Foraging behaviour Research Papers - Academia.edu (original) (raw)

2025, Proceedings of the Tenth International Conference on the Simulation and Synthesis of Living Systems

Escaping local optima and crossing fitness valleys to reach higher-fitness regions of a fitness landscape is a ubiquitous concept in much writing on evolutionary difficulty. The Baldwin effect, an interaction between non-heritable lifetime plasticity (eg learning) and evolution, has been shown to be able to guide evolutionary change and 'smooth out'abrupt fitness changes in fitness landscapes–thus enabling genetic evolution that would otherwise not occur. However, prior work has not provided a detailed study or analysis on the saddle ...

2025, Acta Oecologica

Mistletoes are hemiparasitic flowering plants that function as keystone resources in forests and woodlands of temperate regions, where a positive relationship between mistletoe density and avian species richness has been observed. Mistletoes have been less studied in tropical regions and the relationship between birds and mistletoes has seldom been explored in tropical agricultural systems. Therefore, we studied the presence of infected trees and infection prevalence (i.e., number of parasitized trees/total number of trees) by Psittacanthus (Loranthaceae) mistletoes in 23 hedgerows located in an agricultural landscape of central Mexico during the dry and rainy seasons, and investigated the relationship between bird species richness and abundance and the abundance of mistletoes. We found a mean of 74 mistletoe plants per 100-m transect of only one species, Psittacanthus calyculatus. Thirty-one percent of the trees surveyed were infected and tree species differed in infection prevalence, mesquite (Prosopis laevigata) being the most infected species with 86% of the surveyed trees infected. For both seasons, we found a positive and significant association between bird species richness and number of mistletoe plants. The same pattern was observed for total bird abundance. Many resident and Neotropical migratory birds were observed foraging on mistletoes. Our results show that mistletoes are important in promoting a higher bird species richness and abundance in tropical agricultural landscapes.

2025, Frontiers in Marine Science

The diving behavior of southern elephant seals, Mirounga leonina, is investigated through the analysis of time-depth dive profiles. The originality of this work is to consider dive profiles as continuous curves. For this purpose, a Functional Data Analysis (FDA) approach is proposed for the shape analysis of a collection of dive profiles. Complexity of dive shapes is characterized by a mixture of three main shape variations accounting for about 80% of the entire variability: U or V shape, vertical depth variability during the bottom time, and skewed left or right. Model-based clustering allows the identification of eight dive shape clusters in a quick and automated way. Connection between shape patterns and classical descriptors, as well as the number of prey capture events, is achieved, showing that the clusters are coherent to specific foraging behaviors previously identified in the literature labeled as drift, exploratory and active dives. Finally, FDA is compared to classical methods relying on the computation of discrete dive descriptors. Results show that taking the shape of the dive as a whole is more resilient to corrupted or incomplete sampled data. FDA is, therefore, an efficient tool adapted for processing and comparing dive data with different sampling frequencies and for improving the quality and the accuracy of transmitted data.

2025, Animal Behaviour

Closely related lacertid lizards (Eremias, Nucras) in the Kalahari desert differ in patterns of foraging behaviour. Some species are relatively sedentary ('sit-and-wait'), whereas others are more active ('widely-foraging') predators. We determined whether whole-animal locomotor capacities (cruising endurance on a treadmill, initial speed and maximum burst speed in a racetrack, and sprint endurance in a torus-shaped track) correlated with interspecific differences in foraging behaviour. Two of three widely-foraging species had greater cruising endurance, greater sprint endurance, but lower burst speed than did a sit-and-wait species. However, the two species that sprinted quickly also had limited endurance, and vice versa. Pre-feeding negatively influenced endurance but not sprint capacity. Theoretical models of foraging behaviour should recognize that ectotherms have limited endurance, that there can be a trade-off between s ~e e d and endurance, and that pre-feeding can reduce some aspects of locomotor capacity.

2025, International Review of Hydrobiology

In the eutrophic L. Hiidenvesi, the spring biomass maximum of cladoceran zooplankton is missing and the highest biomass takes place in July–August. The factors behind the delayed biomass peak were studied in four different basins of the lake with concomitant data on cladocerans assemblages, density of the predatory cladoceran Leptodora kindti and food composition of fish. In all the basins, the abundance of Leptodora peaked in June, being highest (up to 800 ind. m–3) in the two most shallow basins (max depth < 4 m). The duration of the high population density was short and in July‐August Leptodora density stayed below 200 ind. m–3, although the water temperature was still favourable. The collapse of the Leptodora population coincided with the change in the feeding habits of fish. In early summer, fish predation was targeted mainly on copepods and zoobenthos, while in high summer Leptodora was one of the main preys of perch, white bream and bleak. The biomass of herbivorous cladoc...

