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1.
Understanding food web interactions in native or agricultural ecosystems is an important step towards establishing sustainable
pest management strategies. While the role of generalist predators as biological control agents is increasingly appreciated,
the study of trophic interactions between individual predator species and their prey provides practical difficulties. Recently,
different approaches have been suggested to determine prey items from predator guts using molecular methods. Macrolophus caliginosus is a generalist predator active in herbaceous agro-ecosystems. We developed a system to identify the DNA of its prey after
ingestion, using Myzus persicae as a model. Esterase (MpEST) and cytochrome oxidase I (MpCOI) genes were targeted in the aphid, while M. caliginosus COI gene was used as control for predator DNA. Real time PCR proved to be specific and sensitive enough to detect prey DNA upon
ingestion after feeding experiments. The system provided a linear amplification response with only 10 fg of prey genomic DNA
as template. The detection system of MpCOI gene was more sensitive than MpEST, while the detection period was similar for both genes. Possibilities for using the system in ecological and biosafety studies
with regard to sustainable pest management are discussed.
相似文献
Salvatore ArpaiaEmail: |
2.
Consumption of aphids by spiders and the effect of additional prey: evidence from microcosm experiments 总被引:1,自引:0,他引:1
Spiders are common generalist predators in agroecosystems and have been suggested to lower herbivore abundance in crops. It
is not clear, however, if spiders can effectively suppress pest populations, and if so, by what mechanisms. In a microcosm
experiment, we examined the consumption of the bird cherry-oat aphid, Rhopalosiphum padi L. (Homoptera: Aphididae), a pest species in wheat fields, by three spider species that differ in their hunting methods.
We then tested the effect of additional prey type on the ability of erigonid spiders to reduce aphids. In a 48-h experiment
Mermessus denticulatus (Banks) (Araneae: Linyphiidae; Erigoninae) consumed more aphids than did Enoplognatha gemina Bosmans and Van Keer (Araneae: Theridiidae) and Bathyphantes cf. extricatus (O·P.-Cambridge) (Araneae: Linyphiidae; Linyphiinae). This difference may be due to the ability of erigonids to forage actively
on the vegetation in addition to using their webs to catch prey. In a 7-week experiment, we provided springtails (Collembola)
in high and low densities as additional prey to mated erigonids, prior to aphid introduction. Spiders in the low-density springtail
treatment built more webs on the vegetation, and caused a 50% reduction in aphid populations. There were significantly fewer
aphids in the low-density springtail treatment, but not in the high-density treatment, in comparison to the control (high-density
springtails without spiders). The results suggest that additional prey density affects predatory interactions between M. denticulatus and R. padi and that erigonids, which occur in high densities in wheat fields in the Negev desert, may be involved in aphid suppression
in these agroecosystems.
相似文献
Efrat Gavish-RegevEmail: |
3.
The kestrel (Falco tinnunculus L.) in Berlin: investigation of breeding biology and feeding ecology 总被引:1,自引:0,他引:1
Approximately 200–250 pairs of kestrels (Falco tinnunculus) breed in Berlin, preferentially in nest boxes. From 2002 to 2004, ten monitoring sites (breeding sites) characterised by different housing structure, land utilisation, vegetation cover and degree of building density were studied in Berlin: four in the city centre, three in a mixed zone and three in the outskirts. All pairs bred in nest boxes, so the reproductive success could easily be determined. Pellets, and feathers of bird prey species, were collected during the breeding seasons, and the food spectrum was determined based on these remains. There was no significant difference in the reproductive success of the kestrels between the three zones. Data on the number of fledged young indicated a sufficient food supply. In total, 9 species of mice and shrews, 23 bird species and 31 beetle species were identified as prey of kestrels. Urban kestrels specialise in hunting birds if mice and shrews are not readily available, with the house sparrow (Passer domesticus) as the favoured prey bird. Of note are anthropogenic food items, such as cutlet bones, that were found only in the city centre. This shows that the kestrel can adapt itself to humans with regard to its diet. There was no urban gradient with regard to reproductive success, but there was with the composition of food, such as the domination of bird prey in the city centre. The number of individual items of bird prey decreased from the centre to the outskirts. In conclusion, the results show that the kestrel is an opportunistic species which survives well anywhere in the city of Berlin.
相似文献
Stefan KupkoEmail: |
4.
Frank R. Thomas 《Human ecology: an interdisciplinary journal》2007,35(2):179-194
Focusing on contemporary shellfish exploitation among several atoll communities in Kiribati, Micronesia, this paper examines
the relationship between human foragers and their invertebrate prey via the prey choice or diet breadth model derived from
optimal foraging theory. Shellfish, like many other reef organisms, are relatively sedentary and predictable, but these characteristics
make them susceptible to over-harvesting. The research reveals that shellfish gatherers are foraging in a manner that matches
the predictions of optimal foraging theory. The work adds to our understanding of optimal foraging decisions in atoll settings
by critically evaluating the depiction of atoll dwellers as conservationists.
