Extensive Foraging Research Articles

The effect of drainage on fine‐root biomass, production, and turnover in hemiboreal old‐growth forests on organic soils

AbstractInformation on the capacity of organic soils to capture and store carbon in old‐growth forests in the hemiboreal forest zone is scarce and fragmented. However, fine‐root data can provide valuable insights into soil carbon fluxes. Thus, the aim of the current study was to provide estimates of the fine‐root biomass (FRB), fine‐root production (FRP), and fine‐root turnover (FRT) rate by tree species and other functional groups in old‐growth (stand age 131–179 years) forests on mesotrophic organic soils dominated by Scots pine (Pinus sylvestris L.), with and without the effects of forest drainage. The sequential soil coring method was used to estimate the FRB and FRP. The total FRB was significantly higher in the undrained sites (6.8 ± 0.3 t ha−1) than in the drained sites (3.97 ± 0.1 t ha−1). The FRB of Scots pine in the undrained forest was significantly higher (1.7 ± 0.1 t ha−1) than in the drained forest (0.5 ± 0.1 t ha−1), supporting an extensive foraging strategy. The significantly higher mean FRB of Norway spruce (Picea abies [L.] Karst.) (1.4 ± 0.1 t ha−1) in the drained sites than the undrained sites (0.7 ± 0.2 t ha−1) can be explained by there being a higher proportion of spruce in the stand compositions, thus a higher standing volume of this species and an increased FRB. The FRB of dwarf shrubs (2.43 ± 0.2 t ha−1) formed the largest part of the total FRB in the undrained sites and the second largest (1.16 ± 0.1 t ha−1), following Norway spruce, in the drained sites. The total FRP was similar between the undrained (2.05 ± 0.31 t ha−1 year−1) and drained (1.82 ± 0.26 t ha−1 year−1) stands. However, considerable variability in the FRP was observed between different sites of the same forest site type. The FRT rate of Scots pine was twice as high in the drained sites than the undrained sites, suggesting faster nutrient and carbon input into the drained soil compared with the undrained soil. Estimates of FRB, FRP, and FRT rates for different functional groups can be used in carbon‐cycle modeling and in further calculations to estimate the carbon budget (balance) in forests on organic soils.

South American Dry Chaco rangelands: Positive effects of cattle trampling and transit on ecohydrological functioning.

Livestock production in drylands requires consideration of the ecological applications of ecohydrological redistribution of water. Intensive cattle trampling and the associated increase of surface runoff are common concerns for rangeland productivity and sustainability. Here, we highlight a regional livestock production system in which cattle trails and trampling surrounding an artificial impoundment are purposely managed to enhance redistribution and availability of water for cattle drinking. Based on literature synthesis and field measurements, we first describe cattle production systems and surface water redistribution in the Dry Chaco rangelands of South America, and then develop a conceptual framework to synthesize the ecohydrological impacts of livestock production on these ecosystems. Critical to this framework is the pioshere-a degraded overgrazed and overtrampled area where vegetation has difficulties growing, usually close to the water points. The Dry Chaco rangelands have three key distinctive characteristics associated with the flat sedimentary environment lacking fresh groundwater and the very extensive ranching conditions: (1) cattle drinking water is provided by artificial impoundments filled by runoff, (2) heavy trampling around the impoundment and its adjacent areas generates a piosphere that favors runoff toward the impoundment, and (3) the impoundment, piosphere, and extensive forage areas are hydrologically connected with a network of cattle trails. We propose an ecohydrological framework where cattle transit and trampling alter the natural water circulation of these ecosystems, affecting small fractions of the landscape through increased runoff (compaction in piosphere and trails), surface connectivity (convergence of trails to piosphere to impoundment), and ponding (compaction of the impoundment floor) that operate together making water harvesting and storage possible. These effects have likely generated a positive water feedback on the expansion of livestock in the region with a relatively low impact on forage production. We highlight the role of livestock transit as a geomorphological agent capable of reshaping the hydrology of flat sedimentary rangelands in ways that can be managed positively for sustainable ranching systems. We suggest that the Dry Chaco offers an alternative paradigm for rangelands in which cattle trampling may contribute to sustainable seminatural production systems with implications for other dry and flat rangelands of the world.

