The domestic cat (Felis catus) shows remarkable sensitivity to the adverse effects of phenolic drugs, including acetaminophen and aspirin, as well as structurally-related toxicants found in the diet and environment. This idiosyncrasy results from pseudogenization of the gene encoding UDP-glucuronosyltransferase (UGT) 1A6, the major species-conserved phenol detoxification enzyme. Here, we established the phylogenetic timing of disruptive UGT1A6 mutations and explored the hypothesis that gene inactivation in cats was enabled by minimal exposure to plant-derived toxicants. Fixation of the UGT1A6 pseudogene was estimated to have occurred between 35 and 11 million years ago with all extant Felidae having dysfunctional UGT1A6. Out of 22 additional taxa sampled, representative of most Carnivora families, only brown hyena (Parahyaena brunnea) and northern elephant seal (Mirounga angustirostris) showed inactivating UGT1A6 mutations. A comprehensive literature review of the natural diet of the sampled taxa indicated that all species with defective UGT1A6 were hypercarnivores (>70% dietary animal matter). Furthermore those species with UGT1A6 defects showed evidence for reduced amino acid constraint (increased dN/dS ratios approaching the neutral selection value of 1.0) as compared with species with intact UGT1A6. In contrast, there was no evidence for reduced amino acid constraint for these same species within UGT1A1, the gene encoding the enzyme responsible for detoxification of endogenously generated bilirubin. Our results provide the first evidence suggesting that diet may have played a permissive role in the devolution of a mammalian drug metabolizing enzyme. Further work is needed to establish whether these preliminary findings can be generalized to all Carnivora.
'Department of Environmental Science, Policy and Management, 151 Hilgard Hall, University of California, Berkeley, California 94720, USA; 2Department of Biology, Tufts University, Medford, Massachusetts 02155, USA; 3International Institute of Tropical Forestry, USDA Forest Service, Box 490, Palmer, Puerto Rico 00721; 4Department of Ecology, Ethology and Evolution, University of Illinois, Champaign, Illinois 61820, USA; and 5Forestry Sciences Lab, USDA Forest Service, 2205 Columbia SE, Albuquerque, New Mexico 87106, USA
Abstract Fireflies are charismatic beetles with attractive bioluminescent courtship displays that have recently been swept onto the global stage of nature tourism. Here, we provide the first comprehensive review of the geographic scope, magnitude, focal species, and other attributes of the major firefly tourism sites worldwide. Through targeted interviews and surveys, we estimate that in recent years over one million tourists travelled annually to sites located in at least 12 countries for firefly‐watching. Rapid proliferation of firefly tourism provides a timely opportunity to examine how such activities may impact local firefly populations, and to highlight the biological factors that make certain species especially vulnerable to tourism‐associated threats. We offer science‐based best practices for firefly ecotourism that can be tailored to fit local circumstances, including recommendations to: (1) Conserve the habitats required for all life stages to thrive, (2) involve local communities as key stakeholders, and (3) provide training programs for guides and interpretive materials for visitors. Finally, we provide suggestions for transforming tourist behavior to minimize impact on firefly populations. By developing management plans that incorporate these recommendations, firefly tourist sites can enhance the visitor experience, protect natural resources, benefit local communities, and help promote the conservation of invertebrate biodiversity.
Abstract An analysis of the effects of colored leg bands on Red-cockaded Woodpeckers, in a long-term field study, showed that males that wore red bands fledged significantly fewer young than males without red bands. Other colors were unrelated to fledging success. Band color had no detectable effect on the fledging success of adult females. The offspring sex ratio of breeding males wearing red bands was significantly female-biased. Offspring sex ratios were not related to the presence or absence of red bands on breeding females. Wearing a red band did not affect the probability of a male attracting a mate or the probability of switching mates. For both sexes, annual age-specific survival was independent of the presence or absence of a red band, but nestlings wearing red bands were less likely to be sighted as fledglings. Males with red bands fledged fewer young, consistent with both the species-recognition hypothesis and the coverable-badge hypothesis. The coverable-badge hypothesis, which predicts that the inability to conceal a voluntary social signal (the red cockade) can be detrimental, is the more parsimonious explanation of our results.
Summary Exotic invasive species can influence population dynamics of native species through top‐down or bottom‐up forces. The present study examined separate and interactive effects of multiple exotic species invasions on the native mustard white butterfly, Pieris napi oleracea Harris (Lepidoptera: Pieridae), using a stochastic simulation model. P. n. oleracea populations in North America have decreased regionally since the 1860s. Competition with an exotic congener ( P. rapae L.), loss of native host plants and parasitism by the introduced broconid wasp ( Cotesia glomerata L.), have been suggested to be independently responsible for its decline. The present study examined these hypotheses, as well as an alternative, invasion by an exotic crucifer, garlic mustard ( Alliaria petiolata [Bieb.] Cavara & Grande). A stochastic simulation model of P. n. oleracea population dynamics revealed that decreasing the number of host plants available for oviposition and larval development (i.e. habitat loss), sharply reduced the probability of populations persistence and decreased population size for those that persisted. Simulated invasion by garlic mustard also substantially decreased both probability of persistence (= 0 at approximately 50% cover) and mean population size. Persistence probability never reached zero under any C. glomerata scenarios, even when larval mortality in the second generation due to parasitism was 100%. The impact of garlic mustard was intensified by the addition of C. glomerata parasitism. Results suggest that bottom‐up forces, loss of host plants through forest understorey loss and/or garlic mustard invasion are the most important forces driving P. n. oleracea population decline. Parasitism by C. glomerata may interact to reduce P. n. oleracea populations more rapidly, but appears insufficient alone to cause local extinction.
Abstract The following critiques express the opinions of the individual evaluators regarding the strengths, weaknesses, and value of the books they review. As such, the appraisals are subjective assessments and do not necessarily reflect the opinions of the editors or any official policy of the American Ornithologists' Union.
We assayed baseline and stress-induced corticosterone concentrations from adult female and nestling tree swallows, Tachycineta bicolor, from New England, U.S.A., sites with different levels of contamination with polychlorinated biphenyls (PCBs) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Corticosterone was compared over 2 years from a highly contaminated PCB site along the Housatonic River (Berkshire County, MA, USA), a midrange contaminated site upstream, and a reference site. Adult females (n=29), sampled only in 2003, showed an inverted-U association with PCBs, with higher stress-induced corticosterone with midrange contamination than at the high-contamination site. In nestlings, stress-induced corticosterone was highest for the highly contaminated site compared with the other sites in 2003 (n=53, 29 nests), with no difference among sites in 2004 (n=93, 27 nests). In 2004, we began testing mechanisms underlying these changes in nestlings at the high- and low-PCB sites. Corticosterone response to dexamethasone injection (used to test negative feedback) was not different between sites, but stress-induced corticosterone was reduced at the contaminated site after adrenocorticotropin hormone injection (used to test adrenal responsiveness), suggesting an inhibited ability to mount a stress response. We also compared nestlings from a stretch of the Woonasquatucket River, Rhode Island, U.S.A., heavily contaminated with TCDD (n=80, 43 nests) with nestlings from an upstream site that had lower levels of TCDD and the Berkshire County reference site. Although there were no stress-induced differences, baseline corticosterone was lower at the higher TCDD site than at the reference site. Altogether these findings suggest that tree swallows chronically exposed to high PCB and TCDD levels exhibit altered baseline and stress-induced corticosterone responses, but the patterns of alteration might not be predictable.
