Predation Mortality Research Articles

Functional response of Harmonia axyridis preying on Acyrthosiphon pisum nymphs: the\xa0effect of temperature

In the current study, we investigated the functional response of Harmonia axyridis adults and larvae foraging on Acyrthosiphon pisum nymphs at temperatures between 15 and 35 °C. Logistic regression and Roger’s random predator models were employed to determine the type and parameters of the functional response. Harmonia axyridis larvae and adults exhibited Type II functional responses to A. pisum, and warming increased both the predation activity and host aphid control mortality. Female and 4th instar H. axyridis consumed the most aphids. For fourth instar larvae and female H. axyridis adults, the successful attack rates were 0.23 ± 0.014 h−1 and 0.25 ± 0.015 h−1; the handling times were 0.13 ± 0.005 h and 0.16 ± 0.004 h; and the estimated maximum predation rates were 181.28 ± 14.54 and 153.85 ± 4.06, respectively. These findings accentuate the high performance of 4th instar and female H. axyridis and the role of temperature in their efficiency. Further, we discussed such temperature-driven shifts in predation and prey mortality concerning prey-predator foraging interactions towards biological control.

Predator-Prey Model with Refuge, Fear and Z-Control

In this paper, we consider a predator-prey model incorporating fear and refuge. Our results show that the predator-free equilibrium is globally asymptotically stable if the ratio between the death rate of predators and the conversion rate of prey into predator is greater than the value of prey in refuge at equilibrium. We also show that the co-existence equilibrium points are locally asymptotically stable if the value of the prey outside refuge is greater than half of the carrying capacity. Numerical simulations show that when the intensity of fear increases, the fraction of the prey inside refuge increases; however, it has no effect on the fraction of the prey outside refuge, in the long run. It is shown that the intensity of fear harms predator population size. Numerical simulations show that the application of Z-control will force the system to reach any desired state within a limited time, whether the desired state is a constant state or a periodic state. Our results show that when the refuge size is taken to be a non-constant function of the prey outside refuge, the systems change their dynamics. Namely, when it is a linear function or an exponential function, the system always reaches the predator-free equilibrium. However, when it is taken as a logistic equation, the system reaches the co-existence equilibrium after long term oscillations.

Predation of Juvenile Japanese Sea Cucumber Apostichopus japonicus by Kelp Crab Pugettia ferox

The predation of commercially important Japanese sea cucumber Apostichopus japonicus by the kelp crab Pugettia ferox, widely distributed in coastal northeast Asia, was examined in field sampling and laboratory experiments. The ossicles of A. japonicus were detected from the stomach contents of a natural population of P. ferox at the rate of 32.4% of 68 individuals collected within artificial intermediate sea cucumber reefs for releasing hatchery-produced juveniles in December 2018. In the following laboratory experiments, a high mortality rate (7.7 ± 2.4 individuals day–1) of juvenile A. japonicus (15.35 ± 2.47 mm) was observed despite the different sizes and sex of P. ferox tested. It was also confirmed that a maximum of five sea cucumbers was killed and cut into small pieces within the first 2 h. Smaller and younger P. ferox individuals (adolescent) between carapace widths of 14.2–17.8 mm actively decorated themselves using pieces of chopped sea cucumber after feeding. Attached pieces of sea cucumber were observed to be fully eaten within a week, suggesting a possible strategy by P. ferox of short-term food storage as well as mimicry. This study demonstrates considerable evidence that predation mortality by sufficiently mobile P. ferox on commercially important A. japonicus can be significant, causing high mortality at the early life stage in the natural environment, especially in areas releasing hatchery-produced juveniles. It is also worth noting that the utilization of freshly chopped sea cucumbers as decoration material and food storage is a unique and novel ecological trait of P. ferox.

Bubbling and hydra effect in a population system with Allee effect

We present a continuous time predator-prey model and predator’s growth subjected to component Allee effect. The model also includes density dependent mortality of predator. We investigate our model both analytically and numerically, and highlighted the effect of density independent mortality and Allee effect. In our system, we find that a fixed point representing the extinction of predator is always a stable point. When coexistence equilibria exists our system is bistable. We have observed that tristability is possible for our model that includes two stable co-existence fixed point. The most important phenomena which we have observed are hydra effect and cascading effect. Due to component Allee effect in predator the system shows multiple hydra effect. We discuss the phenomenon of bubbling, which indicates increasing and decreasing of amplitudes of cycles. We have presented one-parametric as well as two-parametric bifurcation diagram and also all possible bifurcations that the system could go through.

