Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “predation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 649 records · Page 36Linked to original sources
PubMed2006

Effect of food on immature development, consumption rate, and relative growth rate of Toxorhynchites splendens (Diptera: Culicidae), a predator of container breeding mosquitoes.

Food utilization by the larvae of Toxorhynchites splendens (Wiedemann) was studied in the laboratory by offering larvae of Aedes aegypti Linnaeus, Anopheles stephensi (Liston), and Culex quinquefasciatus (Say). Quantitative analyses of data indicated that immature development was significantly faster with increase in food availability. The regression analysis showed that the degrees of the relationship between immature duration (Id) and food availability were higher when offered early instars of prey (first and second instars) than late instars. Consumption rate (Cr) of the predator increased with increase in food availability and this relationship was highly significant when larvae of An. stephensi were offered as food. Consumption rate to food level decreased with increase in the age class of the prey. There was a significant negative correlation between Id and Cr. This aspect helps to increase population turnover of T. splendens in a shorter period when the prey is abundant. Conversely, the predator compensated the loss in daily food intake at low food level by extending Id thereby attains the minimum threshold pupal weight for adult emergence. There was an increase in the relative growth rate (RGR) of the predator when An. stephensi was offered as prey and this was related to the high protein content of the prey per body weight. There was a positive correlation between Cr and RGR. This adaptive life characteristic strategy of this predator is useful for mass-rearing for large scale field release programmes in the control of container breeding mosquitoes is discussed.

Animals↗
PubMed2001

Impact of four insecticides on Japanese beetle (Coleoptera: Scarabaeidae) egg predators and white grubs in turfgrass.

Field experiments were conducted to measure the effects of four commonly used turfgrass insecticides (isofenphos, diazinon, imidacloprid, halofenozide) on white grubs (Coleoptera: Scarabaeidae) and ant predators of white grub eggs. Ant populations were measured over time with canned tuna, whereas predation by the ants was measured with artificially placed Japanese beetle, Popillia japonica Newman, eggs. The effectiveness of each insecticide at controlling Japanese beetle grubs, when applied at different times during the growing season, also was measured. Isofenphos and diazinon significantly reduced both ant numbers and white grub egg predation, whereas imidacloprid and one halofenozide treatment did not significantly impact either measurement. A second halofenozide treatment significantly reduced white grub egg predation. Isofenphos and diazinon were ineffective at controlling Japanese beetle grubs when applied in June but were highly efficacious when applied in August. Evidence of enhanced biodegradation was found in plots that received both June and August applications of diazinon. Both June and August applications of imidacloprid and halofenozide provided good control of white grubs.

Animals↗
PubMed2003

Bionomics of Scymnus (Pullus) louisianae J. Chapin (Coleoptera: Coccinellidae) as a predator of the soybean aphid, Aphis glycines Matsumura (Homoptera: Aphididae).

A field population of Scymnus louisianae Chapin (Coccinellidae) was found attacking soybean aphids, Apis glycines Matsumura (Aphidae), a pest recently introduced into Kentucky. This coccinellid had not previously been found in Kentucky. A greenhouse population of S. louisianae was established and its predation on A. glycines studied under laboratory conditions. Total time to develop from egg to adult was about 20 d. About 70% of immatures survived to adulthood and they consumed approximately 100 aphid nymphs per beetle larva during the beetle's four larval instars. Adults lived for an average of 47 d (mated males) and 63 d (mated females) and, during their total adult lifetime, mated males consumed an average of 665 nymphs and mated females consumed 1261 nymphs. All developmental times and predation rates were comparable to those reported for other aphidophagous Scymnus spp. which, in conjunction with reports that Scymnus spp. are effective predators of cotton aphids, Aphis gossypii Glover, suggests that S. louisianae is a potentially important predator of A. glycines in the southern United States.

Animals↗
PubMed2003

Bt sweet corn and selective insecticides: impacts on pests and predators.

