首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Seasonal catches of the bean bug, Riptortus pedestris (Fabricius), captured in traps containing the synthetic pheromone, were investigated under different field conditions from 2005 to 2007. In soybean fields, the number of bugs attracted to the pheromone traps increased after flowering and peaked 9–13 days after flowering. After these attraction peaks, the populations of adult bugs and nymphs increased in soybean fields. In traps located in grassland, however, only small numbers of the bugs were caught during the soybean flowering stages (from mid August to early September). The sex ratio of adults caught in the pheromone traps differed among soybean growth stages. Before flowering, more males were caught than females. After flowering, trapped females increased in number and the proportion of females exceeded 0.5 throughout the flowering periods. These results suggest that attraction to the pheromone may be affected by host plant phenology, and that females, in particular, respond strongly to the pheromone during flowering of the host plant soybean.  相似文献   

2.
The introduction of American mink (Neovison vison; hereafter mink) into Europe has had severe impacts on many native wildlife species, including the water vole (Arvicola amphibius) in mainland Britain. Although trapping has been widely used to attempt to control mink, managers have little direct evidence of its effect on mink density or distribution, particularly where immigration of mink from nearby areas is inevitable. Such evidence is needed to justify the use of lethal methods in conservation policy. During 2006–2010 we removed mink from the River Monnow Catchment in western Britain, using track-recording rafts to monitor continuously for mink presence, guiding a strategic trapping effort. The area monitored and trapped was increased in stages, from a core sub-catchment with 109 km of water-course in 2006, to a 421-km2 catchment with 203 km of water-course in 2009. In each successive sub-catchment, mink detection and capture rates declined rapidly to near-zero levels after trapping began. Detections and captures showed seasonal peaks in every year corresponding to known dispersal periods, but also declined steadily from year to year, with increasing periods in which we did not detect mink. These results suggested that each sub-catchment was cleared of mink within a few months, with subsequent captures attributable to immigration. On average, we detected each mink 5.1 times before capture (daily probability of detection = 0.059 per mink and raft), and trapped them 3.4 days after deploying traps in response. On average, mink entering the area were likely to have been present for less than 13 days before capture. Water voles had been extinct in the Monnow Catchment since the 1980s. During 2006–2008 (starting 6 months after mink trapping commenced), we released 700 captive-bred water voles into the treatment area to re-establish a wild population. Persistence of this population through the 4 years of the project was considered indicative of effective mink control. This study demonstrates that, even in a mainland context, a systematic trapping strategy can have a substantial impact on the density and distribution of a damaging species, in this case allowing the restoration of a native prey species. © 2013 The Wildlife Society  相似文献   

3.
Circannual and circadian activity patterns of American mink Neovison vison were studied in a fishpond area in northern Germany. Fourteen mink were radiotracked, nine of them (five males, four females) for at least 6 months, some of them even up to 21 months. Both sexes have reduced activity rates in winter months and showed a considerable increase of activity during mating season (March). In summer months—during the pup raising period—female activity continued to be high. Male mink, on the other hand, were less active with the exception of August and September. During this time, dispersal of juveniles takes place with resident males increasingly having to defend their territories. Circadian activity rhythms differed markedly between sexes. All investigated females exhibited a perennial diurnal pattern. Female activity during twilight and night was significantly lower than during daylight. Three investigated male mink showed a typical nocturnal course throughout the year. Daylight activity of these animals was very low, increased during dusk and dawn activity rates and stayed at a higher level during the night. Two males behaved arrhythmic; they did not prefer any time of the day for activity. The observed temporal strategies were discussed in context of intra-sexual territoriality, sexual dimorphism in body size and different environmental factors.  相似文献   