2025

feeding areas during times of peak whelping and nursing (April/May), or molting (May/June and sometimes through August), bearded seals would be forced to seek either sea-ice habitat over deeper waters (perhaps with poor access to food) or coastal regions in the vicinity of haul-out sites on shore (perhaps with increased risks of disturbance, predation, and competition). Both scenarios would require bearded seals to adapt to novel (i.e., suboptimal) conditions, and to exploit habitats to which they may not be well adapted, likely compromising their reproduction and survival rates. Research suggests that, during the time of whelping and nursing, bearded seals prefer areas where the percent concentration of sea ice is >25%. Lacking a more direct measure of the relationship between bearded seal vital rates and ice coverage, the BRT assumed that this preference relationship reflects the species requirements for sea-ice coverage and defined areas within the current core distribution of bearded seals where the ice projections were below 25% concentration, as inadequate for whelping and nursing. The BRT also assumed that ice coverage <15% would be insufficient for molting. In the Chukchi, Beaufort, East Siberian, Kara, Laptev, and Greenland Seas, as well as Baffin Bay and the Canadian Arctic Archipelago, little or no decline in ice extent is expected for the months of March -May during the remainder of the century; in most of these areas there will be a moderate decline of June ice cover and a substantial decline of July ice cover. More southerly waters, such as the Sea of Okhotsk, Bering Sea, Hudson Bay, and Barents Sea, are expected to have substantial reductions in average and minimum March -May ice extents by the middle or end of this century; June and July ice cover in these areas has historically been sparse and variable in June -July and will be even more so in the future. Although the distribution of bearded seal breeding and molting areas are not well documented, these more southerly parts of their range are likely to very important. Ocean acidification, a result of increased carbon dioxide in the atmosphere, may impact bearded seal survival and recruitment through disruption of trophic regimes that are dependent on calcifying organisms. The nature and timing of such impacts are extremely uncertain. Changes in bearded seal prey, anticipated in response to ocean warming and loss of sea ice, have the potential for negative impacts, but the possibilities are complex. Ecosystem responses may have very long lags as they propagate through trophic webs. Because of bearded seals' apparent dietary flexibility, this threat may be of less immediate concern than the threats from sea-ice degradation. Overutilization for commercial, subsistence, recreational, scientific, or educational purposes: Recreational, scientific, and educational utilization of bearded seals is currently at low levels and is not projected to increase to significant threat levels in the foreseeable future for any of the DPSs. Bearded seals' solitary nature has made them less suitable for commercial exploitation than many other seal species. Still, they may have been depleted by commercial harvests in some areas of the Sea of Okhotsk and the Bering, Barents, and White Seas during the mid-20 th century. There is currently no significant commercial harvest of bearded seals and significant harvests seem unlikely in the foreseeable future. Bearded seals have been a very important species for subsistence of indigenous people in the Arctic for thousands of years. The current subsistence harvest is substantial in some areas but there is little or no evidence that subsistence harvests have or are likely to pose serious risk to the species. xiii Diseases, parasites, and predation: A variety of diseases and parasites have been documented to occur in bearded seals. The seals have likely co-evolved with many of these and the observed prevalence is typical and similar to other species of seals. Abiotic and biotic changes to bearded seal habitat potentially could lead to exposure to new pathogens or new levels of virulence, but the BRT considered the potential threats to bearded seals as low. Polar bears are the primary predators of bearded seals, but other predators include brown bears, killer whales, sharks, and walruses. Predation under the future scenario of reduced sea ice is difficult to assess; polar bear predation may decrease, but predation by killer whales, sharks and walrus may increase. Harvests and incidental takes by fisheries and commercial activities are reasonably well regulated throughout the range of bearded seals. Currently, however, there are no effective mechanisms to regulate the global greenhouse gas emissions that are driving-via climate warming-destruction of ringed seal habitat. The BRT implicitly considered impacts of inadequate regulation of greenhouse gas emissions by way of the emissions scenarios used in forecast models; the scenarios were all "non mitigated", meaning that they assumed no globallysignificant framework for regulating or reducing emissions would be implemented. Other natural or human factors affecting the species' continued existence: Contaminants, oil and gas industry activities, fisheries, and shipping all have potential to impact bearded seal populations. Compared to the far-reaching changes expected in sea ice and ocean conditions, the future changes and impacts from these other factors were judged by the BRT as likely to be more localized and less significant. The BRT reviewed published data and consulted with other experts to evaluate the specific threats to population persistence for the E. b. barbatus subspecies and the Beringia and Okhotsk DPSs of bearded seals. Threats were scored quantitatively and the level of certainty in scores was recorded. Risks posed by the inadequacy of existing regulatory mechanisms were not included as part of this scoring. The BRT also assessed the risks to population persistence posed by those threats in demographic terms (abundance, productivity, spatial structure, and diversity). The present population size is very uncertain, but was estimated to be about 188,000 individuals. Sea ice of sufficient concentration is expected to persist in the Canadian Arctic Archipelago and Baffin Bay through the end of the century. Throughout the rest of E. b. barbatus's range, however, the reduction in sea ice is expected to be more dramatic, particularly in the Barents Sea which will become ice free in June within the next few decades. The impacts of the loss of sea ice in the Barents Sea, and the reduction of sea ice in the Kara Sea, could theoretically be offset by the creation of more suitable sea ice habitat in the Laptev Sea which currently has high concentrations of ice and low numbers of bearded seals, though we are not aware of past examples in which similar mitigative shifts in habitat have occurred during rapid climatic changes.

2025, Deep Sea Research Part I: Oceanographic Research Papers

The deep-sea grenadier fishes (Coryphaenoides spp.) are among the dominant predators and scavengers in the ocean basins that cover much of Earth's surface. Baited camera experiments were used to study the behaviour of these fishes. Despite the apparent advantages of rapidly consuming food, grenadiers attracted to bait spend a large proportion of their time in prolonged periods of non-feeding activity. Video analysis revealed that fish often adopted a head-down swimming attitude (mean of 21.3 o between the fish and seafloor), with swimming velocity negatively related to attitude. The fish also swam around and along vertical and horizontal structures of the lander with their head immediately adjacent to the structure. We initially hypothesised that this behaviour was associated with the use of the short chin barbel in foraging. Barbel histology showed numerous taste buds in the skin, and a barbel nerve with about 20,000 axons in adult fish. A tracing experiment in one undamaged animal revealed the termination fields of the barbel neurons in the trigeminal and rhombencephalic regions, indicating both a mechanoreceptory and a gustatory role for the barbel. Our conclusion was that olfactory foraging becomes ineffective at close ranges and is followed by a search phase using tactile and gustatory sensing by the barbel. The development of this sensory method probably co-evolved alongside behavioural changes in swimming mechanics to allow postural stability at low swimming speeds.

2025, Emu - Austral Ornithology

Eutrophication increases the biomass of opportunistic green macroalgae that covers intertidal zones, and macroalgal blooms may affect the intertidal invertebrate community and predation of invertebrates by shorebirds. In San Antonio Bay, Argentina, eutrophication from the discharge of wastewater from a coastal town produces periodic macroalgal blooms. Our aim was to assess if macroalgal blooms affect the foraging behaviour and diet of the American Oystercatcher (Haematopus palliatus). A macroalgal transplant experiment was performed in order to evaluate how epifaunal species respond to a macroalgal canopy. The availability of prey for Oystercatchers, and their foraging behaviour and diet, were analysed in two paired channels with different nutrient loadings. Oystercatchers generally ate the most profitable prey and avoided prey with a profitability value lower than the mean rate of energy intake. During the macroalgal blooms, Oystercatchers avoided two prey species with high profitability values, shifting their foraging strategy and feeding onto a suboptimal prey but with a high encounter rate. Our results suggest that nutrient loadings and the macroalgal blooms that they generate have effects on the diet and foraging behaviour of Oystercatchers, which results in an increase of the average rate of energy intake of Oystercatchers foraging along the channel subject to a macroalgal bloom.

