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1.
Abstract. 1. If synoptic-scale wind systems are important in determining long-distance movements of butterflies, a portion of the variation in daily counts of migrants at a site should be explainable by prior winds.
2. Using special flight traps near Gainesville, Florida, U.S.A., from 29 August until 12 November 1978, we made replicated, continuous counts of four migrant species: Phoebis sennae, Urbanus proteus, Agraulis vanillae and Precis coenia .
3. Significant SSE-ward flights occurred for one or more of the four species on 47 days between 5 September and 6 November (Fig. 1).
4. Seasonal changes in numbers of migrants were similar for the four species (Fig. 1). Median fall migrants were trapped between 22 September ( A.vanillae ) and 1 October ( U.proteus and P.sennae ).
5. Daily fluctuations in total numbers of migrants were largely attributable to local weather, viz temperature, wind speed and cloud cover (Fig. 2).
6. Neither local wind direction (Fig. 3) nor back-tracking the positions of air parcels (Fig. 4) helped explain the daily fluctuations.
7. The characteristic autumn weather patterns of south-eastern U.S.A. and the day-to-day steadiness of the numbers of migrants are incompatible with the hypothesis that synoptic-scale wind systems are important in determining butterfly migrations through Gainesville, Florida, in the autumn.  相似文献   

2.
The diversity, ecology, and seasonality for sand flies from two localities in Jenin District, the Palestinian Territories, were studied. A total of 12,579 sand flies (5,420 Phlebotomus and 7,159 Sergentomyia) were collected during the study period. The genera Phlebotomus and Sergentomyia are represented by 13 and nine species and subspecies, respectively. Species account was given for all collected species. CDC light traps yielded 7,649 (60.8%) of the total captured sand flies, while sticky traps and aspirators contributed to 36.4 and 2.8% of the total collected specimens, respectively. Phlebotomus sergenti and P. syriacus showed two peaks, one in July and one in October. Phlebotomus tobbi showed one peak towards the end of the summer in September and August, while P. papatasi showed a bimodal peaks pattern, one in June and one in October. Phlebotomus canaaniticus showed a peak in August. P. perfiliewi transcaucasicus and P. neglectus showed a peak in October. Sergentomyia dentata showed one peak in August and increasing numbers from June to August, declining afterwards. Other species, such as S. theodori, had one peak in June, S. taizi had steady numbers across the summer, and S. christophersi had a peak in August.  相似文献   

3.
ABSTRACT. 1. Counts of adult Scathophaga stercoraria (L.) on cow pats were made in Houghall, County Durham, in 1964 and 1965.
2. A spring peak of numbers was due to adults (overwintered mainly as pupae or larvae) maturing and going to dung to breed. Numbers then dropped, rising to one or more peaks in late June—early July. In 1964 there was then a summer drop in numbers until late September. In 1965 high numbers persisted in summer associated with cooler, wetter weather. Autumn peaks in both years persisted until severe frosts or snow.
3. Mature adults, developed from eggs laid during the spring peak, form the first generation when breeding in mid-late June. No clear generations can be identified after this, due to eggs being laid daily (females have successive gonotrophic cycles). Changes in adult numbers breeding reflects survival of eggs and newly-hatched larvae 5–6 weeks earlier, and lower survival rates of adults in mid-summer compared with spring and autumn.
4. Adult Scathophaga numbers in vegetation rose as numbers on dung dropped. Females dissected to count ovariole tunica dilatations showed that most flies in vegetation were immature, with some parous flies hunting insects to develop the next batch of eggs.
5. Females on dung were dissected and found to range from immature to seven-parous. Those gravid for the first time were grossly under-represented, possibly due to wider dispersal.
6. It is suggested that seasonal changes in this r-strategist cannot be explained simply in terms of generations nor by the occurrence of adult diapause.  相似文献   

