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The costs of foraging can be high while also carrying significant risks, especially for consumers feeding at the top of the food chain. To mitigate these risks, many predators supplement active hunting with scavenging and kleptoparasitic behaviours, in some cases specializing in these alternative modes of predation. The factors that drive differential utilization of these tactics from species to species are not well understood. Here, we use an energetics approach to investigate the survival advantages of hunting, scavenging and kleptoparasitism as a function of predator, prey and potential competitor body sizes for terrestrial mammalian carnivores. The results of our framework reveal that predator tactics become more diverse closer to starvation, while the deployment of scavenging and kleptoparasitism is strongly constrained by the ratio of predator to prey body size. Our model accurately predicts a behavioural transition away from hunting towards alternative modes of predation with increasing prey size for predators spanning an order of magnitude in body size, closely matching observational data across a range of species. We then show that this behavioural boundary follows an allometric power-law scaling relationship where the predator size scales with an exponent nearing 3/4 with prey size, meaning that this behavioural switch occurs at relatively larger threshold prey body size for larger carnivores. We suggest that our approach may provide a holistic framework for guiding future observational efforts exploring the diverse array of predator foraging behaviours.

Behavioural plasticity can modulate the costs and benefits of sociality and thus may play a prominent role in mediating competition and facilitation during social interactions in mixed-species groups. However, investigations of assembly patterns of mixed-species groups typically treat species' behavioural attributes as static rather than dynamic features that can change in social contexts. We investigate four axes of behavioural plasticity that may modulate interactions within mixed-species groups: (1) species' selective preference for joining certain groups, (2) species' ability to flexibly change their behaviour in response to groupmates' behaviour and (3) shifts and/or (4) flexibility of species' niche breadth resulting in either shrinking or expansion when foraging with conspecifics versus when foraging with heterospecifics. We assess variation in these axes of behavioural plasticity in an Australian mixed-species avian community. All species had selective preferences for flocks of certain strata, and some flexibly matched their flockmates' foraging strata. Three species exhibited patterns of niche shift, and one species showed niche expansion. These findings suggest that species converge in strata in mixed-species flocks despite the potential for increased competition and emphasize that species can plastically react to changes in their social environment in numerous ways. Acknowledgment of such plasticity is likely integral to understanding the nuances of heterospecific interactions. • We examined behavioural plasticity in Australian mixed-species avian flocks. • Birds showed selectively for mixed-species flocks of certain foraging strata. • Many species flexibly converged on the foraging strata of their flockmates. • A few species shifted or expanded their foraging niche when in mixed-species flocks. • Multiple axes of behavioural plasticity modulated mixed-species group participation. [ABSTRACT FROM AUTHOR]

Orcas (Orcinus orca) are the top marine predators of the ocean, targeting multiple taxa including teleost fishes, elasmobranchs, seabirds, sea turtles, pinnipeds, odontocetes and other large cetaceans. According to their foraging strategies, genetics, acoustics, and morphology, orcas differentiate into ecotypes. Despite their cosmopolitan distribution, orcas are poorly studied in areas such as the Humboldt Current System of the Southeast Pacific coast. Since 2018 in northern Chile, presumed Type A orcas have been observed foraging on South American sea lions (Otaria byronia),benefiting from the presence of fishing vessels facilitating their hunt. These orcas were observed also pursuing large mixed groups of dusky (Lagenorhynchus obscurus) and long-beaked common dolphins (Delphinus capensis); however, predation on dusky dolphins was not documented. Here, we provide 28 additional sightings of orcas in two upwelling hotspots along northern Chile (15 around the Chañaral, Choros, and Damas Islandsin the Humboldt Penguin National Reserve from 2010--2023 and 13 in the Mejillones Peninsula from 2022--2023) and the first records of orcas effective hunting on dusky dolphins in this area. We present three new observations of orca tooth rake marks on fin whales (Balaenoptera physalus) dorsal fins in northern Chile. Furthermore, we observed the same orcas on two occasions foraging on dusky dolphins and sharing dolphin meat among group members. Overall, these observations suggest that orcas in northern Chile forage on marine mammals, especially on dusky dolphins, and the number of such predation events seems to be increasing near the coast. [ABSTRACT FROM AUTHOR]

Atlantic bluefin tuna (ABFT; Thunnus thynnus) is a highly migratory species. To investigate the migrations and vertical behaviours of ABFT migrating to Nordic waters, we deployed pop-up satellite archival transmitting tags on 25 ABFT off Norway (curved fork length: 228–292 cm). We obtained 16 full-year migrations, which differed between individuals, and physically recovered 13 tags, which provided 4699 days of archival depth and temperature data. ABFT occupied waters from the Arctic Circle to as far south as Cabo Verde, Africa, and occupied depths down to 1190 m and temperatures from 0.5 to 27.8°C. During their annual migrations, ABFT spent, on average, 68 days in Norwegian waters, 65 days in the Newfoundland Basin, 35 days around the Canary Islands and 33 days in the West European Basin. Most ABFT entered the Mediterranean Sea with a mean entry date of 13 May and visited known spawning grounds, staying, on average, 44 days. All ABFT with full-year deployments returned to Norwegian waters. ABFT displayed high site-fidelity and dynamic vertical diving behaviours that varied between hotspots and seasons. These spatiotemporal data provide important ecological knowledge for sustainable management and the conservation of the recently recovered eastern ABFT stock. [ABSTRACT FROM AUTHOR]

Ingested toxins formulated as baits can be effective in the management of insect pests, but their efficacy may be influenced by insect foraging alongside active ingredients. There are several components that might influence insect consumption of toxic baits, one of which being prior nutritional exposure. In our study, we investigated how protein deprivation following adult emergence influences lethal and sublethal effects of boric acid on the pest tephritid melon fly, Zeugodacus cucurbitae. We performed a series of experiments to address the impact of prior diet on mortality, diet consumption, enzymes involved in detoxification and antioxidation and fly activity. Newly emerged melon fly adults were provided either diet containing 3:1 sucrose/yeast hyrdrolysate or just sucrose for three days prior to bioassays. Overall, protein deprivation had a strong effect on fly interactions with boric acid. In two separate experiments (continuous exposure and short duration feeding), insects only pre‐fed sucrose had significantly higher mortality compared with those pre‐fed protein. Insects that were pre‐fed only sucrose removed more liquid diet over the same duration of the experiments, suggesting compensatory foraging behaviours. Adults pre‐fed sucrose had higher catalase (1.5×) and superoxide dismutase (1.7×) activities compared with adults pre‐fed sucrose‐yeast, but we found no effect of boric acid on their activity or that of glutathione‐S‐transferase or acetylcholinesterase activity. Boric acid consumption also significantly reduced the activity of melon flies. Overall, our results demonstrate that prior diet in fly adulthood can impact subsequent exposure to and efficacy of ingested toxicants. [ABSTRACT FROM AUTHOR]

Prey alter their foraging when threatened by predators. Two mutually inclusive hypotheses explain this response. The first entails that defence behaviours to minimise exposure to predators prevent prey from achieving their preferred diet, while the second postulates that prey deliberately change their diet to fulfil new stress‐induced nutritional demands.We combined field observations and laboratory experiments to determine which hypothesis dictates snail dietary responses to risk of beetle predation.Snails exposed to predation‐risk reduced activity, increased climbing, increased respiration, ate distinctively to achieve a certain nutrient target, and preferred eating on the cage floor at the costs of nutritional imbalance and elevated risk.When only carbohydrates‐rich food was on the floor, stressed snails reduced activity and foraged less, but when only protein‐rich food was on the floor snails increased activity and consumed more carbohydrates than their no‐risk conspecifics.This outcome suggests that nutrient accessibility may determine which hypothesis governs the prey dietary reaction to predation risk. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