2025, Marine Ecology Progress Series

We integrated information from satellite transmitters, GPS loggers and wet/dry activity loggers to compare the at-sea behaviour of 4 sympatric albatross species by night and day: wandering Diomedea exulans, grey-headed Thalassarche chrysostoma, black-browed T. melanophrys and light-mantled sooty Phoebetria palpebrata (in total, 350 foraging trips by 101 individuals). Trip duration, distance and maximum range varied more within species between stages (incubation, broodguard and post-brood) than between species at the same stage, implying that reproductive constraints are more important than interspecific competition in shaping foraging behaviour. Wandering albatrosses spent more time on the water in fewer, longer bouts than other species. The proportion of time spent on the water was similar among the 3 smaller species. The partitioning of foraging activity between day and night varied little between species: all landed and took off more often, but spent less time overall on the water during the day than at night. This supports observations that albatrosses forage most actively during daylight, even though many of their fish and squid prey approach the surface only at night. Albatrosses were more active on bright moonlit nights, seem to have no fixed daily requirement for sleep, rest or digestion time on the water, can navigate in darkness, and are probably unhindered by the slight reduction in mean wind strength at night. They are probably less active at night because their ability to see and capture prey from the air is reduced and it is then more energy-efficient for them to rest or to catch prey using a 'sit-and-wait' foraging strategy.

2025

There is a unique diversity and density of land-based marine predators breeding at Bird Island, South Georgia, operating at a wide variety of spatial and temporal scales. These provide exceptional opportunities for bio-logging studies, the objectives of which have been to investigate trophic interactions in ecosystem contexts (including applications in fish- eries and environmental management and conservation). Associated data from studies on feeding ecology, reproductive performance and population dynamics provide valuable con- textual information for bio-logging analyses. An associated ship-based offshore marine sci- ence programme also provides vital information about the local and regional biological and physical environment, which is both complex and highly variable. Further developments of our bio-logging studies at South Georgia face a number of important challenges. These include: • acquiring samples large enough for statistical analysis; • replicating study sites and/or pop...

2025, Marine Ornithology

The third review of the status and trends of Antarctic and sub-Antarctic seabird populations compiled by the Bird Biology Subcommittee of the Scientific Committee on Antarctic Research at the request of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) is presented. There are suggestions of a population increase at Hope Bay (N.R. Coria unpubl. data) and decrease at Cuverville Island (K. Crosbie unpubl. data) but no reliable information on trends for any site or area. Few data exist for a species that is very difficult to count. Possible increases at Hope Bay and Nelson Island (N.R. Coria & M. Favero unpubl. data) and decreases at Cuverville Island (K. Crosbie unpubl. data).

2025, Journal of Asia-Pacific Entomology

Experience of host-associated olfactory stimuli during development affects subsequent foraging decisions in many parasitoids, leading to host fidelity. We have recently shown that odours emitted by an alien host-plant complex (HPC) may affect this learning process. However, the consequences of this olfactory experience on parasitoid host foraging decisions is unknown. Here, we investigated if olfactory preferences induced by experience might drive parasitoid HPC choice and oviposition decisions. We presented two HPCs in dual choice experiments to Aphidius ervi females that had been reared on each HPC, either in a simple (one HPC) or complex (two HPCs) olfactory environment. HPC choice, time before landing on a HPC and number of aphid attacks were recorded. Early experience had contrasting effects on each of these parameters. Regardless of their origin, parasitoids did not land preferentially on any HPC, but they more frequently attacked one of the two hosts (Acyrthosiphon pisum) once they had landed on its HPC. Females emerging from the A. pisum/faba bean HPC attacked more aphids, regardless of the host species. Finally, the olfactory complexity of the environment had inconsistent effects on foraging decisions. These observations, contrasting with previous results obtained in olfactometer assays, indicate that olfactory preferences induced in early stages are not sufficient to predict parasitoid oviposition decisions. Moreover, the integration of multiple signals at several scales might generate different foraging patterns at each step of the host selection process.

2025, Animal Behaviour

Generalist species usually have to deal with a larger variety of cues during habitat selection than do specialists, and thus, learning has been proposed as a highly profitable strategy to find the most suitable habitat. We analysed the effect of previous experience on the use of visual information by the wasp Diachasmimorpha longicaudata, a generalist fruit fly larval parasitoid, in the context of host habitat selection. These parasitoids search for hosts concealed in plant structures, so visual cues from the hosts' environment could play a key role in host finding. We also studied how different visual cues used by this species interact and affect the habitat choices of female wasps. We studied three forms of visual cues: colour, shape and size. All experiments were conducted under controlled laboratory conditions, using artificial models mimicking fruit. Na€ ıve females showed no preference pattern for colour or shape, but they showed a clear preference for larger models. These results were unaffected when females were previously exposed to host larvae (no sensitization effect). Associative learning was found for colour: tested females developed a clear pattern of preferences after they were exposed to larvae associated with a particular colour. We found that colour and size have a similar effect on the female's choice, and that this effect is neither additive nor multiplicative. Our findings emphasize the importance of both visual cues during host habitat searching by D. longicaudata and the influence of learning on the preference patterns of a generalist parasitoid.

2025, PLOS ONE

Temperature and individual egg size have been long studied in the development of fishes because of their direct effects on individual fitness. Here we studied the combined effects of three important factors for fish development, i.e. egg size, social environment and water temperature. Arctic charr (Salvelinus alpinus), a coldwater fish known to be phenotypically plastic, was used to investigate how these factors may affect growth and foraging behaviour of juvenile fish in a benign environment. We accounted for the social environment during early development by comparing fish raised in groups and in isolation. We examined the effect of egg size and a 2 ˚C difference on foraging behaviour, activity and growth a few weeks after first feeding. Growth trajectories of fish originating from large and small eggs were similar within each temperature: larger fish coming large eggs were at all time larger than smaller fish. There was no indication that small fish raised at a higher temperature grew faster than larger fish raised at a lower temperature. A 2 ˚C difference in temperature affected the behaviour of fish differently according to body size and/or social context. The foraging probability difference between fish raised in groups and fish briefly isolated was higher at 4.5 ˚C than at 6.5 ˚C for both size fish. Finally, there was no repeatability in foraging behaviour and mobility for isolated individuals. These results highlight the importance of small changes in temperature when evaluating growth and behaviour of fishes, and reveal the importance of considering the interaction of temperature with other factors, e.g. individual size and social environment, especially at early stages of development in fishes. We discuss these findings in the context of rapid changes in temperature and how temperature and its interaction with other factors may affect the phenotypes, ecology and evolution of coldwater fishes.

