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1.
Inter-population dispersal by adult stoneflies detected by stable isotope enrichment 总被引:1,自引:0,他引:1
Robert A. Briers John H. R. Gee Helen M. Cariss Rory Geoghegan 《Freshwater Biology》2004,49(4):425-431
1. Dispersal of adult stream insects may be of considerable importance in regional population dynamics and colonisation of new sites, but quantifying the rate and extent of dispersal is difficult. 2. We used stable isotope (15N) enrichment to mark more than 1.5 million larval stoneflies (Leuctra inermis) before they emerged from an upland stream in the Plynlimon area of mid‐Wales, in order to determine directly the rate and pattern of inter‐site dispersal. 3. A small number of isotopically enriched adult stoneflies were captured in samples taken at adjacent streams between 800 m and 1.1 km away from the source population, including a headwater of a different river system. 4. The distribution of marked individuals suggested that wind influences dispersal direction in the uplands, but the low number of captures limits our ability to draw firm conclusions. 5. This is the first direct demonstration of dispersal of insects between streams. The dispersal distances recorded were significantly greater than those suggested by previous direct studies, but much more consistent with indirect studies based on genetic differentiation of populations. 相似文献
2.
Peter Schumacher Donald C. Weber Christian Hagger Silvia Dorn 《Entomologia Experimentalis et Applicata》1997,85(2):169-175
Cydia pomonella L. (Lepidoptera: Tortricidae) is considered to be rather sedentary, but some individuals undertake flights of several kilometres in the field. This paper investigates the genetic influence on this variability. The flight capacity was measured in the laboratory by a flight mill and its heritability was estimated for two different strains. The laboratory strain was kept for more than 45 generations and the field strain from Embrach (northern Switzerland) was recently collected in the field.The multiple-trait-restricted-maximum-likelihood method was used for the estimation of genetic variances and covariances. A mixed full-sib/half-sib design was applied for the field strain and a full-sib design for the laboratory strain. The heritability of total distance was 0.57 for the field strain and 0.37 for the laboratory strain (both sexes). In addition, a heritability of 0.38 for total distance was estimated by parent-offspring regression for the laboratory strain. All three values were significantly different from zero P<0.05 and show that there is a significant additive genetic influence on flight capacity.The genetic correlations between total distance and other flight traits (total duration, flight velocity, longest flight) were between 0.84 and 1.00 for both strains and suggest that these traits actually belong to a single one. High genetic correlations were also found between total distance and the morphological traits body weight and wing length for the field strain, whereas a negative correlation was found between total flight distance and body weight for the laboratory strain. This difference between the two strains was interpreted as a possible trade-off between flight capacity and fecundity. 相似文献
3.
Site-occupancy in relation to flight-morphology in caddisflies 总被引:2,自引:0,他引:2
Per-Ola Hoffsten 《Freshwater Biology》2004,49(6):810-817
1. The relationship between morphology and site‐occupancy provides opportunities to infer differences in dispersal and flight ability, but empirical data for aquatic insects is limited. 2. In this study, 17 species of caddisflies from 10 families were collected from springs, streams and lakes, and total body mass, relative thorax mass, relative wing area (wing loading), and the aspect ratio of the fore and hind wings (combined) were measured. 3. Partial least‐squares regression analysis of two independent distributional data sets produced significant models within which total body mass, relative thorax mass and wing loading were positively associated with site‐occupancy, whereas aspect ratio was negatively associated with site‐occupancy. 4. These results suggest that the faunal composition of streams is influenced by species dispersal abilities. 相似文献
4.
Contradictory results from different methods for measuring direction of insect flight 总被引:1,自引:0,他引:1
1. Stream ecologists have been puzzled by the apparent paradox that invertebrate populations persist in headwater streams despite the high frequency with which individuals drift downstream. To resolve this ‘drift paradox’, directions and distances of both larval and adult movement must be identified. Using over 50 interception traps in combination with results from several mark–capture experiments using 15N as a label, we tested the assumption that interception traps accurately represent the ultimate direction of adult insect flight. 2. In several streams in the Hubbard Brook Experimental Forest, 76% of 15N‐labelled stoneflies (Leuctra ferruginea) had flown upstream from where they emerged to where they were captured. In contrast, over 60% of stoneflies were flying downstream when captured, i.e. on the upstream side of an interception trap. 3. The instantaneous direction, as indicated by the side of the interception trap on which they were captured, indicated the ultimate flight direction for fewer than 1/3 of the individuals captured. Thus, such traps did not accurately reflect the ultimate flight patterns of individuals, as indicated by mark–capture data. 4. Conclusions drawn from interception trap counts regarding the direction of movement and the distribution and persistence of populations may need to be re‐evaluated. We suggest that better tracking methods, including mass mark–capture studies using stable isotopes, be used to evaluate the potentially complex patterns of adult insect movement and the consequences of that movement for individuals and populations. 相似文献
5.