4.
Blowflies (Diptera: Calliphoridae) and flesh flies (Diptera: Sarcophagidae) are potential vectors of rabbit haemorrhagic disease virus (RHDV) in New Zealand. The associations between habitat and weather factors on the abundance of these flies were investigated. Between October 1999 and June 2001, flies were trapped on open pasture and in dense vegetation patches on farmland in the Himatangi area of the North Island. Five calliphorid species were trapped commonly at scrub edges and the most abundant sarcophagid, Oxysarcodexia varia Walker, was trapped mainly on open pasture. An abundance peak of O. varia was probably associated with the occurrence of a rabbit haemorrhagic disease (RHD) outbreak in the study area. Overall abundance of flies varied according to habitat and species, and species numbers differed between seasons and years. The all-day minimum temperature 3 weeks before trapping was a significant variable in all models of fly abundance, whereas average rainfall did not affect fly abundance. The all-day temperature range was significant only for O. varia. The influence of other climatic factors varied between fly species. Climate dependent variations in fly abundance may contribute to the risk of transmission of RHD, which occurred intermittently on the site during the study period.  相似文献   

5.
Abstract. 1. Shortcomings in the methodology of testing mechanical traps for tsetse and other flies have been partically overcome by relating all trap efficiencies to that of electric trapping devices which have been shown, independently, to capture over 95% of tsetse colliding with them.
2. In Rhodesia the classical 'animal' type traps only caught a small percentage of tsetse which approached them. The addition of ox odour increased the number of tsetse visiting the trap but did not affect trap efficiency.
3. Changes in trap design have resulted in increases in trapping efficiency of up to 4–5-fold over classical designs.
4. The addition of large quantities of ox odour increased the efficiency of the most successful trap described here, as well as the absolute number of flies taken. When the odour of livestock of total mass 11.5 tonnes was used, over 2000 tsetse could be trapped in a 3 h period.
5. None of the traps described here was particularly suitable for tabanids but some were used to trap large numbers of biting muscids.
6. The implications for new methods of tsetse control are discussed.  相似文献   

6.
Information on the daily activity patterns of tabanid flies is important in the development of strategies that decrease the risk of pathogens transmitted by them. In addition, this information is useful to maximize numbers of tabanids trapped during short‐term studies and to target feeding behavior studies of certain tabanid species to their times of peak activity. The current study examined the effects of various meteorological factors on the daily activity patterns of common tropical species of tabanids in north Queensland. Each species studied responded differently to weather factors. Tabanus townsvilli Ricardo (Diptera: Tabanidae) was most active during late morning and early afternoon, whereas Pseudotabanus silvester (Bergroth) and Tabanus pallipennis Macquart were most active in the late afternoon. Tabanus dorsobimaculatus Macquart was most active in the morning and early afternoon. Data on daily activity patterns of tabanid flies indicates that in an area such as Townsville, North Queensland, where several species of tabanid are present concurrently in high numbers, the overlapping periods of high activity for these species indicate a high risk of pathogen transmission for most of the day (10.00–19.00 hours). Similarly, because each species responds differently to weather variables, only extreme weather conditions are likely to inhibit activity of all species. These data also indicate that for maximal results, trapping and feeding behavior studies should be tailored to the preferred activity period of the species under investigation.  相似文献   

7.
Elemental stoichiometry of Drosophila and their hosts   总被引:5,自引:1,他引:4  
1. Nitrogen (N) and phosphorus (P) availabilities are important ecological determinants of resource use in nature. Despite the wide range of hosts used by species of the genus Drosophila , elemental composition of natural resources of these flies has never been investigated.
2. Total body N and P contents were determined in seven species of wild-caught Drosophila , their natural hosts, and artificial diets routinely used to rear these flies in the laboratory. The flies tested included D. hydei, D. arizonae, D. simulans and D. pseudoobscura collected from rotting fruit (melons), and the cactophilic D. nigrospiracula, D. mojavensis and D. pachea collected from their specific host plants, Saguaro, Organpipe and Senita cactus, respectively.
3. Natural hosts varied in elemental composition, with fruit showing higher N (2·8–4·3% dry mass) and P (0·50–0·67%) levels compared with cacti (0·5–1·6% N; 0·01–0·29% P). No consistent differences in N and P levels were found between healthy and necrotic cactus tissue.
4. Total body N and P also varied among Drosophila species. This variation mirrored the levels of N and P found in the respective hosts and laboratory diets. N:P ratios were consistently lower in female flies compared with conspecific males suggesting phosphorus demands during oogenesis are high.
5. Potential mechanisms by which Drosophila deal with N or P limitation in nature are discussed.  相似文献   