The Effect of Urea Level and Ripening Time on Nutrient Content on Ammoniation of Sugarcane Shoots Waste

Raising livestock on a large scale, especially ruminants, requires large amounts of green fodder, the availability of natural feed is not yet fully reliable, therefore breeders must provide extensive forage areas that require investment costs. the big one. To obtain nutritional value, as well as good crude fiber and easy to digest, it needs processing first. One of the effective animal feed processing methods which can increase the crude protein content, reduce the crude fiber content, increase the flavor and soften the structure of the feed ingredients so that it is preferred by livestock is the ammoniation method. The purpose of this study was to see the effect of ammonia on the nutritional content of feed waste, to increase the nutritional content of the waste, to find the best urea level, to obtain the best curing time for the ammoniation of sugarcane shoots on the ammonia content of sugarcane shoots waste. This study used a completely randomized design method, the factorial pattern consisted of 3 types of treatment with 3 replications with urea percentage A: 2%, B: 3%, C: 4%, with curing time of 7 days, 14 days and 21 days. Parameters measured, dry matter content, organic matter, crude protein content, crude fat (LK), crude fiber (SK). Keywords: Sugarcane Tops, Ammonia, Nutrient Content, Fiber Fraction.

Honeybees with extensive foraging experience rob nectar more frequently.

Not all flower-visiting animals act as pollinators; some visitors engage in foraging nectar without pollen transfer. The tendency to rob nectar is related to visitors' morphological traits and rewards per foraging effort, and drivers of this variation within visitor species are largely unknown. Because foraging behavior is affected by foraging experience, we focused on the relationship between the tendency to rob nectar and the foraging experience of each forager. We investigated five consecutive visits of European honeybee, Apis mellifera L., on comfrey, Symphytum officinale L., in Japan. We estimated the foraging experience of A. mellifera using wing wear, categorized into six groups. Approximately 60% and 40% of A. mellifera foragers engaged in legitimate visits and nectar robbing, respectively. Moreover, most A. mellifera engaged in only one foraging tactic. The proportion of nectar robbing was related to wing wear and was higher in individuals with extensively damaged wings than those with less damaged wings. The present study suggests that extensively experienced honeybee foragers tend towards nectar robbing.

Variation in fine root traits with thinning intensity in a Chinese fir plantation insights from branching order and functional groups

Thinning is a widely used practice in forest management, but the acclimation mechanisms of fine roots to forest thinning are still unclear. We examined the variations in fine root traits of different branching orders and functional groups along a thinning intensity gradient in a 26-year-old Chinese fir (Cunninghamia lanceolata) plantation. With increasing thinning intensity, the root C concentration (RCC), root N concentration (RNC), specific root area (SRA), and specific root length (SRL) of the absorptive roots (the first two orders) significantly decreased, while root abundance (root biomass and root length density) and root tissue density (RTD) significantly increased. Fifty-four percent of the variation in the absorptive root traits could be explained by the soil N concentration and the biomass and diversity of the understorey vegetation. Conversely, transport root (third- and higher-order) traits did not vary significantly among different thinning intensities. The covariation of absorptive root traits across thinning intensities regarding two dimensions was as follows: the first dimension (46% of the total variation) represented changes in root abundance and chemical traits (related to RCC, RNC), belonging to an extensive foraging strategy; the second dimension (41% of the total variation) represented variations in root morphological traits (related to RTD, SRL and SRA), which is an intensive foraging strategy (i.e., root economic spectrum). These results suggested that the absorptive roots of Chinese fir adopt two-dimensional strategies to acclimate to the altered surroundings after thinning.

