Among-individual diet variation within a lake trout ecotype: lack of stability of niche use

AbstractIn a polymorphic species, stable differences in resource use are expected among ecotypes, and homogeneity in resource use is predicted within an ecotype. Yet, using a broad resource spectrum has been identified as a strategy for fishes living in unproductive northern environments, where food is patchily distributed and ephemeral. We investigated whether individual specialization of trophic resources occurred within the generalist piscivore ecotype of lake trout from Great Bear Lake, Canada, reflective of a form of diversity. Four distinct dietary patterns of resource use within the lake trout ecotype were detected from fatty acid composition, with some variation linked to spatial patterns within Great Bear Lake. Feeding habits of different groups within the ecotype were not associated with detectable morphological or genetic differentiation, suggesting that behavioral plasticity caused the trophic differences. A low level of genetic differentiation was detected between exceptionally large-sized individuals and other individuals. Investigating a geologically young system that displays high levels of intraspecific diversity and focusing on individual variation in diet suggested that individual trophic specialization can occur within an ecotype. The characterization of niche use among individuals, as done in this study, is necessary to understand the role that individual variation can play at the beginning of differentiation processes.

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Dietary versus nondietary fatty acid profiles of lake trout ecotypes from Lake Superior and Great Bear Lake: Are fish really what they eat?

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2019-0343 ◽

2020 ◽

Vol 77 (7) ◽

pp. 1209-1220

Author(s):

L. Chavarie ◽

J. Hoffmann ◽

A.M. Muir ◽

C.C. Krueger ◽

C.R. Bronte ◽

...

Keyword(s):

Fatty Acids ◽

Fatty Acid ◽

Trophic Ecology ◽

Lake Trout ◽

Dietary Fatty Acids ◽

Intraspecific Diversity ◽

Dietary Biomarkers ◽

Bear Lake ◽

Energy Processing ◽

Fatty Acid Biomarkers

Fatty acids are well-established biomarkers used to characterize trophic ecology, food-web linkages, and the ecological niche of many different taxa. Most often, fatty acids that are examined include only those previously identified as “dietary” or “extended dietary” biomarkers. Fatty acids considered as nondietary biomarkers, however, represent numerous fatty acids that can be extracted. Some studies may include nondietary fatty acids (i.e., combined with dietary fatty acids), but do not specifically assess them, whereas in other studies, these data are discarded. In this study, we explored whether nondietary biomarker fatty acids can provide worthwhile information by assessing their ability to discriminate intraspecific diversity within and between lakes. Nondietary fatty acids used as biomarkers delineated variation among regions, among locations within a lake, and among ecotypes within a species. Physiological differences that arise from differences in energy processing can be adaptive and linked to habitat use by a species’ ecotype and likely explains why nondietary fatty acid biomarkers can be a relevant tool to delineate intraspecific diversity. Little is known about the nondietary-mediated differences in fatty acid composition, but our results showed that nondietary fatty acid biomarkers can be useful tool in identifying variation.

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Dietary vs non-dietary fatty acid profiles of lake trout ecotypes from Lake Superior and Great Bear Lake: Are fish really what they eat?

10.1101/714352 ◽

2019 ◽

Author(s):

L Chavarie ◽

J. Hoffmann ◽

A.M. Muir ◽

C.C. Krueger ◽

C.R. Bronte ◽

...

Keyword(s):

Fatty Acids ◽

Fatty Acid ◽

Trophic Ecology ◽

Lake Trout ◽

Dietary Fatty Acids ◽

Intraspecific Diversity ◽

Fatty Acid Profiles ◽

Dietary Biomarkers ◽

Bear Lake ◽

Energy Processing

AbstractFatty acids are well-established biomarkers used to characterize trophic ecology, food-web linkages, and the ecological niche of many different taxa. Most often, fatty acids that are examined include only those previously identified as “dietary” or “extended dietary” biomarkers. Fatty acids considered as non-dietary biomarkers, however, represent numerous fatty acids that can be extracted. Some studies may include non-dietary fatty acids (i.e., combined with dietary fatty acids), but do not specifically assess them, whereas in other studies, these data are discarded. In this study, we explored whether non-dietary biomarkers fatty acids can provide worthwhile information by assessing their ability to discriminate intraspecific diversity within and between lakes. Non-dietary fatty acids used as biomarkers delineated variation among regions, among locations within a lake, and among ecotypes within a species. Physiological differences that arise from differences in energy processing can be adaptive and linked to habitat use by a species’ ecotypes, and likely explains why non-dietary fatty acids biomarkers can be a relevant tool to delineate intraspecific diversity. Little is known about the non-dietary-mediated differences in fatty acid composition, but our results showed that non-dietary fatty acids biomarkers can be useful tool in identifying variation.

