Evolutionary stable strategy application of Nash equilibrium in biology

Every behaviourally responsive animal (including us) make decisions. These can be simple behavioural decisions such as where to feed, what to feed, how long to feed, decisions related to finding, choosing and competing for mates, or simply maintaining one's territory. All these are conflict situations between competing individuals, hence can be best understood using a game theory approach. Using some examples of classical games, we show how evolutionary game theory can help understand behavioural decisions of animals. Game theory (along with its cousin, optimality theory) continues to provide a strong conceptual and theoretical framework to ecologists for understanding the mechanisms by which species coexist

Look before you leap: is risk of injury a foraging cost?

Theory states that an optimal forager should exploit a patch so long as its harvest rate of resources from the patch exceeds its energetic, predation, and missed opportunity costs for foraging. However, for many foragers, predation is not the only source of danger they face while foraging. Foragers also face the risk of injuring themselves. To test whether risk of injury gives rise to a foraging cost, we offered red foxes pairs of depletable resource patches in which they experienced diminishing returns. The resource patches were identical in all respects, save for the risk of injury. In response, the foxes exploited the safe patches more intensively. They foraged for a longer time and also removed more food (i.e., had lower giving up densities) in the safe patches compared to the risky patches. Although they never sustained injury, video footage revealed that the foxes used greater care while foraging from the risky patches and removed food at a slower rate. Furthermore, an increase in their hunger state led foxes to allocate more time to foraging from the risky patches, thereby exposing themselves to higher risks. Our results suggest that foxes treat risk of injury as a foraging cost and use time allocation and daring—the willingness to risk injury—as tools for managing their risk of injury while foraging. This is the first study, to our knowledge, which explicitly tests and shows that risk of injury is indeed a foraging cost. While nearly all foragers may face an injury cost of foraging, we suggest that this cost will be largest and most important for predators

Perceived Risk of Predation Affects Reproductive Life - History Traits in Gambusia holbrooki, but Not in Heterandria formosa

Key to predicting impacts of predation is understanding the mechanisms through which predators impact prey populations. While consumptive effects are well-known, non-consumptive predator effects (risk effects) are increasingly being recognized as important. Studies of risk effects, however, have focused largely on how trade-offs between food and safety affect fitness. Less documented, and appreciated, is the potential for predator presence to directly suppress prey reproduction and affect life-history characteristics. For the first time, we tested the effects of visual predator cues on reproduction of two prey species with different reproductive modes, lecithotrophy (i.e. embryonic development primarily fueled by yolk) and matrotrophy (i.e. energy for embryonic development directly supplied by the mother to the embryo through a vascular connection). Predation risk suppressed reproduction in the lecithotrophic prey (Gambusia holbrokii) but not the matrotroph (Heterandria formosa). Predator stress caused G. holbrooki to reduce clutch size by 43%, and to produce larger and heavier offspring compared to control females. H. formosa, however, did not show any such difference. In G. holbrooki we also found a significantly high percentage (14%) of stillbirths in predator-exposed treatments compared to controls (2%). To the best of our knowledge, this is the first direct empirical evidence of predation stress affecting stillbirths in prey. Our results suggest that matrotrophy, superfetation (clutch overlap), or both decrease the sensitivity of mothers to environmental fluctuation in resource (food) and stress (predation risk) levels compared to lecithotrophy. These mechanisms should be considered both when modeling consequences of perceived risk of predation on prey-predator population dynamics and when seeking to understand the evolution of reproductive modes

A new species of \u3cem\u3eIsometrus\u3c/em\u3e (Scorpiones: Buthidae) from southern India

A new species of Isometrus (Buthidae) is described from India using integrated taxonomic approach. Isometrus kovariki sp. n. is closely related to I. thurstoni, and differs in morphological features and raw genetic divergence of more than 9%

A new species of Isometrus (Scorpiones Buthidae) from southern India

A new species of Isometrus (Buthidae) is described from India using integarted taxonomic approach. Isometrus kovariki sp. n. is closely related to I. thurstoni, and differs in morphological features and raw genetic divergence of more than 9

How to build science-action partnerships for local land-use planning and management: Lessons from Durban, South Africa

The gap between scientific knowledge and implementation in the fields of biodiversity conservation, environmental management, and climate change adaptation has resulted in many calls from practitioners and academics to provide practical solutions responding effectively to the risks and opportunities of global environmental change, e.g., Future Earth. We present a framework to guide the implementation of science-action partnerships based on a real-world case study of a partnership between a local municipality and an academic institution to bridge the science-action gap in the eThekwini Municipal Area, South Africa. This partnership aims to inform the implementation of sustainable land-use planning, biodiversity conservation, environmental management, and climate change adaptation practice and contributes to the development of human capacity in these areas of expertise. Using a transdisciplinary approach, implementation-driven research is being conducted to develop several decision-making products to better inform land-use planning and management. Lessons learned through this partnership are synthesized and presented as a framework of enabling actions operating at different levels, from the individual to the interorganizational. Enabling actions include putting in place enabling organizational preconditions, assembling a functional well-structured team, and actively building interpersonal and individual collaborative capacity. Lessons learned in the case study emphasize the importance of building collaborative capacity and social capital, and paying attention to the process of transdisciplinary research to achieve more tangible science, management, and policy objectives in science-action partnerships. By documenting and reflecting on the process, this case study provides conceptual and practical guidance on bridging the science-action gap through partnerships

Evolutionary stable strategy application of Nash equilibrium in biology

Every behaviourally responsive animal (including us) make decisions. These can be simple behavioural decisions such as where to feed, what to feed, how long to feed, decisions related to finding, choosing and competing for mates, or simply maintaining one's territory. All these are conflict situations between competing individuals, hence can be best understood using a game theory approach. Using some examples of classical games, we show how evolutionary game theory can help understand behavioural decisions of animals. Game theory (along with its cousin, optimality theory) continues to provide a strong conceptual and theoretical framework to ecologists for understanding the mechanisms by which species coexist

Behaviour of American Crows (Corvus brachyrhynchos) when encountering an oncoming vehicle

A carrion feeder attempting to forage on a road benefits greatly from an appropriate response to vehicular traffic. In this observational study, we tested the ability of American Crows (Corvus brachyrhynchos) to judge the behaviour of fast-moving vehicles and avoid collision on a narrow road. Unsurprisingly, American Crows feeding in the same lane as the approaching vehicle always flew off, but interestingly, a significant proportion of American Crows in the opposite lane chose to remain on the road. In addition, 21% of the American Crows in the same lane as the approaching vehicle walked over to the opposite lane to avoid injury, but none of the American Crows in the opposite lane walked over to the lane in which the vehicle was approaching. These are among the first quantitative data indicating that a non-human animal can detect the directionality of oncoming vehicles on a road and, like humans, actively move out of the way or switch lanes to avoid death based on an understanding of the bahaviour of vehicular traffic

Life-history traits and courtship behaviour of four poorly known endemic bush frogs (Amphibhia : Anura: Rhachophoridae) from the Western Ghats of India

The Western Ghats have a high level of anuran endemism. Although there has been an extensive focus on their taxonomy, the ecology of most species are poorly known. In this note we describe the reproductive life-history traits and breeding behavior of four species of endemic bush frogs, Pseudophilautus wynaadensis, Raorchestes akroparallagi, Raorchestes glandulosus, and Raorchestes ponmudi (Amphibia: Anura: Rachophoridae) from Wayanad region of Western Ghats

A Note on Distinguishing Gerbillus Gleadowi and Gerbillus Nanus Based on Their Footprints in the Thar Desert, India

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