TLMPA: Teaching-learning-based Marine Predators algorithm

<abstract> <p>Marine Predators algorithm (MPA) is a newly proposed nature-inspired metaheuristic algorithm. The main inspiration of this algorithm is based on the extensive foraging strategies of marine organisms, namely Lévy movement and Brownian movement, both of which are based on random strategies. In this paper, we combine the marine predator algorithm with Teaching-learning-based optimization algorithm, and propose a hybrid algorithm called Teaching-learning-based Marine Predator algorithm (TLMPA). Teaching-learning-based optimization (TLBO) algorithm consists of two phases: the teacher phase and the learner phase. Combining these two phases with the original MPA enables the predators to obtain prey information for foraging by learning from teachers and interactive learning, thus greatly increasing the encounter rate between predators and prey. In addition, effective mutation and crossover strategies were added to increase the diversity of predators and effectively avoid premature convergence. For performance evaluation TLMPA algorithm, it has been applied to IEEE CEC-2017 benchmark functions and four engineering design problems. The experimental results show that among the proposed TLMPA algorithm has the best comprehensive performance and has more outstanding performance than other the state-of-the-art metaheuristic algorithms in terms of the performance measures.</p> </abstract>

THE RELATIONSHIP BETWEEN FORAGING COMPLEXITY AND FORAGING PLASTICITY: IMPLICATIONS FOR THE CONSERVATION OF PEACH-FRONTED PARAKEETS

Reintroduction processes, whereby animals are reared in captivity and released into the wild, often fail. This failure is often attributed to the fact that released individuals not have the behavioral repertoire to cope with the wild. Compared to captive conditions, wild environments are highly complex, and therefore a released individual with greater behavioral complexity may survive better after release. Moreover, the wild presents both unpredictable features and regular changes, and thus plasticity of behavior may be crucial for survival. Considering the importance of foraging to fitness, foraging complexity and plasticity can be crucial to the success of reintroduction processes. We investigated captive individuals of Eupsittula aurea (Psittaciformes, Psittacidae) to evaluate if: a) food enrichment promotes foraging complexity; and b) there is a relationship between foraging complexity and plasticity. An animal that potentially has a good adjustment to wild environments would be one that has high foraging complexity and plasticity. We housed 40 parakeets under identical conditions that differed only in their diet. Twenty birds, in four replicated enclosures, were randomly allocated to the treatment diet which better replicated what would occur in the wild and consisted of multiple entire fruits, and food spatial randomization. The remaining 20 birds were placed into four control enclosures and received a diet that is currently provisioned for birds in captivity and consisted of small fruit cubes and sunflower seeds, offered on tray at a fixed location. Dietary enrichment does not affect bird foraging complexity. According to our expectations, foraging complexity influenced foraging plasticity for birds that were subject to the enriched environment. Therefore, more extensive foraging repertoires are related to a greater adjustment capacity in enriched environments, and complexity could be considered a good measure of adjustment to reintroduction success.

Additive effects of climate and fisheries drive ongoing declines in multiple albatross species

Environmental and anthropogenic factors often drive population declines in top predators, but how their influences may combine remains unclear. Albatrosses are particularly threatened. They breed in fast-changing environments, and their extensive foraging ranges expose them to incidental mortality (bycatch) in multiple fisheries. The albatross community at South Georgia includes globally important populations of three species that have declined by 40-60% over the last 35 years. We used three steps to deeply understand the drivers of such dramatic changes: (i) describe fundamental demographic rates using multievent models, (ii) determine demographic drivers of population growth using matrix models, and (iii) identify environmental and anthropogenic drivers using ANOVAs. Each species was affected by different processes and threats in their foraging areas during the breeding and nonbreeding seasons. There was evidence for two kinds of combined environmental and anthropogenic effects. The first was sequential; in wandering and black-browed albatrosses, high levels of bycatch have reduced juvenile and adult survival, then increased temperature, reduced sea-ice cover, and stronger winds are affecting the population recovery potential. The second was additive; in gray-headed albatrosses, not only did bycatch impact adult survival but also this impact was exacerbated by lower food availability in years following El Niño events. This emphasizes the need for much improved implementation of mitigation measures in fisheries and better enforcement of compliance. We hope our results not only help focus future management actions for these populations but also demonstrate the power of the modelling approach for assessing impacts of environmental and anthropogenic drivers in wild animal populations.