It is commonly recognized that predation and the risk of predation can have profound effects on behaviors and population ecology of prey. Comparatively, little attention has been paid to the trade-offs hosts make to manage the risk of parasitism, but there is evidence that hosts make behavioral trade-offs to avoid parasitism in ways that resemble those made by prey animals under the risk of predation. Mosquitoes are common hematophagous ectoparasites which parasitize a wide range of vertebrates, resulting in blood loss, distraction, and disease transmission. Many hosts engage in defensive behaviors to repel or kill mosquitoes and these behaviors likely come at the expense of activities such as foraging and vigilance for predators. We placed a mosquito attractant (BG-Sweetscent) and repellant (allethrin) near artificial foraging patches in areas where mosquitoes were common and measured the amount of grain left after a night of foraging (giving-up density) to investigate whether mosquitoes influenced Cotton Mouse (Peromyscus gossypinus) foraging. We predicted that in patches with mosquito attractants, mosquito harassment would cause mice to engage in defensive behaviors which would distract or deter them from foraging, resulting in less grain consumption relative to control patches. Conversely, we predicted that in mosquito-repellent patches, mice would experience less harassment, resulting in more grain consumption. Indoor arena trials found no evidence that the mosquito treatments influenced cotton mouse behavior in the absence of mosquitoes. However, we found no evidence that mosquito treatments affected giving-up densities. [ABSTRACT FROM AUTHOR]

Invasive species often have harmful effects on human activities and biodiversity. The Tapinoma nigerrimum complex includes three species that exhibit invasive traits and the ability to form supercolonies, including Tapinoma magnum and Tapinoma darioi. While these species are native to the Mediterranean basin, they have recently been reported as invasive in more northern regions of Europe. However, T. magnum and T. darioi show different invasion patterns in Europe, suggesting differences in thermal preferences between these species. We aimed to determine whether there was any difference in activity pattern depending on temperature or season between the two Tapinoma species and between Tapinoma and co‐occurring native Mediterranean ants.We measured ambient temperature and ant foraging activity around the nest entrances of T. darioi and T. magnum in urbanised sites around Montpellier, southern France, over almost 1 year.We did not detect differences in activity between the two species according to temperature, but T. magnum was more active than T. darioi in winter. Compared to the co‐occurring native species, the two Tapinoma species were more active at low temperatures and earlier in the year.These results suggest that the difference in invasion success between T. magnum and T. darioi may not be explained by temperature preference. The difference in activity between native Mediterranean species and invasive Tapinoma suggests a coexistence through niche partitioning. In addition, our results suggest that control measures against invasive Tapinoma species would be more effective if applied at the end of winter. [ABSTRACT FROM AUTHOR]

What do seabirds perceive about the world? How do they do so? And how do they use the information available to them to make foraging decisions? Social cues provide seabirds with information about the location of prey. This can, of course, be passive and not involve higher‐order cognitive processes (e.g. simple conspecific or heterospecific attraction). However, seabirds display many behaviours that promote learning and the transmission of information between individuals: the vast majority of seabirds are colonial living, have an extended juvenile phase that affords them time to learn, routinely form intra‐ and interspecific associations, and can flexibly deploy a combination of foraging tactics. It is worth evaluating their foraging interactions in light of this. This review describes how seabirds use social information both at the colony and at sea to forage, and discusses the variation that exists both across species and amongst individuals. It is clear that social interactions are a critical and beneficial component of seabird foraging, with most of the variation concerning the way and extent to which social information is used, rather than whether it is used. While it may seem counterintuitive that large groups of potential competitors congregating at a patch can result in foraging gains, such aggregations can alter species dynamics in ways that promote coexistence. This review explores how competitive interference at a patch can be mitigated by behavioural modifications and niche segregation. Utilising others for foraging success (e.g. via social cues and facilitation at a patch) is likely to make population declines particularly damaging to seabirds if the quantity or quality of their social foraging interactions is reduced. Environmental changes have the potential to disrupt their social networks and thus, how these species obtain food and transfer information. [ABSTRACT FROM AUTHOR]

Recent studies have found that growing or wild-harvesting some of one's own food is associated with food security in high-income societies. Yet this research has not established causal relationships, and it measures household food security using indicators that assess only access to market food. To disentangle how non-market food production interacts with food security, we interviewed 26 key informants who play central roles in communities of gardeners, hunters, fishers, foragers, and homesteaders in northern New England, U.S.A. These informants indicated that non-market food production relates ambiguously to short-term food access in high-income societies where market food is cheap relative to wages. But non-market production can enhance all other recognized dimensions of food security: availability, adequacy, acceptability, agency, utilization, stability, and sustainability. Causation can run the other way, too: food insecurity was said to increase the likelihood and intensity of engagement in non-market food production. Yet poverty can deprive food-insecure households of the equipment, money, skills, and land access needed for successfully producing their own food. Overall, our informants portrayed non-market food production as a skills-based safety net for reliably feeding oneself from the landscape through personal and societal crises, from the distant past to the climate-change future. [ABSTRACT FROM AUTHOR]

Female solitary bees collect pollen for their brood at the expense of using sugars in the nectar as fuel for flight. When flowers provide both pollen and nectar, solitary bees can refuel from the flowers to sustain pollen foraging. However, not all flowers provide both pollen and nectar. This study investigates how females of the solitary bee Andrena taraxaci orienticola secure fuel to sustain pollen foraging when flowers provide scarce nectar. By using DNA barcoding, we identified the Japanese dandelion Taraxacum platycarpum as their primary food source. This dandelion produces almost no nectar in the early morning when female bees collect almost no nectar but collect substantial amounts of pollen. We also found that these bees leave the nest with significantly more nectar at the first flight of the day than at later flights. When we restricted their fuel load by preventing nectar feeding, significantly more females failed to collect pollen on the first flight of the following day. These results suggest females hold back some part of the nectar collected at the end of a day's foraging and use it the following morning as fuel to sustain pollen foraging from flowers providing little nectar. [ABSTRACT FROM AUTHOR]

Animals interact with their worlds using sensory information (sounds, smells, sights) that is perceived differently by each species. This sensory information and how it is interpreted underpins most behaviours, but especially foraging decisions. Creating sensory misinformation, that is uninformative or unrewarding cues, is a new approach with applications for managing wildlife and conserving threatened species across a range of global contexts. Here we discuss recent research that demonstrates the power of strategically deploying olfactory misinformation to reduce predation on birds by predators, consumption of vulnerable seedlings by herbivores, and seeds by rodents as well as how multimodal misinformation may work. Single and multimodal sensory tactics can alter foraging decisions by both herbivores and predators, with profound consequences for the survival of prey and plants. There remains much to understand regarding sensory perception and learning but results to date suggest there are enormous opportunities to harness innovative sensory tactics in the future to improve many conservation and wildlife management scenarios. [ABSTRACT FROM AUTHOR]

Animals frequently engage in anti-predator behaviour, but the intensity and choice of behaviour is likely dependent on the environment. We used a common-garden experiment to test whether Allenby's gerbils (Gerbillus andersoni allenbyi) from different sites in the Negev Desert show different responses to the same level of risk. We tested whether animals from less covered (more risky) environments cope with predation risk better by foraging longer and faster in open microhabitats. To do so, we captured individuals from three areas that differ in vegetation cover and then quantified food consumption and apprehension in a standard outdoor vivarium (an enclosure). This vivarium simulated a natural environment, with natural moonlight, artificial cover, and two live owls. Animals from less vegetated environments consumed more food but foraged slower and with more apprehension. We also found that some populations prefer to forage more in the first quarter of the lunar cycle than the third, and others prefer the opposite, despite these moon phases having equal luminosity. That suggests an evolutionary coordination game might be at play. Our results show anti-predator behaviour is diverse among populations and similar within, which may hint the existence of different ecotypes if further differences are found. Significance statement: In this study, we analysed whether anti-predator behaviour is consistent within populations, and different among them. We found that gerbils have different anti-predator behaviour depending on their site of origin, and that difference continues even when placed in a common environment. Animals from environments poor in cover foraged slowly and more carefully but did so for a longer time. Interestingly, we also found that when animals from different locations are placed in the same environment together, the average behaviour of this mixed group is similar to the most cautious of the mix. [ABSTRACT FROM AUTHOR]