Prevalence of Black Gill (Hyalophysa lynni) in White Shrimp Litopenaeus setiferus and Brown Shrimp Farfantepenaeus aztecus along the Texas Gulf Coast

AbstractShrimp black gill is an emerging disease caused by a parasitic ciliate, Hyalophysa lynni, that attacks gill tissue in white shrimp Litopenaeus setiferus and brown shrimp Farfantepenaeus aztecus and induces an immune response that produces melanized tissue in shrimp gills. This immune response causes necrosis and damage in shrimp gill tissue, which limits shrimp metabolic capability and can lead to high predation mortality among infected individuals. Shrimp black gill was first observed in the southeast Atlantic shrimp fishery in the United States, and this ciliate has been increasing in prevalence in shrimp populations of this region since 2000. The Gulf of Mexico, with its lucrative shrimp fishery and extended warmwater conditions during the year, is a potential region for H. lynni spread. White and brown shrimp were sampled from seven major bays along the Gulf coast of Texas from March to November 2019 and underwent PCR analysis to detect H. lynni presence in gill tissue. From March to November, 65% of the collected shrimp samples tested positive for H. lynni. Samples from all seven bays tested positive for H. lynni, with the upper‐coast bays having a significantly higher disease prevalence than lower‐coast bays. Both white and brown shrimp samples tested positive for H. lynni; however, white shrimp samples had a significantly higher disease prevalence. Overall, disease prevalence showed a temporal pattern of low prevalence in the spring, peaking during the late fall. Generalized additive mixed models detected a high water temperature and a salinity level of 30‰ or less as significant contributors to high disease prevalence. This study validates the commonality of H. lynni presence in the western Gulf of Mexico, serves as a baseline for future shrimp black gill sampling efforts in this region, and contributes to the understanding and management of potential disease threats to the Texas shrimp fishery.

Predicting targets and costs for feral‐cat reduction on large islands using stochastic population models

AbstractFeral cats are some of the most destructive invasive predators worldwide, particularly in insular environments; hence, density‐reduction campaigns are often applied to alleviate the predation mortality they add to native fauna. Density‐reduction and eradication efforts are costly procedures with important outcomes for native fauna recovery, so they require adequate planning to be successful. These plans should include empirical density‐reduction models that can guide yearly culling quotas, and resource roll‐out for the duration of the culling period. This ensures densities are reduced over the long term and that resources are not wasted. We constructed a stochastic population model with cost estimates to test the relative effectiveness and cost‐efficiency of two main culling scenarios for a 10‐year eradication campaign of cats on Kangaroo Island, Australia: (a) constant proportional annual cull (one‐phase), and (b) high initial culling followed by a constant proportional maintenance cull (two‐phase). A one‐phase cull of at least 0.35 of the annual population size would reduce the final population to 0.1 of its original size, while a two‐phase cull with an initial cull of minimum 0.6 and minimum 0.5 maintenance cull would reduce the final population to 0.01 of its initial size within the 10‐year time frame. Cost estimates varied widely depending on the methods applied (shooting, trapping, aerial poison baits, Felixer™ poison‐delivery system), but using baiting, trapping and Felixers with additional shooting to meet culling quotas was the most cost‐effective combination (minimum cost: AU$19.56 million; range: AU$16.87 million–AU$20.69 million). Our model provides an adaptable and general assessment tool for cat reductions in Australia and potentially elsewhere, and provides relative culling costs for the Kangaroo Island campaign specifically.

Light and energetics at seasonal extremes limit poleward range shifts

Seasonality in light becomes increasingly extreme at high latitudes, both in terms of the diel light–dark cycle and the duration of light summers and dark winters. In contrast to temperature, this latitudinal gradient in light seasonality is not affected by climate change. A key question is therefore whether light may act as a fixed constraint on warming-driven redistributions of organisms at high latitudes. One answer is provided by studying mechanistic models of visual foraging and temperature-driven physiology along latitudinal gradients to project where populations survive and acquire resources to reproduce, and where they demise. Here we contrast such models for two widespread planktivorous fish types. We identify two processes through which seasonality in light can act as a barrier to poleward range expansions at high latitudes: (1) longer dark winters lead to greater depletion of overwinter energy stores and (2) a longer duration of midnight sun entails higher foraging-related predation mortality. Using mechanistic models that incorporate visual foraging and temperature-driven physiology for two fish types, the authors reveal how latitudinal light gradients, which are not affected by climate change, can constrain warming-related shifts to high latitudes.