4.
R. Mearns  I. Newton 《Ibis》1984,126(3):347-355
In south Scotland, most Peregrines returned to the same territories to breed in successive years, though a few females changed territory from one year to the next.
Annual mortality among breeding birds was at most 9% among females (or 11% in both sexes combined). There may have been considerable annual variation, however, and excluding one exceptional year out of five reduced the estimate for females to 7%. These estimates are maxima, but are still considerably lower than those obtained from ring recoveries of dead birds reported by members of the public.
Among trapped birds, four males first bred at age two years, one at three and another at four or five; two females first bred at one year, 13 at two years old and one at three. Five other females which were seen to be in first-year plumage but were not trapped, also laid eggs, and 12 other such paired females held territory but did not lay. Only one paired male held territory in first-year plumage.
In their movements between natal and breeding territories, some females moved further than males, with median distances of 83 and 58 km respectively. In addition, of birds trapped breeding in the study area, a greater proportion of the males than of the females had been born locally, despite an equal sex ratio among fledglings; this was also consistent with a greater dispersal of females. In general, Peregrines made much longer movements in their first year of life than subsequently. Movements were in any direction.  相似文献   

5.
  • 1 Demographic data on an invasive species of management concern, the American mink, are presented. Data were obtained on three feral mink populations in Europe distinguished by differences in the time elapsed since population establishment.
  • 2 Demographic data are presented in the form of life tables, age–sex distributions and sex ratios. Mink lived a maximum of 6 years, and mortality of 1‐year‐olds and adults differed substantially between populations.
  • 3 The data support the hypothesis that mink populations subject to culling have a higher proportion of young (less than 1 year old) to adults compared with non‐culled populations.
  相似文献   

6.
We studied the morphology of American mink Neovison vison in five out of the six introduced populations in Spain. The spatial and temporal variation of body weight (BW), body length (BL), tail length, hind-foot length and ear length were analysed. Temporal trends in BW and BL in relation to years since mink introduction were also analyzed. In addition, we tested the effect of sex, age (juvenile, subadult and adult) and age–sex interaction, on each parameter. Morphological parameters differed between populations, illustrating the high variability of body size of American mink in different environments, and the phenotypic plasticity of the species. Annual variations were synchronized between populations, suggesting a large-scale effect on all of them. BW and BL showed a decreasing trend in both males and females in relation to years since introduction. This decrease may be related to mink's diet. Differences in sex and age were found, pointing to sexual dimorphism in adults, subadults and juveniles. The dimorphism in non-adult individuals suggests that subadult males may have a competitive advantage from subadult females in feeding and/or hunting on bigger prey from an early age (resource partitioning hypothesis).  相似文献   

7.
Abstract. Four species of ticks found to infest 1391 American mink (Mustela vison) in Britain in five years were, in declining order of frequency, Ixodes hexagonus, Ixodes canisuga, Ixodes ricinus and Ixodes acuminatus. Ixodes hexagonus and I.canisuga occurred on 40% and 2.5% of mink respectively. Infestation rates (the proportion of infested mink) of adult females, nymphs and larvae were similar and tended to be lower in summer. The distribution of infestation size (the number of ticks per host) for adult females describes a negative binomial. The mean infestation size of nymphs varied with the sex of the host and was 5.2 for males and 4.2 for females. Mink are competent hosts for /. hexagonus.  相似文献   

8.
American mink (Neovison vison) are an ecologically damaging invasive species in Europe and Iceland where attempts to control them typically rely on trapping. The focus and efficiency of trapping can be improved by using track-recording mink rafts to identify where mink are present before traps are deployed. This paper describes development of operating strategy for the use of mink rafts with traps, to optimise capture efficiency against costs. We worked sequentially on two unconnected chalk streams in central southern England. On 17 km of the River Itchen, we operated a very high density of rafts (5.9 per km) through spring and summer to generate multiple detections of each mink present. All rafts recording mink tracks were armed with traps, and captured mink were euthanased. After removal of mink until no further detections were made, we calculated that each mink was detected 5.3 times at 5.1 raft sites, and on this basis, rationalised raft density to a standard one per kilometer of river. We set a trap deployment time (10 days) that encompassed the longest observed lapse from detection to capture (7 days), and extended the check interval for rafts in monitoring mode from 1 week to 2 weeks to further reduce costs. These operating rules were then deployed for 12 months on the 44-km River Wylye beginning in autumn. Rafts indicated that the river was cleared of mink through the capture of seven individuals, each of which was detected 3.6 times at 2.7 raft sites, on average, and was trapped within 6 days of detection giving a response time of less than 20 days. Although these operating rules may need refinement for other environments, we believe this is a sound basis for effective mink control.  相似文献   

