Find research datasets worth reusing
Search datasets from major research repositories and use ShareScore to quickly assess how well each record supports discovery, access, and reuse.
16
datasets available to search
ShareScore release 0.9.0
Dataset results
16 results for “exploitative competition”
Eat or be eaten: Implications of potential exploitative competition between wolves and humans across predator- savvy and -naive deer populations
<p>Recolonization of predators to their former ranges is becoming increasingly prevalent. Such recolonization places predators amongst their prey once again; the latter having lived without predation (from such predators) for considerable time. This renewed coexistence creates opportunities to explore predation ecology at both fundamental and applied levels.</p> <p>We used a paired experimental design to investigate white-tailed deer risk allocation in the Upper and Lower Peninsulas (UP and LP) in Michigan, USA. Wolves are functionally absent in the LP, while deer in the UP coexist with a re-established wolf population. We treated 15 sites each in UP and LP with wolf olfactory cues and observed deer vigilance, activity, and visitation rates at the interface of habitat covariates using remote cameras. Such a paired design across wolf versus no-wolf areas allowed us to examine indirect predation effects while accounting for confounding parameters such as the presence of other predators and human activity.</p> <p>While wolf urine had no effect across most metrics in both UP and LP, we observed differences in deer activity in areas with versus without wolves. Sites treated with wolf urine in the UP showed a reduction in crepuscular deer activity, compared to control/novel-scent treated sites. Further, we observed a strong positive effect of vegetation cover on deer vigilance in these sites. This indicates that simulated predator cues likely affect deer vigilance more acutely in denser habitats, which presumably facilitates predation success. Such responses were however absent among deer in the LP that are presumably naïve towards wolf predation.</p> <p>Where human and non-human predators hunt shared prey, such as in Michigan, predators may constrain human hunting success by increasing deer vigilance. Hunters may avoid such exploitative competition by choosing hunting/bait sites located in open areas. Our results pertaining to fundamental predation ecology have strong applied implications that can promote human-predator coexistence.</p>
Reward-based option competition in human dorsal stream and transition from stochastic exploration to exploitation in continuous space
<p>Primates exploring and exploiting a continuous sensorimotor space rely on dynamic maps in the dorsal stream. Two complementary perspectives exist on how these maps encode rewards. Reinforcement learning models integrate rewards incrementally over time, efficiently resolving the exploration/exploitation dilemma. Working memory buffer models explain rapid plasticity of parietal maps but lack a plausible exploration/exploitation policy. The reinforcement learning model presented here unifies both accounts, enabling rapid, information-compressing map updates and efficient transition from exploration to exploitation. As predicted by our model, activity in human fronto-parietal dorsal stream regions, but not in <em>MT+</em>, tracks the number of competing options, as preferred options are selectively maintained on the map while spatiotemporally distant alternatives are compressed out. When valuable new options are uncovered, posterior beta<sub>1</sub>/alpha oscillations desynchronize within 0.4-0.7 s, consistent with option encoding by competing beta<sub>1</sub>-stabilized subpopulations. Altogether, outcomes matching locally cached reward representations rapidly update parietal maps, biasing choices toward often-sampled, rewarded options.</p>
Collective foraging: Experimentally-increased competition decreases group performance exploiting a permanent resource
<p><span>Foraging collectively offers advantages, such as access to social information on food locations, but it may also intensify competition for local resources. Social information may be most advantageous during ecologically challenging conditions, when food sources are scarce or unpredictable, which predicts more collective foraging during such conditions. Alternatively, higher within-group competition when resources are scarce might destabilize social groups and reduce collective foraging. </span></p> <p><span>To evaluate these effects, we experimentally decreased the number and predictability of food sources (feeders with <em>ad libitum</em> seeds) available to wild-caught common waxbills (<em>Estrilda astrild</em>) living in a large open-air mesocosm. </span></p> <p><span>Compared to control periods, in the treatment with few food sources competitive aggressiveness at feeders increased, the social network became more fragmented, with on average weaker associations between individuals, and foraging groups became smaller. Foraging groups also spent less time per visit to the feeding area, individuals spent less time at the feeders per group visit and had to make more visits to the feeding area per day, all of which indicate less efficient exploitation of the food sources. These effects were also observed when the number of feeders changed unpredictably across days. </span></p> <p><span>Even though the collective behaviour of waxbills appeared to exacerbate, rather than mitigate, the ecological challenges of reduced or unpredictable food sources, we suggest that, in nature, this increased aggressiveness and fragmentation of the social network may function adaptively as an early trigger to explore alternative foraging locations before local food sources are severely depleted.</span></p>