Sweet corn, Zea mays L., is attacked by a variety of insect pests that can cause severe losses to the producer. Current control practices are largely limited to the application of broad-spectrum insecticides that can have a substantial and deleterious impact on the natural enemy complex. Predators have been shown to provide partial control of sweet corn pests when not killed by broad-spectrum insecticides. New products that specifically target the pest species, while being relatively benign to other insects, could provide more integrated control. In field trials we found that transgenic Bt sweet corn, and the foliar insecticides indoxacarb and spinosad are all less toxic to the most abundant predators in sweet corn (Coleomegilla maculate [DeGeer], Harmonia axyridis [Pallas], and Orius insidiosus [Sav]) than the pyrethroid lambda cyhalothrin. Indoxacarb, however, was moderately toxic to coccinellids and spinosad and indoxacarb were somewhat toxic to O. insidiosus nymphs at field rates. Bt sweet corn and spinosad were able to provide control of the lepidopteran pests better than or equal to lambda cyhalothrin. The choice of insecticide material made a significant impact on survival of the pests and predators, while the frequency of application mainly affected the pests and the rate applied had little effect on either pests or predators. These results demonstrate that some of the new products available in sweet corn allow a truly integrated biological and chemical pest control program in sweet corn, making future advances in conservation, augmentation and classical biological control more feasible.

Animals↗
PubMed2006

Effects of pool depth and risk of predation on oviposition habitat selection by temporary pool dipterans.

Natural selection should favor females that oviposit in sites providing the best available conditions for her progeny. In temporary pools, two important conditions include risk of desiccation and risk of predation to larvae. In an artificial pool experiment, we compared oviposition responses of two dipterans, Culiseta longiareolata Macquart (Culicidae) and Chironomus riparius Meigan (Chironomidae), in very shallow pools that, if left to dry, would not have had a long enough hydroperiod for larvae to complete development, versus deeper pools that would have a sufficiently long enough hydroperiod for development. Water depth was crossed with the presence or absence of the predatory backswimmer Notonecta maculata F. (Hemiptera: Notonectidae). Oviposition patterns were consistent with larval vulnerability of the two species to predation by N. maculata. C. longiareolata, whose larvae are highly vulnerable to predation, strongly avoided ovipositing in pools containing this predator, whereas C. riparius, whose larvae are considerably less vulnerable, did not display oviposition avoidance. Pool depth did not affect oviposition habitat selection in either dipteran.

Animals↗
PubMed2001

Selective predation on parasitized prey--a comparison between two helminth species with different life-history strategies.

In Lake Fjellfrøsvatn, northern Norway, the larval helminths Cyathocephalus truncatus and Cystidicola farionis use Gammarus lacustris as intermediate hosts and Arctic charr (Salvelinus alpinus) as final hosts. There was sampled 1,433 live G. lacustris from the lake and 1,964 G. lacustris from stomach contents of the charr. Prevalence of infection were, respectively, 0.49% and 3.72% for C. truncatus, and 0.21% and 0.20% for C. farionis. Usually, only 1 parasite was present in each host, and the 2 parasite species never co-occurred. Gammarus lacustris amphipods parasitized by C. truncatus were positively selected by the Arctic charr and were consumed approximately 8 times as often as were the unparasitized amphipods or the amphipods infected with C. farionis. This suggests that G. lacustris amphipods infected with C. truncatus larvae are more susceptible to predation than noninfected specimens, probably because of parasite-induced alterations in behavior or visibility. Alternatively, this could also be explained by selection toward the largest G. lacustris specimens observed, which are also the most frequently parasitized amphipods. However, the data show clearly that this was not a result of size-selective predation by the charr. In contrast, the presence of C. farionis did not increase the susceptibility to predation of its intermediate host. The discrepancy between the 2 helminth species supports the hypothesis that parasite-increased susceptibility to predation is related to the life history strategies of the parasites.

Animals↗
PubMed2006

Reciprocal phenotypic plasticity in a predator-prey interaction between larval amphibians.

In biological interactions, phenotypic change in interacting organisms induced by their interaction partners causes a substantial shift in some environmental factor of the partners, which may subsequently change their phenotype in response to that modified environmental factor. Few examples of such arms-race-like plastic responses, known as reciprocal phenotypic plasticity, have been identified in predator-prey interactions. We experimentally identified a reciprocal defensive plastic response of a prey species against a predator with a predaceous phenotype using a model system of close predator-prey interaction. Rana pirica tadpoles (the prey species) were reared with larvae of the salamander Hynobius retardatus (the predator species) having either a predaceous or a typical, nonpredaceous phenotype. The H. retardatus larvae with the predaceous phenotype, which is known to be induced by the presence of R. pirica tadpoles, induced a more defensive phenotype in the tadpoles than did larvae with the typical phenotype. The result suggests that the reciprocal phenotypic plasticity of R. pirica tadpoles is in response to a phenotype-specific signal under a close-signal recognition process.