Potential of Ulocladium atrum for biocontrol of onion leaf spot through suppression of sporulation of Botrytis spp. 总被引:1,自引:0,他引:1
J. Köhl W.W.L. Molhoek H.M. Goossen-van de Geijn C.H. Lombaers van der Plas 《BioControl》2003,48(3):349-359
Epidemics of onion leaf spotcaused by Botrytis spp. depend onnecrotic leaf tissue for inoculum build up inthe crop. Ulocladium atrum Preuss. is astrong competitor on necrotic above-groundplant tissues. The potential of the antagonistto reduce colonisation of necrotic leaf tissueby Botrytis spp. and subsequentsporulation was studied in two fieldexperiments. U. atrum colonised necrotictissues and consistently reduced thesporulation of fungal competitors. Althoughincidence of Botrytis spp. was low,significantly lower spore loads of Botrytis spp. were found on spore trapslocated within U. atrum treated onionplots as compared to untreated control plots.The number of leaf spots caused by Botrytis spp. was low in both fieldexperiments but was significantly reduced by60% after U. atrum applications in thesecond experiment. Spraying of the fungicideRonilan resulted in the same control level.Results show that U. atrum has apotential for biological control against diseases caused by Botrytis spp. in onions. 相似文献
6.
Athena Wai Lam Morgan Gueuning Carolin Kindler Matthew Van Dam Nadir Alvarez Rawati Panjaitan Helena Shaverdo Lloyd T. White George K. Roderick Michael Balke 《Molecular ecology》2018,27(16):3346-3356
The habitat template concept applied to a freshwater system indicates that lotic species, or those which occupy permanent habitats along stream courses, are less dispersive than lentic species, or those that occur in more ephemeral aquatic habitats. Thus, populations of lotic species will be more structured than those of lentic species. Stream courses include both flowing water and small, stagnant microhabitats that can provide refuge when streams are low. Many species occur in these microhabitats but remain poorly studied. Here, we present population genetic data for one such species, the tropical diving beetle Exocelina manokwariensis (Dytiscidae), sampled from six localities along a ~300 km transect across the Birds Head Peninsula of New Guinea. Molecular data from both mitochondrial (CO1 sequences) and nuclear (ddRAD loci) regions document fine‐scale population structure across populations that are ~45 km apart. Our results are concordant with previous phylogenetic and macroecological studies that applied the habitat template concept to aquatic systems. This study also illustrates that these diverse but mostly overlooked microhabitats are promising study systems in freshwater ecology and evolutionary biology. With the advent of next‐generation sequencing, fine‐scale population genomic studies are feasible for small nonmodel organisms to help illuminate the effect of habitat stability on species’ natural history, population structure and geographic distribution. 相似文献
7.
关于睑虎属Goniurosaurus物种的研究主要集中在新种描述和系统进化等方面,对种群密度量化的研究较少。为研究海南吊罗山国家级自然保护区海南睑虎Goniurosaurus hainanensis种群的资源现状,2019年7—9月,在保护区内选取2个不同海拔梯度的样区(A样区551~688 m和B样区289~448 m),采用标记重捕法对该物种的种群密度进行了调查,并分别采用Schnabel法和Lincoln指数法进行种群密度估算。结果显示:采用Schnabel法估算的种群密度A样区为501只/hm2,B样区为1 999只/hm2;采用Lincoln指数法估算的种群密度A样区为583只/hm2,B样区为1 403只/hm2。结果表明:该物种的种群密度随海拔升高呈下降趋势。 相似文献
8.
José Herrera-Russert Alejandro López-López José Serrano Adolfo Cordero-Rivera José Galián 《Insect Conservation and Diversity》2021,14(6):793-799
- The tiger beetle Cephalota deserticoloides is a species found in a few localised sites in south-eastern Iberia, where it is a highly specialised inhabitant of the arid saline steppe habitat. Although regarded as vulnerable, very little is known about the actual population dynamics and degree of endangerment of this taxon, which may be worse than previously reported.
