Effects of diet on female fecundity and larval development in the carrion beetle Necrophila japonica

The carrion beetle subfamily Silphinae (Coleoptera: Silphidae) contains dominant macroinvertebrates of soil ecosystems in temperate zones. However, their feeding habits, which determine the role of each species in the ecosystem, have not been sufficiently studied. Moreover, although a diet shift from necrophagy on vertebrate carcasses to predatory feeding on invertebrates is known to occur in this subfamily, the processes and mechanisms of this shift have also been inadequately addressed. We examined female fecundity and larval development on various diets in a Silphinae species, Necrophila (Eusilpha) japonica (Motschulsky). The experimental diets included a meat diet and various invertebrate diets, which reflect the ‘ancestral’ feeding habit in Silphinae, necrophagy, and the ‘derivative’ feeding habit, predatory feeding. Female fecundity was significantly higher on the meat diet (minced beef) than on an insect larvae diet (mealworms and dipteran larvae) but did not significantly differ from that on an earthworm diet. Larval developmental performance was significantly higher on the earthworm diet than on the meat and insect larvae diets. Our results for larval development were consistent with those of previous stable isotope analyses of the same species, in which isotopic values of larval samples agree with those of hypothetical consumers that utilize earthworms. The consistency of results among different methods indicates that N. japonica larvae are most likely earthworm feeders. In contrast, our results for the female fecundity experiment differed from those of previous stable isotope analyses, in which vertebrate carcasses unlikely serve as the staple diet of adults in the field; thus, the feeding habits of N. japonica adults remain unresolved. Our observations that females and larvae performed best on the meat and earthworm diets, respectively, may indicate that, in Silphinae, the diet shift from necrophagy to predatory habits occurs earlier in larvae than in adults.     

No relationship between individual genetic diversity and prevalence of avian malaria in a migratory kestrel

Insight into the genetic basis of malaria resistance is crucial for understanding the consequences of this parasite group on animal populations. Here, we analyse the relationship between genotypic variation at 11 highly variable microsatellite loci and prevalence of three different lineages of avian malaria, two Plasmodium (RTSR1, LK6) and one Haemoproteus (LK2), in a wild population of the endangered lesser kestrel (Falco naumanni). Although we used a large sample size (584 typed individuals), we did not find any significant association between the prevalence of the studied parasite lineages and individual genetic diversity. Although our data set is large, the 11 neutral markers typed may have had low power to detect such association, in part because of the low parasite prevalence observed (less than 5% of infected birds). However, the fact that we have detected previous correlations between genetic diversity and other traits (ectoparasitism risk, fecundity) in the study population using the same panel of neutral markers and lower sample sizes suggests that other factors could underlie the absence of such a similar correlation with avian malaria. Differences in the genetics of the studied traits and in their particular basis of inbreeding depression (dominance vs. overdominance) may have led to malaria prevalence, but not other traits, being uncoupled with individual genetic diversity. Also, we cannot discard the possibility that the absence of association was a consequence of a low pathogenic effect of these particular malaria lineages on our lesser kestrel population, and thus we should not expect the evolution of genetic resistance against these parasites.     

Social phenotype extended to communities: Expanded multilevel social selection analysis reveals fitness consequences of interspecific interactions

In social species, fitness consequences are associated with both individual and social phenotypes. Social selection analysis has quantified the contribution of conspecific social traits to individual fitness. There has been no attempt, however, to apply a social selection approach to quantify the fitness implications of heterospecific social phenotypes. Here, we propose a novel social selection based approach integrating the role of all social interactions at the community level. We extended multilevel selection analysis by including a term accounting for the group phenotype of heterospecifics. We analyzed nest activity as a model social trait common to two species, the lesser kestrel (Falco naumanni) and jackdaw (Corvus monedula), nesting in either single‐ or mixed‐species colonies. By recording reproductive outcome as a measure of relative fitness, our results reveal an asymmetric system wherein only jackdaw breeding performance was affected by the activity phenotypes of both conspecific and heterospecific neighbors. Our model incorporating heterospecific social phenotypes is applicable to animal communities where interacting species share a common social trait, thus allowing an assessment of the selection pressure imposed by interspecific interactions in nature. Finally, we discuss the potential role of ecological limitations accounting for random or preferential assortments among interspecific social phenotypes, and the implications of such processes to community evolution.     