8.
The seasonal abundance of horse and deer flies (family Tabanidae) was analyzed using Mosquito Magnet® traps at 5 sites located near/in the demilitarized zone, northern Gyeonggi-do, Republic of Korea from late April to early October for 4 consecutive years (2010-2013). A total of 2,999 horse and deer flies (tabanids) belonging to 5 genera and 20 species were collected. Chrysops mlokosiewiczi (90.9%) was the most frequently collected, followed by Haematopota koryoensis (4.8%) and C. suavis (1.0%). The remaining 17 species comprised only of 3.3% of all species collected. C. mlokosiewiczi demonstrated bimodal peak populations during mid-June and early August, while H. koryoensis demonstrated a unimodal peak during mid-July. Overall numbers of tabanids collected were influenced by the previous year’s winter temperatures and precipitation. Population abundance was influenced by habitat with most of tabanids collected from habitats near forested areas, followed by rice paddies, and a beef farm.  相似文献   

9.
Abstract. 1. A study was made of larval and adult Mycetophilidae in coppiced beech woodland in southern England. Adult mycetophilids were trapped throughout 1968 using sticky traps at ground level. Larvae inhabiting terrestrial fungi were collected from all sporophores from a defined area of the woodland floor between August and October 1968.
2. Larval mycetophilids were extracted from only 12.6% of all sporophores collected and from fifteen of thirty-eight species of fungi present. Some species of fungi were never inhabited by larval mycetophilids while others appeared to be highly attractive to them. Since it was not possible to identify the larvae beyond the level of tribe it was impossible to ascertain host preferences for different species. Peak numbers of larvae occurred at the beginning of September and the beginning of October.
3. Adult mycetophilids had two peaks of activity, the first in March and April when the dominant species were Boletina gripha and Phronia basalis and the second in autumn when species of the genus Mycetophila were dominant. Phronia basalis is a species whose larvae inhabit dead wood and the abundance of this species (40% of all adults) probably reflects the amount of rotting wood in this type of habitat. The autumn peak of adult activity was due to species known to inhabit agaric sporophores and came about 1 month after the peak of larval numbers in fungi.
4. The adult fauna was rich with 107 species representing about a quarter of the known British fauna. However, only twelve species were trapped in sufficient numbers to allow deductions concerning seasonal activity.
5. The results were discussed with respect to the problems of assessing populations of insects inhabiting fungal sporophores and to the previous work on this neglected group.  相似文献   

10.
Invertebrate drift in a glacial river and its non-glacial tributary   总被引:1,自引:0,他引:1  
1. Invertebrate drift was studied in a glacially fed river and a non-glacial tributary in western Norway. Samples were taken during two consecutive 24-h periods in May, July and October 1997. The 3 months are characterized by snowmelt, ice melt and rainfall runoff, respectively. The main glacial river has colder, more turbid water, especially during the period of maximum ice melt during summer.
2. Chironomidae, especially the genus Diamesa , dominated the drift in the main river in May and October, constituting 97 and 99% of total numbers, respectively. Simuliidae, Plecoptera, Ephemeroptera and Trichoptera were the other main components.
3. A comparison of drift and benthos data revealed that the tributary was of little significance for colonization of the main glacial river. Only some additional species in very low numbers were recorded downstream of the confluence.
4. During July significant differences in diel drift pattern of Chironomidae and Simuliidae existed between the glacial and non-glacial reaches. There was a mid-day peak independent of discharge in the glacial river, but this peak was not noted in the tributary. Species of the genus Diamesa appear to be adapted for daytime drift, possibly evolved through the absence of predators and competitors that are typical of rhithral systems where nocturnal drift is more usual.  相似文献   