2025, Journal of Ethology

We investigated how free-ranging mares of two species of equids (donkeys and Shetland ponies) modify their foraging behaviour to meet the increased nutritional requirements induced by lactation. We initially hypothesised that lactating mares would graze for a longer time and/ or graze faster than non-lactating (dry) mares. The grazing behaviour of free-ranging animals, foraging in two lowproductive dune areas, was recorded during 1 year. Results show that in both species lactating animals did not spend more time grazing than non-lactating mares. However, lactating animals took more bites, and therefore achieved a higher bite rate than dry mares. Several factors affected the differences between lactating and non-lactating animals. Lactating mares took more bites only in grassy and rough vegetations and they did this only in patches with a short sward height. In addition, lactating mares took more bites of grasses only and not of forbs or woody plants. We conclude that the extra grazing effort of the lactating animals was not distributed randomly. Lactating mares invested their extra grazing effort principally towards those items that are the most grazed by the equids in general. We propose some hypotheses to explain why lactating mares increase their bite rate instead of augmenting the time spent grazing.

2025

Worldwide. populations ofwild cats have been reduced and fragmented by exploitation and contemporary land uses. Although many ofthese populations are now protected from legal exploitation. they continue to decline as human-related factors (e.g.. habitat degradation. poaching. and vehicle coIlisions) and stochastic events limit survival and reproduction. Local efforts to protect endangered populations of felids willlikely fail because of the area requirements of these wide-ranging carnivores. Previous research has demonstrated the imponance of rnaintaining demographic connections (via habitat corridors) to ensure long-term viability ofthese populations. However. such management efforts may require decades to implement and small populations may perish before such effons are completed. action.

2025, Animal Behaviour

I examined the potential genetic and environmental determinants of population differences in the foraging behaviour of the colonial spider Parawixia bistriata by using reciprocal transplant and prey manipulation experiments. The population differences noted from a previous study are primarily associated with the degree to which this spider captures prey as a group: P. bistriata show a higher frequency of group capture of prey in dry habitats with lower prey levels than in wet habitats where prey levels are higher. I recorded data on the tendency to capture and feed in groups and the number of individuals feeding on that prey. The transplant experiments revealed population differences in the tendency to capture prey as a group. Individuals from dry habitat showed a greater tendency to participate in group capture and feeding of prey in their native habitat than did individuals from wet habitat or than individuals that were transplanted to dry and wet habitats. In addition, the size of capture and feeding groups showed a significant habitat effect. Individuals from wet habitat did not differ in their tendency to attack prey when transplanted to dry habitat, suggesting that P. bistriata from wet habitat represents an ecotype that lacks behavioural plasticity. In contrast, individuals from dry habitat showed a plastic response. Potential causes of the behavioural plasticity shown by spiders from dry habitat are discussed. Group-foraging behaviour can have a significant effect on the fitness of these spiders, as suggested by their success under low prey conditions.

2025, Animal Behaviour

2025, Evolutionary Ecology Research

Problem: Infer relative danger from spatially segregated predators in large-scale marine systems, using individual differences in prey foraging behaviour. Mathematical models: Optimization of trade-offs between predation risk and energy gain. Key assumption: Foraging individuals choosing to incur higher risk of predation should experience higher energetic gain than individuals choosing safer foraging options. Organisms: Alaskan harbour seals foraging under predation risk from killer whales and Pacific sleeper sharks in shallow and deep strata, respectively. Sleeper sharks are elusive predators and their interactions with prey are difficult to measure directly. Method: Our method infers the relative danger from different predator types that is theoretically most plausible according to intermediate consumer behaviour. We predicted net energy gain and predation risk per foraging dive, parameterizing an analytical model with data on seal behaviour and the spatial distributions of predators and resources. We used assumptions about relative danger from different predator types as treatments in a computer experiment. We sought the treatment combination best supporting the assumption that individuals that risk more should gain more by plotting the individual seals' predicted cumulative energy gain against cumulative predation risk. Improved statistical fit for a positive and monotonic relationship implied greater support. Conclusions: Our key assumption was best supported when assuming that relative danger from sleeper sharks is much greater than that from killer whales, suggesting that sub-lethal effects of sharks on Alaskan harbour seals might be much stronger than previously thought.

2025

2025, Journal of Asia-Pacific Entomology

Foraging behaviour of four honeybee species (Apis mellifera A. cerana, A. dorsata and A. jlorea) was studied in relation to energy production rates of Prunus persica and a simultaneously blooming weed, Lepidagathus incurva. Energy produced ranged from a minimum of O.642±O.Ol joules (L. incurva)/flowerl day to a maximum of 1.49±O.14 joules/day (P. persica). The weed having higher nectar sugar concentration and high flowering density attracted more number of bees as compared to peach. The foraging rates of bees were much higher on the weed and they could harvest more energy per unit time from the weed flowers. Evidently, food acquisition efficiency and quality of food determines the foraging decision of bees.

2025, Acta Oecologica

Many species of waders forage extensively at night, but there is very little information on the relevance of this behaviour for the energy budget of waders wintering in estuarine wetlands. Quantitative data on diurnal and nocturnal intake rates can indicate the extent to which birds need to forage at night to supplement their diurnal energetic intake, or rather show a preference for nocturnal foraging. We compared day and night foraging behaviour, diet, and energy consumption of several wader species in the Tejo estuary, Portugal. There were significant differences between diurnal and nocturnal foraging behaviour. In general, birds moved less at night and scolopacid waders tended to use more tactile foraging methods. Although birds consumed the same type of prey in the two periods, the relative importance of each type changed. Overall, energy consumption was higher during the day except in grey plover, which achieved higher crude intake rates at night. Our results support the assertion that night foraging is an important part of the energy balance of waders during late winter, but that in most species it is less profitable than diurnal foraging.