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Dietary and non-dietary contributions to among-individual variation in carbon and nitrogen isotopic composition of lake trout

Ecological Indicators ◽

10.1016/j.ecolind.2021.107349 ◽

2021 ◽

Vol 123 ◽

pp. 107349 ◽

Cited By ~ 1

Author(s):

T.A. Johnston ◽

A.D. Ehrman ◽

J.J. Montgomery ◽

H.K. Swanson

Keyword(s):

Isotopic Composition ◽

Individual Variation ◽

Lake Trout ◽

Carbon And Nitrogen ◽

Nitrogen Isotopic Composition

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Diet of the endangered spirlin (Alburnoides bipunctatus) at the centre of its distribution in Europe

Marine and Freshwater Research ◽

10.1071/mf18013 ◽

2018 ◽

Vol 69 (11) ◽

pp. 1712

Author(s):

L. Marszał ◽

M. Grzybkowska ◽

D. Błońska ◽

J. Leszczyńska ◽

M. Przybylski

Keyword(s):

Resource Use ◽

Diet Composition ◽

Feeding Habits ◽

Open Water ◽

Size Class ◽

Habitat Segregation ◽

Chironomid Larvae ◽

Size Classes ◽

Taxonomic Groups ◽

Distribution In Europe

The feeding habits of spirlin Alburnoides bipunctatus were investigated in a tributary of the River Vistula (Poland). To evaluate size-related patterns of resource use, fish were assigned to three size classes, defined according to size at first maturation: small (29–70-mm total length, TL), medium (71–90mm TL) and large (91–104mm TL). There was a significant ontogenetic shift in the feeding pattern among size classes, marked by differences in the proportion of the main taxonomic groups of prey consumed: small spirlin primarily consumed chironomid larvae, whereas medium and large spirlin showed a preference for Coleoptera, Ephemeroptera and imagines of unidentified insects. The proportion of prey taken from the water column was significantly lower for small- than medium- and large-sized spirlin. This difference was attributed to the benthic habits of small spirlin compared with medium and large spirlin. The shift to open water feeding in spirlin corresponded with sexual maturation, with habitat segregation between the smallest size class (comprising juveniles) and larger size classes (mature individuals). Size-specific changes in the diet composition of this species have not previously been documented.

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Nymphal feeding habits of two Anacroneuria species (Plecoptera, Perlidae) from Sierra Nevada de Santa Marta, Colombia

Journal of Limnology ◽

10.4081/jlimnol.2018.1858 ◽

2018 ◽

Vol 78 (1) ◽

Cited By ~ 1

Author(s):

Yesely M. Hurtado ◽

Cesar E. Tamaris-Turizo ◽

Manuel J. López Rodriguez ◽

J. Manuel Tierno de Figueroa

Keyword(s):

Sierra Nevada ◽

Rainy Season ◽

Feeding Habits ◽

Niche Overlap ◽

Trophic Niche ◽

Freshwater Ecosystems ◽

Use Of Resources ◽

Trophic Resources ◽

Tropical Areas ◽

Dry Seasons

The knowledge of the diet of aquatic insects is important to assess the use of resources and overlap of trophic niche between species, as well as to understand their role in the food web of the freshwater ecosystems they inhabit. This is particularly necessary in tropical areas where information on this topic is scarce. The aim of the present work is to describe the feeding habits of the species Anacroneuria marta Zúñiga and Stark, 2002 and Anacroneuria caraca Stark, 1995 in the middle section of the Gaira River (Sierra Nevada de Santa Marta, Colombia). We performed three samplings during the rainy and dry seasons in the two main different microhabitats of the reach (leaf packs and gravel) in 2014. The diet of a total of 87 and 90 individuals of A. caraca and A. marta, respectively, was studied. With this information, niche breadth for each species and niche overlap between them in terms of trophic resources were calculated. The main trophic resource for both species in the dry and rainy season was the animal matter. In the dry season, FPOM was also important in the diet of A. caraca, and A. marta ingested a great quantity of CPOM in the rainy season. Larvae of Trichoptera, were the most ingested prey in both species, followed by Chironomidae, Coleoptera Hydrophilidae, and Ephemeroptera. No differences in diet between both species were detected, so this could favor the niche overlap in terms of trophic resources and could lead to competition between them. The possible ecological scenarios are discussed.