- In this work, mark-recapture estimates of total population size are presented for one of the main known populations of C. deserticoloides. Additionally, some further remarks on seasonality and co-occurring tiger beetle species are made.
- At the seasonal peak of adult activity, the area under consideration holds a relatively dense tiger beetle population with around 865 simultaneously active adult beetles, which is numerically comparable to those of other endangered cicindelids. These results will help assess the conservation status of C. deserticoloides and set the stage for more long-term efforts, which are clearly needed to analyse population viability, and the priority of C. deserticoloides and its habitat as targets for protective measures.
- Our observations indicate that a reconsideration of the current International Union for Conservation of Nature (IUCN) listing of C. deserticoloides is strongly justified, from its current status as ‘vulnerable’ to a new listing as ‘endangered’.
9.
Abstract The effect of colonisation of the alimentary tract of newly hatched chicks by different Salmonella serotypes on the establishment in the gut by other Salmonella strains inoculated afterwards was assessed. Although profound inhibition of colonisation had been found previously to be genus-specific, considerable variation was found within the Salmonella genus. Some strains were found to be much more inhibitory than others and some were more easily inhibited than were others. There was not an absolute relationship between inhibitory activity and colonisation ability. No relationship was seen between inhibition and serotype or phage types within serotypes. There was no correlation between in vivo inhibition and the extent of inhibition that occurred in early stationary phase cultures in rich, undefined broth cultures. 相似文献
10.
The negative effects and duration of an immunomark (egg albumin) and fluorescent powder for marking phytoseiids were examined. Neither mark caused significant mortality, run-off, or reduction in fecundity. The fluorescent powder mark was more durable, but neither mark has sufficient durability to be used in a long-term mark-recapture study. 相似文献
11.
Species-specific life-history information is critical for successful conservation, particularly in establishing an accurate baseline status. Obtaining such information is challenging for most species, but in particular for rare and threatened marine species. To facilitate future conservation of the endangered Knysna seahorse (Hippocampus capensis) this study aimed to determine important life-history information for this species. Visible implant fluorescent elastomer (VIFE) tags were used to mark 78 seahorses within a residential marina estate in the Knysna estuary, South Africa, in February 2018. Using a mark-resight approach, the size and movement patterns of the population and growth rate of seahorses were determined over a 14-month period. The closed population estimate for H. capensis, within Thesen Islands Marina, was estimated to be 134 (118–152 95% C.I. ) in February 2018 compared to only 72 (48–108 95% C.I. ) in February 2019. The species showed rapid initial growth with males and females having similar rates of growth based on the specialised von Bertalanffy growth function model. The importance of Reno mattresses as a habitat for H. capensis was confirmed based on the high abundance and site fidelity of the population, which emphasises the conservation potential of heavily modified environments for threatened seahorse species. The use of VIFE tags was deemed effective in studying this endangered seahorse and allowed the collection of important information for this species which can be used in future Red List assessments and conservation actions. 相似文献
12.
Crustacean and rotifer composition of temporary ponds in the Doñana National Park (SW Spain) during floods 总被引:1,自引:1,他引:1
The zooplankton of 18 temporary ponds in the Doñana National Park (SW Spain) was studied during floods in February and May 1997. A total of 37 rotifer taxa and 34 crustaceans species were identified (17 cladocerans, 2 ostracans, 4 diaptomids, 7 cyclopodids, 1 harpacticoid, 1 anostracan, 1 notostracan and 1 conchostracan). Zooplankton samples were collected separately from the littoral and the open-water of 12 different ponds. Commonly distributed zooplankton species (frequency of appearance 50%) were not segregated to either the littoral or the open-water according to a chi-square test (P>0.005). The study ponds were divided into seasonal, intermediate and ephemeral ponds according to the length of their hydroperiod. The total numbers of both crustacean and rotifer taxa were highest in the intermediate-hydroperiod ponds (26 and 32 taxa, respectively). The total number of zooplankton taxa collected in both February and May was not significantly correlated to the hydroperiod of the temporary ponds of Doñana during the study period (r=0.165, P=0.526). 21 rotifer taxa and 20 crustacean species were found in the ephemeral ponds; the number of restricted species was also relatively high (3 rotifers and 4 crustaceans). Therefore, the ephemeral ponds held a relatively rich community during floods compared to other temporary ponds of Doñana despite their small size and short wet phase. 相似文献
13.
