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Bumble bees (Bombus spp.) are important pollinators of both crops and wildflowers. Their contribution to this essential ecosystem service has been threatened over recent decades by changes in land use, which have led to declines in their populations. In order to design effective conservation measures, it is important to understand the effects of variation in landscape composition and structure on the foraging activities of worker bumble bees. This is because the viability of individual colonies is likely to be affected by the trade‐off between the energetic costs of foraging over greater distances and the potential gains from access to additional resources. We used field surveys, molecular genetics, and fine resolution remote sensing to estimate the locations of wild bumble bee nests and to infer foraging distances across a 20‐km² agricultural landscape in southern England, UK. We investigated five species, including the rare B. ruderatus and ecologically similar but widespread B. hortorum. We compared worker foraging distances between species and examined how variation in landscape composition and structure affected foraging distances at the colony level. Mean worker foraging distances differed significantly between species. Bombus terrestris, B. lapidarius, and B. ruderatus exhibited significantly greater mean foraging distances (551, 536, and 501 m, respectively) than B. hortorum and B. pascuorum (336 and 272 m, respectively). There was wide variation in worker foraging distances between colonies of the same species, which was in turn strongly influenced by the amount and spatial configuration of available foraging habitats. Shorter foraging distances were found for colonies where the local landscape had high coverage and low fragmentation of seminatural vegetation, including managed agri‐environmental field margins. The strength of relationships between different landscape variables and foraging distance varied between species, for example the strongest relationship for B. ruderatus being with floral cover of preferred forage plants. Our findings suggest that management of landscape composition and configuration has the potential to reduce foraging distances across a range of bumble bee species. There is thus potential for improvements in the design and implementation of landscape management options, such as agri‐environment schemes, aimed at providing foraging habitat for bumble bees and enhancing crop pollination services.

Seabird populations have declined worldwide, and several of the potential threats are of anthropogenic origin. To understand how changes in seabird populations relate to environmental conditions it is important to know the functional relationships between prey availability and foraging behaviour, prey choice and breeding performance over several years. This was studied by linking breeding success of European shag Phalacrocorax aristotelis to variation in diet composition, and investigating the underlaying mechanism driving this variation, primarily based on behavioural costs associated with foraging, such as foraging range and diving effort. We obtained demographic data and foraging trip metrics (using GPS-loggers and time–depth recorders) from a shag colony at Sklinna, Central Norway, during the 2011–2016 breeding seasons. Breeding population size was closely and positively correlated with breeding success, which in turn was positively correlated with the proportion of saithe Pollachius virens in the diet. When the dietary proportion of uncommon prey species increased, breeding success decreased. Breeding success was negatively influenced by increasing distance travelled and accumulated dive depths on an annual basis. Summed dive depths were greatest when prey species other than saithe dominated the diet. We found that in years with low availability of saithe fewer shags bred, and those that did had lower breeding success. This indicates that in years with poor feeding conditions, there might not be sufficient resources in the foraging area to support the whole breeding population of shags.

Efficient communication is highly important for the evolutionary success of social animals. Honeybees (genus Apis ) are unique in that they communicate the spatial information of resources using a symbolic ‘language’, the waggle dance. Different honeybee species differ in foraging ecology but it remains unknown whether this shaped variation in the dance. We studied distance dialects—interspecific differences in how waggle duration relates to flight distance—and tested the hypothesis that these evolved to maximize communication precision over the bees' foraging ranges. We performed feeder experiments with Apis cerana , A. florea and A. dorsata in India and found that A. cerana had the steepest dialect, i.e. a rapid increase in waggle duration with increasing feeder distance, A. florea had an intermediate, and A. dorsata had the lowest dialect. By decoding dances for natural food sites, we inferred that the foraging range was smallest in A. cerana , intermediate in A. florea and largest in A. dorsata . The inverse correlation between foraging range and dialect was corroborated when comparing six (sub)species across the geographical range of the genus including previously published data. We conclude that dance dialects constitute adaptations resulting from a trade-off between the spatial range and the spatial accuracy of communication.

