scholarly journals Recently-adopted foraging strategies constrain early chick development in a coastal breeding gull

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7250 ◽  
Author(s):  
Alejandro Sotillo ◽  
Jan M. Baert ◽  
Wendt Müller ◽  
Eric W.M. Stienen ◽  
Amadeu M.V.M. Soares ◽  
...  
Keyword(s):  
Urban Environments ◽  
Food Sources ◽  
Foraging Strategies ◽  
Feeding Strategies ◽  
Food Quantity ◽  
Larus Fuscus ◽  
Chick Development ◽  
Foraging Niche ◽  
Anthropogenic Food Sources ◽  
Free Ranging

Human-mediated food sources offer possibilities for novel foraging strategies by opportunistic species. Yet, relative costs and benefits of alternative foraging strategies vary with the abundance, accessibility, predictability and nutritional value of anthropogenic food sources. The extent to which such strategies may ultimately alter fitness, can have important consequences for long-term population dynamics. Here, we studied the relationships between parental diet and early development in free-ranging, cross-fostered chicks and in captive-held, hand-raised chicks of Lesser Black-backed Gulls (Larus fuscus) breeding along the Belgian coast. This traditionally marine and intertidal foraging species is now increasingly taking advantage of human activities by foraging on terrestrial food sources in agricultural and urban environments. In accordance with such behavior, the proportion of terrestrial food in the diet of free-ranging chicks ranged between 4% and 80%, and consistent stable isotope signatures between age classes indicated that this variation was mainly due to between-parent variation in feeding strategies. A stronger terrestrial food signature in free-ranging chicks corresponded with slower chick development. However, no consistent differences in chick development were found when contrasting terrestrial and marine diets were provided ad libitum to hand-raised chicks. Results of this study hence suggest that terrestrial diets may lower reproductive success due to limitations in food quantity, rather than quality. Recent foraging niche expansion toward terrestrial resources may thus constitute a suboptimal alternative strategy to marine foraging for breeding Lesser Black-backed Gulls during the chick-rearing period.

scholarly journals The multidimensional nutritional niche of fungus-cultivar provisioning in free-ranging colonies of a neotropical leafcutter ant

2021 ◽  
Author(s):  
Antonin J.J. Crumière ◽  
Aidan James ◽  
Pol Lannes ◽  
Sophie Mallett ◽  
Anders Michelsen ◽  
...  
Keyword(s):  
Large Scale ◽  
Foraging Strategies ◽  
Generalist Herbivore ◽  
Leafcutter Ants ◽  
Microbial Symbiont ◽  
Foraging Niche ◽  
Generalist Insect ◽  
Atta Colombica ◽  
Free Ranging

AbstractThe foraging trails of Atta leafcutter colonies are among the most iconic scenes in Neotropical ecosystems, with thousands of ants carrying freshly cut plant fragments back to their nests where they are used to provision a fungal food crop. We tested a hypothesis that the fungal cultivar’s multidimensional requirements for macronutrients (protein and carbohydrates) and minerals (Al, Ca, Cu, Fe, K, Mg, Mn, Na, P and Zn) govern the foraging breadth of Atta colombica leafcutter ants in a Panamanian rainforest. Analyses of freshly cut plant fragments carried by leafcutter foragers showed that the combination of fruits, flowers, and leaves provide for a broad realized nutritional niche that can maximize cultivar’s performance. And, while the leaves that comprised the most harvested resource also delivered an intake target containing protein in excess of the amounts that can maximize cultivar growth, in vitro experiments showed that the minerals P, Al, and Fe can enhance the cultivar’s tolerance to protein-biased substrates, and potentially expand the ants’ foraging niche. Yet, the cultivar also exhibits narrow margins between mineral limitation and toxicity that may render plant fragments with seemingly optimal blends of macronutrients unsuitable for provisioning. Our approach highlights that optimal foraging is inherently multidimensional and links the foraging behavior of a generalist insect herbivore to the fundamental nutritional niche of its microbial symbiont.Significance StatementColonies of Atta colombica leafcutter ants can contain millions of specialized workers exhibiting large-scale generalist herbivory. Yet, this generalist foraging niche also depends on the poorly understood physiological needs of the ants’ domesticated fungal cultivar. We show the cultivar’s fundamental nutritional niche is broad for carbohydrates but narrower for protein and a suite of minerals, but that the cultivar’s sensitivity to excess protein is also mediated by Al, Fe, and P. More generally, this study decouples the multidimensional foraging strategies that enable a generalist herbivore to navigate a complex nutritional landscape and mix many imbalanced foods to achieve balanced cultivar provisioning.