Effects of the European Union Agricultural and Environmental Policies in the Sustainability of Most Common Mediterranean Soils

Agro-environmental measures promoted by the European Union focus mainly on environmental protection by maintaining sustainable levels of productivity that are adequate to the agro-ecological conditions of each region on different Member States. Among these European Union promoted measures the one known as “Extensive Forage Systems” is particularly relevant for the Mediterranean Region. In order to analyze the impact of this measure and to verify if the high expenditure of communitarian funds, with its implementation in Mediterranean soils, is aligned with the predicted benefits, a seven-year study in a southern Portugal region was conducted. In this regard, several soil chemical parameters such as organic matter, pH, electrical conductivity, “available” phosphorus, “available” potassium and heavy metal levels (Cd, Cr, Cu, Zn, Mn, Pb and Ni), were assessed, in 1329 different plots in order to represent some of the existing diversity of the Mediterranean environment, identified by the Portuguese Parcel Identification System, and considering the possibility to evaluate the evolution of these parameters on the main soil types of the region. The obtained results enabled us to verify that the application of the agro-environmental measure “Extensive Forage Systems” did not lead, during the 7 years of the study, to any significant change in terms of organic matter, soil pH and/or heavy metals content. Still it contributed for a small growth on “available” phosphorus and potassium levels and to a significant increase on Soil electrical conductivity (EC). As a final conclusion we can refer that the application of the agro-environmental measure “Extensive Forage Systems”, in soil, clime and cultural conditions prevailing in this study (Typical Mediterranean conditions from the South of Europe), did not reach its main objective, which was to increase the organic matter content in soils.

Species-specific differences in the fine structure of learning walk elements in Cataglyphis ants.

Cataglyphis desert ants are famous navigators. Like all central place foragers, they are confronted with the challenge to return home, i.e. relocate an inconspicuous nest entrance in the ground, after their extensive foraging trips. When leaving the underground nest for the first time, desert ants perform a striking behavior, so-called learning walks that are well structured. However, it is still unclear how the ants initially acquire the information needed for sky- and landmark-based navigation, in particular how they calibrate their compass system at the beginning of their foraging careers. Using high-speed video analyses, we show that different Cataglyphis species include different types of characteristic turns in their learning walks. Pirouettes are full or partial rotations (tight turns about the vertical body axis) during which the ants frequently stop and gaze back in the direction of the nest entrance during the longest stopping phases. In contrast, voltes are small walked circles without directed stopping phases. Interestingly, only Cataglyphis ant species living in a cluttered, and therefore visually rich, environment (i.e. C. noda and C. aenescens in southern Greece) perform both voltes and pirouettes. They look back to the nest entrance during pirouettes, most probably to take snapshots of the surroundings. In contrast, C. fortis inhabiting featureless saltpans in Tunisia perform only voltes and do not stop during these turns to gaze back at the nest - even if a set of artificial landmarks surrounds the nest entrance.

Contrasting Daily and Seasonal Activity and Movement of Sympatric Elk and Cattle

Elk (Cervus elaphus L.) and cattle (Bos taurus L.) co-occur on rangelands throughout western North America. Literature regarding range relations between elk and cattle, however, is contradictory, describing interspecific competition in some cases and complementary or facilitative relations in others. A better understanding of how sympatric elk and cattle behave at fine spatiotemporal scales is needed to properly allocate resources for these species. We used intensively sampled Global Positioning System (GPS) tracking data (1-sec intervals) to classify elk and cattle behavior and investigate their activity and movement strategies in the Blue Mountains of northeastern Oregon, United States, during summer and fall 2007. An ensemble classification approach was used to identify stationary, foraging, and walking behavior classes within the GPS datasets of mature beef and captive elk cows grazing in forested pastures during two randomized experiments, one in summer and the other fall. During summer, elk traveled farther per day, had larger walking budgets, exhibited more and longer walking bouts, and had higher walking velocities than beef cows. Cattle tended to emphasize intensive foraging over extensive movement and thus displayed larger foraging budgets and longer foraging bouts than elk. Site-by-species interactions, however, were detected for some foraging responses. During fall, when forage quality was limiting, elk exhibited a more foraging-centric mobility strategy while cattle emphasized an energy conservation strategy. These differing movement and energetic strategies tended to support the concept that elk and cattle occupy differing behavioral niches. Extensive foraging by elk and intensive foraging by cattle during summer correspond well with behaviors expected for elk searching out forbs in graminoid-dominated habitats and cattle foraging intensively on graminoids. Behaviors exhibited in the fall were consistent with elk continuing to exercise more selectivity among the available forage than cattle. These differing strategies, consequently, would moderate the potential for direct interspecific competition during summer and fall.