9.
The perception and assessment of predation risk often cause changes in the activities of animals and induce behavioural responses that may in turn affect their movements and distribution. To simulate high predation risk in a midfield pond riparian habitat, we used fresh faeces from ranch American mink Neovison vison and recorded behavioural responses of water voles Arvicola amphibius. In areas where mink odour was deployed, the numbers of captured vole individuals and their trappability were significantly lower than in control areas. Several voles migrated from the zones with deployed mink faeces to the areas without faeces, thus proving that increased predation risk affects the distribution of individuals in a population. The response to mink odour was much more pronounced in females than in males; in areas with deployed mink faeces, not a single female was trapped. We conclude that although American mink is a non‐native, invasive predator, water voles respond to mink odour by reducing their activity and/or by avoiding places with higher predation risk.  相似文献   

10.
In autumn 1991, aphid parasitoids of the genusPraon (Hymenoptera; Braconidae) were caught in water traps with lures containing synthetic aphid sex pheromone components at three sites in England and one in Germany. At two of the English sites and at the German site, the traps were placed in winter cereal fields whilst the third English site was in woodland. Three species were caught,P. volucre, P. dorsale andP. abjectum. Those caught in cereal fields were almost entirelyP. volucre, whilstP. dorsale dominated at the woodland site. Of the known aphid sex pheromone components, the most effective lure was the (+)-(4aS, 7S, 7aR)-nepetalactone. Nepetalactone traps placed at the woodland site in spring and summer caught fewPraon females, and attraction may be confined to the autumn, when sexual female aphids are present in the field. Male parasitoids did not respond to the aphid pheromones at any time, although they were caught in suction traps operated at the woodland site during the autumn. At the cereal sites height had a significant influence on the efficiency of the pheromone traps, those placed just above the crop canopy being most effective. There was no evidence that any other genus of parasitoid responded to aphid sex pheromones at these sites.  相似文献   

11.
The stable fly Stomoxys calcitrans (L.) is a cosmopolitan biting fly of both economic and welfare concern, primarily as a result of its painful bite, which can cause blood loss, discomfort and loss of productivity in livestock. Between June and November in 2016 and May and December in 2017, Alsynite sticky‐traps were deployed at four Donkey Sanctuary sites in southwest England, which experience recurrent seasonal biting fly problems. The aim was to evaluate the seasonal dynamics of the stable fly populations and the risk factors associated with abundance. In total, 19 835 S. calcitrans were trapped during the study period. In both years, abundance increased gradually over summer months, peaking in late August/September. There were no relationships between seasonally detrended abundance and any climatic factors. Fly abundance was significantly different between sites and population size was consistent between years at three of the four sites. The median chronological age, as determined by pteridine analysis of flies caught live when blood‐feeding, was 4.67 days (interquartile range 3.8–6.2 days) in males and 6.79 days (interquartile range 4.8–10.4 days) in females; there was no significant, consistent change in age or age structure over time, suggesting that adult flies emerge continuously over the summer, rather than in discrete age‐related cohorts. The data suggest that flies are more abundant in the vicinity of active animal facilities, although the strong behavioural association between flies and their hosts means that they are less likely to be caught on traps where host availability is high. The implications of these results for fly management are discussed.  相似文献   

