metabolic biomass-matching treatment where smaller sap-feeding herbivore (SH) species were stocked into mesocosms such that the product of their density and metabolic body mass (metabolic biomass) was equal to the large herbivore (LH) species. We compared the magnitude of the direct effects of herbivore species on plants in the different treatments. We also compared the magnitude of indirect effects between predators and plants mediated by herbivores in the different treatments. 3. Consistent with the hypothesis, we found that increasing metabolic biomass translated into a 9-14-fold increase in magnitude of herbivore direct effects and up to a fivefold increase in indirect effects on plants. Moreover, metabolic biomass matching caused interaction strengths among herbivore species to converge. This result came about through increases in the herbivore mean effects as well as decreases in variation in effects among treatment replicates as herbivore metabolic biomass increased. 4. We found, however, that herbivore feeding mode rather than herbivore metabolic biomass explained differences in the sign of indirect effects in the different food webs. 5. We conclude that increasing herbivore metabolic biomass not only strengthened the direct and indirect effects on plants but also made those effects more consistent across space. Nevertheless, metabolic biomass alone could not completely explain variation in the nature of indirect effects in the food web, suggesting that additional consideration of consumer traits like feeding mode will provide a more nuanced understanding of trophic interaction strengths in food webs.

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