Consequences of toxic secondary compounds in nectar for mutualistbees and antagonist butterflies.

Attraction of mutualists and defense against antagonists are critical challenges for most organisms and can be especially acute for plants with pollinating and non-pollinating flower visitors. Secondary compounds in flowers have been hypothesized to adaptively mediate attraction of mutualists and defense against antagonists, but this hypothesis has rarely been tested. The tissues of milkweeds (Asclepias spp.) contain toxic cardenolides that have long been studied as chemical defenses against herbivores. Milkweed nectar also contains cardenolides, and we have examined the impact of manipulating cardenolides in nectar on the foraging choices of two flower visitors: generalist bumble bees, Bombus impatiens, which are mutualistic pollinators, and specialist monarch butterflies, Danaus plexippus, which are herbivores as larvae and ineffective pollinators as adults. Although individual bumble bees in single foraging bouts showed no avoidance of cardenolides at the highest natural concentrations reported for milkweeds, a pattern of deterrence did arise when entire colonies were allowed to forage for several days. Monarch butterflies were not deterred by the presence of cardenolides in nectar when foraging from flowers, but laid fewer eggs on plants paired with cardenolide-laced flowers compared to controls. Thus, although deterrence of bumble bees by cardenolides may only occur after extensive foraging, a primary effect of nectar cardenolides appears to be reduction of monarch butterfly oviposition.

A race against time: habitat alteration by snow geese prunes the seasonal sequence of mosquito emergence in a subarctic brackish landscape

Species compositions in highly seasonal habitats often exhibit predictable patterns through time. However, the roles that ecological interactions play in shaping the sequence of species phenologies through a season are largely unexplored. Across the tundra on the Hudson Bay Lowlands, extensive foraging by lesser snow goose populations has been driving alterations to the landscape. Here, I show that this widespread and dramatic disturbance increases evaporation rates of ephemeral ponds and consequently constricts the temporal availability of seasonal aquatic habitats for larval mosquitoes. I also show that this constriction decreases the temporal diversity of closely related univoltine mosquito species that have varying emergence schedules. Three species of mosquitoes emerged through the season from four sampled ephemeral ponds associated with no goose grubbing; only one species emerged, early in the season, from the four ponds that experienced heavy grubbing. This study demonstrates a mechanism for temporal composition change in a ubiquitous and abundant group of arthropods on the tundra. It does not show life history evolution of emergence time of mosquitoes; however, it highlights the rather unexplored role of ecological interactions in altering the diversity of phenologies across seasonal time.

Root Production of Fagus crenata Blume Saplings Grown in Two Soils and Exposed to Elevated CO2 Concentration: an 11-Year Free-Air-CO2 Enrichment (FACE) Experiment in Northern Japan

We examined the root production of a set of Fagus crenata (Siebold’s beech) saplings grown in an infertile immature volcanic ash soil (VA) and another set in a fertile brown forest soil (BF) with both sets exposed to elevated CO2. After the saplings had been exposed to ambient (370–390 μmol mol−1) or elevated (500 μmol mol−1) CO2, during the daytime, for 11 growing seasons, the root systems were excavated. Elevated CO2 boosted the total root production of saplings grown in VA and abolished the negative effect of VA under ambient CO2, but there was no significant effect of elevated CO2 on saplings grown in BF. These results indicate the projected elevated CO2 concentrations may have a different impact in regions with different soil fertility while in regions with VA, a higher net primary production is expected. In addition, we observed large elevated CO2-induced fine-root production and extensive foraging strategy of saplings in both soils, a phenomenon that may partly (a) adjust the biogeochemical cycles of ecosystems, (b) form their response to global change, and (c) increase the size and/or biodiversity of soil fauna. We recommend that future researches consider testing a soil with a higher degree of infertility than the one we tested.