12.
In the first attempt to re-establish a population of the red-winged grasshopper, Oedipoda germanica (Latr.), threatened with extinction in Germany, 32 adults (19 females, 13 males) were taken from a population in a limestone quarry, individually marked, and translocated to the “Leutratal” nature reserve near Jena, Thuringia, formerly inhabited by the species. A simulation model with two scenarios was run to determine the probability of re-establishment of this small translocated population. One of the two scenarios indicated that populations of 20 females could survive with optimal life history parameters. In 1994, the year of translocation, during seven nights of observation between July and September, 25 adults were re-observed at least once. About 50% of the females and 70% of the males were found in a 20 m radius of the release point, whereas a maximum distance of about 70 m was recorded for a female. Using minimum female life-span and oviposition data from greenhouse experiments, 545 eggs were estimated to have been laid by the initial inoculum in 1994. In the subsequent years 1995 and 1996, only seven and three grasshoppers were observed within 30 m of the release point in 1994. However, the translocated population obviously went extinct in 1997 because no O. germanica could be found in that or following years. By comparing source and release habitat, the possible causes of the failed re-establishment were elucidated. In the year of release a short mean adult life span of 26 days was observed, assumed to be the consequence of high predation, and resulting in a lower reproductive rate. In the following years, low soil temperature of the release habitat probably delayed egg hatching for about 1 week, delaying phenology and thereby reducing the period over which eggs could be laid. A rapid population decline resulted in only three females found in the year before extinction.  相似文献   

13.
We studied correlates of habitat use of riparian feral American minkMustela vison Schreber, 1777 during winter in Biscay (Northern Iberian Peninsula). We live-trapped and radio-tagged 10 American mink (5 males and 5 females) and successfully radiotracked 7 of them (3 males and 4 females). During resting periods both sexes selected areas with dense scrub and near to deep waters. Both sexes used underground dens as well as resting sites located above the ground, but during cold days females rested in buildings much more often than males. Active females used areas of dense scrub, and males used large scrub patches. The results are interpreted in the light of mink hunting techniques and perceived predation risk: on larger scales, mink select areas primarily by food abundance, while on very small scales they use scrub and similar structures providing safe areas to hunt, forage and rest. The strong preference for banks with dense scrub provides options for management of the species.  相似文献   

14.
Cole L  Polfus L  Peters ES 《PloS one》2012,7(3):e32657

Background

Head and neck cancer (HNC) incidence, mortality and survival rates vary by sex and race, with men and African Americans disproportionately affected. Risk factors for HNC include tobacco and alcohol exposure, with a recent implication of human papillomavirus (HPV) in the pathogenesis of HNC. This study describes the epidemiology of HNC in the United States, examining variation of rates by age, sex, race/ethnicity and potential HPV-association.

Methods

We used the North American Association of Central Cancer Registries (NAACCR) Cancer in North America (CINA) Deluxe Analytic Data to analyze HNC incidence for 1995–2005 from forty population-based cancer registries. We calculated age-adjusted incidence rates and incidence trends using annual percent change by age, sex, race/ethnicity and HPV-association.

Results

Males and Non-Hispanic Blacks experienced greater HNC incidence compared to women and other race/ethnicity groupings. A significant overall increase in HNC incidence was observed among HPV-associated sites during 1995–2005, while non HPV-associated sites experienced a significant decline in HNC incidence. Overall, younger age groups, Non-Hispanic Whites and Hispanics experienced greater increases in incidence for HPV-associated sites, while HNC incidence declined for Non-Hispanic Blacks independent of HPV-association. In particular, for HPV-associated sites, HNC incidence for Non-Hispanic White males aged 45–54 increased at the greatest rate, with an APC of 6.28% (p<0.05). Among non HPV-associated sites, Non-Hispanic Black males aged 0–44 years experienced the greatest reduction in incidence (APC, −8.17%, p<0.05), while a greater decline among the older, 55–64 year age group (APC, −5.44%, p<0.05) occurred in females.