11.
Abstract. 1. The numbers and types of flies resting on water-lily leaves varied through the diurnal cycle. The different patterns of occupancy were recorded in relation to time of day and to microclimatic conditions at the leaf surface.
2. Overall fly activity on the leaves varied according to gross climatic patterns on particular days. The timing of activity differed according to species.
3. Smaller, darker flies (especially ernpids and Notiphila ) were common on the leaves early and late in the day, with the more reflective dolichopodids occurring only towards midday and in full sun. Hence there were clearcut correlations between both the size and reflectance properties of flies, and the climate (in particular radiation received at the leaf surface); though this pattern was superimposed on a diurnal activity effect.
4. The timing of insect activity on the leaves could therefore be related to hygrothermal considerations, particularly the raising and maintenance of body temperature and avoidance of heat stress. Different types of fly used the favourable microclimate around the leaves as a resting site at times appropriate to their own biological requirements.  相似文献   

12.
Abstract.  1. During their development in natural conditions, Drosophila larvae and pupae face heterogeneous environmental conditions (HEC). Analysing the morphology of wild-living adults is a means of evaluating the effects of HEC.
2. Two drosophilid species of the Zaprionus genus that recently invaded the Nile delta were investigated, and three metric, size-related traits, and one meristic trait, the sternopleural bristle number, were measured. Data were compared with those of F1 generation reared under favourable laboratory conditions.
3. Body size was smaller in nature, but also extremely variable among individuals, with an average coefficient of variation (CV) of 9.1 ± 0.3, against a much lesser value of 2.4 ± 0.1 in laboratory flies. Correlations among size traits were also greater in nature (0.96 ± 0.01) than in the laboratory (0.75 ± 0.04).
4. By contrast, sternopleural bristles produced similar results in wild-living and laboratory flies. In nature, mean numbers were only slightly less than in the laboratory and the CVs were almost identical (10.87 ± 0.70 vs 10.80 ± 0.76).
5. Fluctuating asymmetry of sternopleural bristles was also identical in the two kinds of flies, and was not influenced by HEC, indicating a high level of developmental canalisation with respect to HEC.
6. The implications of the results for the problems of field heritability and developmental stability are discussed.  相似文献   

13.
Abstract.  1. The population dynamics of native herbivore species in central Appalachian deciduous forests were studied by analysing patterns of synchrony among intra- and interspecific populations and weather.
2. Spatial synchrony of 10 Lepidoptera species and three weather variables (minimum temperature, maximum temperature, precipitation) from 12 sites was measured using cross-correlation functions relating levels of synchrony to the distance separating each set of populations. Based on both the pattern of synchrony and the region-wide cross-correlation coefficients, Lepidoptera species appear to be synchronised, at least in part, by local weather conditions.
3. Interspecific cross-correlations were calculated for all sympatric species pairs and trends in interspecific synchrony were related to phylogenetic relatedness, life-history timing, and weather. Interspecific synchrony was highest among species whose larvae were present during the same time of the season, but there was no relationship between interspecific synchrony and phylogenetic affinity.
4. Spatial synchrony of weather variables was significantly related to both species of some interspecific pairs, indicating weather as a potential mechanism involved in synchronising populations of different species.  相似文献   

