No evidence of predator odor avoidance in a North American bird community

Recent advances in our understanding of avian chemical communication have highlighted the importance of olfaction in many aspects of avian life.Prior studies investigating predator avoidance behaviors in response to predator odor cues have produced mixed results across species and contexts.Here we assess if a community of birds in eastern Pennsylvania displays avoidance behaviors towards predator odor cues in a natural foraging setting.We use clay caterpillars to measure foraging activity by birds in the presence of predator(bobcat)urine,non-predator(rabbit)urine,and water controls in two different environmental contexts(field vs.forest).Although we detected a weak trend for birds to forage less at predator urine-treated sites,we found no significant difference in avian foraging between the site types.We did find that foraging rates between environmental contexts changed significantly over the course of the experiment,with forest sites showing decreasing foraging rates and field sites showing increasing foraging rates.Our results reinforce the published literature that avoidance of predator odors by birds may not be ubiquitous across contexts and species.

The effects of anthropogenic noise on nest predation with respect to predator species across different habitats and seasons

Noise pollution is a maj or component of sensory pollution that can disrupt the well-being and functioning of living organisms,affect a variety of life history traits in animals,and reduce their reproductive success.In this study,we used artificial nest experiments with noise manipulation to investigate the influence of anthropogenic noise on nest predation during the breeding and non-breeding seasons and in different forest habitats.We found that the noise treatment did not alter the predation rates or survival probabilities of birds in artificial nests.However,the diversity and species composition of nest predators in artificial pine forests varied between breeding and nonbreeding seasons,which may be explained by season-specific adaption of nest predators to bird nests or the unstable ecosystems of artificial forests.The diversity and species composition of nest predators differed between the different forests,probably because of differences in habitat heterogeneity.Predation time varied with treatment,season,and habitat,although most predators were nocturnal mammals.Niche segregation or changes in optimal foraging time may explain this phenomenon.

Multi-Stage Improvement of Marine Predators Algorithm and Its Application

The metaheuristic algorithms are widely used in solving the parameters of the optimization problem.The marine predators algorithm(MPA)is a novel population-based intelligent algorithm.Although MPA has shown a talented foraging strategy,it still needs a balance of exploration and exploitation.Therefore,a multi-stage improvement of marine predators algorithm(MSMPA)is proposed in this paper.The algorithm retains the advantage of multistage search and introduces a linear flight strategy in the middle stage to enhance the interaction between predators.Predators further away from the historical optimum are required to move,increasing the exploration capability of the algorithm.In the middle and late stages,the searchmechanism of particle swarmoptimization(PSO)is inserted,which enhances the exploitation capability of the algorithm.This means that the stochasticity is decreased,that is the optimal region where predators jumping out is effectively stifled.At the same time,self-adjusting weight is used to regulate the convergence speed of the algorithm,which can balance the exploration and exploitation capability of the algorithm.The algorithm is applied to different types of CEC2017 benchmark test functions and threemultidimensional nonlinear structure design optimization problems,compared with other recent algorithms.The results show that the convergence speed and accuracy of MSMPA are significantly better than that of the comparison algorithms.

一类食饵具有阶段结构的时滞Predator-Prey系统的周期解(英文)

研究了一类时滞Predator-Prey系统,其中Prey种群是具有两个生命阶段的种群,即幼年阶段和成年阶段。Predator种群只能捕食Prey幼年种群。通过应用Gaines和Mawhin重合度理论的连续函数定理,给出了系统正周期解存在的充分条件。

Antipredator Behavioral Responses of Native and Exotic Tadpoles to Novel Predator

Factors related to the invasion process, such as high abundance of invaders, residence time, and functional distinctiveness, are well documented, but less attention has been given to the effects of antipredator strategy of invasive species during colonization. In this study, we explored the antipredator strategy of an introduced species by comparing the predator avoidance behaviors of two native anuran species and one introduced （“exotic”） species in the presence of different predators. The two native anuran species used in the study were Black-spotted Pond FrogRana nigromaculata and Terrestrial Frog Rana limnocharis. The introduced （invasive） species used was American bullfrogLithobates catesbeianus. Chinese pond turtleChinemys reevesii, Red-backed rat snakeElaphe rufodorsata, and Big-headed turtle Platysternon megacephalum were used as predator species. Chinese pond turtles and Red-backed rat snakes are native predators of Black-spotted Pond Frogs and Terrestrial Frogs, while Big-headed turtles are novel （“unfamiliar”） to the two frogs. All three predator species are novel （“unfamiliar”） to the American bullfrog. The results show that tadpoles of the two native species displayed behaviors of recognizing the two native predators, but did not display the capability of identifying the novel predator. Results from our study also suggest that American bullfrog tadpoles exhibited strong antipredator behavioral responses by displaying the capability of identifying “unfamiliar” predators without cohabitation history and prior exposure to them. Such antipredator behavioral responses could have resulted in more favorable outcomes for an invading species during the invasive introductory process.