2025, Basic and Applied Ecology

Shrublands are important habitats for grazing ruminants in the Mediterranean area. Kermes oak (Quercus coccifera L.) is considered one of the main woody species of agricultural importance in Greek shrublands. Classifications based on leaf morphology and grazing value identified five (I to V) rangeland types of kermes oak. Previously, based on observational studies, it was suggested that small ruminants would almost completely avoid grazing type V kermes oak (greater physical defences, spines) whenever coexisting with type II. Current shrubland management is based on these observational findings; however, other factors such as the nutrient and chemical content of the kermes oak types are likely to affect the diet selection of herbivores. Here we present two indoor controlled choice experiments that aimed to quantify the nutritional value and the chemical and physical defence properties of II and V kermes oak rangeland types and their effects on the diet selection of small ruminants. The nutritional value of both kermes oak types was similar. Any preference for a particular type of kermes oak by ruminants was likely to be based on plant defences (leaf spines and/or chemical defences). Both old and new growth of type V kermes oak was significantly avoided by goats in its natural form (i.e. presence of both chemical and physical defences) when presented as a choice with type II. Type V kermes oak was selected at an average level of 37% in its natural form. Old growth of type V kermes oak was significantly avoided by goats in its ground form when presented with type II but new growth of type V was not with goats selecting both types II and V to a similar extent. The diet selection results are discussed in relation to the effectiveness of physical and chemical plant defences and current shrubland management practices in Greece. Buschländer sind wichtige Habitate für grasende Wiederkäuer im mediteranen Gebiet. Die Kermes-Eiche (Quercus coccifera L.) ist in griechischen Buschländern eine der holzigen Hauptarten mit landwirtschaftlicher Bedeutung. Klassifikationen auf Basis der Blattmorphologie und des Beweidungswerts kennzeichnen fünf (I bis V) Weidelandtypen von Kermes-Eiche. Auf Basis beobachtender Untersuchungen wurde bisher angenommen, dass kleine Wiederkäuer den Weidelandtyp V Kermes-Eiche (größere physikalische Abwehr, Dornen) fast gänzlich meiden, wo immer er mit dem Typ II koexistiert. Das heutige Buschland-Management basiert auf diesen Beobachtungsergebnissen. Jedoch beeinflussen andere Faktoren wie der Nährstoff-und chemische Gehalt der Kermes-Eichen-Typen wahrscheinlich die Nahrungswahl der Herbivoren. Hier präsentieren wir zwei kontrollierte Laborexperimente, die darauf zielen, den Nährwert und die physikalischen und chemischen Abwehreigenschaften der Kermes-Eichen-Weidelandtypen II und V und ihre Wirkung auf die

2025, The Condor

The Pelagic Cormorant {Phalacrocorax pelagicus) is the most widespread cormorant in the North Pacific, but little is known about its foraging and diving behavior. However, knowledge of seabirds' foraging behavior is important to understanding their function in the marine environment. In 2006, using GPS dataloggers, we studied the foraging behavior of 14 male Pelagic Cormorants rearing chicks on Middleton Island, Alaska. For foraging, the birds had high fidelity to a small area 8 km north ofthe colony. Within that area, the cormorants' diving activity was of two distinct kinds-near-surface dives (1-6 m) and benthic dives (28-33 m). Individuals were consistent in the depths of their dives, either mostly shallow or mostly deep. Few showed no depth preference. Dive duration, time at maximum depth, and pauses at the water surface between consecutive dives were shorter for shallow dives than for deep dives. The cormorants made dives of both types throughout the day, but the frequency of deep dives increased toward evening. Maximum foraging range was 9 km; maximum total distance traveled per trip was 43.4 km. Trip durations ranged from 0.3 to 7.7 hr. Maximum depth of a dive was 42.2 m, and duration of dives ranged from 4 to 120 sec. We found that Pelagic Cormorants at Middleton Island were faithful to one particular foraging area and individuals dived in distinct patterns. Distinct, specialized foraging behavior may be advantageous in reducing intra-and interspecific competition but may also render the species vulnerable to changing environmental conditions.

2025, Journal of Biology and Nature

Insect pollinators are critical to global agricultural productivity, with their ecosystem services directly influencing crop yield and quality. This review focuses on the role of insect pollinators in enhancing the yield and quality of Guizotia abyssinica, an important oilseed crop cultivated primarily in Africa and Asia. Niger, which relies heavily on cross-pollination, benefits immensely from the activities of honeybees, wild bees and other pollinators. Pollination by insects has been shown to increase seed set, oil content, and overall yield, making it a key factor in the crop's cultivation. However, challenges such as habitat loss, pesticide use, and climate change threaten pollinator populations, emphasizing the need for sustainable practices and conservation efforts. This review highlights the importance of integrating pollination management strategies into Niger farming systems, including the introduction of managed pollinators, habitat conservation, and farmer education. Addressing these challenges can not only improve Niger yields but also promote biodiversity and resilience in agricultural ecosystems.

2025, Marine Ecology Progress Series

Many pelagic seabirds are thought to regulate reproductive effort by adopting a dual foraging strategy, alternating or mixing short foraging trips over local shelf waters (maximising provisioning rates) with longer trips over distant oceanic water (allowing restoration of lost condition). Many species also respond to chick condition, decreasing food supply to over-fed, and sometimes increasing it to under-fed chicks. Analysis of tracking data from 4 albatross species breeding at South Georgia provided evidence that adults responded to prevailing environmental conditions, but did not provide evidence for a dual foraging strategy. Trip durations and maximum foraging ranges tended to follow a positively skewed, unimodal distribution, with the exception of the light-mantled albatross for which no significant modes were apparent. Individual distributions deviated from this, but none were strongly bimodal or showed regular alternation of trip lengths, trip distance or predominant bathymetric regime. There were significant relationships between meal mass and trip duration, time since the last feed and chick condition on return, reflecting responses to current rather than predicted chick needs. On average, adults returned with smaller meals after 1 to 2 d trips, but otherwise stayed away until a threshold payload was obtained; consequently, provisioning rate (g d -1 ) was much greater after shorter trips. Lack of dual foraging may reflect the diversity of foraging zones available in this highly productive region. By inference, this would mean that adoption of dual foraging elsewhere is a consequence of greater heterogeneity in resource availability in waters surrounding those colonies.