Twists and turns more costly than direct flight for foraging gannets

![Figure][1] Northern gannet in flight. Photo credit: David Gremillet Soaring above the ocean, gannet parents embark on extensive foraging odysseys to find food for their young. For the parents, the voyage is an exercise in balancing the energy that they expend locating food against the

No evidence that brushtail possums (Trichosurus vulpecula) forage on dung beetles (Coleoptera: Scarabaeidae) in New Zealand

Additional species of exotic dung beetle have been approved for unconditional release onto New Zealand pastures by New Zealand's Environmental Protection Authority. We investigated whether brushtail possums (Trichosurus vulpecula) forage on dung beetles; such behaviour could have implications for efforts to control bovine tuberculosis in New Zealand. The gut contents of possums trapped on farmland adjacent to pastures with abundant Mexican dung beetles (Copris incertus) were screened for dung beetle parts. While high proportions of grass in possum guts (up to 80% of total contents) indicated extensive foraging activity on pasture, no dung beetle parts were recovered. With no evidence that possums use dung beetles as a food source, we conclude that releases of additional dung beetle species are unlikely to alter possum foraging behaviour.

Temporal shifts in motion behaviour and habitat use in an intertidal gastropod

Animal movements in heterogeneous environments shape most ecological processes from individuals to ecosystems. The identification of the processes underlying animal movements thus has critical implications in a wide range of fields. Changes in the motion behaviour of free-ranging species have mainly been reported across different spatial scales but have been less investigated over time. Here the processes potentially triggering temporal changes in movement, microhabitat occupation and distribution patterns of the intertidal herbivorous gastropod Nerita atramentosa were examined on a south Australian rocky shore during 8 successive daytime low tides considered in four different months. The observed temporal shift in microhabitat occupation and aggregation behaviour was likely an adaptation to both abiotic and biotic stressors such as temperature and food distribution. In contrast, the temporal changes observed in N. atramentosa motion behaviour are consistent with optimal foraging strategies driven by the presumed variability in both microalgal density and distribution. Individuals seemed to switch from an extensive foraging strategy in February and May to an intensive strategy in August and October. Specifically, N. atramentosa seemed to adopt two different foraging strategies, a Lévy-like foraging strategy in May and a ballistic foraging strategy in February when the resources are expected to be respectively non-depleted and depleted. The Brownian foraging strategy theoretically expected under high food density conditions was however not observed. The potential role of the behavioural flexibility observed in N. atramentosa motion behaviour is discussed in relation to the persistence of this species under disrupted environmental conditions.

Flying Foxes Prefer to Forage in Farmland in a Tropical Dry Forest Landscape Mosaic in Fiji

To test flying fox adaptations to a habitat mosaic with extreme deforestation, the abundance, habitat choice and feeding behavior of the Pacific flying fox, Pteropus tonganus, were investigated across 16 islands of the Yasawa archipelago, Fiji. The habitat mosaic is formed by 4.3 percent tropical dry forest and 3.3 percent farmland, leaving exotic grasslands and stands of Leucaena leucocephala to overrun the vast majority of land. Pteropus tonganus abundance was high (5757 bats) despite deforestation and hunting. Roosting sites were restricted to native forest fragments. Grasslands and stands of L. leucocephala were completely void of bats at all times. The mean foraging density in farmland was four times higher than in forests and foraging competition was routinely observed in farmland but was extremely rare in forests. The author suggests that during the study, extensive foraging in farmland was supporting the high P. tonganus population. Additionally, the preferential foraging in farmland was responsible for the low foraging densities within forests and dramatically less intraspecies competition for forest resources. Further research is needed on seed dispersal within forests and to test for seasonal variations in bat abundance and feeding.