The growth and ascocarp formation of Aigialus parvus, Lignincola laevis and Verruculina enalia in single and mixed cultures on wood of Avicennia alba, Bruguiera cylindrica and Rhizophora apiculata was studied. In pure cultures, these fungi grew well on all three species of wood. Except for Aigialus parvus on B. cylindrica, all three fungi also formed abundant ascocarps. The time needed for ascocarp formation after inoculation ranged from six to eight weeks for L. laevis on all wood species, and for V. enalia on Avicennia alba; to ten weeks for V. enalia on B. cylindrica and R. apiculata; and 12 weeks for Aigialus parvus on Avicennia alba and R. apiculata.Mixed cultures involving two or three of the test fungi delayed the onset of sporulation and affected the abundance of ascocarps formed. Sporulation by Aigialus parvus on Avicennia alba and R. apiculata was markedly reduced by L. laevis alone or in combination with V. enalia. Likewise, sporulation by L. laevis was suppressed by Aigialus parvus and/or V. enalia. In contrast, the presence of L. laevis enhanced ascocarp formation by V. enalia on all types of wood. These observations suggest the presence of interference competition among the test fungi. 相似文献
14.
J. Y. Takekawa A. K. Miles D. H. Schoellhamer N. D. Athearn M. K. Saiki W. D. Duffy S. Kleinschmidt G. G. Shellenbarger C. A. Jannusch 《Hydrobiologia》2006,567(1):307-327
Commercial salt evaporation ponds comprise a large proportion of baylands adjacent to the San Francisco Bay, a highly urbanized
estuary. In the past two centuries, more than 79% of the historic tidal wetlands in this estuary have been lost. Resource
management agencies have acquired more than 10 000 ha of commercial salt ponds with plans to undertake one of the largest
wetland restoration projects in North America. However, these plans have created debate about the ecological importance of
salt ponds for migratory bird communities in western North America. Salt ponds are unique mesohaline (5–18 g l−1) to hyperhaline (> 40 g l−1) wetlands, but little is known of their ecological structure or value. Thus, we studied decommissioned salt ponds in the
North Bay of the San Francisco Bay estuary from January 1999 through November 2001. We measured water quality parameters (salinity,
DO, pH, temperature), nutrient concentrations, primary productivity, zooplankton, macroinvertebrates, fish, and birds across
a range of salinities from 24 to 264 g l−1. Our studies documented how unique limnological characteristics of salt ponds were related to nutrient levels, primary productivity
rates, invertebrate biomass and taxa richness, prey fish, and avian predator numbers. Salt ponds were shown to have unique
trophic and physical attributes that supported large numbers of migratory birds. Therefore, managers should carefully weigh
the benefits of increasing habitat for native tidal marsh species with the costs of losing these unique hypersaline systems. 相似文献
15.
The validity of the metapterygoid bone of pike Esox lucius for use in age determination and backcalculation of total length ( L T ) was evaluated by using tagged pike recaptured after 4 months to 3 years. A regression equation for the relationship between pike L T and metapterygoid length was estimated, and no significant deviations between the backcalculated and expected L T at tagging were found for recaptured pike. The results confirm that 1) the checks are formed annually and 2) no false checks appeared on the metapterygoids of pike. 相似文献
16.
Jan Vymazal 《Hydrobiologia》1984,111(3):171-179
Benthic invertebrates in a tropical river (Menik Ganga) recolonised denuded substrates within 2–3 weeks, though full diversity
was not achieved until 4 weeks. No well defined succession was observed. All taxa apparently colonised at random from drift,
upstream and vertical sources. Traps colonised from only one of these sources developed as abundant and diverse a fauna as
control traps in 5 weeks. Strong spatial heterogeneity in the number and composition of colonisers was observed between replicate
traps. It is suggested that colonisation resulted from random foraging activities and most colonists were derived from veryshort
distances. 相似文献
17.