Changes in buoyancy of marine mammals can be used to infer environmental changes. In multiple seal species, how "fast" an animal sinks reveals body condition changes through shifts in buoyancy as the ratio between lean and lipid tissue changes. However, quantifying similar at‐sea changes in Weddell seals (Leptonychotes weddellii) has remained unexplored. Here, we present a method of inferring buoyancy of Weddell seals by monitoring descent rates from 4‐s time‐depth data, to reveal in situ insight of their life cycle. We defined a Buoyancy Indicator Segment (BIS) as the descent rate of a dive segment created with the broken‐stick method that was systematically filtered to only include characteristic nonstroking and directed travel segments while excluding lung buoyancy biases. We found that BISs predicted body condition changes in Weddell seals, being a function of dive duration, mean depth, and time‐of‐year. Descent rates quickened with troughs in early April due to postmolt muscle recovery, early July due to winter conditions, and early September possibly due to pregnancy. Each trough was followed by weight gain, with slowing descent rates reaching peaks in late May, early August, and late October. This new approach showed that determining at‐sea condition is possible for Weddell seals, deriving a powerful species and environmental monitoring tool. [ABSTRACT FROM AUTHOR]

Prey adopt various antipredator responses to minimize the risk of predation, and the fitness costs of antipredator responses can have emergent effects on the population dynamics of prey species. While the trade‐off between food acquisition and predation avoidance has long been recognized in predicting antipredator responses, less attention has been paid to the dynamics of the food‐safety trade‐off driven by temporal variation in multiple risk factors under changing seasonal conditions. Here, we monitored foraging and vigilance behaviour of a central prey species, snowshoe hares (Lepus americanus), at fine temporal scales over the winter with various types of predation risk, while also experimentally manipulating predation risk by attracting predators to foraging patches. Hares increased foraging and decreased vigilance over the winter, but hares under chronic risk decreased their antipredator efforts to a lesser degree, indicating that those individuals prioritized risk avoidance over food acquisition. Hares also decreased foraging and increased antipredator efforts in response to the temporal activity of predators and environmental cues of predation risk. However, the magnitude of the responses to the environmental cues was mediated by time of winter. While we did not detect a reactive response of hares to acute risk, we did find that hares exhibiting camouflage mismatch proactively increased vigilance. Overall, our results highlight the importance of species‐specific traits and changing seasonal conditions in addition to temporal variation in multiple risk factors in predicting antipredator responses and the context dependence of risk effects. [ABSTRACT FROM AUTHOR]

Context: Understanding tuna diet and its drivers can provide valuable insights into the dynamics of pelagic ecosystems and their capacity to adapt to environmental and human-induced stressors. Aims: To reconstruct tropical tuna dietary histories by using different metrics of stomach fullness and to assess their association with fisheries-related, environmental and biological covariates. Methods: We examined stomachs from 8229 skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares) and bigeye tuna (T. obesus) captured in the western and central Pacific Ocean between 2001 and 2021, classified each on the basis of categorical and continuous fullness metrics, then built statistical models to gauge covariate effects. Key results: Only models for the binary fullness metric (i.e. empty or non-empty) performed well. Tuna with empty stomachs were more likely to be caught on active gear (e.g. purse seine) and earlier in the day. Skipjack and bigeye tuna with empty stomachs were more likely to be associated with floating objects (e.g. fish-aggregating devices). Conclusions: Our results add to the evidence that tropical tunas forage more effectively during the day and more actively when not associated with floating objects. At the individual level, tuna stomach fullness is highly variable. Implications: Further research is needed to understand the factors governing this promising indicator of ecosystem change. In this study, we sought to reconstruct tropical tuna dietary histories by using different metrics of stomach fullness and to assess their association with fisheries-related, environmental and biological covariates. Our results add to the evidence that tropical tunas forage more effectively during the day and more actively when not associated with floating objects. Further research is needed to understand the factors governing this promising indicator of ecosystem change. [ABSTRACT FROM AUTHOR]

ABSTRACT Through killing and instilling fear in their prey, large terrestrial carnivores shape the structure and function of ecosystems globally. Most large carnivore species have experienced severe range and population declines due to human activities, and many are now threatened with extinction. Consequently, the impacts of these predators on food webs have been diminished or lost completely from many ecosystems. Kill rates provide a fundamental metric for understanding large carnivore ecology and assessing and comparing predation within and across ecological communities. Our systematic review of large terrestrial mammalian carnivore kill rates reveals significant positive geographic (North America, Europe, and Africa) and taxonomic (grey wolf Canis lupus, puma Puma concolor, lion Panthera leo, and Eurasian lynx Lynx lynx) bias, with most studies apparently motivated by human–carnivore conflict over access to ungulate prey and wildlife management objectives. Our current understanding of the behaviour and functional roles of many large carnivore species and populations thus remains limited. By synthesising and comparing kill rates, we show that solitary carnivores (e.g. brown bears Ursus arctos and most felids) exhibit higher per capita kill rates than social carnivores. However, ungulate predation by bears is typically limited to predation of neonates during a short period. Lower per capita kill rates by social carnivores suggests group living significantly reduces energetic demands, or, alternatively, that group‐living carnivores defend and consume a greater proportion of large prey carcasses, or may acquire more food through other means (e.g. scavenging, kleptoparasitism) than solitary hunters. Kill and consumption rates for Canidae – measured as kilograms of prey per kilogram of carnivore per day – are positively correlated with body mass, consistent with increasing energy costs associated with a cursorial hunting strategy. By contrast, ambush predators such as felids show an opposite trend, and thus the potential energetic advantage of an ambush hunting strategy for carnivores as body mass increases. Additionally, ungulate kill rates remain relatively constant across solitary felid body sizes, indicative of energetic constraints and optimal foraging. Kill rate estimates also reveal potential insights into trophic structuring within carnivore guilds, with subordinate carnivores often killing more than their larger counterparts, which may be indicative of having to cope with food losses to scavengers and dominant competitors. Subordinate carnivores may thus serve an important role in provisioning food to other trophic levels within their respective ecosystems. Importantly, kill rates also clarify misconceptions around the predatory behaviour of carnivores (e.g. spotted hyaenas Crocuta crocuta and wolverines Gulo gulo are often considered scavengers rather than the capable hunters that they are) and thus the potential impacts of various carnivore species on their ecological communities. Despite the importance of kill rates in understanding predator–prey interactions, their utility is not widely recognised, and insufficient research limits our ability to fully appreciate and predict the consequences of modified predation regimes, justify current management actions affecting carnivores, or inform effective conservation measures. Together with other important research on predator–prey interactions, robust kill rate studies that address the research deficiencies we highlight will provide a deeper understanding of the foraging behaviours and potential ecosystem impacts of many of the world's carnivores, thus aiding effective conservation and management actions. [ABSTRACT FROM AUTHOR]

Earthworms are a resilient group of species thriving in varied habitats through feeding on decaying organic matter, and are therefore predicted to survive an abrupt sunlight reduction scenario, e.g., a nuclear winter. In this study, the feasibility and cost-effectiveness of foraging earthworms to reduce global famine in such a scenario with or without global catastrophic infrastructure loss was considered. Previously reported earthworm extraction methods (digging and sorting, vermifuge application, worm grunting, and electroshocking) were analysed, along with scalability, climate-related barriers to foraging, and pre-consumption processing requirements. Estimations of the global wild earthworm resource suggest it could provide three years of the protein needs of the current world human population, at a median cost of USD 353·kg−1 dry carbohydrate equivalent or a mean cost of USD 1200 (90% confidence interval: 32–8500)·kg−1 dry carbohydrate equivalent. At this price, foraging would cost a median of USD 185 to meet one person's daily caloric requirement, or USD 32 if targeted to high-earthworm-biomass and low-labour-cost regions; both are more expensive than most existing resilient food solutions. While short-term targeted foraging could still be beneficial in select areas given its quick ramp-up, earthworms may bioaccumulate heavy metals, radioactive material, and other contaminants, presenting a significant health risk. Overall, earthworm foraging cannot be recommended as a scalable resilient food solution unless further research addresses uncertainties regarding cost-effectiveness and food safety. [ABSTRACT FROM AUTHOR]