scholarly journals An exploration of the relationship between recruitment communication and foraging in stingless bees

2021 ◽  
Author(s):  
Robbie I’Anson Price ◽  
Francisca Segers ◽  
Amelia Berger ◽  
Fabio S Nascimento ◽  
Christoph Grüter
Keyword(s):  
Stingless Bees ◽  
Sugar Content ◽  
Social Information ◽  
Food Resources ◽  
Food Sources ◽  
Foraging Strategies ◽  
High Quality ◽  
Recruitment Communication ◽  
Eusocial Bees ◽  
The Relationship

Abstract Social information is widely used in the animal kingdom and can be highly adaptive. In social insects, foragers can use social information to find food, avoid danger or choose a new nest site. Copying others allows individuals to obtain information without having to sample the environment. When foragers communicate information they will often only advertise high quality food sources, thereby filtering out less adaptive information. Stingless bees, a large pantropical group of highly eusocial bees, face intense inter- and intra-specific competition for limited resources, yet display disparate foraging strategies. Within the same environment there are species that communicate the location of food resources to nest-mates and species that do not. Our current understanding of why some species communicate foraging sites while others do not is limited. Studying freely foraging colonies of several co-existing stingless bee species in Brazil, we investigated if recruitment to specific food locations is linked to (1) the sugar content of forage, (2) the duration of foraging trips and (3) the variation in activity of a colony from one day to another and the variation in activity in a species over a day. We found that, contrary to our expectations, species with recruitment communication did not return with higher quality forage than species that do not recruit nestmates. Furthermore, foragers from recruiting species did not have shorter foraging trip durations than those from weakly-recruiting species. Given the intense inter- and intraspecific competition for resources in these environments, it may be that recruiting species favour food resources that can be monopolised by the colony rather than food sources that offer high-quality rewards.

Anthropogenic Food Sources in the Co-Existence of Humans with Liminal Animals in Northern Environments

2017 ◽  
pp. 147-162 ◽  
Author(s):  
Linda Kalof ◽  
Cameron Whitley ◽  
Stephen Vrla ◽  
Jessica Bell Rizzolo
Keyword(s):  
Food Sources ◽  
Anthropogenic Food Sources ◽  
Anthropogenic Food

Foraging strategies and prey encounter rate of free-ranging Little Penguins

2006 ◽  
Vol 149 (2) ◽  
pp. 139-148 ◽  
Author(s):  
Yan Ropert-Coudert ◽  
Akiko Kato ◽  
Rory P. Wilson ◽  
Belinda Cannell
Keyword(s):  
Foraging Strategies ◽  
Encounter Rate ◽  
Free Ranging

scholarly journals Patterns of Feeding by Householders Affect Activity of Hedgehogs (Erinaceus europaeus) during the Hibernation Period

Animals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1344 ◽  
Author(s):  
Abigail Gazzard ◽  
Philip J. Baker
Keyword(s):  
Food Sources ◽  
Energy Deficit ◽  
Net Energy ◽  
Survey Period ◽  
Erinaceus Europaeus ◽  
Ecological Features ◽  
Hibernation Period ◽  
Negative Effect ◽  
Anthropogenic Food Sources ◽  
The Town

West European hedgehogs (Erinaceus europaeus) are likely to encounter unusual ecological features in urban habitats, such as anthropogenic food sources and artificial refugia. Quantifying how these affect hedgehog behaviour is vital for informing conservation guidelines for householders. We monitored hedgehog presence/absence in gardens in the town of Reading, UK, over the winter of 2017–2018 using a volunteer-based footprint tunnel survey, and collected data on garden characteristics, supplementary feeding (SF) habits, and local environmental conditions. Over a 20-week survey period, hedgehog presence was lowest between January and March. Occupancy analysis indicated that SF significantly affected hedgehog presence/absence before, during, and after hibernation. The number of nesting opportunities available in gardens, average temperatures, and daylength were also supported as important factors at different stages. In particular, our results suggest that SF could act to increase levels of activity during the winter when hedgehogs should be hibernating. Stimulating increased activity at this sensitive time could push hedgehogs into a net energy deficit or, conversely, help some individuals survive which might not otherwise do so. Therefore, further research is necessary to determine whether patterns of feeding by householders have a positive or negative effect on hedgehog populations during the hibernation period.