Adaptation, Physiological↗
PubMed2006

Predators exert top-down control of soybean aphid across a gradient of agricultural management systems.

The discovery of soybean aphid, Aphis glycines Matusumura, in North America in 2000 provided the opportunity to investigate the relative strength of top-down and bottom-up forces in regulating populations of this new invasive herbivore. At the Kellogg Biological Station Long Term Ecological Research site in agroecology, we contrasted A. glycines establishment and population growth under three agricultural production systems that differed markedly in disturbance and fertility regimes. Agricultural treatments consisted of a conventional-tillage high-input system, a no-tillage high-input system, and a zero-chemical-input system under conventional tillage. By selectively restricting or allowing predator access we simultaneously determined aphid response to top-down and bottom-up influences. Irrespective of predator exclusion, our agricultural manipulations did not result in bottom-up control of A. glycines intrinsic rate of increase or realized population growth. In contrast, we observed strong evidence for top-down control of A. glycines establishment and overall population growth in all production systems. Abundant predators, including Harmonia axyridis, Coccinella septempunctata, Orius insidiosus, and various predaceous fly larvae, significantly reduced A. glycines establishment and population increase in all trials. In contrast to other systems in which bottom-up forces control herbivore populations, we conclude that A. glycines is primarily controlled via top-down influences of generalist predators under a wide range of agricultural management systems. Understanding the role of top-down and bottom-up forces in this context allows agricultural managers to focus on effective strategies for control of this invasive pest.

Agriculture↗
PubMed2004

Predation resistance and nematocyst scaling for Metridium senile and M. farcimen.

Previous studies suggest that large body size reduces the risk of predation for acontiate sea anemones. For two species of Metridium, we found significant increases in the length of the acontial threads and in the mean lengths of the unfired acontial nematocyst capsules, with increasing body size. This supports the hypothesis that more damaging acontial defenses protect larger acontiate anemones from their predators. Metridium is planktivorous, and food size does not increase substantially with body size; so we expected smaller increases in nematocyst size for the feeding tentacles. In fact, scaling exponents were significantly smaller for the tentacle nematocysts than for acontial nematocysts of the same types in 3 out of 4 cases. This suggests that nematocyst scaling responds predictably to selection pressure. When specimens of the same size were compared, the non-clonal, subtidal species, M. farcimen, had significantly larger acontial nematocysts than did its clonal congener, M. senile, which lives at the upper tidal limits for major subtidal predators in the northeastern Pacific. Therefore, larger acontial nematocysts may be particularly advantageous where predation levels are high. These data demonstrate that closely related anemone species can be distinguished on the basis of ecologically and functionally relevant differences in nematocyst scaling.

Adaptation, Biological↗
PubMed2006

Laboratory evaluation of the effect of alternative prey and vegetation on predation of Culex annulirostris immatures by Australian native fish species.

The impact of alternative prey and simulated vegetation on Culex annulirostris Skuse predation efficacy by Australian smelt, Retropinna semoni (Retropinnidae); crimson-spotted rainbowfish, Melanotaenia duboulayi (Melanotaeniidae); empire gudgeon, Hypseleotris compressa (Eleotridae); estuary perchlet, Ambassis marianus (Ambassidae); firetail gudgeon, Hypseleotris galii (Eleotridae); fly-specked hardyhead, Craterocephalus stercusmuscarum (Atherinidae); and Pacific blue-eye, Pseudomugil signifer (Atherinidae), was evaluated in Queensland, Australia. The presence of chironomid midge larvae and tusked frog, Adelotus brevis (Leptodactylidae), tadpoles did not have a significant negative impact on the predation rates of Cx. annulirostris by these 7 fish species. Hypseleotris galii, M. duboulayi, and R. semoni demonstrated strong preference for larvae of Cx. annulirostris over both alternative prey species. In the presence of alternative prey species, the mean predation rate of M. duboulayi on larvae of Cx. annulirostris remained greater than that of other fish species tested. When evaluated at varying densities of simulated vegetation, predation rates of all fish species were similar to those reported in open conditions.