Conclusions

This study provides evidence that HPV-associated tumors are disproportionately affecting certain age, sex and race/ethnicity groups, representing a different disease process for HPV-associated tumors compared to non HPV-associated tumors. Our study suggests that HPV tumor status should be incorporated into treatment decisions for HNC patients to improve prognosis and survival.  相似文献   

15.
Carnitine palmitoyltransferase (CPT) deficiencies are common disorders of mitochondrial fatty acid oxidation. The CPT system is made up of two separate proteins located in the outer (CPT1) and inner (CPT2) mitochondrial membranes. While CPT2 is an ubiquitous protein, three tissue-specific CPT1 isoforms––the so-called “liver” (CPT1-A), “muscle” (CPT1B) and «brain» (CPT1-C) CPT1s––have been shown to exist. Amino acid and cDNA nucleotide sequences have been identified for all of these proteins. CPT1-A deficiency presents as recurrent attacks of fasting hypoketotic hypoglycemia. Twenty four CPT1A mutations have been reported to date. CPT1-B and -C deficiencies have not been hitherto identified. CPT2 deficiency has several clinical presentations. The “benign” adult form (more than 200 families reported) is characterized by episodes of rhabdomyolysis triggered by prolonged exercise. The prevalent S113L mutation is found in about 50% of mutant alleles. The infantile-type CPT2 presents as severe attacks of hypoketotic hypoglycemia, occasionally associated with cardiac damage commonly responsible for sudden death before 1 year of age. In addition to these symptoms, features of brain and kidney dysorganogenesis are frequently seen in the neonatal-onset CPT2 deficiency, almost always lethal during the first month of life. Around 40 CPT2 mutations (private missense or truncating mutations) have hitherto been detected. Treatment is based upon avoidance of fasting and/or exercise, a low fat diet enriched with medium chain triglycerides and carnitine. Prenatal diagnosis may be offered for pregnancies at a 1/4 risk of infantile/severe-type CPT2 deficiency.  相似文献   

16.
1. Fluctuating asymmetry has been used widely to investigate questions concerned with evolution and behaviour, and to study the effects of environmental pollution. Damselflies have been used to answer questions in both fields, but no attempt has been made to combine the knowledge from these areas to investigate whether and how evolutionary ecology and behaviour interfere with the use of fluctuating asymmetry as a bioindicator of water pollution. 2. Four hypotheses were formulated to investigate possible interferences: (1) Paired males should be less asymmetrical than unpaired males. (2) Males caught at breeding sites should be less asymmetrical than females caught at breeding sites. (3) Damselflies caught earlier in the season should be less asymmetrical than those caught later in the year. (4) Damselflies caught at control sites should be less asymmetrical than those caught at sites within areas of high pesticide usage. 3. No significant difference in asymmetry levels was found between paired and unpaired males. 4. Males were significantly less asymmetrical than females. 5. Damselflies caught earlier in the year were less asymmetrical than those caught later. 6. The data used to test the hypothesis that fluctuating asymmetry in the wings of mature damselflies reflects the level of pesticides used in the surrounding environment were equivocal. 7. The findings suggest that evolutionary ecology and behaviour interfere with the suitability of fluctuating asymmetry in mature damselflies as a biomonitoring tool and it is concluded that fluctuating asymmetry in emerging adults should be much more appropriate as a bioindicator.  相似文献   