The Path to an Ecosystem Approach for Forage Fish Management: A Case Study of Atlantic Menhaden

Atlantic menhaden (Brevoortia tyrannus) support the largest fishery by volume on the United States East Coast, while also playing an important role as a forage species. Managers’ and stakeholders’ increasing concerns about the impact of Atlantic menhaden harvest on ecosystem processes led to an evolution in the assessment and management of this species from a purely single-species approach to an ecosystem approach. The first coastwide stock assessment of Atlantic menhaden for management used a single-species virtual population analysis (VPA). Subsequent assessments used a forward projecting statistical catch-at-age framework that incorporated estimates of predation mortality from a multispecies VPA while analytical efforts continued toward the development of ecosystem models and explicit ecological reference points (ERPs) for Atlantic menhaden. As an interim step while ecosystem models were being developed, a series of ad hoc measures to preserve Atlantic menhaden biomass for predators were used by managers. In August 2020, the Atlantic States Marine Fisheries Commission formally adopted an ecological modeling framework as a tool to set reference points and harvest limits for the Atlantic menhaden that considers their role as a forage fish. This is the first example of a quantitative ecosystem approach to setting reference points on the United States Atlantic Coast and it represents a significant advance for forage fish management. This case study reviews the history of Atlantic menhaden stock assessments and management, outlines the progress on the current implementation of ERPs for this species, and highlights future research and management needs to improve and expand ecosystem-based fisheries management.

Analysis of Covid-19 in India using mathematical modeling

An infectious disease COVID-19 is caused by virus called coronavirus. The corona virus transmitted from individual to individual through droplets / contact. The first conformed case of India was on 30 January 2020 occurred in Kerala. As still no vaccine is available for controlling it so from initial stage government of India started different initiatives like lockdown, work from home, suspension of train services and international flights, implemented rules and regulation such as limiting the number of passengers in the vehicle, banning on social gathering to control on this virus. Ministry of Health and Family Welfare (MoHFW) was launched a nationwide training for front line health worker on COVID19. Hence the implication of the study becomes very crucial. In this paper the special case of India is considered from the initial period to October 2020. Based on available data, the analysis of this viruses is studied also the different cases of stability is checked by considering logistic growth in prey population. The parameter which used to study this case are predators, prey, time, prey’s growth rate, attack rate, predator or consumer mortality rate, conversion efficiency and maximum curing capacitive rate.

Scrabbling around for understanding of natural mortality

The authors have collaborated for the past 40 years on a sequence of initiatives for a range of fisheries and marine ecosystems projects. These had natural mortality (M) as a common thread and have helped increase understanding of this elusive parameter. Here, we provide a reprise as well as an extension of our earlier results. Taken together, these help to develop an understanding of M of exploited fish stocks, particularly those of the North Sea. Firstly, a reprisal is given of the key findings about M due to predation by important fish stocks of the North Sea. Estimates were first produced by the ICES Multispecies Working Group using multispecies virtual population analysis (MSVPA) in combination with extensive stomach content data - collected for all four quarters and around the whole North Sea during 1981. Results from this initiative demonstrate that predation mortality (M2) represents a large portion of M for many North Sea fish species, but varies markedly both by age and by year, thus refuting the then widely adopted hypothesis that M was constant. Moreover, these variations were sufficiently large to overturn single species predictions of sustainable yield. M2 results from the 1980′s also indicated that mortality levels were related to prey size and species. The paper then reprises results from studies made by the private working group (PWG) that the authors formed to continue their collaboration. These focused first on size spectra of fish communities both by data analysis and by developing a simple trait-based model (cartoon) of the North Sea - the charmingly simple model (CSM). This modelling led to further questions about the basis of the coexistence of fish species in an ecosystem given that egg production scales approximately with asymptotic weight. This led to a plausible hypothesis that differential natural mortality rates are required that increase with the von Bertalanffy parameters of curvature K and asymptotic length L∞, but decrease with fish length. Data from the literature supported this hypothesis, which was further refined into canonical form: M=K(L∞/L)1.5. However, this hypothesis is also questioned because this form might not be compatible with the predicted and observable fact that size-spectra slopes become more negative with increased general levels of fishing. Clearly, changes in size spectra should cause changes in M2. Results of new modelling work are presented where the CSM is modified to include differential natural mortality rates by K and L∞. The results suggest that M responds both to general levels of fishing and the slope of the ensuing size spectrum. This suggests that a more general expression for predation mortality would be M2=α(F)K(L∞χ)(Lβ(F)), where χ is likely to be close to the 1.5 value used in the canonical form. The work thus provides a likely form for M2 but by no means a universally applicable formula. It remains a hypothesis needing to be tested and perhaps calibrated against data from the sea. Such calibrations might indeed point toward a universal formula for M2.