14.
Species composition and abundance relations of flies attracted to and bred from different sizes (20-100 g) and types of carrion (small mammal, cow liver, bird, and fish) were studied experimentally in natural breeding conditions in South Finland. Large pieces of carrion did not attract significantly more individuals or species than did small ones, but there was a positive correlation between size of carrion and numbers of flies bred, apparently because of competition. Altogether 10 species emerged from 50 cultures, and on average 2.78 ± 1.22 (SD) species emerged from one culture. The number of co-occurrences among the emerging flies indicated random colonization. Variation in species composition between like pieces of carrion was not less than variation between carcasses of different size or type; hence, size and type of carrion are not important determinants of community structure within the size and type ranges used.
Lucilia illustris (Meig.) was the predominant species, comprising 50% of flies trapped and 85% of flies bred. The difference indicates changing species composition in the community. Two sets of cultures were left open for egg-laying for 2 and 7 d. Competition was less Intensive in the former cultures, which produced 4.0 individuals per gram of carrion, contrasting with only 1.4 individuals per gram in the latter cultures. Competition delayed development in all species, but least in L. illustris , which suggests that fast developing species are at a competitive advantage. In agreement with this, abundance was positively correlated with the rate of development.  相似文献   

15.
Abstract. 1. A survey was made of the distribution of Lonchopteridae over 2 years at forty sites in northern England. Material was collected by pitfall trapping.
2. Two species, Lonchoptera lutea and L.furcata , were taken in approximately similar numbers. No other species were recorded.
3. Considerable separation of the two species was found, with both species occurring at ten sites, whilst one species only was taken at twenty-five sites. L.furcata occurred coinrnonly on upland mineral sods, shallow peat soils and on lowland bogs whilst L.lutea was numerically most abundant on upland blanket bog.
4. Almost 39% of the L.lutea specimens and 14% of the L.furcata captures were males.
5. The capture of numbers of males of L.furcata is unusual, since the species is regarded as being parthenogenetic and males occur only in a very small part of the species' range. Confirmation of the association between the males and females of L.furcata is given, whilst there is close agreement between the cliaetotaxy of British males and females, and British and continental European females. The suggestion that the males belong to an undescribed species is rejected.
6. The seasonal capture of L.lutea adults is similar at all altitudes. Captures of males of L.furcata show an abrupt seasonal change above and below about 420 m; captures being in mid-summer in the higher altitude zone and between October and December at lower altitudes. The captures of females of L.furcata show the same trend, but this is partially obscured by the longer life-span of the females. It is suggested that this difference represents a change in the lifecycle, possibly from an annual to a biannual one at the higher altitudes.
7. The biology and distribution of the Lonchopteridae at low altitudes requires investigation.  相似文献   

16.
The bionomics of sand flies (Diptera: Phlebotominae) was studied monthly for two consecutive years in alluvial gallery forests in the department of Casanare, Northeastern Colombia. A total of 2,365 specimens and 10 species were captured using CDC light traps and Shannon traps, and from diurnal resting places, and human landing collections. Lutzomyia fairtigi Martins (55%), Lutzomyia micropyga (Mangabeira) (20.9%), and Lutzomyia antunesi (Coutinho) (13.5%) were the predominant species in the region. Lutzomyia flaviscutellata and Lutzomyia panamensis, potential vectors of Leishmania in Colombia and neighboring countries, were also collected, but in low numbers. Lu. fairtigi is an endemic species to Colombia, and minimal data are available on its biology and distribution. The present study provides additional information about Lu. fairtigi, such as the diurnal activity displayed by females on cloudy days, the greater density during the rainy season (April to October), marked anthropophilia, and the presence of flagellates in the midgut of one female.  相似文献   

17.
A study of the phlebotomine sand fly fauna was carried out in the Rio Preto State Park (Minas Gerais, Brazil) aiming to associate the presence of vector species with the risk of leishmaniasis transmission in that region. Sand flies were captured using HP light traps for four months from January to October 2013. The traps were exposed continuously for 40 h each month, in nine fixed sites. A total of 3129 sand flies were captured, belonging to 19 species. Lutzomyia evandroi (Costa Lima & Antunes 1936) was the predominant species (76.48%). The distribution of the phlebotomine sand flies and climatic factors (temperature, humidity, and rainfall) was evaluated. The summer was the season with higher occurrence of insects captured (82.4%). The presence of cutaneous and visceral vector species in park areas requires attention and regular monitoring of sand fly fauna in this conservation area to ensure the well-being of visitors and the regional ecotourism.  相似文献   