Foraging ecology of sea kraits Laticauda spp. in the Neo-Caledonian Lagoon

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 350:145-151 (2007) - DOI: https://doi.org/10.3354/meps07133 Foraging ecology of sea kraits Laticauda spp. in the Neo-Caledonian Lagoon François Brischoux1,2,*, Xavier Bonnet1, Richard Shine3 1Centre d’études Biologiques de Chizé—CNRS, 79360 Villiers en Bois, France 2Université François Rabelais, 3 rue des Tanneurs, 37041 Tours, Cedex 1, France 3Biological Sciences A08, University of Sydney, New South Wales 2006, Australia *Email: brischoux@cebc.cnrs.fr ABSTRACT: To understand the magnitude and ecological impact of predation, we need to know not only predator abundance and feeding rates, but also the area from which the prey are taken. Previous work on amphibious sea snakes (sea kraits Laticauda spp.) in New Caledonia has documented the former parameters, and suggested that these marine snakes may be major predators within coral-reef ecosystems. To estimate the area over which these snakes forage, we have developed methods based on detailed assessments of (1) the eel species consumed (and, hence, their habitats of origin), (2) the state of digestion (and, hence, time since capture) of prey items inside snakes returning to their home islands after foraging trips, and (3) the rate of digestion of prey in experimental trials. In combination with data on rates of snake movement, we conclude that one species (Laticauda laticaudata) forages mostly on soft-bottom habitats within 23 km of the home island, whereas the other species (L. saintgironsi) forages on coral substrates within 38 km of the home island. The distribution of estimated foraging ranges was similar between these 2 species (about one-third of prey taken within a few kilometres of the home island; the rest from a wide range of much further sites), despite interspecific divergence in traits such as prey types, prey sizes and rates of digestion. These extensive foraging ranges suggest that sea kraits are significant predators of eels over the entire area of the lagoon; and imply that populations of these top predators can be affected by disturbance to prey resources even many kilometres from the home island. KEY WORDS: Sea snakes · Diet · Foraging range · Foraging habitat Full text in pdf format PreviousNextCite this article as: Brischoux F, Bonnet X, Shine R (2007) Foraging ecology of sea kraits Laticauda spp. in the Neo-Caledonian Lagoon. Mar Ecol Prog Ser 350:145-151. https://doi.org/10.3354/meps07133 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 350. Online publication date: November 22, 2007 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2007 Inter-Research.

Experience‐dependent plasticity in the mushroom bodies of the solitary bee Osmia lignaria (Megachilidae)

All members of the solitary bee species Osmia lignaria (the orchard bee) forage upon emergence from their natal nest cell. Conversely, in the honey bee, days-to-weeks of socially regulated behavioral development precede the onset of foraging. The social honey bee's behavioral transition to foraging is accompanied by neuroanatomical changes in the mushroom bodies, a region of the insect brain implicated in learning. If these changes were general adaptations to foraging, they should also occur in the solitary orchard bee. Using unbiased stereological methods, we estimated the volume of the major compartments of the mushroom bodies, the neuropil and Kenyon cell body region, in adult orchard bees. We compared the mushroom bodies of recently emerged bees with mature bees that had extensive foraging experience. To separate effects of general maturation from field foraging, some orchard bees were confined to a cage indoors. The mushroom body neuropil of experienced field foragers was significantly greater than that of both recently emerged and mature caged orchard bees, suggesting that, like the honey bee, this increase is driven by outdoor foraging experience. Unlike the honey bee, where increases in the ratio of neuropil to Kenyon cell region occur in the worker after emerging from the hive cell, the orchard bee emerged from the natal nest cell with a ratio that did not change with maturation and was comparable to honey-bee foragers. These results suggest that a common developmental endpoint may be reached via different development paths in social and solitary species of foraging bees.