Predator-Proof Bomas as a Tool in Mitigating Human-Predator Conflict in Loitokitok Sub-County Amboseli Region of Kenya

Human-wildlife conflict (HWC) arises when wildlife shares the same physical space with humans. HWC, particularly livestock predation results in great negative impacts both to pastoralist and carnivores. Various approaches including compensation, livestock guarding, translocation of the problematic predator, and predator-proof bomas (PPB) have been used to mitigate such conflicts. We assessed PPB in mitigating human-predator conflict in Loitokitok sub-county by focusing on its effectiveness, most problematic predator, community’s perceptions, and comparing the PPB and traditional bomas characteristics. Data were obtained from 90 homesteads in Olgulului, Mbirikani and Kimana/Tikondo group ranches. Correlation and paired t-tests were used to analyze the data. Our findings suggest that the boma sizes correlated with the total number of livestock in the boma (r = 0.386, n = 90, p = 0.000) but not the number of people. Hyena and lion accounted for the highest loss of shoats and cattle, with hyena mostly killing shoats (37%) and lions preying largely on cattle (34%). The most problematic predator was as hyena (68%). We found positive relationships between the most problematic predator and total number of livestock (r = 0.319, n = 90, p = 0.002), and boma circumference (r = 0.295, n = 90, p = 0.005). Livestock predation was high in boma during the wet seasons (April, September, October and December). The erection of PPB reduced livestock predation by 91.11% (n = 45) and time spend guarding livestock at night. We recommend a continuous maintenance of the PPB as a long term solution to livestock loss at night and a close guarding of livestock during the day by adults to reduce day time predations.

The Influence of Transgenic cry1Ab/cry1Ac,cry1C and cry2A Rice on Non-Target Planthoppers and Their Main Predators Under Field Conditions

Transgenic Bt rice has been shown to be an effective means of controlling Lepidoptera pests of rice. However, the potential roles of transgenic rice on planthoppers and their predators need to be investigated before its commercialization. Population density, species dominance and population dynamics are important parameters of arthropods populations in field. So the impacts of three transgenic Bt rice strains expressing crylAb/crylAc, crylC and cry2A on population density, species dominance and population dynamics of three species of planthoppers （Nilaparvata lugens, Sogatella furcifera and Laodelphax striatellus） and their three main predators （ Cyrtorhinus lividipennis, Pirata subpiraticus and Theridium octomaculatum） were evaluated at three sites in Hubei Province, China, in the current study. The results showed that among three species of planthoppers, both in transgenic and non-transgenic rice field, the predominant species ofplanthoppers within phytophagous guild was S. furcifera at any site either growing season （46-50%）. Significantly higher population density ofN. lugens was observed in T2A-1 field relative to Minghui 63 field at Wuxue in 2010. The species dominance of predator, P. subpiraticus, in TT51 field was significantly higher than that in T 1 C-19 and T2A-1 fields in 2009 at Xiaogan site. Sampling date significantly influenced six arthropods except for P. subpiraticus in 2010. The interaction between rice strain^sampling date had no significant adverse effects on the population dynamics of three species of planthoppers and their predators, except for several individual species in 2009. The interaction among rice strain^sampling date^sampling site also had no significant effect on six arthropods except for S. furcifera in 2009. The results indicated that transgenic Bt rice expressing crylAb/crylAc, cry2A and crylC had no significant adverse effects on the population dynamics of three planthoppers and their predators in most investigated data and sampling site.