Influence of trawling on the behaviour and spatial distribution of Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Moreton Bay, Australia

2003 ◽  
Vol 81 (12) ◽  
pp. 1947-1955 ◽  
Author(s):  
B Louise Chilvers ◽  
Peter J Corkeron ◽  
Marji L Puotinen
Keyword(s):  
Spatial Distribution ◽  
Bottlenose Dolphins ◽  
Geographical Information ◽  
Foraging Strategies ◽  
Tursiops Aduncus ◽  
Moreton Bay ◽  
Spatial Use ◽  
Free Ranging ◽  
Marine Wildlife ◽  
Southeast Queensland

Sympatric communities of inshore Indo-Pacific bottlenose dolphins (Tursiops aduncus) have previously been identified within Moreton Bay, southeast Queensland, Australia. The two communities overlap in distribution, yet are almost completely socially segregated and forage in distinctly different ways. The correlation between this social segregation, the different foraging strategies, and a human activity (trawling) has previously been demonstrated. This paper investigates the possible effects of trawling on the behaviour and spatial distribution of these two communities. A geographical information system is used to determine the spatial use of each community. The behavioural budgets of both communities showed significantly higher levels of foraging behaviours than reported for most other bottlenose dolphin communities. The spatial use of both communities changed seasonally. These results provide further detail on how human activities may indirectly influence the behaviour and spatial use of free-ranging marine wildlife.

scholarly journals Domestic Cat Abundance and Activity Across a Residential Land Use Gradient

2021 ◽  
Vol 9 ◽  
Author(s):  
Kevin F. P. Bennett ◽  
Brian S. Evans ◽  
J. Alan Clark ◽  
Peter P. Marra
Keyword(s):  
Land Use ◽  
Native Species ◽  
Management Strategies ◽  
Urban Environments ◽  
Camera Traps ◽  
Domestic Cat ◽  
Land Use Patterns ◽  
Residential Land ◽  
Residential Land Use ◽  
Free Ranging

Free-ranging domestic cats are a detriment to wildlife and humans by preying on native species and transmitting disease. As a result, removing free-ranging cats from the landscape has become a conservation and public health priority. Estimating cat population size with an unbiased sampling design, however, especially in human-dominated areas, is logistically challenging and rarely done. The lack of robust cat population sampling limits our understanding of where cats pose risks, which is important for evaluating management strategies, such as trap-remove or trap-neuter-return. We hypothesized that cat abundance and activity both depend on human land use and demographics. Using a network of sites participating in a community science program, we conducted transect and camera trap surveys to test predictions of cat population abundance and activity across a gradient of residential land use intensity. Both sampling methods determined that cat abundance was greatest in areas with intermediate human population density and lower educational attainment. Transect data also provided evidence that cat abundance was greatest at intermediate levels of impervious surface cover (e.g., road and buildings), while data from camera traps also showed that cat abundance was positively associated with household income. Using counts of cats observed on cameras, we found that the timing of cat activity varied depending on the degree of urban intensity. Cats were more strictly nocturnal in medium and high intensity residential land-use areas, possibly because a greater proportion of these cats are unowned or because they avoid human activity. These results suggest that transect surveys conducted during the day may undercount cats in urban environments where unowned free-ranging cats predominate. Taken together, our results highlight the importance of incorporating human demographics, land use patterns, and urban context in estimating the abundance of free-ranging cats to better inform management decisions and improve conservation outcomes.

Influences of Diet on the Life Histories of Aquatic Insects

1979 ◽  
Vol 36 (3) ◽  
pp. 335-342 ◽  
Author(s):  
N. H. Anderson ◽  
Kenneth W. Cummins
Keyword(s):  
Food Quality ◽  
Aquatic Insects ◽  
Life Histories ◽  
Functional Feeding Groups ◽  
Feeding Strategies ◽  
Laboratory Studies ◽  
Benthic Species ◽  
Food Quantity ◽  
Effects Of Temperature

Benthic species are partitioned into functional feeding groups based on food-acquiring mechanisms. Effects of food quality on voltinism, growth rate, and size at maturity are demonstrated for representatives of gougers and shredders, collectors, and scrapers. Food quality for predators is uniformly high, but food quantity (prey density) obviously influences their life histories. A food switch from herbivory to predation, or some ingestion of animal tissues, in the later stages is a feature of the life cycle of many aquatic insects. Temperature interacts with both food quality and quantity in effects on growth as well as having a direct effect on control of metabolism. Thus further elaboration of the role of food in life history phenomena will require controlled field or laboratory studies to partition the effects of temperature and food. Key words: aquatic insects, feeding strategies, functional groups, life histories

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