Animals↗
PubMed2004

Social learning about predators: a review and prospectus.

In comparison with social learning about food, social learning about predators has received little attention. Yet such research is of potential interest to students of animal cognition and conservation biologists. I summarize evidence for social learning about predators by fish, birds, eutherian mammals, and marsupials. I consider the proposal that this phenomenon is a case of S-S classical conditioning and suggest that evolution may have modified some of the properties of learning to accommodate for the requirements of learning socially about danger. I discuss some between-species differences in the properties of socially acquired predator avoidance and suggest that learning may be faster and more robust in species in which alarm behavior reliably predicts high predatory threat. Finally, I highlight how studies of socially acquired predator avoidance can inform the design of prerelease antipredator training programs for endangered species.

Adaptation, Psychological↗
PubMed2001

Seed size variation and predation of seeds produced by wild and crop-wild sunflowers.

The movement of pollen between crop and wild sunflowers (both Helianthus annuus) has led to concerns about the possible introduction of crop transgenes into wild populations. The persistence of crop traits in wild populations will depend in part on the relative fitness of crop-wild hybrid vs. wild plants. Using seeds from two large experimental field plots, we found that seeds produced by crop-wild plants were twice the size of wild seeds and differed in coloration. Head diameter, date of flowering, identity of mother plant, and levels of predispersal predation explained some variation in mean seed size. We hypothesized that postdispersal vertebrate seed predation would be affected by seed size, with hybrid seeds preferentially eaten. In each of three field trials, significantly more hybrid seeds were eaten (62% of hybrid seed; 42% of wild seed). Within the category of wild seeds, larger seeds were preferentially eaten; however among hybrid seeds, predation was not significantly related to seed size. In this study, differential predation thus reduces hybrid fitness and would presumably slow the spread of transgenes into wild populations.

Journal Article↗
PubMed2000

[Impact of starvation on predation by male adult Chrysopa septempunctata].

The predation on Schizaphis graminum by male adult Chrysopa septempunctatata at various levels of starvation was examined in this paper. Th results showed that the functional reactive types of predator were not altered by its starvation duration, and the amount(Na) of catched S. graminum by C. septempunctata within 24 hrs varied with duration time(t), which could be expressed by the model: Na = 100/(1 + e-0.3088 - 0.0996t). The relationship between predation rate(v) and time(x) could be described as v = 6.7117 x-0.7928. The male adult predators preferred feeding on the young preys.

Animals↗
PubMed2004

Laboratory evaluation of the predation efficacy of native Australian fish on Culex annulirostris (Diptera: Culicidae).

The introduction and establishment of fish populations can provide long-term, cost-effective mosquito control in habitats such as constructed wetlands and ornamental lakes. The predation efficacy of 7 native Brisbane freshwater fish on 1st and 4th instars of the freshwater arbovirus vector Culex annulirostris was evaluated in a series of 24-h laboratory trials. The trials were conducted in 30-liter plastic carboys at 25+/-1 degrees C under a light:dark cycle of 14:10 h. The predation efficacy of native crimson-spotted rainbowfish Melanotaenia duboulayi (Melanotaeniidae), Australian smelt Retropinna semoni (Retropinnadae), Pacific blue-eye Pseudomugil signifer (Atherinidae), fly-specked hardyhead Craterocephalus stercusmuscarum (Atherinidae), firetail gudgeon Hypseleotris galii (Eleotridae), empire gudgeon Hypseleotris compressa (Eleotridae), and estuary perchlet Ambassis marianus (Ambassidae) was compared with the exotic eastern mosquitofish Gambusia holbrooki (Poeciliidae). This environmentally damaging exotic has been disseminated worldwide and has been declared noxious in Queensland. Melanotaenia duboulayi was found to consume the greatest numbers of both 1st and 4th instars of Cx. annulirostris. The predation efficacy of the remaining Australian native species was comparable with that of the exotic G. holbrooki. With the exception of A. marianus, the maximum predation rates of these native species were not statistically different whether tested individually or in a school of 6. Based on these data, M. duboulayi, H. compressa, and A. marianus warrant further investigation as biological control agents in pilot field trials.

Animals↗
PubMed2005

Chemical detection of the predator Notonecta irrorata by ovipositing Culex mosquitoes.