Feeding ecology is an essential component of an organism's life, but foraging comes with risks and energetic costs. Species in which populations exhibit more than one feeding strategy, such as sea turtles, are good systems for investigating how feeding ecology impacts life‐history traits, reproduction and carried over effects across generations. Here, we investigated how the feeding ecology of loggerhead sea turtles (Caretta caretta) nesting at the Cabo Verde archipelago correlates with reproductive outputs and offspring quality. We determined the feeding ecology of female turtles before and during the breeding season from stable isotope analysis of carbon and nitrogen and correlated isotopic ratio with female and offspring traits. We found that female turtles feeding at higher trophic positions produced larger clutches. We also found that females with higher δ13C values, typical of productive foraging areas, had greater fat reserves, were less likely to be infected by leech parasites and produced heavier offspring. The offspring of infected mothers with higher δ13C values performed best in crawling and self‐righting trials than those of non‐infected mothers with higher δ13C values. This study shows adult female loggerheads that exploit productive areas build capital reserves that impact their reproductive success and multiple proxies for offspring quality. Overall, our findings provide valuable insights into the complex interplay between feeding ecology and reproductive success, and reveal the transgenerational carry‐over effects of both feeding ecology and health on offspring quality in sea turtles. [ABSTRACT FROM AUTHOR]

Foraging profitability is one of the significant factors affecting habitat selection in fishes. The food habits of the fish species vary seasonally due to the dynamic nature of their environment. For that, the dietary analysis of a fish is essential in the case of fish diversity research. Most of the variations in prey size consumed by piscivores were correlated to the differences in piscivore body size, which morphological constraints can explain. The present study aimed to investigate the ecomorphological assemblage of small indigenous freshwater fish species from smaller lentic freshwater bodies based on a range of morphological traits and evaluate fish assemblages with respect to the feeding guilds. Freshwater ponds around Birbhum district, West Bengal (India) were selected for the collection of fish species, namely Amblypharyngodon mola, Puntius sophore, Esomus danrica, Lepidocephalichthys guntea, Chanda nama, Parambassis lala, Trichogaster fasciata, Anabas testudineus and Glossogobius giuris. Morphometric and gut content analysis were done, and the trophic guild matrix, taxonomic distance matrix, and morphological matrix were calculated. The result showed a strong association between ecomorphological traits and trophic structure, indicating an independent assemblage pattern beyond the taxonomic influence. [ABSTRACT FROM AUTHOR]

Competition among pollinators for floral resources is a phenomenon of both basic and applied importance. While competition is difficult to measure directly under field conditions, it can be inferred indirectly through the measurement of floral resource depletion. In this study, we conducted a pollinator exclusion experiment to calculate nectar depletion rates in summer across 16 grassland sites in the German regions of Franconia and Saxony‐Anhalt. Overall depletion rates were estimated at 95% in Franconia and 79% in Saxony‐Anhalt, indicating strong nectar limitation and likely competition among pollinators for nectar. Despite being ubiquitous in our study regions, honey bees were scarce at our sites at the time of nectar sampling. This demonstrates that wild pollinators alone are capable of massive nectar depletion, and the addition of managed honey bees to wild pollinator communities may intensify already competitive conditions. Nevertheless, the manifest diversity of the pollinator communities at our sites indicates that other factors, such as non‐trophic constraints or temporal variation in nectar limitation, can mitigate competitive exclusion despite immediate conditions of acute nectar scarcity. [ABSTRACT FROM AUTHOR]

Carcasses are patchily distributed and often short‐lived resources, placing scavenging animals under pressure to locate them before they rot or are depleted by competitors. Scavengers may search for carcasses directly, or indirectly, using social information. Aggregations of feeding animals and their conspicuous competitive behaviour may be more readily detectable to searching scavengers than the carcass itself. Moreover, the actions of attendant scavengers upon the carcass, breaking it apart and releasing odour or chemical cues, may further enhance its detectability to others foraging nearby. Here we test this idea. In the first of two experiments performed in the field, we found that hermit crabs (Pagurus bernhardus) were attracted to shelled mussels (Mytilus edulis) that other hermit crabs were already feeding on. They showed no strong tendency to approach aggregations of conspecifics in the absence of food, nor conspecifics that were confined close to mussels but prevented from feeding on them. We speculated that through breaking up the carcass, the feeding hermit crabs released chemical cues and drifting particles of mussel tissue that further attracted other hermit crabs. We tested this in a second experiment, finding that finely chopped mussels attracted significantly more hermit crabs than did intact mussels. We suggest that scavenger feeding action upon carcasses makes these more detectable to others by releasing odour and particle plumes, a form of inadvertently produced social information. [ABSTRACT FROM AUTHOR]

To compensate for mineral deficiencies in food sources, numerous ungulate species use various methods, such as salt licking, soil ingestion, and gnawing on antlers or bones. While osteophagia, the act of gnawing on antlers or bones, is well-documented in cervid species, it has only been observed in sika deer (Cervus nippon) on Mageshima Island in southern Japan despite their widespread distribution. This study aimed to provide an initial account of the observations of osteophagia in sika deer from central Japan. One of the 15 camera traps deployed in the Hakone Nature Forest of Tamagawa University for wildlife monitoring serendipitously captured multiple instances of adult female sika deer gnawing on a four-tined antler on July 9th and 16th in 2018. These occurrences coincided with the fawning season of the species during which mineral deficiencies in the diet are prevalent, suggesting that osteophagia serves as a response to nutrient deficiencies in the diet of sika deer in central Japan. Thus, systematic surveys may yield additional evidence of this behavior in sika deer across diverse geographical areas given the absence of studies on osteophagia in sika deer conducted in other regions. Digital video images related to the article are available at http://www.momo-p.com/showdetail-e.php?movieid=momo240508cn01a. [ABSTRACT FROM AUTHOR]

Crypsis is a common strategy used by animals to avoid detection. In many bird taxa, plumage colour patterns are assumed to play a role in crypsis, but few studies have directly measured plumage crypsis on ecologically relevant substrates from the perspective of relevant signal receivers. To address this gap, we tested whether the plumage colour patterns of three North American woodpeckers commonly found in New Jersey (U.S.A.) are more cryptic to avian predators on trees utilized for foraging than a random subset of trees from their habitat. We focused on the red-bellied woodpecker, Melanerpes carolinus , downy woodpecker, Dryobates pubescens , and hairy woodpecker, Leuconotopicus villosus. First, we took standardized photographs of the bark of trees on which we observed woodpeckers foraging, as well as photographs of the bark of trees from transects in the same area. Next, we superimposed standardized photographs of woodpecker specimens (dorsal view) onto the bark samples and adjusted the resulting images to estimate how they would appear to the visual system of an avian predator. We then estimated four types of achromatic crypsis from each bird/bark combination image: granularity matching, contrast matching, luminance matching and disruptive coloration. We also estimated how well woodpeckers matched the bark substrates in terms of colour by quantifying the degree of colour similarity in a colour space representing a typical avian predator. We found that woodpeckers were more cryptic against trees they utilized for foraging in terms of disruptive coloration, luminance matching and colour matching, suggesting that the need to be cryptic while foraging is likely to have shaped the evolution of woodpecker plumage patterning. • We tested degree of crypsis of woodpecker plumage on foraging and nonforaging trees. • All three woodpecker species tested were more cryptic on foraging trees. • Crypsis strategies included disruptive coloration, luminance matching and colour matching. • Woodpecker species showed some degree of crypsis specialization. • Avian predator visual acuity influences effectiveness of woodpecker crypsis. [ABSTRACT FROM AUTHOR]

Analyzing data from the verbal fluency task (e.g., "name all the animals you can in a minute") is of interest to both memory researchers and clinicians due to its broader implications for memory search and retrieval. Recent work has proposed several computational models to examine nuanced differences in search behavior, which can provide insights into the mechanisms underlying memory search. A prominent account of memory search within the fluency task was proposed by Hills et al. (2012), where mental search is modeled after how animals forage for food in physical space. Despite the broad potential utility of these models to scientists and clinicians, there is currently no open-source program to apply and compare existing foraging models or clustering algorithms without extensive, often redundant programming. To remove this barrier to studying search patterns in the fluency task, we created forager, a Python package (https://github.com/thelexiconlab/forager) and web interface (https://forager.research.bowdoin.edu/). forager provides multiple automated methods to designate clusters and switches within a fluency list, implements a novel set of computational models that can examine the influence of multiple lexical sources (semantic, phonological, and frequency) on memory search using semantic embeddings, and also enables researchers to evaluate relative model performance at the individual and group level. The package and web interface cater to users with various levels of programming experience. In this work, we introduce forager's basic functionality and use cases that demonstrate its utility with pre-existing behavioral and clinical data sets of the semantic fluency task. [ABSTRACT FROM AUTHOR]