相似文献
Frank R. ThomasEmail: Email: |
5.
José A. Alayón-Gamboa Francisco D. Gurri-García 《Human ecology: an interdisciplinary journal》2008,36(3):395-407
Energy flows were studied for the 2002–2003 agricultural cycle in four households for which agriculture is part of a diversified
survival strategy and four that practice agriculture as a business. Home garden inputs and outputs were measured monthly.
Quantified inputs were: household labour, household agro-system production, and purchased external renewable and non-renewable
energy. Outputs measured were: sales, family and animal foods. While both strategies had similar indicators in biomass and
energy production, vegetable richness, and soil quality, household garden function and sustainability differed between subsistence
and commercial householders. Subsistence gardens complemented family diet and contributed to household system resiliency.
They relied heavily on renewable energy sources from within their agro-system. Gardens in commercial households reduced fruit
tree area and increased animal husbandry for the market. They depended more on purchased non-renewable energy sources and
were less sustainable and much less energy efficient than traditional gardens.
相似文献
Francisco D. Gurri-GarcíaEmail: |
6.
Sub-Antarctic Marion Island has had a permanent research station for 50 years and the islands Wandering Albatrosses have been intensively studied for 20 years. The reactions of breeding birds to approaches by a human on foot were recorded. Three response variables were calculated: intensity of vocal reaction (IVR), intensity of non-vocal reaction (INR) and overall response index (ORI). At 5 m from the nest, twice as many birds stood and/or vocalised as at 15 m. Nearest neighbour distance, age and gender did not explain individual variability of responses. Study colony birds had higher IVR scores than non-study colony birds; birds at colonies closest to the station had the highest ORI scores. A better breeding record was associated with lower IVR and ORI scores, but a causative relationship remains to be demonstrated. A minimum viewing distance of 25 m is recommended for breeding Wandering Albatrosses.
相似文献
Marienne S. de VilliersEmail: Fax: +27-21-6503434 |
John CooperEmail: |
Peter G. RyanEmail: |
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9.
Brad E. Erisman Jorge A. Rosales-Casián Philip A. Hastings 《Environmental Biology of Fishes》2008,82(1):23-33
The sexual pattern and sexual development of the leopard grouper, Mycteroperca rosacea, were investigated from 483 specimens collected from the Gulf of California, Mexico. Histological and population data indicated
a gonochoric sexual pattern. Some juveniles passed through an immature bisexual phase of gonadal development, but no evidence
of post-maturational sex change was found. The immature bisexual phase is believed to be associated only with male development.
The size distribution and size at sexual maturity were similar for both males and females. In accordance with predictions
of the size-advantage model, the gonochoric sexual pattern of M. rosacea is likely influenced by its group-spawning mating system.
相似文献
Brad E. ErismanEmail: |
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11.
Douglas Medin Norbert Ross Douglas Cox Scott Atran 《Human ecology: an interdisciplinary journal》2007,35(3):315-329
There is a continuing controversy over Native American fishing and hunting rights. We show that Native American (Menominee)
and European American fish experts have a common knowledge base and share values and attitudes associated with fishing practices
(though organized around different ethical principles). Nonetheless, perceived group differences are dramatic (especially European American perceptions of Native Americans). Cultural differences in models
of nature and associated inference processes appear to mediate these stereotypes and may hold the key to reducing intergroup
conflict over resources.
相似文献
Douglas MedinEmail: |
12.
Peter Godfrey-Smith 《Biology & philosophy》2007,22(3):429-437
Jablonka and Lamb's claim that evolutionary biology is undergoing a ‘revolution’ is queried. But the very concept of revolutionary
change has uncertain application to a field organized in the manner of contemporary biology. The explanatory primacy of sequence
properties is also discussed.
相似文献
Peter Godfrey-SmithEmail: |
13.
14.
This paper introduces a threshold policy with hysteresis (TPH) for the control of one-predator one-prey models. The models studied are the Lotka–Volterra and Rosenzweig–MacArthur
two species density-dependent predator–prey models and the Arditi–Ginzburg nondimensional ratio-dependent model. The proposed
policy (TPH) changes the dynamics of the system in such a way that a bounded oscillation is achieved confined to a region
that does not allow extinction of either species. The policy can be designed by a suitable choice of so called virtual equilibrium
points in a simple and intuitive manner.
相似文献
Amit Bhaya (Corresponding author)Email: |
15.