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Combining resource use assessment techniques reveals trade‐offs in trophic specialization of polymorphic perch

Ecosphere ◽

10.1002/ecs2.1387 ◽

2016 ◽

Vol 7 (8) ◽

Cited By ~ 12

Author(s):

Kristin Scharnweber ◽

Ursula Strandberg ◽

Maria Helena Katarina Marklund ◽

Peter Eklöv

Keyword(s):

Resource Use ◽

Trophic Specialization ◽

Trade Offs ◽

Assessment Techniques

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Fatty acid signatures and stomach contents of four sympatric Lake Trout: assessment of trophic patterns among morphotypes in Great Bear Lake

Ecology Of Freshwater Fish ◽

10.1111/eff.12195 ◽

2014 ◽

Vol 25 (1) ◽

pp. 109-124 ◽

Cited By ~ 14

Author(s):

Louise Chavarie ◽

Kimberly Howland ◽

Colin Gallagher ◽

William Tonn

Keyword(s):

Fatty Acid ◽

Lake Trout ◽

Stomach Contents ◽

Bear Lake

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Individual variation in resource use by opossums leading to nested fruit consumption

Oikos ◽

10.1111/j.1600-0706.2012.00070.x ◽

2012 ◽

Vol 122 (7) ◽

pp. 1085-1093 ◽

Cited By ~ 29

Author(s):

Maurício Cantor ◽

Mathias Mistretta Pires ◽

Guilherme Ortigara Longo ◽

Paulo Roberto Guimarães ◽

Eleonore Zulnara Freire Setz

Keyword(s):

Resource Use ◽

Individual Variation ◽

Fruit Consumption

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Human-modified landscapes alter mammal resource and habitat use and trophic structure

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1904384116 ◽

2019 ◽

Vol 116 (37) ◽

pp. 18466-18472 ◽

Cited By ~ 14

Author(s):

Marcelo Magioli ◽

Marcelo Zacharias Moreira ◽

Renata Cristina Batista Fonseca ◽

Milton Cezar Ribeiro ◽

Márcia Gonçalves Rodrigues ◽

...

Keyword(s):

Habitat Use ◽

Resource Use ◽

Trophic Structure ◽

Behavioral Plasticity ◽

Agricultural Landscape ◽

Hot Spot ◽

Negative Consequences ◽

Agricultural Matrix ◽

Forest Remnant ◽

Significant Difference

The broad negative consequences of habitat degradation on biodiversity have been studied, but the complex effects of natural–agricultural landscape matrices remain poorly understood. Here we used stable carbon and nitrogen isotopes to detect changes in mammal resource and habitat use and trophic structure between preserved areas and human-modified landscapes (HMLs) in a biodiversity hot spot in South America. We classified mammals into trophic guilds and compared resource use (in terms of C3- and C4-derived carbon), isotopic niches, and trophic structure across the 2 systems. In HMLs, approximately one-third of individuals fed exclusively on items from the agricultural matrix (C4), while in preserved areas, ∼68% depended on forest remnant resources (C3). Herbivores, omnivores, and carnivores were the guilds that most incorporated C4carbon in HMLs. Frugivores maintained the same resource use between systems (C3resources), while insectivores showed no significant difference. All guilds in HMLs except insectivores presented larger isotopic niches than those in preserved areas. We observed a complex trophic structure in preserved areas, with increasing δ15N values from herbivores to insectivores and carnivores, differing from that in HMLs. This difference is partially explained by species loss and turnover and mainly by the behavioral plasticity of resilient species that use nitrogen-enriched food items. We concluded that the landscape cannot be seen as a habitat/nonhabitat dichotomy because the agricultural landscape matrix in HMLs provides mammal habitat and opportunities for food acquisition. Thus, favorable management of the agricultural matrix and slowing the conversion of forests to agriculture are important for conservation in this region.

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