Search results for "foraging"
showing 10 items of 204 documents
Changes in group size during resource shifts reveal drivers of sociality across the tree of life
2020
ABSTRACTFrom biofilms to whale pods, organisms have repeatedly converged on sociality as a strategy to improve individual fitness. Yet, it remains challenging to identify the most important drivers—and by extension, the evolutionary mechanisms—of sociality for particular species. Here, we present a conceptual framework, literature review, and model demonstrating that the direction and magnitude of the response of group size to sudden resource shifts provides a strong indication of the underlying drivers of sociality. We catalog six functionally distinct mechanisms related to the acquisition of resources, and we model these mechanisms’ effects on the survival of individuals foraging in group…
Risk taking in natural predation risk gradients: support for risk allocation from breeding pied flycatchers
2011
Predation risk is vital in foraging decisions because activity involves some degree of risk. In a natural setting, predation risk shows temporal variation, which has been largely neglected in antipredator studies. We tested a prediction of the risk allocation hypothesis in which allocation to antipredator behaviours will depend on temporal variation in perceived risk. Individuals are predicted to allocate heightened antipredator behaviours to brief infrequent periods of high risk, but with increasing frequency of high-risk periods, individuals will invest less in these behaviours. We tested this prediction using pied flycatchers, Ficedula hypoleuca , breeding at different distances from spa…
Nectar-Inhabiting Bacteria Affect Olfactory Responses of an Insect Parasitoid by Altering Nectar Odors
2022
AbstractFloral nectar is ubiquitously colonized by a variety of microorganisms among which yeasts and bacteria are the most common. Microorganisms inhabiting floral nectar can alter several nectar traits, including nectar odor by producing microbial volatile organic compounds (mVOCs). Evidence showing that mVOCs can affect the foraging behavior of insect pollinators is increasing in the literature, whereas the role of mVOCs in altering the foraging behavior of third-trophic level organisms such as insect parasitoids is largely overlooked. Parasitoids are frequent visitors of flowers and are well known to feed on nectar. In this study, we isolated bacteria inhabiting floral nectar of buckwhe…
Ground-level predation on artificial caterpillars indicates no enemy-free time for lepidopteran larvae
2017
Lepidoptera is one of the most diverse orders of insects, their larvae are very abundant in many habitats, and frequent prey of various predators. To decrease predation risk, caterpillars developed several means of defence, among them timing their activity to avoid predators (seeking enemy-free time). Although the enemy-free time hypothesis is often invoked to explain caterpillar behaviour, empirical evidence for it is scarce. We tested whether such enemy-free time exists in a temperate forest by comparing predation pressure on artificial caterpillars during day and night on the ground in forest fragments in Denmark. We found a high predation rate, 23.9% d(-1), and higher predation rate at …
Quantum planning for swarm robotics
2023
Computational resources of quantum computing can enhance robotic motion, decision making, and path planning. While the quantum paradigm is being applied to individual robots, its approach to swarms of simple and interacting robots remains largely unexplored. In this paper, we attempt to bridge the gap between swarm robotics and quantum computing, in the framework of a search and rescue mission. We focus on a decision-making and path-planning collective task. Thus, we present a quantum-based path-planning algorithm for a swarm of robots. Quantization enters position and reward information (measured as a robot’s proximity to the target) and path-planning decisions. Pairwise information-exchan…
Prehatching maternal investment and offspring immunity in the pied flycatcher (Ficedula hypoleuca).
2007
Maternal investment in offspring immunity via egg quality may be an adaptive evolutionary strategy shaped by natural selection. We investigated how maternal investment in eggs can influence offspring immunity by conducting two experiments. First, we manipulated foraging performance of the mothers before egg laying by attaching a small weight to their back feathers. During the nestling period, we investigated offspring total antibody production at the age of 7 days and after antibody challenge, and conducted a partial cross-fostering design to separate the effects of the experiment and rearing-related variation on offspring immunity. In a separate experiment, partial cross-fostering with ant…
Switching spatial scale reveals dominance-dependent social foraging tactics in a wild primate.
2017
When foraging in a social group, individuals are faced with the choice of sampling their environment directly or exploiting the discoveries of others. The evolutionary dynamics of this trade-off have been explored mathematically through the producer-scrounger game, which has highlighted socially exploitative behaviours as a major potential cost of group living. However, our understanding of the tight interplay that can exist between social dominance and scrounging behaviour is limited. To date, only two theoretical studies have explored this relationship systematically, demonstrating that because scrounging requires joining a competitor at a resource, it should become exclusive to high-rank…
Spider cues stimulate feeding, weight gain and survival of crickets
2014
1. To avoid predation, prey often change their behaviour upon encountering cues of predator presence. Such behavioural changes should enhance individual survival, but are likely to be energy-demanding. This should deplete energy reserves of the prey, unless it increases food intake. 2. These hypotheses were studied by conducting two microcosm experiments. In the first, crickets were kept on plants previously occupied by a spider or on control plants. After 3 days leaf consumption and weight gain of the crickets were quantified. In the second experiment, crickets were kept in the presence or absence of spider cues for 3 days. Spiders were then added and predation of the crickets was recorded…
Costs of courtship and mating in a sexually cannibalistic orb-web spider: female mating strategies and their consequences for males
2002
The costs of courtship and mating may include increased risks of predation, the transmission of pathogens, and a loss of foraging opportunities. Thus, a female's decision to tolerate a courting male will depend upon how these costs offset the benefits of mating, which will depend on her reproductive and nutritional status. While these costs may be similar for mated and unmated females, the benefits of mating will be less for mated than virgin females. However, the cost of lost foraging opportunities may be higher for females with fewer nutritional reserves necessary for forming eggs. We examined how these costs and benefits influence the courtship and mating behaviour of male and female orb…
Changes in diets of individual Baltic ringed seals (Phoca hispida botnica) during their breeding season inferred from stable isotope analysis of mult…
2008
The stable isotope ratios (� 13 C and � 15 N) of three tissues with different metabolic rates (plasma, liver, and muscle) were used to investigate temporal variation in diet among nine individual Baltic ringed seals (Phoca hispida botnica Gmelin) from the Bothnian Bay, northeast Baltic Sea. The isotope values from plasma should reflect the most recent diet, values from liver the diet of the past weeks prior to sampling, and values from muscle should integrate diet over almost the entire breeding season of the ringed seals. In general, � 13 C values of liver were more enriched in 13 C than were those of either muscle or plasma, suggesting that the diet of the seals may have included a higher…