18.
1 The Bibury long‐term data set contains information on annual fluctuations in the abundance of over 100 grasses and forbs in roadside verge vegetation over the period from 1958 to the present. Monitoring has been carried out every July by the same individual. The data set represents a unique long‐term record of the dynamics of a complete plant community.
2 Records for the most abundant taxa (including bare ground and litter) were used to determine the effect of climate variability on the year‐to‐year performance of the selected species. Residuals about the long‐term mean log biomass of each species (de‐trended where the species showed a significant increase or decrease in abundance over time) were correlated against indices of interannual climate variability. Plant and weather records were compared over 3‐month seasonal periods (March–May, June–August, September–November, December–February) or 6‐month seasonal periods (March–August, September–February), with time lags of 0, 1 and 2 years.
3 Principal components analysis (PCA) was used to formulate annual weather indices, using either conventional weather variables (temperature, rainfall and sunshine) or the Lamb catalogue of daily weather types.
4 Between 5% and 70% more correlations were observed than might be expected to occur by chance, depending on the season and the PCA index, indicating markedly non‐random plant–weather relationships. Total vegetation production was positively correlated with minimum spring temperature. The distribution of correlations was generally evenly distributed across the three lag periods.
5 In general, those species favoured by environmental stress or disturbance were promoted following warm dry springs and summers, whereas those favoured by more productive conditions were promoted following a wet growing season.  相似文献   

19.
Abstract. 1. Ants, parasitoids and flies are about equally frequent at foliar nectaries of Byttneria aculeata (Sterculiaceae) in lowland Costa Rica during the dry season, a pattern previously unreported but also observed at other plants in the area.
2. Species of Ectatomma, Crematogaster and Camponotus were the most frequent of twenty-four ant species on Byttneria, eight of which nested in the hollow stems. Ants spent most time at nectaries and little in patrolling.
3. Collections at nectaries yielded large numbers of species of parasitoid Hymenoptera with few individuals of each. Rearing studies of leaf-feeding herbivores yielded several species of parasitoids, including one species taken at a nectary and two others congeneric or closely related.
4. Flies appear to be nectar thieves, in the same sense as non-pollinating floral visitors, despite close association with Byttneria.
5. Ant-plants may be poor models for the larger number of species of less specialized plants with extrafloral nectaries. Plants which have only extrafloral nectaries may better suit the needs of parasitoids than ants, and plants such as Byttneria may benefit as much from parasitoids as from ants.  相似文献   

20.
Hyperiid amphipods were sampled in and around warm-core eddyJ in the Tasman Sea off eastern Australia in August, Septemberand October 1979. Samples were taken at night to a depth of400 m with a midwater trawl (RMT-8). In all, 22 798 hyperiidsrepresenting 38 species and 10 families were collected. Sevenspecies, individually found in numbers >4% of the total amphipodpopulation, together contributed 87.1% to the total. Of these,Scina crassicornis, Phronima sedensataria, P.atlantica, Phrosinasemilunata, Primno johnsoni and Brachyscelus crusculum wereusually found in highest numbers outside the eddy. Streetsiachallengeri was the only abundant species with significantlyhigher numbers inside the eddy. Outside the eddy, samples werecharacterized by large numbers of few species, whereas abundanceswere more evenly distributed between species inside the eddy.The size distributions of two abundant species (B.crusculumand S.challengeri) were not significantly different betweenthe inside and outside of eddy J. Hyperiid faunal patterns wereassociated with depth and temperature (August), position withrespect to the eddy (September, October) and the presence ofgelatinous zooplankton (September, October).  相似文献   

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