17.
Résumé Après avoir mis en évidence, par une expérience préliminaire, l'efficacité du piégeage sexuel chez S. cerealella, en dehors de sa période normale d'activité, l'auteur a utilié cette méthode au cours des années 1968, 1969 et 1970 pour préciser le cycle biologique de cette espèce dans le Sud-Ouest de la France.A cette occasion, l'action de différents facteurs sur le rendement du piégeage sexuel a pu être étudiée. Parmi les facteurs physiques, le plus important paraît être la luminosité: c'est au crépuscule, pendant une heure environ, que se font les captures.Parmi les facteurs biotiques, la présence de la plante-hôte, le Maïs, et le stade phénologique de celle-ci ont une action déterminante sur le taux des captures: ces dernières sont plus nombreuses à partir de la floraison mâle jusqu'à l'approche de la maturité des grains.
Summary In order to determine if sex trapping could be utilised as a method of studying the dispersal of S. cerealella, 120 males reared in the laboratory were released and caught in a sex trap containing 100 virgin females. This first experiment took place in April 1968, outside the normal period of insect activity in nature. During the 10 days following the male release, we caught, at dusk, 40 males in this sex trap (30% of the release). This method was later used to determine the life cycle of the Angoumois grain moth in South-West France. S. cerealella appears in late May and early June in nature. It appears to produce three generations a year. The first and the second would be passed either on maize in cribs or stores, or on other cultivated or wild Graminaceae; on the other hand, the third generation would be spent on ears of maize in the fields.Among the climatic factors which influence the trapping rates of males, daylight seems the most important. The males are trapped only at dusk and for a period of about one hour. Temperature, aerial-humidity, and wind are not negligible.The sex attractiveness of virgin females seems such as to draw males from considerable distances: an experiment with several sex traps, each containing 5 virgin females only, has proved that it was possible to trap males at several hundred metres from the release point.Among biotic factors excluding those pertaining to the insect itself, the host-plant seems to be the principal factor for the number of trapped males. The maize has adouble effect by its mere presence and its phenological stage: continuous trapping from June to November by two sex traps on uncultivated fields and two other sex traps on maize fields gave respectively the following results: 393 and 6520 males.The experiment of trapping males after release in uncultivated areas and in corn fields gave the following results (% of males covered), for the three periods studied:July 9–13 whorl stage: 7.3%August 27–31 late tasseling and silking stage: 19.6%October 4–8 milking stage of kernels, maturity: 19.0%
  相似文献   

18.
Synopsis A 16-month study (August 1972 to November 1973) of Sarotherodon mossambicus in the Plover Cove Reservoir, Hong Kong revealed a sex ratio of 1:1 for small fish (below 19 cm standard length), but above this length males predominated in the population. Monthly sex composition also showed this approximately 1:1 ratio except during the months of August and September, when again males predominated. Males and females reached M50 at an average length of 17.8 cm and 16.2 cm respectively. Maturity and gonosomatic index studies showed that spawning occurred from May to October with peaks in June and August, and there were at least two spawnings each year. The relationship between fecundity and standard length of females collected during both spawnings was computed to be F = 118.49L–1150.91.  相似文献   

19.
Anistoroaei R  Christensen K 《Hereditas》2006,143(2006):198-201
Short tandem repeats are a source of highly polymorphic markers in mammalian genomes. Genetic variation at these hypervariable loci is extensively used for linkage analysis and to identify individuals, and is very useful for interpopulation and interspecies studies. Fifty-nine microsatellite markers from American mink were tested in the ferret, under the same conditions as for the mink. Of the 59, 43 of them (73.5%) amplified a ferret sequence; 5 amplification products differed in size from the respective mink sequences. Ten amplified fragments from ferret were sequenced. The sequences that were identical in size to those from mink displayed a high degree of conservation, with some differences at the repeat motif sites. These results could aid cross-utilization of markers between these two species.  相似文献   

20.
The diets of free-ranging male and female mink were sampled by analysing faeces collected from radio-tagged individuals. Significant sex differences were apparent in the predation upon three of the five principal prey groups. The larger males preyed much more heavily upon lagomorphs, the largest prey taken, while females preyed more upon fish and crustaceans than did males. These differences were consistent in each season except the autumn (September to November), when males preyed more heavily upon fish and crustacea than did females. Due to their large size, adult lagomorphs are felt to be relatively unavailable to female mink. Male mink are apparently large enough to specialize on lagomorphs, and male mink niche breadth was consistently lower than that of females. Dietary overlap approximated to 40% in all seasons except summer (68%), when female predation upon lagomorphs reached a peak. This reduction in intraspecific feeding competition was felt to be a valuable side-effect of body-size dimorphism.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号