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排序方式: 共有225条查询结果,搜索用时 15 毫秒
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J. C. LEMAN C. B. WEDDLE S. N. GERSHMAN A. M. KERR G. D. OWER J. M. ST JOHN L. A. VOGEL S. K. SAKALUK 《Journal of evolutionary biology》2009,22(1):163-171
A growing body of evidence suggests that resources invested in reproduction often come at the expense of the ability to mount an immune response. During mating, female sagebrush crickets, Cyphoderris strepitans, consume the ends of the male’s hind wings and ingest his haemolymph. Previous research has shown that this behaviour impairs the ability of males to secure additional matings. One hypothesis to account for this effect is that wing wounding triggers an energetically costly immune response, such that nonvirgin males are unable to sustain the costly acoustical signalling needed to attract additional females. To test this hypothesis, we injected virgin males with lipopolysaccharides (LPS) to provoke an immune response, and monitored their mating success in the field. LPS‐injected virgin males took significantly longer to mate than sham‐injected virgin males, and spent significantly less time calling. We also compared virgin, nonvirgin and experimentally wing‐wounded virgin males with respect to: (1) their ability to encapsulate a foreign invader via the accumulation of haemocytes and deposition of melanin and (2) baseline levels of phenoloxidase (PO), a key enzyme in the biochemical cascade leading to the production of melanin. Although encapsulation ability did not differ with reproductive experience, virgin males had significantly higher levels of PO than either nonvirgin or experimentally wing‐wounded virgin males. These results suggest that wing‐wounding alone is sufficient to impair male immunity, and that males trade‐off investment in reproduction and immunity. 相似文献
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Justin E. Harbison Marco E. Metzger William E. Walton Renjie Hu 《Journal of vector ecology》2009,34(2):182-190
Water samples from 11 belowground stormwater treatment Best Management Practices (BMPs) were evaluated for their capacity to support rapid development of the West Nile virus (WNV) mosquito vector, Culex quinquefasciatus. The observed minimum development time from egg to pupa ranged from six to over 30 days. Concentrations of potential food resources (total suspended solids and the particulate organic matter in water samples) were significantly correlated to development times. In addition, the rate of immature mosquito development was both site‐dependent and variable in time, suggesting that factors favorable to rapid development were strongly influenced by watershed characteristics and seasonal changes in temperature. Measured temperatures in belowground BMPs suggest that these structures may remain amenable to WNV virus activity longer each year than sites aboveground. 相似文献
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VESNA MILANKOV JASMINA LUDOŠKI GUNILLA STÅHLS JELENA STAMENKOVIĆ ANTE VUJIĆ 《Zoological Journal of the Linnean Society》2009,155(4):819-833
This paper examines molecular and phenotypic variability in the widely spread European hoverfly species complex Merodon avidus. Herein, based on the mitochondrial DNA (mtDNA) sequences of the cytochrome c oxidase subunit I (COI) and morphometric wing parameters, M. avidus is shown to comprise a complex of cryptic species, and one variety is redefined as a valid species: M. bicolor Gil Collado, 1930 (as var. of spinipes). The species M. bicolor, M. avidus A, and M. avidus B were clearly delimited based on their wing size. A total of 29 M. avidus and M. bicolor individuals presented 20 mtDNA haplotypes, four of which were shared by M. avidus A and M. avidus B, three were confined to M. bicolor, seven to M. avidus A, and six to M. avidus B. Sequence divergences between lineages occurring in the Balkan and in Spain ranged from 4.93 to 6.0 (uncorrected p in %) whereas divergences between M. avidus A and M. avidus B were 0.26 to 1.56. Divergence among morphologically identified individuals of M. avidus A and M. avidus B species ranged from 0.13 to 1.58, and from 0.13 to 0.52, respectively. The phenotypic substructuring and observed genetic uniqueness of populations in spatially and temporally fragmented M. avidus taxa were used to identify genetic units. The early split of two allopatric lineages, Spanish M. bicolor and Balkan M. avidus, was followed by diversification in each lineage. Present‐day morphological uniformity masks much of the genetic complexity of lineages within the M. avidus complex. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 819–833. 相似文献
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Reduced productivity of Culex pipiens and Cx. restuans (Diptera: Culicidae) mosquitoes in parking area catch basins in the northeast Chicago metropolitan area 下载免费PDF全文
Justin E. Harbison Bridget Hulsebosch Jennifer Buczek Amy Runde Roger Nasci 《Journal of vector ecology》2017,42(1):148-154
From June to September, 2016, 100 catch basins in eight parking areas were monitored weekly for the presence of mosquito pupae in the operational area of the North Shore Mosquito Abatement District (NSMAD) located just north of Chicago, IL, U.S.A. Weekly results from these basins were compared to weekly samples taken from residential street catch basins, the most common type of catch basin treated seasonally by the NSMAD with larvicides. Over the 17 study weeks, residential street basins had a mean rate of productivity (pupae per basin‐visit) 12 times that of parking area catch basins. The two parking area sites with the highest mean rate of productivity were associated with county forest preserves. Productivity in both street and parking area basins was positively associated with the presence of three or more deciduous trees within 20 m of basins and if they were located directly adjacent to curbs. Alternatively, productivity was negatively associated with the proportion of impervious surface within 10 m of basins and weekly rainfall. Findings suggest that reduced catch basin larvicide applications may be appropriate in many parking area sites. 相似文献
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Bedhomme S Chippindale AK Prasad NG Delcourt M Abbott JK Mallet MA Rundle HD 《Journal of genetics》2011,90(3):443-452
Sexually dimorphic traits are likely to have evolved through sexually antagonistic selection. However, recent empirical data suggest that intralocus sexual conflict often persists, even when traits have diverged between males and females. This implies that evolved dimorphism is often incomplete in resolving intralocus conflict, providing a mechanism for the maintenance of genetic variance in fitness-related traits. We used experimental evolution in Drosophila melanogaster to directly test for ongoing conflict over a suite of sexually dimorphic cuticular hydrocarbons (CHCs) that are likely targets of sex-specific selection. Using a set of experimental populations in which the transmission of genetic material had been restricted to males for 82 generations, we show that CHCs did not evolve, providing experimental evidence for the absence of current intralocus sexual conflict over these traits. The absence of ongoing conflict could indicate that CHCs have never been the target of sexually antagonistic selection, although this would require the existing dimorphism to have evolved via completely sexlinked mutations or as a result of former, but now absent, pleiotropic effects of the underlying loci on another trait under sexually antagonistic selection. An alternative interpretation, and which we believe to be more likely, is that the extensive CHC sexual dimorphism is the result of past intralocus sexual conflict that has been fully resolved, implying that these traits have evolved genetic independence between the sexes and that genetic variation in them is therefore maintained by alternative mechanisms. This latter interpretation is consistent with the known roles of CHCs in sexual communication in this species and with previous studies suggesting the genetic independence of CHCs between males and females. Nevertheless, direct estimates of sexually antagonistic selection will be important to fully resolve these alternatives. 相似文献
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V. M. ST.J. READ F.L.S. 《Zoological Journal of the Linnean Society》1988,93(3):225-257
This paper brings together the scattered literature on the Onychophora from Trinidad, Tobago and the Lesser Antilles. The 11 known species from this area are described, incorporating new material collected by the author. Scanning electron micrographs of the dorsal integument are presented for all but one species. Parthenogenesis is reported in a population of Epiperipatus imthurni from Trinidad. 相似文献