We tested the oviposition response of Culex mosquitoes to the predator Notonecta irrorata in an outdoor artificial pool experiment employing equal numbers of control and predator pools. There was a strong oviposition avoidance by Culex of Notonecta pools; 83% of egg rafts were found in control pools during the period in which Notonecta were present. After removing Notonecta, mosquitoes continued to avoid ovipositing in the former Notonecta pools for two additional days suggesting a predator-released kairomone as the cue used by the mosquitoes to detect the presence of this predator.

Animals↗
PubMed2006

[Predation of Typhlodromus bambusae Ehara on Sehizotetranychus bambsae].

The simulation study under laboratory condition showed that the functional responses of Typhlodromus bambuse to Schizotetranychus bambuse at different development stages could be expressed by the curve of Holling Type II. The number of prey consumed by predator quickly increased with initial prey density, but soon leveled off. At 25 +/- 0.5 degrees C, the handling time (Th) of T. bambuse to S. bambusae at the stages of egg, larva, protonymph, deurtonymph and female was in order of egg<larva<protonymph<deurtonymph<female, and the selection coefficient (Q) of T. bambusae to S. banzbusae egg, larva, protonymph, deurtonymph and female adult was 1.47, 1.34, 1.16, 0.90 and 0.15, respectively. The numerical response of T. bambusae to S. bambusae revealed that the fecundity of the Phytoseiidae mite was significantly affected by the prey density. When the ratio of predator to prey was 1: 1-9, the daily oviposition of the predator varied from 0.5 to 2.0 eggs per female, which was increased with increasing prey density, while if the ratio was 1:15 or more, the daily oviposition decreased to about 1.8 eggs per female, which was probably due to the interference of high prey density to predation.

Animals↗
PubMed2006

Effects of temperature on predation by the stinkbugs Picromerus bidens and Podisus maculiventris (Heteroptera: Pentatomidae) on noctuid caterpillars.

Environmental risks associated with the use of non-indigenous organisms for augmentative biological control have received growing attention. In Europe, the native pentatomid predator Picromerus bidens (Linnaeus) has been considered a potential alternative to the North American pentatomid Podisus maculiventris (Say) for the control of lepidopteran, coleopteran and hymenopteran defoliator pests. In the current study, prey consumption and developmental duration of the predatory stages of P. bidens and P. maculiventris were investigated at three temperatures (18, 23 and 27 degrees C) in the laboratory using caterpillars of Spodoptera littoralis as prey. Development time from second to fifth instar was longer for P. bidens than for P. maculiventris, taking on average 17-44 and 14-32 days, respectively, at the different temperatures. Total nymphal consumption of fourth instar S. littoralis caterpillars indicated a greater voracity of P. bidens as compared with P. maculiventris at both the low and high temperatures tested (18 and 27 degrees C). At 23 degrees C, however, the predation rate of P. maculiventris nymphs exceeded that of P. bidens nymphs. Effect of temperature on the functional response of P. bidens to densities of fourth instar Spodoptera exigua was assessed on potted green bean plants. Female adults of P. bidens exhibited a type II functional response at 18 and 23 degrees C but a type III response at 27 degrees C. Searching efficiency was not affected by temperature but handling time decreased from 4.2 to 1.4 h as temperature increased from 18 to 23 degrees C. However, the predator spent twice as much time handling prey at 27 degrees C (2.9 h) than at 23 degrees C. This study indicates high predation rates of P. bidens at a wide range of temperatures and suggests that the species may be a valuable asset for the biological control of defoliating caterpillars, provided that obstacles to its mass production can be overcome.

Animals↗
PubMed1988

A laboratory study of predation by damselfly nymphs, Enallagma civile, upon mosquito larvae, Culex tarsalis.

The nymph of the damselfly, Enallagma civile, feeds on the larvae of the mosquito Culex tarsalis amongst a variety of other small aquatic invertebrates. Average daily consumption of 3rd instar Cx. tarsalis larvae by the last nymphal stage of E. civile was 6.06 larvae (range 4.64-8.67). Experiments in which density of prey (mosquito larvae) and predators (E. civile nymphs) were varied, showed that more prey was consumed as prey density increased. However, fewer prey were consumed at higher predator densities; mutual interferences among predators at higher predator densities was suspected.

Animals↗