Fishing-induced versus natural selection in different brown trout (Salmo trutta) strains

Wild, adfluvial brown trout (Salmo trutta) are iconic targets in recreational fisheries but also endangered in many native locations. We compared how fishing and natural selection affect the fitness-proxies of brown trout from two pure angling-selected strains and experimental crosses between an adfluvial, hatchery-bred strain and three wild, resident strains. We exposed age 1+ parr to predation risk under controlled conditions where their behaviour was monitored with PIT-telemetry, and stocked age 2+ fish in two natural lakes for experimental fishing. Predation mortality (16% of the fish) was negatively size-dependent, while capture probability, also reflecting survival, in the lakes (38.9% of the fish) was positively length- and condition-dependent. Angling-induced selection against low boldness and slow growth rates relative to gillnet fishing indicated gear-dependent potential for fisheries-induced evolution in behaviours and life-histories. Offspring of wild, resident fish showed slower growth rates than the crossbred strains. Strain effects suggested significant heritable scope for artificial selection on life-history traits and demonstrated that choices of fish supplementation by stocking may override the genetic effects induced by angling.

Effects of artificial light at night and predator cues on foraging and predator avoidance in the keystone inshore mollusc Concholepas concholepas.

The growth of Artificial Light At Night (ALAN) is potentially having widespread effects on terrestrial and coastal habitats. In this study we addressed both the individual effects of ALAN, as well as its combined effect with predation risk on the behaviour of Concholepas concholepas, a fishery resource and a keystone species in the southeastern Pacific coast. We measured the influence of ALAN and predation risk on this mollusc's feeding rate, use of refuge for light and crawling out of water behaviour. These behavioural responses were studied using light intensities that mimicked levels that had been recorded in coastal habitat exposed to ALAN. Cues were from two species known to prey on C.concholepas during its early ontogeny: the crab Acanthocyclus hassleri and the seastar Heliaster helianthus. The feeding rates of C.concholepas were 3-4 times higher in darkness and in the absence of predator cues. In contrast, ALAN-exposed C.concholepas showed lower feeding activity and were more likely to be in a refuge than those exposed to control conditions. In the presence of olfactory predator cues, and regardless of light treatment, C.concholepas tended to crawl-out of the waterline. We provide evidence to support the hypothesis that exposure to either ALAN or predation risk can alter the feeding behaviour of C.concholepas. However, predator cue recognition in C.concholepas was not affected by ALAN in situations where ALAN and predator cues were both present: C.concholepas continued to forage when predation risk was low, i.e., in darkness and away from predator cues. Whilst this response means that ALAN may not lead to increased predation mortality in C.concholepas, it will reduce feeding activity in this naturally nocturnal species in the absence of dark refugia. Such results may have implications for the long-term health, productivity and sustainability of this keystone species.

Invasive dynamics for a predator–prey system with Allee effect in both populations and a special emphasis on predator mortality

We considered a non-linear predator–prey model with an Allee effect on both populations on a two spatial dimension reaction-diffusion setup. Special importance to predator mortality was given as it may be often controlled through human-made harvesting processes. The local dynamics of the model was studied through boundedness, equilibrium, and stability analysis. An extensive numerical stability analysis was performed and found that bi-stability is not possible for the non-spatial model. By analyzing the spatial model, we found the condition for successful invasion and the persistence region of the species based on the predator Allee effect and its mortality parameter. Four different dynamics in this region of the parameter space are mainly explored. First, the Allee effect on both populations leads to various new types of species spread. Second, for a high value of per-capita growth rate, two completely new spreads (e.g., sun surface, colonial) have been found depending on the Allee effect parameter. Third, the Allee coefficient on the predator population leads to spatiotemporal chaos via a patchy spread for both linear and quadratic mortality rates. Finally, a more rigorous analysis is performed to study the chaotic nature of the system within the whole persistence domain. We have studied the possibility of chaos through temporal variation in different invasion regions. Furthermore, the chaotic fluctuation is studied through the sensitivity of initial conditions and by investigating the dominant Lyapunov exponent value.