Primary nectar-robbers feed through holes they make in flowers, often bypassing the plant's reproductive organs in the process. In many robbed plants, multiple holes are made in a single flower. Why a flower should be robbed repeatedly is difficult to understand: a hole signals that a nectar forager has already fed, which would seem likely to predict low rewards. We tested three explanations for this pattern in Corydalis caseana (Fumariaceae), a bumble bee pollinated and robbed plant: (1) multiple holes appear only after all flowers have been robbed once; (2) individual foragers make multiple holes during single visits; and (3) it is more profitable for bees to rob older flowers, even if they have already been robbed. We tested these hypotheses from 2014 to 2016 in a Colorado, USA population using data on robbing rates over time, floral longevity, nectar accumulation in visited and unvisited flowers, and the accumulation of robbing holes across the life of flowers. Multiple holes were already appearing when two-thirds of flowers still lacked a single hole, allowing us to reject the first hypothesis. The second hypothesis cannot offer a full explanation for multiple robbing holes because 35% of additional holes appeared in flowers one or more days after the first hole was made. Repeated sampling of bagged and exposed inflorescences revealed that flowers filled at a constant rate and refilled completely after being drained. Consequently, young flowers are of consistently low value to foragers compared to older flowers even if they had previously been robbed, consistent with the third hypothesis. While further studies are needed, these results offer a simple explanation for the paradoxical clustering of nectar-robbing damage in this and possibly other plant species. [ABSTRACT FROM AUTHOR]

Foraging for wild resources links urban citizens to nature and biodiversity while providing resources important for local livelihoods and culture. However, the abundance and distributional (in)equity of forageable urban tree resources have rarely been examined. Consequently, this study assessed the abundance of forageable street trees and their distribution in Lagos metropolis, Nigeria. During a survey of 32 randomly selected wards across 16 local government areas (LGAs) in the metropolis, 4017 street trees from 46 species were enumerated. The LGA with the highest number of street trees was Ikeja, with 818 trees, while Lagos Island had the lowest count, with two trees. This disparity in tree numbers could be attributed to variations in human population density within each LGA. Ninety‐four percent of the street trees surveyed had at least one documented use and 76% had two, making them potentially forageable. However, the most common species had relatively low forageability scores. Only 5.6% of the total street tree population was rated as highly forageable, with a usability score of at least 11 out of 15. The most forageable street trees were fruit trees and non‐native species. The forageable street trees in the LGAs showed a significant disparity in their distribution, as evidenced by a Gini coefficient of 0.81. Overall, richer neighborhoods had a higher street tree abundance, richness, and forageability potential. To meet greening and foraging goals and address the current inequitable distribution, we suggest allocating more funds for greening, particularly in low‐income neighborhoods. Further research should evaluate forageable species from other sites to acquire a detailed understanding of the distribution and abundance of forageable resources in Lagos metropolis. [ABSTRACT FROM AUTHOR]

Stingless bees are a widespread group of highly social bees found in tropical regions throughout much of the world. Despite an impressive diversity, relatively little is known about worker behaviour and division of labour. In this study, we investigate the progression of colony tasks over the lifespan of worker bees in colonies of the two most commonly kept Australian species: Tetragonula carbonaria and T. hockingsi. We marked cohorts of 25–100 newly emerged female bees with a paint dot and released them back into colonies housed in observation hives before recording twice weekly behaviours of marked bees within the nest. Foragers were observed through a clear plastic entrance tube. We replicated this with 5–6 marked cohorts across three colonies for each species. We found the two species were similar to each other in the frequency and age distribution of behaviours. Young worker bees were mostly found cleaning, filling or constructing brood cells and collecting honey from food pots. Middle aged bees were more likely to build or maintain food pots or supporting structures, with guarding and foraging occupying the oldest bees. There was, however, significant overlap in timing of tasks. Moreover, fast cohorts progressed to foraging in less than half the time of the slowest cohorts. Despite subtle differences between our Tetragonula species and other stingless bees, it adds to the evidence that progression from safe to risky jobs with age is an ancestral feature shared across stingless bees, and has similarities to honeybees despite an independent evolutionary origin. [ABSTRACT FROM AUTHOR]

When foraging, internal needs for particular nutrients might affect food choice, and external constraints, such as predation risk, might impact trade-offs between foraging and risk avoidance. Examining both internal and external constraints simultaneously can provide important insights into how animals make decisions. We examined how internal nutritional needs and external cues of mortality risk jointly impact the foraging behavior of ants. Ant colonies require carbohydrates to support workers energetically and proteins to raise brood. Furthermore, colonies adjust their foraging activity in response to the environment, such as food availability and the presence of predators or heterospecifics. Here we examine the foraging decisions of groups of Argentine ants Linepithema humile, which differ in their nutritional needs in high-risk environments. We starved groups of ants for either proteins or carbohydrates and determined the foraging choices that ants made when cues of heterospecifics were present. We found that ants preferentially forage for carbohydrates in high-risk conditions. Furthermore, starvation for carbohydrates increased the ants preference for carbohydrates, even when cues of heterospecifics were present at both carbohydrates and protein resources. Starvation for protein also resulted in preferential foraging for carbohydrates, but it increased visitation to a protein food source in high-risk environments compared to when ants were starved for carbohydrates or for both resources. Examining the effect of both nutrition and mortality risk on foraging simultaneously provides insights about state-dependent risk-taking behavior that may have important implications for predicting the invasion of species into novel habitats.

Childhood is a period of life unique to humans. Childhood may have evolved through the need to acquire knowledge and subsistence skills. In an effort to understand the functional significance of childhood, previous research examined increases with age in returns to foraging across food resources. Such increases could be due to changes in knowledge, or other factors such as body size or strength. Here, we attempt to unpack these age-related changes. First, we estimate age-specific foraging returns for two resources. We then develop nonlinear structural equation models to evaluate the relative importance of ecological knowledge, grip strength and height in a population of part-time children foragers on Pemba island, Tanzania. We use anthropometric measures (height, strength, n = 250), estimates of ecological knowledge (n = 93) and behavioural observations for 63 individuals across 370 foraging trips. We find slower increases in foraging returns with age for trap hunting than for shellfish collection. We do not detect any effect of individual knowledge on foraging returns, potentially linked to information sharing within foraging parties. Producing accurate estimates of the distinct contribution of specific traits to an individuals foraging performance constitutes a key step in evaluating different hypotheses for the emergence of childhood.

BACKGROUND: Kangaroo rats are small mammals that are among the most abundant vertebrates in many terrestrial ecosystems in Western North America and are considered both keystone species and ecosystem engineers, providing numerous linkages between other species as both consumers and resources. However, there are challenges to studying the behavior and activity of these species due to the difficulty of observing large numbers of individuals that are small, secretive, and nocturnal. Our goal was to develop an integrated approach of miniaturized animal-borne accelerometry and radiotelemetry to classify the cryptic behavior and activity cycles of kangaroo rats and test hypotheses of how their behavior is influenced by light cycles, moonlight, and weather. METHODS: We provide a proof-of-concept approach to effectively quantify behavioral patterns of small bodied (< 50 g), nocturnal, and terrestrial free-ranging mammals using large acceleration datasets by combining low-mass, miniaturized animal-borne accelerometers with radiotelemetry and advanced machine learning techniques. We developed a method of attachment and retrieval for deploying accelerometers, a non-disruptive method of gathering observational validation datasets for acceleration data on free-ranging nocturnal small mammals, and used these techniques on Merriams kangaroo rats to analyze how behavioral patterns relate to abiotic factors. RESULTS: We found that Merriams kangaroo rats are only active during the nighttime phases of the diel cycle and are particularly active during later light phases of the night (i.e., late night, morning twilight, and dawn). We found no reduction in activity or foraging associated with moonlight, indicating that kangaroo rats are actually more lunarphilic than lunarphobic. We also found that kangaroo rats increased foraging effort on more humid nights, most likely as a mechanism to avoid cutaneous water loss. CONCLUSIONS: Small mammals are often integral to ecosystem functionality, as many of these species are highly abundant ecosystem engineers driving linkages in energy flow and nutrient transfer across trophic levels. Our work represents the first continuous detailed quantitative description of fine-scale behavioral activity budgets in kangaroo rats, and lays out a general framework for how to use miniaturized biologging devices on small and nocturnal mammals to examine behavioral responses to environmental factors.