Effects of Transgenic Bt+CpTI Cotton on Field Abundance of Non-Target Pests and Predators in Xinjiang, China

Transgenic insect-resistant cotton is being increasingly planted in Xinjiang cotton-planting regions, where geographical climate conditions and species composition of pests and natural enemies are greatly unique in China. Limited studies have been conducted on the ecological impacts of transgenic insect-resistant cotton, especially for transgenic double genes （Bt＋CpTI） cotton, in this region. In this study, the potential effects of transgenic Bt＋CpTI cotton on the seasonal abundance of non-target pests and predators were assessed from 2009 to 2011 in Korla, Xinjiang. The results showed that species composition and seasonal abundance of 5 groups of pests and 5 groups of predators were not significantly different between transgenic Bt＋CpTI cotton and non-transgenic cotton every year. It suggests that transgenic Bt＋CpTI cotton per se does not affect the population dynamics of non-target pests and predators on this crop in Xinjiang.

Nest predators, nest-site selection and nest success of the Emei Shan Liocichla(Liocichla omeiensis), a vulnerable babbler endemic to southwestern China

Background: The Emei Shan Liocichla(Liocichla omeiensis) is a globally vulnerable babbler, endemic to southwestern China. We investigated its nest predators, nest-site selection and nest success at the Laojunshan National Nature Reserve in Sichuan, China in order to identify the precise nesting-habitat requirements of the species, and to test whether the nest-site-selection cues, preferred by the Emei Shan Liocichla, are positively associated with nest success.Methods: We used infrared cameras to determine nest predators. We compared the microhabitat attributes between nest and random sites, as well as successful and failed nests. We used Binary Logistic Regression to determine the most important variables affecting nest-site selection of the Emei Shan Liocichla. We used the nest survival analysis in Program MARK to estimate daily nest survival rates(DSR). Nest success was calculated using the Mayfield method.Results: In total 56 nests were found. The DSR for all nests that contained at least one egg was 0.9564 ± 0.0091(95 % CI 0.9346–0.9711)(n = 40), while the total nest success was 27.5 %. We identified four categories of predators in 10 nest predation events, i.e. squirrels(n = 5), snakes(n = 3), raptors(n = 1) and wasps(n = 1). We found that:(1) nest predation was the primary reason for nest failure of the Emei Shan Liocichla,(2) tree cover, bamboo cover, liana abundance and distance to forest edge or gap were the most important variables affecting nest-site selection of this species, and(3) the nest-site-selection variables we measured appeared not to be positively associated with nest success.Conclusions: Our findings suggest that the Emei Shan Liocichla tended to select nest sites near forest edges or gaps with good concealment and that nest-site selection by this species was nonrandom but not necessarily adaptive. Reducing forest-edge development and protecting bamboo stands should be effective for conservation of this species.

POSITIVE PERIODIC SOLUTION OF A NEUTRAL PREDATOR-PREY SYSTEM

In this paper, the existence o f a positive periodic solution to the following neutral predator_prey system (t)=rH(t)1-a 1(t)H(t-τ)+a 2(t-τ)K-α(t)H(t)P(t), (t)=-b(t)P(t)+β(t)H(t)P(t) is studied,in which r,a 2,K and τ are positive constants, and a 1(t ),α(t),b(t) and β(t) are positive continuous functions of period ω .

A QTL associated with leaf trichome traits has a major influence on the abundance of the predatory mite Typhlodromus pyri in a hybrid grapevine population

The abundance of predatory phytoseiid mites,Typhlodromus pyri,important biological control agents of spider mite pests in numerous crops,is positively influenced by the density of leaf trichomes and tuft-form domatia in vein axils.Identification of the genetic regions controlling both trophic levels could facilitate the improvement of predatory mite habitat in breeding programs.The abundance of T.pyri and non-glandular trichomes was measured in a segregating F1 family derived from the cross of the complex Vitis hybrid,‘Horizon’,with Illinois 547-1(V.rupestris B38×V.cinerea B9),finding positive correlation among traits.High density genetic maps were used to localize one major quantitative trait locus(QTL)on chromosome 1 of Illinois 547-1 associated with both predatory mite abundance and leaf trichomes.This QTL explained 23%of the variation in phytoseiid abundance and similar amounts of variance in domatia rating(21%),domatia size(16%),leaf bristle density(37%in veins and 33%in blades),and leaf hair density(20%in veins and 15%in blades).Another nine QTL distributed among chromosomes 1,2,5,8,and 15 were associated solely with trichome density,and explained 7–17%of the phenotypic variation.Combined,our results provide evidence of the genetic architecture of non-glandular trichomes in Vitis,with a major locus influencing trichome densities,domatia size and predatory mite abundance.This information is relevant for breeding grapevines with a more favorable habitat for biological control agents.