Characterizing juvenile salmon predation risk during early marine residence.

Predation mortality can influence the distribution and abundance of fish populations. While predation is often assessed using direct observations of prey consumption, potential predation can be predicted from co-occurring predator and prey densities under varying environmental conditions. Juvenile Pacific salmon Oncorhynchus spp. (i.e., smolts) from the Columbia River Basin experience elevated mortality during the transition from estuarine to ocean habitat, but a thorough understanding of the role of predation remains incomplete. We used a Holling type II functional response to estimate smolt predation risk based on observations of piscivorous seabirds (sooty shearwater [Ardenna griseus] and common murre [Uria aalge]) and local densities of alternative prey fish including northern anchovy (Engraulis mordax) in Oregon and Washington coastal waters during May and June 2010–2012. We evaluated predation risk relative to the availability of alternative prey and physical factors including turbidity and Columbia River plume area, and compared risk to returns of adult salmon. Seabirds and smolts consistently co-occurred at sampling stations throughout most of the study area (mean = 0.79 ± 0.41, SD), indicating that juvenile salmon are regularly exposed to avian predators during early marine residence. Predation risk for juvenile coho (Oncorhynchus kisutch), yearling Chinook salmon (O. tshawytscha), and subyearling Chinook salmon was on average 70% lower when alternative prey were present. Predation risk was greater in turbid waters, and decreased as water clarity increased. Juvenile coho and yearling Chinook salmon predation risk was lower when river plume surface areas were greater than 15,000 km2, while the opposite was estimated for subyearling Chinook salmon. These results suggest that plume area, turbidity, and forage fish abundance near the mouth of the Columbia River, all of which are influenced by river discharge, are useful indicators of potential juvenile salmon mortality that could inform salmonid management.

Predator tactics and prey densities modulate the strength of trophic interactions in a temperate rocky reef

Evaluating the species-specific effects of multiple predators on shared prey helps to identify the mechanisms regulating predator impacts. Here, we investigate the trophic impact of two predators of the Chilean rocky subtidal, the fish Graus nigra [F] and the octopus Robsonella fontaniana [O] on their shared prey, the porcelain crab, Petrolisthes violaceus. Manipulative laboratory experiments were performed to evaluate mortality and behavior of porcelain crab in different treatments, including prey alone; prey with single predator ([O] or [F]); and prey with combined predators ([F + F], [O + O], and [O + F]). Different prey densities (N = 3, 9, and 12 individuals) were used to explore density-dependent predation mortality for single and combined predators using an orthogonal (crossed) design that allows to tease apart the effects of predator taxonomic identity from prey density. Behavioral responses of interacting species were registered every 4 h for 2 consecutive days, and were used to identify predator foraging strategies and prey refuge use. Mortality values (proportional prey mortality and predator per capita consumption) were compared among treatments. Results indicated differences in mortality among treatments. The cause of increase of prey proportional mortality was due to an increase in prey availability outside the refuge in fish treatments at high initial prey densities, while it was density independent in octopus’ treatments. Changes in predator per capita consumption were registered depending on the predator combination and the initial prey density. These patterns may reflect contrasting predator foraging strategies and changes in refuge use by porcelain crabs, suggesting effects on prey mortality and predator impacts.

Pelican–Tilapia interaction in Salton sea: an eco-epidemiological model with strong Allee effect and additional food

The effect of diseases in ecological system is an important issue from mathematical and experimental points of view. We have analysed the dynamic nature of an eco-epidemiological model consisting of susceptible Tilapia fish, infected Tilapia fish and their predator the Pelican birds. Again, the susceptible prey population is subjected to a strong Allee effect. Moreover, the provision of additional food to predator is one of the momentous concepts in the field of biological control. Beddington–DeAngelis-type functional response has been taken to represent the interaction between susceptible prey and predator, whereas predator consumes the infected prey as Volterra-type (Holling type I) functional response. Feeding on infected prey increases the death rate of predator and is regarded to contribute negative growth, whereas consumption of susceptible prey enhances predator growth rate and is regarded to contribute positive growth. It is assumed that the predator population has sufficient resistance power to overcome the effect of environmental toxicants and so they are free from transmission of infection. In this work, we have studied some basic properties, such as non-negativity, uniform boundedness, and stability criteria of all feasible equilibria. The existence of transcritical bifurcations has been observed around the planer equilibrium points taking the mortality rate of predator and transmission rate as bifurcation parameters. Also, we have incorporated gestation delay in the system to examine the changing nature of the delay parameter via Hopf bifurcation. Further, the formulae for direction, period, and the stability of bifurcating periodic solutions have been established. Several numerical simulations are illustrated using MATLAB to validate all the theoretical results.