Individual differences in behavior have large consequences for the way in which ecology impacts fitness. Individuals differ in how they explore their environment and how exploratory behavior benefits them. In group-living animals, behavioral heterogeneity can be beneficial because different individuals perform different tasks. For example, exploratory individuals may discover new food sources and recruit group members to exploit the food, while less exploratory individuals forgo the risks of exploration. Here we ask how individual variation in exploratory behavior affects the ability of Argentine ant Linepithema humile colonies to (1) locate novel food sources, (2) exploit known food resources, and (3) respond to disruptions while foraging. To address these questions, we conducted field experiments on L. humile foraging trails in which we manipulated food availability near and at the foraging trails and disrupted the foraging trails. We sampled individuals based on their response to the perturbations in the field and tested their exploratory behavior in the lab. We found that exploratory individuals benefit the colony by locating novel foods and increasing resource exploitation, but they do not play an important role in the recovery of a foraging trail after disruption. Thus, the benefits of behavioral heterogeneity to the group, specifically in exploratory behavior, differ across ecological contexts.

Recent studies show that Traditional Ecological Knowledge (TEK) of Indigenous Peoples’ food systems and the transfer of that knowledge to their children are critical to physical and mental health, promote the transfer of language and culture, and further resilience. The aim of this exploratory, medical ecological study was to document TEK about foraging and plant use among the Dukha, a small, semi-nomadic reindeer herding community in Northern Mongolia. Field research was conducted at multiple remote camps in 2019 and 2023. Methods included semi-structured, open-ended interviews (N = 16), photo identification, and participant observation (N = 34 families). Study Informants identified 27 foraged plants. Results placed Dukha foraging practices within a framework illustrating the interconnectedness of their worldview and cultural norms, including the physical and spiritual aspects of the landscape, with health, illness, and curing. Dukha curative knowledge of the flora aligns with both Traditional Mongolian Medicine (TMM) and scientific studies on healing and preventative care. Through foraging and plant use, the Dukha balance relationships with the land and spirits, benefit from better nutrition and physical activity, utilise healing qualities of Indigenous flora, and foster the intergenerational transfer of language and traditional knowledge. [ABSTRACT FROM AUTHOR]

Abstract Background Animal movement arises from complex interactions between animals and their heterogeneous environment. To better understand the movement process, it can be divided into behavioural, temporal and spatial components. Although methods exist to address those various components, it remains challenging to integrate them in a single movement analysis. Methods We present an analytic workflow that integrates the behavioural, temporal and spatial components of the movement process and their interactions, which also allows for the assessment of the relative importance of those components. We construct a daily cyclic covariate to represent temporally cyclic movement patterns, such as diel variation in activity, and combine the three components in a multi-modal Hidden Markov Model framework using existing methods and R functions. We compare the trends and statistical fits of models that include or exclude any of the behavioural, spatial and temporal components, and perform variance partitioning on the model predictions that included all components to assess their relative importance to the movement process, both in isolation and in interaction. Results We apply our workflow to a case study on the movements of plains zebra, blue wildebeest and eland antelope in a South African reserve. Behavioural modes impacted movement the most, followed by diel rhythms and then the spatial environment (viz. tree cover and terrain slope). Interactions between the components often explained more of the movement variation than the marginal effect of the spatial environment did on its own. Omitting components from the analysis led either to the inability to detect relationships between input and response variables, resulting in overgeneralisations when drawing conclusions about the movement process, or to detections of questionable relationships that appeared to be spurious. Conclusions Our analytic workflow can be used to integrate the behavioural, temporal and spatial components of the movement process and quantify their relative contributions, thereby preventing incomplete or overly generic ecological interpretations. We demonstrate that understanding the drivers of animal movement, and ultimately the ecological phenomena that emerge from it, critically depends on considering the various components of the movement process, and especially the interactions between them.

Earthworms are a resilient group of species thriving in varied habitats through feeding on decaying organic matter, and are therefore predicted to survive an abrupt sunlight reduction scenario, e.g., a nuclear winter. In this study, the feasibility and cost-effectiveness of foraging earthworms to reduce global famine in such a scenario with or without global catastrophic infrastructure loss was considered. Previously reported earthworm extraction methods (digging and sorting, vermifuge application, worm grunting, and electroshocking) were analysed, along with scalability, climate-related barriers to foraging, and pre-consumption processing requirements. Estimations of the global wild earthworm resource suggest it could provide three years of the protein needs of the current world human population, at a median cost of USD 353·kg−1 dry carbohydrate equivalent or a mean cost of USD 1200 (90% confidence interval: 32–8500)·kg−1 dry carbohydrate equivalent. At this price, foraging would cost a median of USD 185 to meet one person’s daily caloric requirement, or USD 32 if targeted to high-earthworm-biomass and low-labour-cost regions; both are more expensive than most existing resilient food solutions. While short-term targeted foraging could still be beneficial in select areas given its quick ramp-up, earthworms may bioaccumulate heavy metals, radioactive material, and other contaminants, presenting a significant health risk. Overall, earthworm foraging cannot be recommended as a scalable resilient food solution unless further research addresses uncertainties regarding cost-effectiveness and food safety.

Predator and prey traits are important determinants of the outcomes of trophic interactions. In turn, the outcomes of trophic interactions shape predator and prey trait evolution. How species' traits respond to selection from trophic interactions depends crucially on whether and how heritable species' traits are and their genetic correlations. Of the many traits influencing the outcomes of trophic interactions, body size and movement traits have emerged as key traits. Yet, how these traits shape and are shaped by trophic interactions is unclear, as few studies have simultaneously measured the impacts of these traits on the outcomes of trophic interactions, their heritability, and their correlations within the same system. We used outcrossed lines of the ciliate protist Paramecium caudatum from natural populations to examine variation in morphology and movement behaviour, the heritability of that variation, and its effects on Paramecium susceptibility to predation by the copepod Macrocyclops albidus. We found that the Paramecium lines exhibited heritable variation in body size and movement traits. In contrast to expectations from allometric relationships, body size and movement speed showed little covariance among clonal lines. The proportion of Paramecium consumed by copepods was positively associated with Paramecium body size and velocity but with an interaction such that greater velocities led to greater predation risk for large body‐sized paramecia but did not alter predation risk for smaller paramecia. The proportion of paramecia consumed was not related to copepod body size. These patterns of predation risk and heritable trait variation in paramecia suggest that copepod predation may act as a selective force operating independently on movement and body size and generating the strongest selection against large, high‐velocity paramecia. Our results illustrate how ecology and genetics can shape potential natural selection on prey traits through the outcomes of trophic interactions. Further simultaneous measures of predation outcomes, traits, and their quantitative genetics will provide insights into the evolutionary ecology of species interactions and their eco‐evolutionary consequences. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Background: Animal movement arises from complex interactions between animals and their heterogeneous environment. To better understand the movement process, it can be divided into behavioural, temporal and spatial components. Although methods exist to address those various components, it remains challenging to integrate them in a single movement analysis. Methods: We present an analytic workflow that integrates the behavioural, temporal and spatial components of the movement process and their interactions, which also allows for the assessment of the relative importance of those components. We construct a daily cyclic covariate to represent temporally cyclic movement patterns, such as diel variation in activity, and combine the three components in a multi-modal Hidden Markov Model framework using existing methods and R functions. We compare the trends and statistical fits of models that include or exclude any of the behavioural, spatial and temporal components, and perform variance partitioning on the model predictions that included all components to assess their relative importance to the movement process, both in isolation and in interaction. Results: We apply our workflow to a case study on the movements of plains zebra, blue wildebeest and eland antelope in a South African reserve. Behavioural modes impacted movement the most, followed by diel rhythms and then the spatial environment (viz. tree cover and terrain slope). Interactions between the components often explained more of the movement variation than the marginal effect of the spatial environment did on its own. Omitting components from the analysis led either to the inability to detect relationships between input and response variables, resulting in overgeneralisations when drawing conclusions about the movement process, or to detections of questionable relationships that appeared to be spurious. Conclusions: Our analytic workflow can be used to integrate the behavioural, temporal and spatial components of the movement process and quantify their relative contributions, thereby preventing incomplete or overly generic ecological interpretations. We demonstrate that understanding the drivers of animal movement, and ultimately the ecological phenomena that emerge from it, critically depends on considering the various components of the movement process, and especially the interactions between them. [ABSTRACT FROM AUTHOR]