一类含扩散与时滞的Prey-Predator模型的周期解

利用上下解方法以及比较原理研究了一类含扩散与时滞的Prey-Predator模型,证明在一定条件下该模型的零平衡态及半平凡周期解的全局稳定性,并获得了这个系统具有一对周期拟解的充分条件.对任意的非负初值函数,这一对周期拟解构成的区间是此系统的一个吸引子.

Generalization of predator recognition:Velvet geckos display anti-predator behaviours in response to chemicals from non-dangerous elapid snakes

Many prey species detect chemical cues from predators and modify their behaviours in ways that reduce their risk ofpredation. Theory predicts that prey should modify their anti-predator responses according to the degree of threat posed by thepredator. That is, prey should show the strongest responses to chemicals of highly dangerous prey, but should ignore or respondweakly to chemicals from non-dangerous predators. However, if anti-predator behaviours are not costly, and predators are rarelyencountered, prey may exhibit generalised antipredator behaviours to dangerous and non-dangerous predators. In Australia, mostelapid snakes eat lizards, and are therefore potentially dangerous to lizard prey. Recently, we found that the nocturnal velvetgecko Oedura lesueurii responds to chemicals from dangerous and non-dangerous elapid snakes, suggesting that it displays generalisedanti-predator behaviours to chemicals from elapid snakes. To explore the generality of this result, we videotaped the behaviourof velvet geckos in the presence of chemical cues from two small elapid snakes that rarely consume geckos: the nocturnalgolden-crowned snake Cacophis squamulosus and the diurnal marsh snake Hemiaspis signata. We also videotaped geckos in trialsinvolving unscented cards (controls) and cologne-scented cards (pungency controls). In trials involving Cacophis and Hemiaspischemicals, 50% and 63% of geckos spent long time periods (> 3 min) freezing whilst pressed flat against the substrate, respectively.Over half the geckos tested exhibited anti-predator behaviours (tail waving, tail vibration, running) in response to Cacophis(67%) or Hemiaspis (63%) chemicals. These behaviours were not observed in control or pungency control trials. Our resultssupport the idea that the velvet gecko displays generalised anti-predator responses to chemical cues from elapid snakes.Generalised responses to predator chemicals may be common in prey species that co-occur with multiple, ecologically similar,dangerous predators [Current Zoology 56 (3): 337-342, 2010].

NONLINEAR SINGULARLY PERTURBED PREDATOR-PREY REACTION DIFFUSION SYSTEMS

A class of nonlinear predator prey reaction diffusion systems for singularly pe rturbed problems are considered.Under suitable conditions, by using theory of di fferential inequalities the existence and asymptotic behavior of solution for in itial boundary value problems are studied.

Predator SFC系统在模具生产现场的管理及应用

PredatorSFC数控生产现场信息集成化管理系统这一革命性的解决方案提供了整个数控生产现场流程的完整规划,自动化管理每一个人的使用细节。它将生产现场的详细信息资料集中管理保存,通过人性化的设置为每一个人提供所需要的详细信息资料。

Effects of Predators on the Belowground Life Stages (Prepupae and Pupae) of the Western Flower Thrips, <i>Frankliniella occidentalis</i>(Thripidae: Thysanoptera): A Review

Western flower thrips, Frankliniella occidentalis, is a major cosmopolitan insect pest causing direct and indirect damage to greenhouse-grown horticultural crops. The primary way of managing western flower thrips populations is by routinely applying insecticides, which target the aboveground life stages: larvae and adult. However, insecticides are minimally effective against the pupal stages (prepupae and pupae) that reside in the growing medium or soil. Therefore, soil-dwelling biological control agents including: predatory mites [Stratiolaelaps scimitus and Hypoaspis = (Geolaelaps) aculeifer], and a rove beetle, Dalotia coriaria may be a viable option to induce mortality on the pupal stages. These predators will feed on the pupal stages of the western flower thrips and can provide mortality on a life stage that is tolerant of insecticide applications. However, these biological control agents need to be used in conjunction with other plant protection strategies, such as insecticides and/or biological control agents that target the aboveground life stages (larvae and adult) to effectively manage western flower thrips populations in greenhouse production systems.