Using niche construction theory to generate testable foraging hypotheses at Liang Bua.

Niche construction theory (NCT) has emerged as a promising theoretical tool for interpreting zooarchaeological material. However, its juxtaposition against more established frameworks like optimal foraging theory (OFT) has raised important criticism around the testability of NCT for interpreting hominin foraging behavior. Here, we present an optimization foraging model with NCT features designed to consider the destructive realities of the archaeological record after providing a brief review of OFT and NCT. Our model was designed to consider a foragers decision to exploit an environment given predation risk, mortality, and payoff ratios between different ecologies, like more-open or more-forested environments. We then discuss how the model can be used with zooarchaeological data for inferring environmental exploitation by a primitive hominin, Homo floresiensis, from the island of Flores in Southeast Asia. Our example demonstrates that NCT can be used in combination with OFT principles to generate testable foraging hypotheses suitable for zooarchaeological research.

Ocean warming impairs the predator avoidance behaviour of elasmobranch embryos.

Embryogenesis is a vulnerable stage in elasmobranch development due in part to high predation mortality. Embryonic elasmobranchs respond to potential predators by displaying a freezing behaviour, characterized by the cessation of pharyngeal respiration followed immediately by coiling of the tail around the body. We hypothesized that the duration of this freeze response is limited by the embryo's requirement for oxygen. Here, Scyliorhinus canicula embryos were incubated at either 15°C or 20°C during embryogenesis and tested for the duration of, and metabolic consequence of, the freeze response at their respective incubation temperature. Freeze response duration was negatively impacted by routine metabolic rate; embryos at 20°C had 7-fold shorter freeze duration than those at 15°C, potentially increasing their susceptibility to predation. These data demonstrate the capacity for climate change stressors to affect animal behaviour and suggest that this may occur by eliciting changes in the organism's metabolism. We suggest altered predator avoidance behaviour is a new factor to consider when assessing the impact of climate change on the conservation and management of oviparous elasmobranch species.

Impacts of deep-water spills on mesopelagic communities and implications for the wider pelagic food web

Mesopelagic fishes link lower trophic levels and higher predators, as well as production at the surface to the deep sea. Mesopelagic fish may be vulnerable to deep entrained oil plumes of the type seen in the 2010 Deepwater Horizon spill; even at low concentrations, exposure to polycyclic aromatic hydrocarbons (PAHs) may cause lethal and sublethal effects, such as endocrine disruption, growth inhibition, and genetic damage. A reduction in the abundance of mesopelagic fish could potentially shift predation pressure by large pelagics to epipelagic forage or other species, with potential fisheries consequences. We explored this hypothesis on the West Florida Shelf using an Atlantis model for the Gulf of Mexico. Atlantis is a 3-dimensional, spatially explicit marine and coastal modeling framework that incorporates multiple submodels integrating biophysical, chemical, ecological, and fisheries dynamics. We found that biomass, trophic niche width, and predation mortality exerted by mesopelagic predators showed small but varied responses across different contributions of mesopelagics to predator fish diet under oil impacts. We observed shifts in the diet of pelagic predators with increasing availability of mesopelagic fish prey, suggesting that pelagic fish predator populations are more vulnerable to oil exposure if they are tightly coupled to the mesopelagic food web. These results suggest that when measured at the population level, oil-spill impacts may be harder to detect due to the response of individual fish species.

Biosafety of pesticides and entomopathogens to the anthocorid predator Blaptostethus pallescens Poppius (Heteroptera: Anthocoridae)

Laboratory experiments conducted to study the biosafety of insecticides, acaricides and entomopathogens viz. imidacloprid, chlorpyriphos, fenazaquin, spiromesifen, azadirachtin, Beauveria bassiana and Lecanicillium lecanii in different concentrations to Blaptostethus pallescens, revealed that imidacloprid and chlorpyriphos were highly toxic with maximum mortality. The acaricides fenazaquin and spiromesifen were less toxic which recorded minimum mortality of predator and more egg laying and hatching. Azadirachtin showed higher oviposition and was on par with spiromesifen. Azadirachtin and acaricides are compatible with B. pallescens than entomopathogens.