农村室内持续用毒饵盒彻底灭鼠后家鼠群落的演替现象——小麝鼩(Crocidura suaveolens)的入侵

关于家鼠群落的演替现象,夏武平等曾报道大兴安岭森林采伐地区不同伐区人房内褐家鼠(Rattus norvegicus)、小家鼠(Mus musculus)与黑线姬鼠(Apodemus agrarius)数量的比较(夏武平、罗泽珣,1962);近年郑智民又报道了厦门市1933-1936年褐家鼠为优势种,到1974-1978年,历时40余年,由于种种原因小家鼠变成优势种(郑智民,1982)。     

Farmland habitat selection of wintering lesser kestrels in a Spanish pseudosteppe: implications for conservation strategies

The lesser kestrel Falco naumanni is a globally threatened species, whose breeding populations seem to have declined due to recent agricultural changes. However, nothing is known about habitat requirements during winter, despite the fact that several populations are overwintering in areas affected by agricultural transformations. We studied population size and habitat selection by wintering lesser kestrels in a Spanish pseudosteppe (Los Monegros), where traditional fallow systems for cereals are rapidly being replaced by intensive and/or irrigated crops. About 15% of the adult population wintered in the study area, as determined by systematic roadside counts compared with accurate censuses made during the breeding season. Wintering lesser kestrels preferred to forage on field margins and stubble, while avoiding abandoned fields, ploughs, scrubland, growing cereals and, mainly, the expanding irrigated crops. This work confirms the need to incorporate the habitat requirements of threatened species over their complete annual cycles; while breeding lesser kestrels scarcely use fallow (ploughed at that time), during the winter, fallow (stubble at that time) is their main foraging habitat. Both fallow land and the present agricultural calendar should be maintained to assure the conservation of wintering lesser kestrel populations.     

Lesser Scaup Breeding Probability and Female Survival on the Yukon Flats,Alaska

ABSTRACT Information on the ecology of waterfowl breeding in the boreal forest is lacking, despite the boreal region's importance to continental waterfowl populations and to duck species that are currently declining, such as lesser scaup (Aythya affinis). We estimated breeding probability and breeding season survival of female lesser scaup on the Yukon Flats National Wildlife Refuge, Alaska, USA, in 2005 and 2006. We captured and marked 93 lesser scaup with radiotransmitters during prelaying and nesting periods. Although all marked lesser scaup females were paired throughout prelaying and incubation periods, we estimated breeding probability over both years as 0.12 (SE = 0.05, n = 67) using telemetry. Proportion of lesser scaup females undergoing rapid follicle growth at capture in 2006 was 0.46 (SE = 0.11, n = 37), based on concentration of yolk precursors in blood plasma. By combining methods based on telemetry, yolk precursors, and postovulatory follicles, we estimated maximum breeding probability as 0.68 (SE = 0.08, n = 37) in 2006. Notably, breeding probability was positively related to female body mass. Survival of female lesser scaup during the nesting and brood-rearing periods was 0.92 (SE = 0.05) in 2005 and 0.86 (SE = 0.08) in 2006. Our results suggest that breeding probability is lower than expected for lesser scaup. In addition, the implicit assumption of continental duck-monitoring programs that all paired females attempt to breed should be reevaluated. Recruitment estimates based on annual breeding-pair surveys may overestimate productivity of scaup pairs in the boreal forest.     

Sound Intensity of Booming in Lesser Prairie-Chickens

ABSTRACT Wildlife managers traditionally monitored lesser prairie-chicken (Tympanuchus pallidicinctus) populations using road-based lek surveys and assumed booming can be heard ≥1.6 km from a lek. To assess this assumption, we measured sound intensity (decibels) of booming lesser prairie-chickens. Our results indicated sound intensity 1.6 km from a lek would be less than or equal to the sound intensity of a whisper. Thus, 1.6 km is probably too great a distance for audible detection of booming in many conditions.     

黄粉虫不同虫态肠道细菌分离及鉴定

目的研究黄粉虫肠道细菌的类群与其取食的关系,为进一步开发利用提供理论依据。方法从人工饲养的黄粉虫幼虫、蛹和成虫肠道环境中分离纯化获得9个细菌菌株,对其菌体形态、染色反应、培养性状、生理生化反应进行系统研究。结果研究结果表明,上述9个细菌菌株分别属于放线杆菌属（Actunobacillus）、丙酸杆菌属（Propionibacterium）、柠檬酸杆菌属（Citrobacter）、沙雷菌属（Serratia）、芽胞杆菌属（Bacillus）、皮杆菌属（Dermabacter）、短状杆菌属（Brachybacterium）、棍状杆菌属（Clavibacter）和微小杆菌属（Exiguobcacterium）。结论通过对黄粉虫不同虫态即幼虫、蛹和成虫肠道细菌分离,其细菌种类存在一定差别。