Of wolves and bears: Seasonal drivers of interference and exploitation competition between apex predators
<p>Competition between apex predators can alter the strength of top-down forcing, yet we know little about the behavioral mechanisms that drive competition in multipredator ecosystems. Interactions between predators can be synergistic (facilitative) or antagonistic (inhibitive), both of which are widespread in nature, vary in strength between species and across space and time, and affect predation patterns and predator-prey dynamics. Recent research suggests gray wolf (<i>Canis lupus</i>) kill rates decrease where they are sympatric with brown bears (<i>Ursus arctos</i>), however, the mechanisms behind this pattern remain unknown. We used data from two long-term research projects in Scandinavia (Europe) and Yellowstone National Park (North America) to test the role of interference and exploitation competition from bears on wolf predatory behavior, where altered wolf handling and search time of prey in the presence of bears are indicative of interference and exploitation competition, respectively. Our results suggest the mechanisms driving competition between bears and wolves were dependent on the season and study system. During spring in Scandinavia, interference competition was the primary mechanism driving decreased kill rates for wolves sympatric with bears; handling time increased, but search time did not. In summer, however, when both bear and wolf predation focused on neonate moose, the behavioral mechanism switched to exploitation competition; search time increased, but handling time did not. Interference competition, however, did affect wolf predation dynamics in Yellowstone during summer, where wolves prey more evenly on neonate and adult ungulates. Here, bear presence at a carcass increased the amount of time wolves spent at carcasses of all sizes and wolf handling time for small prey, but decreased handling time for the largest prey. Wolves facilitate scavenging opportunities for bears, however, bears alter wolf predatory behavior via multiple pathways and are primarily antagonistic to wolves. Our study helps clarify the behavioral mechanisms driving competition between apex predators, illustrating how interspecific interactions can manifest into population-level predation patterns.</p>
Data for: Exploitation competition between seed predators and dispersers introduced to Hawaiian forests
<p>Exploitation competition occurs when one group of organisms reduces the availability of a resource for another group of organisms. For instance, plants produce a certain number of fruits for seed dispersal by fruit-eating animals (hereafter frugivores), and fruit consumption by one group of frugivores can reduce the number of fruits available for other frugivores. However, it is uncertain whether exploitation competition is common among frugivores, particularly in novel ecosystems, where food resources are generally thought to be abundant and invasive species are dietary generalists. In a novel ecosystem in Hawai'i, we used gut passage experiments with captive birds to identify roles of introduced frugivores and found they were either distinctly seed dispersers or predators. We then experimentally tested how frugivory by seed predators influenced frugivory by seed dispersers. Specifically, we used exclosures around fruiting plants that blocked seed predator access, while permitting seed disperser access, and we had two control treatments that allowed for access by all frugivores (n=139 plants). When seed predators were excluded from plants, there was more frugivory by dispersers compared to controls, and results varied by year and plant species. Overall, we show that introduced frugivores occupied distinct ecological roles (seed predator or seed disperser), exploitation competition occurred between these introduced frugivore groups, and seed predators had both direct (via seed destruction) and indirect (via reduction in frugivory by dispersers) effects on seed dispersal. Thus, in this novel ecosystem, multiple frugivory is subtractive, and competition for fruit between introduced seed predators and seed dispersers scales up to affect invasions and the conservation of native flora. </p>
Evidence of exploitative competition between honey bees and native bees in two California landscapes
Open the record for dataset details and reuse information.
Of wolves and bears: Seasonal drivers of interference and exploitation competition between apex predators
Open the record for dataset details and reuse information.