Diversity of Insect Pest and Predator Species in Monsoon and Summer Rice Fields of Taungoo Environs, Myanmar

Paddy fields are natural and artificial wetland ecosystems that supply rice for the people and provide the wildlife especially insect diversity of different functional aspects. A total of 71 insect species belonging to 40 families under eight orders were observed during the study period. Among the 71 insect species, 18 species of beetles, nine species of bugs, eight species of dragonfly, five species of butterflies, four species of leafhoppers, plant hoppers and moths, three borer and spiders, two crickets, one species of skippers, grass hopper, hispa, ant, weevil, hairy caterpillar, leaf roller, katydid, thrips, maggot and water boatmen were recorded in the study sites. Total of 41 species of pests, 18 species of predators and 12 species of beneficial species (they function as pollinating the flowering plants in the paddy field wetland ecosystem) were recorded in the study sites. In the monsoon season, the 41 species of pest species, 18 species of predator species and 12 species of beneficial species were recorded from monsoon rice field. According to Shannon Evenness value (H'/S = -0.012564), the data showed that the insect species recorded from the one habitat was not the similar to another. In summer paddy fields, 36 species of pest species, 16 species of predator species and 9 species of beneficial species were recorded. Total arthropod insect species were recorded 61 species from the dry rice fields. According to Shannon Evenness value (H'/S = -0.000120), the data showed that the insect species recorded from the one habitat was not the similar to another. Population growth and duration of life cycle of insects is mainly dominated by the temperature, the duration of life cycle is shorter in the high temperature than in the low temperature.

Potential of Hemianax ephippiger (Odonata-Aeshnidae) nymph as predator of Fasciola intermediate host, Lymnaea natalensis

Objective: To evaluate the predatory capacity of the Odonata, Hemianax ephippiger nymph as a biocontrol agent for the freshwater snail Lymnaea natalensis, intermediate host of Fasciola gigantica. Methods: Observations on the searching, attacking and devouring of the snails with a series of laboratory-based predation experiments, whose aims were to determine daily predation rate, differential predation on small-, medium- and large-sized snails were carried out. Results: Laboratory evaluation revealed that, the Odonata nymph could kill and consume all three sizes of snails. Searching and handling time of the predator differed depending on snail size and predator vulnerability. The predation rate varied also with respect to snail size and density.Conclusions: Our observations suggested that the predator Hemianax ephippiger may be a suitable bio-control agent of Lymnaea natalensis snail population.

Natural predators of polyps of three scyphozoans:Nemopilema nomurai,Aurelia coerulea,and Rhopilema esculentum

Jellyfish blooms have become a hot research topic in recent decades because they pose a serious threat to fisheries,coastal industries,tourism,and the marine ecosystem.The life cycle of scyphozoan jellyfish consists of a pelagic medusa stage and a benthic polyp stage,where asexual reproduction and strobilation of the polyps directly affect the abundance of ephyra and subsequently medusa abundance.The dynamics of polyps are affected by both environmental and biological factors,and predation by natural predators is one of the most important biological factors.Nemopilema nomurai,Aurelia coerulea,and Rhopilema esculentum are three scyphozoan species that are commonly found in Chinese coastal waters,and previous studies reported that the survivorship of polyps differs among the three species when they are exposed to the same benthic community.To identify potential natural predators of polyps of these three species in Chinese coastal waters and to determine whether the predation rates on polyps of the three species differ,we collected 39 species of macrozoobenthos from the Bohai Sea,Yellow Sea,and East China Sea from May 2014 to June 2016 and conducted predation tests and predation rate measurements.We found that the nudibranchs Pleurobranchaea novaezealandiae,Okenia plana,and Chromodoris tinctoria and the sea anemones Paracalliactis sinica,Calliactis japonica,Anthopleura incerta,and Anthopleura midori could prey on the polyps of all three scyphozoan species.The predation rates increased with the body length of the predators.The predations rates were also related to the polyp species,although the different predators showed no consistent preference for a particular species of polyp.Our results indicate that introducing predators to locations inhabited by polyps might be a way to control the benthic polyp populations and prevent subsequent jellyfish blooms.

Stability of the Bifurcation Solutions for a Predator-Prey Model

The bifurcation solution of the nonnegative steady state of a reaction diffusion system was investigated. The combination of the sturm type eigenvalue and the theorem of bifurcation was used to study the local coexistence solutions, and obtain the stability of bifurcation solutions. The system model describes predator prey interaction in an unstirred chemostat.