1. Foraging range is a key aspect of the ecology of 'central place foragers'. Estimating how far bees fly under different circumstances is essential for predicting colony success, and for estimating bee-mediated gene flow between plant populations. It is likely to be strongly influenced by forage distribution, something that is hard to quantify in all but the simplest landscapes; and theories of foraging distance tend to assume a homogeneous forage distribution. 2. We quantified the distribution of bumblebee Bombus terrestris L. foragers away from experimentally positioned colonies, in an agricultural landscape, using two methods. We mass-marked foragers as they left the colony, and analysed pollen from foragers returning to the colonies. The data were set within the context of the 'forage landscape': a map of the spatial distribution of forage as determined from remote-sensed data. To our knowledge, this is the first time that empirical data on foraging distances and forage availability, at this resolution and scale, have been collected and combined for bumblebees. 3. The bees foraged at least 1·5 km from their colonies, and the proportion of foragers flying to one field declined, approximately linearly, with radial distance. In this landscape there was great variation in forage availability within 500 m of colonies but little variation beyond 1 km, regardless of colony location. 4. The scale of B. terrestris foraging was large enough to buffer against effects of forage patch and flowering crop heterogeneity, but bee species with shorter foraging ranges may experience highly variable colony success according to location.

Recent reports of global declines in pollinator species imply an urgent need to assess the abundance of native pollinators and density-dependent benefits for linked plants. In this study, we investigated (1) pollinator nest distributions and estimated colony abundances, (2) the relationship between abundances of foraging workers and the number of nests they represent, (3) pollinator foraging ranges, and (4) the relationship between pollinator abundance and plant reproduction. We examined these questions in an alpine ecosystem in the Colorado Rocky Mountains, focusing on four alpine bumble bee species ( Bombus balteatus , B. flavifrons , B. bifarius , and B. sylvicola ), and two host plants that differ in their degrees of pollinator specialization ( Trifolium dasyphyllum and T. parryi ). Using microsatellites, we found that estimated colony abundances among Bombus species ranged from ~18 to 78 colonies/0.01 km 2 . The long-tongued species B. balteatus was most common, especially high above treeline, but the subalpine species B. bifarius was unexpectedly abundant for this elevation range. Nests detected among sampled foragers of each species were correlated with the number of foragers caught. Foraging ranges were smaller than expected for all Bombus species, ranging from 25 to 110 m. Fruit set for the specialized plant, Trifolium parryi , was positively related to the abundance of its Bombus pollinator. In contrast, fruit set for the generalized plant, T. dasyphyllum , was related to abundance of all Bombus species. Because forager abundance was related to nest abundance of each Bombus species and was an equally effective predictor of plant fecundity, forager inventories are probably suitable for assessing the health of outcrossing plant populations. However, nest abundance, rather than forager abundance, better reflects demographic and genetic health in populations of eusocial pollinators such as bumble bees. Development of models incorporating the parameters we have measured here (nest abundance, forager abundance, and foraging distance) could increase the usefulness of foraging worker inventories in monitoring, managing, and conserving pollinator populations.

Foraging range, an important component of bee ecology, is of considerable interest for insect-pollinated plants because it determines the potential for outcrossing among individuals. However, long-distance pollen flow is difficult to assess, especially when the plant also relies on self-pollination. Pollen movement can be estimated indirectly through population genetic data, but complementary data on pollinator flight distances is necessary to validate such estimates. By using radio-tracking of cowpea pollinator return flights, we found that carpenter bees visiting cowpea flowers can forage up to 6 km from their nest. Foraging distances were found to be shorter than the maximum flight range, especially under adverse weather conditions or poor reward levels. From complete flight records in which bees visited wild and domesticated populations, we conclude that bees can mediate gene flow and, in some instances, allow transgene (genetically engineered material) escape over several kilometers. However, most between-flower flights occur within plant patches, while very few occur between plant patches.

Wild pollinators have been shown to enhance the pollination of Brassica napus (oilseed rape) and thus increase its market value. Several studies have previously shown that pollination services are greater in crops adjoining forest patches or other seminatural habitats than in crops completely surrounded by other crops. In this study, we investigated the specific importance of forest edges in providing potential pollinators in B. napus fields in two areas in France. Bees were caught with yellow pan traps at increasing distances from both warm and cold forest edges into B. napus fields during the blooming period. A total of 4594 individual bees, representing six families and 83 taxa, were collected. We found that both bee abundance and taxa richness were negatively affected by the distance from forest edge. However, responses varied between bee groups and edge orientations. The ITD (Inter‐Tegular distance) of the species, a good proxy for bee foraging range, seems to limit how far the bees can travel from the forest edge. We found a greater abundance of cuckoo bees (Nomada spp.) of Andrena spp. and Andrena spp. males at forest edges, which we assume indicate suitable nesting sites, or at least mating sites, for some abundant Andrena species and their parasites (Fig. ). Synthesis and Applications. This study provides one of the first examples in temperate ecosystems of how forest edges may actually act as a reservoir of potential pollinators and directly benefit agricultural crops by providing nesting or mating sites for important early spring pollinators. Policy‐makers and land managers should take forest edges into account and encourage their protection in the agricultural matrix to promote wild bees and their pollination services. Left, a Nomada sp male; right, an Andrena sp male. Our study provides one of the first well‐documented examples in temperate ecosystems that forest edges, largely unrecognized source of pollinators to agriculture compared with other seminatural habitats, actually act as a reservoir of potential pollinators that benefit crops in providing nesting or mating sites for important early spring pollinators. Biologic and ecological traits were used to explain observed species distribution patterns in oilseed rape field.