Eat or be eaten: Implications of potential exploitative competition between wolves and humans across predator- savvy and -naive deer populations
Open the record for dataset details and reuse information.
Data for: Exploitation competition between seed predators and dispersers introduced to Hawaiian forests
Open the record for dataset details and reuse information.
Reward-based option competition in human dorsal stream and transition from stochastic exploration to exploitation in continuous space
Open the record for dataset details and reuse information.
Collective foraging: Experimentally-increased competition decreases group performance exploiting a permanent resource
Open the record for dataset details and reuse information.
Exploitative competition for floral resources reduces sugar intake but differently impacts the foraging behaviour of two non-bee flower visitors
<p>Identifying which behavioural strategies maximize individual fitness is a key objective in ecology. Organisms are known to adapt their foraging behaviour to their environment in response to abiotic and biotic constraints, such as the distribution of resources or the presence of competitors. For instance, bees are known to avoid recently visited flowers and thus focus their foraging on more rewarding patches. Whether other flower-visiting insects adapt their foraging behaviour in response to exploitative competition for floral resources remains unknown. Here, we asked if a predatory hoverfly (<em>Episyrphus balteatus</em>) and a parasitoid (<em>Aphidius colemani</em>) 1) are physiologically impacted by flower resource limitation following exploitation of flowers by a competitor (either the bumblebee <em>Bombus terrestris</em> or <em>E. balteatus</em>); 2) have the ability to discriminate flowers that were previously exploited by a competitor; and 3) modify their foraging behaviour accordingly. <em>Episyrphus balteatus </em>and <em>A. colemani</em> individuals foraging on previously exploited flowers were found to be less concentrated in sugar compounds, especially in fructose and glucose, suggesting that previously exploited flowers contained less available sugars. Nevertheless, individuals did not avoid previously exploited patches in the choice experiment. On the contrary, <em>E. balteatus </em>females preferentially landed on inflorescences that had previously been exploited by conspecifics (but not by <em>B. terrestris</em>), while <em>A. colemani </em>did not show preferences between inflorescences. However, female hoverflies spent more time feeding on unexploited patches, suggesting that exploited patches were resource limited. To our knowledge, this study provides the first evidence of the use of social cues among <em>E. balteatus </em>individuals in food foraging strategies. It also shows that even insects with tiny nectar requirements, such as parasitoids, can suffer from heavy exploitative competition. Such results may have applied consequences for the understanding of natural enemy conservation, in particular in agroecosystems where competition with honeybees may be important.</p>
Exploitative competition for floral resources reduces sugar intake but differently impacts the foraging behaviour of two non-bee flower visitors
Open the record for dataset details and reuse information.
Data from: A shift from exploitation to interference competition with increasing density affects population and community dynamics
Intraspecific competition influences population and community dynamics and occurs via two mechanisms. Exploitative competition is an indirect effect that occurs through use of a shared resource and depends on resource availability. Interference competition occurs by obstructing access to a resource and may not depend on resource availability. Our study tested whether the strength of interference competition changes with protozoa population density. We grew experimental microcosms of protozoa and bacteria under different combinations of protozoan density and basal resource availability. We then solved a dynamic predator–prey model for parameters of the functional response using population growth rates measured in our experiment. As population density increased, competition shifted from exploitation to interference, and competition was less dependent on resource levels. Surprisingly, the effect of resources was weakest when competition was the most intense. We found that at low population densities, competition was largely exploitative and resource availability had a large effect on population growth rates, but the effect of resources was much weaker at high densities. This shift in competitive mechanism could have implications for interspecific competition, trophic interactions, community diversity, and natural selection. We also tested whether this shift in the mechanism of competition with protozoa density affected the structure of the bacterial prey community. We found that both resources and protozoa density affected the structure of the bacterial prey community, suggesting that competitive mechanism may also affect trophic interactions.
Data from: A shift from exploitation to interference competition with increasing density affects population and community dynamics
Open the record for dataset details and reuse information.
Data from: Interference versus exploitative competition in the regulation of size-structured populations
Open the record for dataset details and reuse information.
ScienceDex guides
Understand access before you commit
These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.
Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.