Negative density dependence (NDD) in biotic interactions of interference such as plant–plant competition, granivory and herbivory are well-documented mechanisms that promote species' coexistence in diverse plant communities worldwide. Here, we investigated the generality of a novel type of NDD mechanism that operates through the mutualistic interactions of frugivory and seed dispersal among fruit-eating birds and plants. By sampling community-wide frugivory interactions at high spatial and temporal resolution in Pennsylvania, Puerto Rico, Peru, Brazil and Argentina, we evaluated whether interaction frequencies between birds and fruit resources occurred more often (selection), as expected, or below expectations (under-utilization) set by the relative fruit abundance of the fruit resources of each plant species. Our models considered the influence of temporal scales of fruit availability and bird phylogeny and diets, revealing that NDD characterizes frugivory across communities. Irrespective of taxa or dietary guild, birds tended to select fruits of plant species that were proportionally rare in their communities, or that became rare following phenological fluctuations, while they mostly under-utilized abundant fruit resources. Our results demonstrate that negative density-dependence in frugivore–plant interactions provides a strong equalizing mechanism for the dispersal processes of fleshy-fruited plant species in temperate and tropical communities, likely contributing to building and sustaining plant diversity. This article is part of the theme issue 'Diversitydependence of dispersal: interspecific interactions determine spatial dynamics'. [ABSTRACT FROM AUTHOR]

Aerial insectivorous birds breeding in North America have experienced decades of population declines for reasons hypothesized to be related to changes in their insect prey. In agricultural landscapes, land management practices can affect insect communities, leading to concerns that ongoing trends toward more intensive cultivation could affect the ability of farmland-breeding aerial insectivores to forage and provision their offspring with aerial insect prey. To understand how differences in agricultural intensity may affect the foraging behavior of different aerial insectivore species, we used GPS tags to compare the movements and habitat use of 2 species with different foraging ecologies, Hirundo rustica (Barn Swallow) and Tachycineta bicolor (Tree Swallow), breeding at 17 sites in agricultural landscapes in Saskatchewan, Canada. Although we identified differences in foraging behavior consistent with each species' reported ecological traits, including T. bicolor foraging farther and over larger areas than H. rustica , overall foraging behavior was similar between species. Resource selection function analyses indicated that both species used wetlands disproportionately often relative to local wetland availability, especially when detected farther from their nests. Hirundo rustica and T. bicolor both also avoided cropped foraging habitat, using it proportionally less than it was locally available. In landscapes with greater wetland cover, both species selected for wetland habitat more strongly, and among T. bicolor , higher wetland density decreased maximum foraging distance and home range area. In contrast, we found no effect of crop cover on foraging habitat selection or foraging movements. These findings suggest that H. rustica and T. bicolor breeding in Saskatchewan agroecosystems share similar foraging strategies, with wetland habitats appearing to be highly important despite comprising only a small proportion of landscape area. Overall, these results indicate that protecting wetland habitats should be a priority for aerial insectivore conservation in the intensive agricultural landscapes such as the Canadian prairies. [ABSTRACT FROM AUTHOR]

Insectivorous bats in temperate zones have evolved strategies such as migration or hibernation to overcome challenges of reduced resource availability and increased energy demand during winter. In the southeastern United States Coastal Plain, bats are either year‐round residents and remain active during winter or are migrants from colder areas seeking milder temperatures. Southeastern Coastal Plain forests also may represent important areas for remnant populations of species impacted by white‐nose syndrome. Working pine (Pinus spp.) forests comprise a large proportion of southeastern Coastal Plain forests, yet winter bat habitat associations and how forest management affects bat use remain understudied. Hence, we used hierarchical multispecies spatial occupancy models to evaluate factors influencing winter bat occupancy and foraging habitat associations in working forests of the southeastern Coastal Plain. From January to March 2020–2022, we deployed Anabat Swift acoustic detectors and measured site‐ and landscape‐level covariates on six working landscapes. We detected five species of bats and three species groups at 93% (224/240) of sites. We observed higher species richness at sites with high proportions of contiguous forest and low levels of basal area. At the species level, occupancy patterns were influenced by site and landscape covariates, which had varying effects on species with distinct foraging strategies. Temperature was an important predictor of detectability. Our findings offer new insights into the ecology of bats in working forest landscapes during winter, where we highlight positive responses in occupancy with contiguous forests and lower levels of basal area, as in previous summer work. By providing valuable information on winter community composition and foraging habitat associations, we hope to guide management decisions for forest attributes important to these species, thus increasing conservation opportunities within working forests. [ABSTRACT FROM AUTHOR]

Previous studies of overwintering migratory birds in neotropical environments have found that species co-occur in the same habitats despite high diet overlap. Hence, discovering subtle diet differences within habitats can help explain patterns in bird species diversity. The Yucatan Peninsula in Mexico is an important region for overwintering migratory birds, but little is known about how habitat differences in food resources contribute to bird diversity. To address the knowledge gap, we compared the degree of overlap in the diet of all terrestrial migratory birds within and between mangrove and tropical dry forests on the Yucatan Peninsula's northern coast. We collected data on the consumption of food items through direct observation of birds feeding on four transects in each habitat every week (12 weeks) during the non-breeding season (i.e., overwinter, December-February). We recorded 19 species, 15 species in mangrove and 15 species in forest, with 11 of those found in both habitats. In both habitats, diet overlap was high. However, species present only in the tropical dry forest had less overlap than species occurring in both habitats, indicating that diet specialization might restrict the range of habitats that a species can occupy. On the other hand, species present only in the mangrove had similar diet overlap to species present in both habitats. The diet variation that did exist was greater within than between habitats possibly due to intraspecific diet differences among different geographic locations. Although small, within-habitat diet differences might be key to allowing species to coexist locally in the Yucatan, thus supporting studies demonstrating a similar mechanism in other neotropical regions. More generally, the information we provide on bird diet can be used to discover whether threats like anthropogenic development precipitate species loss via altering the resource base upon which birds rely. [ABSTRACT FROM AUTHOR]

Predaceous diving beetle adults scavenge for carrion in freshwater habitats. We identified two scavenging strategies used by adult Dytiscus sinensis Feng (Coleoptera: Dytiscidae) to locate and consume food at the bottom of water when needing to surface for air store renewal: dine‐in then relocate the food (dine‐in strategy) and carry the food to the surface (take‐away strategy). In 5‐cm‐deep water, a higher proportion of individuals successfully located food within an 8‐min test window than in 25‐cm‐deep water. Their latencies to locating food did not differ among depths. Dytiscus sinensis adults preferred the take‐away strategy in 5‐cm‐deep water and a higher proportion of them adopted the dine‐in strategy in 25‐cm‐deep water. Further, a 10‐cm‐deep test showed that the success rate or efficiency of relocating food did not increase with the experience of locating it the first time. This might explain why D. sinensis preferred the take‐away strategy in shallower water, in which it had lower risks of losing the food. The present study revealed a direct bottom‐up benefit for dytiscids foraging in shallower water where finding and securing food were easier. Our findings demonstrate that the surfacing requirement of dytiscid adults was reflected in foraging strategies with depth‐dependent preferences. [ABSTRACT FROM AUTHOR]