P.-D. Plisnier H. Mgana I. Kimirei A. Chande L. Makasa J. Chimanga F. Zulu C. Cocquyt S. Horion N. Bergamino J. Naithani E. Deleersnijder L. André J.-P. Descy Y. Cornet 《Hydrobiologia》2009,625(1):117-134
The abundance of two main pelagic fish species in Lake Tanganyika (Stolothrissa tanganicae and Lates stappersii) has always been observed to fluctuate considerably at different time scales. The inverse correlation between the abundance
of these species has often been interpreted as the consequence of predator−prey relations (avoidance behaviour by the prey).
However, currently the two species often appear spatially segregated in the lake, S. tanganicae dominating in the north while L. stappersii is generally abundant in the south where it feeds mostly on shrimps. A fluctuating abundance of the species is nevertheless
observed. As these fish species have a major importance for the fisheries, we investigated the limnological variability in
relation to the short-term variability of fish catches. The abundance of S. tanganicae was positively correlated to plankton biomass (r = 0.65), while water transparency (r = 0.56), depth of mixed layer (r = −0.70) and oxygenated water appeared important drivers for the abundance of L. stappersii. Alternating “mixing” and “stable” states of the epilimnion related to seasonal and internal waves variability are probably
determinant for the short-term variability in abundance of S. tanganicae and L. stappersii. In the framework of this study, remote sensing has shown a potentially interesting application for fisheries research at
Lake Tanganyika. We observed a close correspondence between phytoplankton blooms at the time of trade winds changes and increased
catches of S. tanganicae in the south. The anti-correlated abundance of S. tanganicae and L. stappersii probably mainly reflects the underlying fluctuating limnological environment. Fisheries studies need to integrate limnological
and planktonic monitoring to better understand large and complex ecosystems such as Lake Tanganyika.
相似文献
P.-D. PlisnierEmail: |
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We surveyed slender lorises (Loris lydekkerianus) in Karnataka, south India intermittently during November 2001–July 2004 and estimated their relative abundance via direct sightings. Two subspecies, Loris lydekkerianus lydekkerianus and L. l. malabaricus, with different morphological traits, occur in the eastern drier region and the western wet region of the state, respectively. The distribution of Loris lydekkerianus lydekkerianus is patchy in a small region in the southeast, which contradicts earlier reports of its abundance throughout the state. Loris lydekkerianus malabaricus occurs throughout the Western Ghats as a contiguous population. The encounter rates of Loris lydekkerianus lydekkerianus and L. l. malabaricus are 0.41 individuals/km and 0.21 individuals/km, respectively. Whereas several forest tracts in the distributional range of Loris lydekkerianus malabaricus are protected areas, no such area exists in the distributional range of L. l. lydekkerianus. Loris lydekkerianus faces serious challenges of conservation because it largely occurs in commercial plantations, which can be relatively unstable habitats as harvesting can take place at any time.
相似文献
Mewa SinghEmail: |
18.
Mycena aphanes and Mycena exilis, belonging to section Filipedes and section Polyadelphia, are proposed as new species. They are described and illustrated and compared to other species in the two sections. Mycena aphanes is a strikingly characteristic Mycena with fulvous or yellowish brown colours of both pileus and stipe. Mycena exilis is characterized by its occurrence on fallen Salix leaves, a pale brown pileus, occasionally with a pale pink tinge, narrowly adnate lamellae, four-spored basidia, and the
presence of clamp connections.
相似文献
Gro GuldenEmail: |
19.
J. Stephen Athens 《Biological invasions》2009,11(7):1489-1501
Paleoenvironmental and archaeological investigations from the ’Ewa Plain of O’ahu provide insight into the problem of understanding
lowland native forest loss in Hawai’i. Data from pollen analysis of a pond core record, avian paleontology, and archeology,
document a precipitous decline of the native forest starting before Polynesian settlement on the ’Ewa Plain but after Polynesian
colonization of O’ahu. It is hypothesized that rats, introduced by Polynesian colonizers, increased exponentially in the absence
of significant predators or competitors, feeding on a largely endemic vegetation that had evolved in the absence of mammalian
predators. Rats radiated ahead of human colonizers on O’ahu, eating their way through the vegetation, perhaps before the colonizers
had encountered much of the pristine lowland forest into which the rats had radiated. This hypothesis is supported by several
observations, including the almost complete absence of extinct or extirpated avian faunal remains in archaeological deposits,
the present distribution of endemic vegetation in Hawai’i, rat ecology, population biology, and other evidence.
相似文献
J. Stephen AthensEmail: |
20.
Roger Sansom 《Biology & philosophy》2008,23(4):475-491
I show that gene regulation networks are qualitatively consistent and therefore sufficiently similar to linearly seperable
connectionist networks to warrant that the connectionist framework be applied to gene regulation. On this view, natural selection
designs gene regulation networks to overcome the difficulty of development. I offer some general lessons about their evolvability
that can be learned by examining the generic features of connectionist networks.
相似文献
Roger SansomEmail: |