2025, Biologia

Food plant preferences of some Lepidoptera species associated with particular colour of the flowers were investigated. Based on 1,329 field observations of 43 Lepidoptera and 66 plant species, Lepidoptera showed a high tendency (G-test, G adj = 698.6, df = 6, P < 0.001) to use the yellow (29%) and pink (28%) coloured flowers for foraging. Compared to the other colours it was evident that plants with red flowers (2%) were not preferred. Moreover, the plants with red (H = 0.435) and yellow-white (H = 0.543) flowers were not visited by diverse Lepidoptera species. Although yellow and pink flowers were most frequently visited, the highest degrees of the Lepidoptera diversity values were associated with the plants having blue (H = 0.647) and purple (H = 0.634) flowers. Species of Nymphalidae were most numerous (14 spp.) in the study area and the members of this family were observed 430 times on 39 different plant species, but never on plants with red flowers. Pieris rapae was the most...

2025, Journal of entomology and zoology studies

During early spring, the hibernated queens were trapped from Papaver rhoea, Caryopteris bicolor, Delphinium ajacis, Adhatoda vasica, Brassica juncea and Lupinus mutabilis for initiating rearing of bumble bee, Bombus haemorrhoidalis Smith. Bumble bee colonies were reared under laboratory condition by maintaining 27±1°C temperature and 65-70 percent relative humidity and by continuously feeding the sucrose solution (50%) and fresh pollen pellets collected by honey bees. The average time for wax secretion was 9.33±1.45, 6.50±1.55 and 6.00±1.01 days during February, March and April, respectively whereas development time from egg to adult was ranged between 17 to 33 days. The developmental period of bumble bee colonies was found to be less in queens trapped during March and April.

2025, Journal of entomology and zoology studies

The Bombus haemorrhoidalis queens were collected while foraging on Adhatoda vasica, Brassica juncea, Hypericum oblongifolium, Papaver rhoeas, Scutellaria linearis, Cydonia oblonga and Antirrhinum majus from February to April. The laboratory reared bumble bee (Bombus haemorrhoidalis Smith) queens established in the field was introduced in flowering (at 5- 10% flowering) bell pepper crop and used for pollination in polyhouse. The number of bumble bees visiting bell pepper flowers were maximum (6.83 bumble bees/m2/5min) during 1600-1800h, whereas, minimum (2.00 bumble bees) during 1200-1400h. The maximum foraging rate (6.17 flowers/min) of B. haemorrhoidalis was during 0800-1000h, whereas, minimum (3.40 flowers) during 1200-1400h. The bumble bees spent maximum time on a single flower (6.90 sec/flower) during 0800-1000h, whereas, minimum time (4.47 sec) during 1200-1400h.

2025, International Journal of Current Microbiology and Applied Sciences

Foraging behavior of bumble bees and honey bees with respect to foraging activity, foraging rate, foraging speed, loose pollen grains and abundance were studied by utilization of bumble bees (B. haemorrhoidalis) and European honey bees for the pollination of kiwifruit cv. Allison under caged condition at kiwifruit orchard of Dr. YS Parmar University of Horticulture & Forestry, Nauni, Solan (HP) during 2017. The results revealed that high activity of bumble bees in cage with one colony and cage with two colonies were recorded during 1600-1800hr whereas activity of honey bees was maximum during 1200-1400hr. Bumble bees visited more number of flowers per minute than honey bees, however, honey bees took more time for completing a single foraging trip and spent significantly more time per flower than bumble bee. Peak abundance of bumble bees was recorded at 1600-1800hr and it was between 1200-1400hr for honey bees. Pollination index showed that B. haemorrhoidalis scored higher than A. mellifera. B. haemorrhoidalis carried more number of loose pollen grains adhered to its body as compared to A. mellifera. Number was almost double than that carried by A. mellifera. The present study suggests that bumble bee foragers preferred to visit kiwifruit bloom during morning and evening time than mid-day with more activity, foraging rate and foraging speed during these hours of the day while honey bees preferred mid-day hours with more activity, foraging rate and foraging speed to visit kiwifruit bloom.

2025, Journal of Biology and Nature

Niger plants are highly dependent on pollination, particularly by Apis spp., for increased seed yield and genetic diversity. Honey bees, being the most efficient pollinators of niger, exhibit distinct foraging behaviors influenced by multiple factors, including floral rewards, diurnal activity patterns, environmental conditions and competition with other pollinators. Their foraging activity is characterized by peak visitation rates during the morning hours, typically between 9:00 AM and 1:00 PM, when nectar secretion is at its maximum and weather conditions are optimal. Nectar and pollen collection are vital for both colony sustenance and crop pollination, with honey bees displaying remarkable flower constancy, a behavior that enhances pollination efficiency and crossfertilization. Studies indicate that open pollination by honey bees significantly improves seed set, oil content and germination rates, leading to a substantial increase in crop productivity compared with self-pollination. However, various factors such as pesticide use, habitat loss and climatic variations can negatively impact honey bee foraging activity, thereby affecting niger pollination and seed yield. Additionally, the strategic placement of beehives near niger fields can maximize pollination benefits while contributing to high-quality honey production, as niger nectar yields honey with a light color and distinct flavour. The intricate interaction between honey bees and niger highlights the importance of pollination services in agricultural ecosystems and underscores the need for research-driven conservation initiatives. Understanding honey bee foraging dynamics in niger fields is essential for developing sustainable agroecosystems that optimize both seed yield and pollinator health. This review comprehensively examines the foraging behavior of honey bees on G. abyssinica, emphasizing their ecological and economic significance, the factors influencing pollination efficiency and the critical role of pollinator conservation in ensuring sustainable crop production and biodiversity maintenance.