Interactions among predators can have cascading impacts on communities and ecosystems. These interactions often occur around carrion, where the carrion provides a food reward, but also a risk of encountering other, potentially dominant, predators. Understanding how predators balance risk and reward at carrion, and how perceived risk changes in response to carcass origins and conditions, provides valuable insight into intraguild interactions. We investigated Coyote (Canis latrans) behavior at carrion simulated as cache sites treated with Cougar (Puma concolor) scent versus carrion used as control sites to better understand how Coyotes assess risk while feeding on carrion. Coyotes displayed similar behavior between sites treated and untreated with Cougar scent, suggesting that the presence of Cougar scent did not alter perceived risk by Coyotes in our study. Instead, Coyote behavior responded to carcass age, elevation, and whether avian scavengers had visited the carcass. Coyotes spent more time feeding, more time on camera, and touched carcasses quicker as carcass age increased. Avian scavengers appeared to compete with Coyotes, and while the presence of avian scavengers reduced time to carcass detection by Coyotes, it also decreased time spent feeding. These results suggest that carcass condition is a more important indicator of risk and reward than the presence of dominant predator scent to Coyotes. Predator scent may be an unreliable cue of immediate predator presence. Alternatively, all carcasses may be risky because dominant predators also scavenge carrion, creating similar risk regardless of previous visitation by dominant predators. These results provide insights into predator interactions and can also inform the use of scent cues in wildlife management. [ABSTRACT FROM AUTHOR]

As global heating and other anthropogenic influences alter tropical marine environments, it is unclear how marine bird populations will be impacted and whether their current roles in tropical marine ecosystems will change. Although marine birds roost and breed on tropical islands in large numbers, the direct trophic interactions between these birds and their prey across the tropics are poorly documented. We present a first framework for evaluating the dependence on and contributions of marine birds to tropical coral reef ecosystems and use it to examine the evidence for different kinds of interaction, focusing primarily on avian diets. We found 34 publications between 1967 and 2023 that presented a total of 111 data sets with enough detail for quantitative dietary analysis of tropical marine birds. Only two bird species out of 37 (5.4%) had diets of >50% coral reef fishes and only one, the Pacific Reef Egret, appeared to depend almost entirely on reef‐based production. Marine birds are also prey for other marine organisms, but insufficient data are available for quantitative analysis. Evidence for indirect effects of birds in tropical marine environments is stronger than for direct dependence on coral reefs, particularly in relation to nutrient concentration and the fertilisation impacts of guano on corals. Dispersal of propagules (e.g. seeds, spores, invertebrate eggs) by bathing, drinking, resting or foraging birds is under‐studied and poorly documented. Although the degradation of coral reefs appears unlikely to have a significant direct impact on food availability for most marine bird populations, indirect effects involving marine birds may be disrupted by global environmental change. [ABSTRACT FROM AUTHOR]

The Eurasian woodcock prefers habitats where its main prey, earthworms, can be found in higher densities. Although they are forest‐dwelling birds, they regularly visit pastures and natural grasslands at night, where earthworm abundance is generally higher. However, there is little information on fine‐scale habitat use in relation to variation in habitat characteristics and prey availability, particularly beyond the breeding season. In our study, we investigated if the nocturnal occurrence of woodcocks during migratory stopover periods differed between two neighbouring fields, or management units, with similar vegetation structure, and if within‐field variation in the spatial patterns of woodcock sightings were associated with fine‐scale earthworm densities and soil parameters. Specifically, we used GPS tracking data of two tagged woodcocks and direct observation data to study patterns of occurrence of birds in a mixed forest‐pasture landscape in Hungary during pre‐ and post‐breeding periods. We compared these patterns with fine‐scale soil characteristics and earthworm abundance, acquired by field sampling. We found that the field with higher earthworm abundance was visited by woodcocks more frequently, and this correlation was similarly observed at the intra‐field level. Our results demonstrate that woodcocks select foraging sites with higher earthworm densities at multiple spatial scales, both between fields (coarse scale), and within fields (fine‐scale). Considering that woodcocks tended to return to the same field to forage at night, the strong associations between occupancy and resources provide a basis for developing habitat management strategies at the field level for conservation. As earthworm densities and soil parameters are good indicators of woodcock foraging habitat, measuring those variables, at least at a coarse scale, could aid in predicting important habitats for the species across the landscape. [ABSTRACT FROM AUTHOR]

Leading collective movements and arriving first at feeding sites may improve food acquisition. Specifically, the first individual to discover and exploit a feeding site may gain a feeding advantage known as the "finder's advantage." The aim of this research was to verify if the probability of leading group movements to feeding sites in mantled howler monkeys (Alouatta palliata) varied by sex and reproductive status, and whether finders had higher foraging success than followers. We studied 18 adult individuals from two groups in La Flor de Catemaco over a year (978 h), and sampled group movements (n = 211) and foraging behavior (n = 215 feeding episodes). Gestating females were leaders and finders of group movements to feeding sites more often than expected but were also replaced in the leading position more frequently than individuals of other sex/reproductive states. Feeding behavior was not influenced by the order of arrival at feeding sites per se, but gestating females had higher food intake rate, bite rate, and feeding time when arriving earlier (i.e., occupying front group positions) than later. Therefore, leadership and the finder's advantage occur in this species and are probably employed by gestating females to maintain their energetic condition. Highlights: Gestating mantled howler monkeys are more likely than expected to lead their groups to feeding sites and find food resources than individuals of other sex/reproductive states.Gestating females have increasing food intake rate, bite rate, and feeding time when arriving early at feeding sites.Leadership during group movements toward feeding sites and the "finder's advantage" are probably used by females to offset the costs of reproduction. [ABSTRACT FROM AUTHOR]

Nectar, an important reward in plant-pollinator interactions, mainly provides sugars, but also other nutrients. Nectar sugar content is known to affect pollinator preferences, while the effect of other nectar nutrients on flower visitor choices is less well understood. To explore whether nectar nutrients affect the foraging preferences of the stingless bee Trigona fulviventris, we conducted feeding choice experiments with sucrose solution enriched with either an amino acid mixture (in high and low concentrations), sodium chloride (table salt), a fatty acid mixture, or quinine (a bitter tasting substance used as negative control) against pure sucrose solution in a lowland rainforest in Costa Rica. Bees were first trained to feeders presenting either a yellow (only sucrose solution) or a blue (sucrose solution plus tested substance) visual cue that the bees could use to associate with the solution content. They were subsequently offered a choice between the blue and yellow feeders in an unrewarded test. The bees preferred pure sucrose solutions over sucrose solutions with quinine, amino acids, or fatty acids, but not over solutions with salt. Our findings indicate that T. fulviventris is able to differentiate various nutrients in nectar and prefers pure sucrose solution or sucrose solutions with salt. Sugar and salt may therefore represent important nutrients in nectar and are likely key cues to assess nectar quality in tropical stingless bees. In contrast, other nutrients appear to compromise the bees' taste for nectar and are likely obtained from other sources. [ABSTRACT FROM AUTHOR]

Using the frameworks of creativity as problem solving and Integrated Constraints in Creativity (IConIC), this article develops the proposal that creativity is best understood in terms of a cycle of constraint exploration and exploitation. This general thesis, which applies to varied domains and levels of creativity, is supported by three specific proposals about the role of constraints in creativity, each of which is developed and illustrated with examples. First, constraints provide the criteria for the evaluation of creative outcomes, which can vary as a function of the emphasis on novel usefulness or useful novelty. Second, constraints are critical in each step of the creative process: problem finding, problem construction, and problem solving. Third, constraints play a key role in both open-ended and closed-ended creative problems. These arguments are supported by specific predictions, concerning: (a) task differences in whether novelty or usefulness are emphasized more; (b) individual differences in the processing of constraints (some may favor flexible constraint exploration, while others may favor persistent constraint exploitation), which I hypothesize also correlate with (c) engagement in different types of creative problem-solving (more open-ended, of the sort encountered in art, vs. more closed-ended, of the sort encountered in science, business, and engineering). [ABSTRACT FROM AUTHOR]