Dean R. Evans Keith A. Hobson Jackson W. Kusack Michael D. Cadman C. Myles Falconer Greg W. Mitchell 《Ibis》2020,162(2):331-344
Migratory animals face severe time and energy constraints during their annual cycle. These constraints may be exacerbated in young animals by conditions experienced during development that can affect both phenotype and phenology. For young migratory songbirds, the period between fledging and autumn migration, the post-fledging period, is believed to represent a time of intense selective pressure. However, there has yet to be a study that has assessed post-fledging survival for the entirety of the post-fledging period, probably due to the challenge of following juveniles as they move broadly across the landscape (tens to hundreds of kilometres). To overcome this challenge, we used an automated radiotelemetry array spanning 60 000 km2 in southern Ontario, Canada, and miniature digital radiotelemetry tags to track 216 juvenile Barn Swallows Hirundo rustica continuously from fledging to migration. We hypothesized that young that fledged in better condition and earlier in the breeding season would have higher survival relative to birds fledging in poorer condition, because they have more energy to deal with resource constraints, and that early-fledging birds would depart on migration earlier than late-fledging birds because there is probably a fixed period of time required post-fledging to prepare for migration. We found that average cumulative apparent survival was 42% and that condition in the nest was a strong positive predictor of post-fledging apparent survival. We also found that birds that fledged earlier in the season departed on migration earlier in the autumn relative to late-fledging birds. Contrary to our prediction, average apparent survival was equal for early- and late-fledging birds. Our results suggest that factors during development that promote better nestling condition are critical for predicting future apparent survival prior to migration. Differences in annual apparent survival between early- and late-fledging songbirds, as commonly observed, may be driven by events occurring at later stages of the annual cycle. 相似文献
18.
Yvan Moënne-Loccoz Brendan McHugh Peter M. Stephens Fiona I. McConnell Jeremy D. Glennon David N. Dowling Fergal O'Gara 《FEMS microbiology ecology》1996,19(4):215-225
Abstract: The ability to utilise additional siderophores may increase the ecological fitness of biocontrol inoculants of Pseudomonas in the rhizosphere. Plasmid pCUP2 carries a copy of the gene pbu A coding for the membrane receptor of ferric pseudobactin M114. Pseudomonas sp. B24Rif containing pCUP2 can utilise ferric pseudobactin of P. fluorescens M114 in addition to its own siderophore. A larger fraction of the culturable resident fluorescent pseudomonads in the rhizosphere of sugarbeet grown in a low-iron sandy loam soil could supply siderophore-complexed iron to B24Rif(pCUP2) rather than to B24Rif. However, B24Rif and B24Rif(pCUP2) were found at similar population levels in the rhizosphere for 21 days after their inoculation on seeds. A total of 25 of 43 isolates of resident fluorescent Pseudomonas unable to cross-feed iron to B24Rif could cross-feed B24Rif(pCUP2) and they were subdivided into seven different strains by arbitrary-primed PCR fingerprinting. The siderophores produced by 11 of them were typed by HPLC and they were similar to pseudobactin M114. However, the ability to utilise ferric pseudobactin M114 did not improve the ecological fitness of B24Rif in the rhizosphere of sugarbeet although a larger fraction of the culturable resident fluorescent pseudomonads could supply pseudobactin M114-complexed iron to B24Rif(pCUP2) than to B24Rif. 相似文献
19.
Dispersal is one of the most fundamental components of ecology. Dispersal is also particularly relevant in an era of unprecedented habitat loss and climate change. We used a unique dataset to examine dispersal in gray ratsnakes (Pantherophis spiloides). Over a decade, we marked and released >1,500 hatchlings while monitoring the population of ratsnakes over a large area (≈1,900 ha). We tested the hypotheses that dispersal should be (a) largely restricted to within the local population given previous genetic evidence of limited gene flow at greater distances and (b) male biased because male gray ratsnakes are under strong sexual selection. We recaptured 69 gray ratsnakes that had been marked as hatchlings after periods ranging from 1 day to 11 years. We found that dispersal distance increased with time, but was not significantly sex-biased, and that gray ratsnakes are extremely faithful to their communal hibernacula (only 2.8% of 497 juvenile and adult ratsnakes captured at least twice at communal hibernacula changed sites between years). Thus, dispersal is largely limited to the period from hatching until an individual joins a communal hibernaculum. Based on the spatial patterns of dispersal we observed, the most plausible explanation for dispersal is that hatchling ratsnakes disperse from their natal site to join a neighboring communal hibernaculum. Our study yielded the most reliable data on dispersal distances from birth by a snake to date. 相似文献