2025, Western North American Naturalist

2025

Foraging bumblebees focus mainly on one flower species (their 'major'), and occasionally visit other flowers ('minors') that are less rewarding. Minoring allows tracking of potential alternative resources that might become more profitable with time. This is expected to provide an adaptive benefit under unstable foraging conditions, but to reduce foraging efficiency when resources are steady. We tested how predictability of food sources affects minoring and foraging success, using Bombus terrestris workers that fed on sucrose solution in artificial flowers. Bees exposed to three colour-distinct flower types with fluctuating food rewards performed more minoring (visits to a fourth, nonrewarding flower type) than bees that encountered a stable reward schedule. This difference was mostly due to a higher frequency of flower type shifts in the fluctuating-reward treatment. Flowers of the highest-rewarding type were visited less frequently in the fluctuating-reward than in the stable-reward treatment. This suggests that the fluctuating-reward schedule limited the bees' ability to track the most profitable flower type. Intervals between successive visits were longer in the fluctuating-reward than in the stable-reward treatment, possibly because the fluctuating schedule required time-consuming neural processing. As expected, the number of minoring visits correlated negatively with the number of colour shifts and with foraging success in the stable-reward treatment. In the fluctuating-reward treatment, on the other hand, sucrose intake rates were independent of minoring and colour shift frequencies. We suggest that novelty seeking by foragers can evolve when food sources offer fluctuating rewards, which reduce foraging success but also the cost of exploring new resources.

2025, Canadian Journal of Forest Research

We examined the distribution and foraging behaviour of northern waterthrushes (Seiurus noveboracensis) in recently harvested and intact landscapes of Newfoundland. Data were collected along six 1-km segments of stream and adjoining upland habitat resulting in four treatments (harvested or intact, upland or stream) with three replicates each. Although known as a riparian specialist, we found waterthrush territories equally distributed across intact upland and riparian habitats. However, few waterthrushes occupied harvested uplands, while large numbers packed into riparian buffer strips adjacent to these 5- to 10-year-old postharvest clearcuts. Arthropod abundance and biomass were highly variable between years and across the four treatments, generating significant year × treatment interaction effects. Riparian habitat (in both intact and harvested areas) had consistently greater numbers of arthropod prey and more biomass than either upland habitat type. Northern waterthrushes foraging...

2025, seb-ecologia.org.br

2025, Canadian Journal of Zoology

Migrating Western Sandpipers, Calidris mauri (Cabanis, 1857), observed feeding at an intertidal stopover site on the Fraser River delta, British Columbia, shifted their foraging mode from surface-pecking to probing over a 3-week period in April and May. We tested possible mechanisms to account for the field observations. Using control and shorebird exclusion plots over a 3-month period bracketing the migration, we determined that neither seasonal nor shorebird-induced changes in the relative availability of epifaunal compared with infaunal prey accounted for the decline in the prevalence of epifaunal feeding behaviour. However, strong peaks in both epi- and in-faunal prey densities coincided with the migration period, suggesting that migratory timing may be linked with the productivity schedule of major stopover sites. Males, which precede females in the migration and have relatively shorter bills, were observed to engage in epifaunal feeding more frequently than females. Thus, whil...

2025

Résu m é : Lors de l'exploitation de sources sucrées de grande taille, M. sabuleti pratique une récolte collective basée sur l'utilisation d'un recrutem ent de m asse. Au niveau global, l'exploitation de deux sources de saccharose est, en général, de type asym étrique : l'activité de la colonie se concentre sur une des deux sources, l'autre étant sous-exploitée. Le com portem ent collectif de M. sabuleti présente néanm oins une certaine flexibilité : si une source 0,5M est découverte avant une source IM, les colonies restent prisonièrcs de leur premier choix; par contre, si une source 0,1M est découverte avant une source IM, les sociétés déplacent rapidem ent leur activité vers la source riche. L'interprétation de nos résultats fait appel à un modèle mathématique sim ple capable de simuler les situations de choix testées. Par ailleurs, nos résultats sont comparés à ceux obtenus sur deux autres espèces étudiées dans des conditions expérim entales comparables. Mots-clés : For micidae, My r mica sabuleti, r ec r utement alimentai r e, décisions collectives, modélisation mathématique. Summary : From food re cruitme nt to colle ctive décisions : tiie case of My r mica sabuleti. When exploiting large sugar sources, the colonies of M. sabuleti use mass recruitment. At the Society level, the exploitation of 2 sources of sucrose is generally asymmetrical : the activity of the colony concentrâtes on one source, the other being underexploited. Nevertheless, the collective behaviour of M. sabuleti shows a certain degree of flexibility : if a 0,5M source is discovered before a IM source, the colonies stay with their first choice. By contrast, if a 0,1M source is discovered before a IM source, the societies rapidly shift their activity towards the richer source. The interprétation of our results is based upon a sim ple m athem atical m odel which sim ulâtes the tested choice situations. In addition, our results are com pared to others obtained using two other species studied under comparable expérimental conditions.

2025

RESUME: Les ouvrières d e Leptothorax unifasciatus s'orientent principalement sur d es repères visuels (ampoule lumineuse) au cours d es activités d 'affouragement. Néanmoins, les ouvrières tracent également une piste chimique n'agissant pas comme système d e recrutement, mais comme repère d 'orientation ind ivid uel. Ces pistes ind ivid uelles sont reconnues même parmi plusieurs autres pistes. La stratégie ind ivid ualiste d es ouvrières utilisée par les sociétés d e L. unifasciatus d ans l'exploitation d u champ trophique est comparée aux systèmes d'organisation collective d éveloppés par d 'autres espèces (par ex. Irid omyrmex humilis). La sélection d e l'une ou l'autre d e ces stratégies est interprétée en fonction d e la taille d es sociétés et d e l'efficacité d e la technique d e recrutement pratiquée. Mots clés: Leptothorax, foraging, recrutement, mémoire, orientation. SUMMARY: Visual orientation and individual-specific trails of Leptothorax unifasc i atus: An example of an indlvidualistic strategy. Workers of Leptothorax unifasciatus orient principally on visual eues (60 watt light-bulb) when foraging. Nevertheless, thèse also lay down a trail, which d oes not recruits nestmates, but acts as an ind ivid ual spécifie orientation eue. Ind ivid ual trails are recognized even when several other trails are superimposed. The ind ivid ual strategy used by workers of L. unifasciatus societies when foraging is compare d to the collective organisation-Syste m s d evelope d by other species (e.g., Irid omyrmex humilis). Sélection of one of thèse stratégies is interpreted in relation to the colony size and the accuracy of the recruitment mechanism performed .