An ultimate benefit of marine protected areas (MPAs) is to reverse trophic cascades caused by human-driven collapse of critical ecological interactions. Here we demonstrate that, despite a small scale (0.28 km²) and not being fully protected, an MPA with strict fishing management and habitat enhancement by artificial reefs (ARs) in southwest Japan can lead to well-established macroalgal communities on widespread sea urchin barrens through cascading effects of predator recovery. Areas with low urchin densities occurred in and around daytime lobster (Panulirus japonicus) shelters primarily formed by quarry-rock ARs inside the MPA. We confirmed in the laboratory that lobsters preyed on two dominant sea urchins (Echinometra sp. A and Heliocidaris crassispina), with size- and species-dependent predation. The area with few urchins extended farther (~65 m) from an AR with numerous lobsters than from a natural shelter (patch reef) with far fewer lobsters. Causation of this pattern was confirmed by a tethering experiment showing that predation on urchins was similarly high at and near lobster shelters but decreased at ~100 m from the AR to a similar level as at an unprotected site. Time-lapse photography revealed that predation on tethered urchins was due mostly to the largest size class of lobsters (>100 mm carapace length), which comprised only 7% of the population, highlighting the importance of large-sized lobsters in controlling urchin abundance in localized areas adjacent to urchin-dominated barrens. Despite an ongoing once-a-year fishing event permitted within the MPA, lobster populations were persistent, demonstrating that the cascading effect of the lobsters on urchins and ultimately macroalgae was robust to temporary reductions in predator population size. Erect macroalgal cover was not simply accounted for by snapshot urchin density or biomass, suggesting a hysteresis effect of the phase shifts between macroalgal dominance and urchin barren states.

A bee’s ability to return home, its homing ability, can be used as a proxy for the maximum foraging distance of that species. Body size is hypothesized to affect foraging distance with larger bees having larger foraging ranges. In this study, we estimated the maximum foraging distance of six different afrotropical stingless bee species ( Meliponula bocandei , Meliponula ferruginea , Meliponula togoensis , Meliponula beccarii , Plebeina armata and Hypotrigona gribodoi. ) in two different landscapes (urban and natural). We conducted translocation experiments in which marked bees were released at different distances. Time of return and number of bees that returned to the hive were recorded. Our findings showed that the maximum homing distance of the studied bees in an urban landscape ranged between 400 and 800 m, while in a natural landscape it ranged between 800 and 1800 m. The distance at which 50% of the released bees returned, was found to range between 200 and 400 m in an urban and 400–1200 m in a natural landscape. It is plausible that the shorter range in an urban landscape is caused by urban beekeepers feeding their bees close to the colonies, so the urban bees are less likely to forage at greater distances. In addition, artificial structures such as tall buildings, electrical posts, as well as busy traffic, could possibly interfere with the foraging behavior of bees in urban landscapes. The rate of return was higher for closer distances up to 400–600 m in urban and natural landscapes, respectively. Our study suggests that urban beekeepers could assist their bees by cultivating diverse flowering plants close to colonies.

The relationship between colony size and foraging distance was examined in extended foraging arenas with juvenile colonies of the Formosan subterranean termite, Coptotermes formosanus Shiraki. Our results showed that as long as royal pairs are present, larger colonies foraged at longer distances, and the oldest workers distributed farther away from the central nest. The results agree with the scaling model that predicts a large foraging range for animals of larger body size. An analysis of published data from population survey studies and field trials of bait toxicants showed that field colonies of the eastern subterranean termite, Reticulitermes flavipes (Kollar), follow the scaling model, while C. formosanus colonies were inconsistent with the model prediction. Reasons for the inconsistency with field data of C. formosanus are discussed.