2025, Marine Biology

Southern elephant seals are important apex predators in a highly variable and unpredictable marine environment. In the presence of resource limitation, foraging behaviours evolve to reduce intraspecific competition increasing a species' overall probability of successful foraging. We examined the diet of 141 (aged 1-3 years) juvenile southern elephant seals to test the hypotheses that differences between ages, sexes and seasons in diet structure occur. We described prey species composition for common squid and fish species and the mean size of cephalopod prey items for these age groups. Three cephalopod species dominated the stomach samples, Alluroteuthis antarcticus, Histioteuthis eltaninae and Slosarczykovia circumantarcticus. We found age-related differences in both species composition and size of larger prey species that probably relate to ontogenetic changes in diving ability and haul-out behaviour and prey availability. These changes in foraging behaviour and diet are hypothesised to reduce intra-specific food competition concomitant with the increase in foraging niche of growing juveniles.

2025, Comparative Biochemistry and Physiology Part A: Physiology

Southern elephant seals spend two periods on land each year, during breeding and moult, exposed to intensive UV radiation. The time between periods on land are spent at sea, with little exposure to the sun. A study of serum 25-OH-4 and 1,25(OH),eD, on southern elephant seals was carried out at South Georgia. Samples were collected on four different occasions: early and late breeding, and early and late moult. The levels of 25OH-4 increased when seals were on land, and decreased when at sea. Two annual peaks of 25OH-D3 were found, both of which immediately followed periods of intensive exposure of UV radiation. 1,25(OH)z-D, levels showed a seasonal variation, but no significant changes while being on land were detected. The diving behaviour at sea for southern elephant seals and no detectable change in 25-OH-D3 indicates that the seals feed on prey containing vitamin D. COMP BlOCHEM PHYSIOL 114A;1:9-14, 1996.

2025, The Glasgow Naturalist

The nesting behaviour of the great tit (Parus major) from nest preparation to fledging was followed continuously by video-recording in two identical nest-boxes over two seasons during 2020 and 2021 in the same large rural garden. Unexpectedly, the production of a series of regurgitation pellets (RPs) by the nestlings was recorded during the 2020 season. No pellet regurgitation was recorded during the 2021 season. Recordings were also made of adult great tits producing small RPs as they roosted. I suggest that this unprecedented RP production by nestlings resulted from the consumption of suboptimal food items due to the poor breeding season of 2020.

2025

The grassland biome of the Free-State Province of South Africa meets all the suggested habitat requirements The results of this study suggest that in areas that experience hot or cold environments, some form of cover

2025, Pachyderm

The grassland biome of the Free-State province of South Africa meets all the suggested habitat requirements for the white rhino, but in contrast to warmer savannah areas experiences extremely cold winters. The aim of this study was to investigate the habitat utilization of white rhinos in the Free-State area. Five major plant community types were identified and data on movement and habitat utilization of white rhinos were collected over one year. Adult cows (n = 5) had a mean range size of 3.78 km² (SE ± 0.37) during the wet and 4.08 km² (SE ± 0.570) during the dry season, but no significant differences between the two seasons were found. The bull had a range size of 8.13 km² during the wet and 6.37 km² during the dry season. Based on availability, the expected utilization of each habitat type differed significantly from the observed usage during both the wet (i.e. χ² = 2,236.6; 6 df; p = 0.05) and dry season (χ² = 4,721.3; 6 df; p = 0.05). Wetland, Damkom, Savannah, and Grassveld h...

2025, Journal of Insect Behavior

Bumblebees and honeybees deposit short-lived scent marks on flowers that they visit when foraging. Conspecifics use these marks to distinguish those flowers that have recently been emptied and, so, avoid them. The aim of this study was to assess how widespread this behavior is. Evidence for direct detection of reward levels was found in two bee species: Agapostemon nasutus was able to detect directly pollen availability in flowers with exposed anthers, while Apis mellifera appeared to be able to detect nectar levels of tubular flowers. A third species, Trigona fulviventris, avoided flowers that had recently been visited by conspecifies, regardless of reward levels, probably by using scent marks. Three further bee/flower systems were examined in which there was no detectable discrimination among flowers. We argue that bees probably rely on direct detection of rewards where this is allowed by the structure of the flower and on scent marks when feeding on flowers where the rewards are hidden. However, discrimination does not always occur. We suggest that discrimination may not always make economic sense; when visiting flowers with a low handling time, or flowers that are scarce, it may be more efficient to visit every flower that is encountered.

2025, Marine Ecology Progress Series

Mle lnvestlgated the foraging behaviour of king pengulns In relation to sea-surface temperature distribution over 3 years near the Crozet Archipelago, South Indlan Ocean. Wlthln their range there are 2 hydrographlc frontaI systems, whose seasonal patterns of productivity are predictable. These are the Polar Front and the Sub-Antarctic Front. During the austral summer the foraging range of breeding king pengulns was restricted to the Polar Frontal Zone, limlted to the south by the Polar Front and to the north by the Sub-Antarctic Front. Most b ~r d s travelled towards the colder water situated south of Crozet, w h ~l e other birds moved east to warmer water Blrds travelling south spent more time than expected in the coldest waters generally associated with the Polar Front. Birds travelling east reached the southern limit of the Sub-Antarctic Front (sea-surface temperature between 8 and 10°C). Within the Polar Frontal Zone birds differed In their foraging behaviour, with incubating birds remaining at sea for longer times and covering longer distances. During the incubation period, king penguins travelling south tended to spend their time in areas with a sea-surface temperature between 4 and 5°C. which coincide with the location of the Polar Front. Though these birds remained a t sea longer, they did not go any further south than birds hilv~ng a n egg ready to hatch or than birds in the brooding period, which appeared to travel more directly towards the Polar Front. As the breeding season progressed, the Polar Front moved further south, out of the range of the king penguins espcc~ally those with a newly hatched c h ~c k that were limited in the amount of time that they could spend at sea. King penguins breeding a t Crozet may choose between 2 strategies, in w h ~c h some blrds forage towards the Sub-Antarctic Front but most travel south towards the Polar Front.