Niche breadth in clonal and sexual fish (Poeciliopsis): a test of the frozen niche variation model

2001 ◽  
Vol 58 (7) ◽  
pp. 1313-1318 ◽  
Author(s):  
Melissa M Gray ◽  
Stephen C Weeks
Keyword(s):  
Niche Breadth ◽  
Gut Contents ◽  
Sympatric Populations ◽  
Clonal Population ◽  
Sexual Population ◽  
Dietary Breadth ◽  
Maintenance Of Sex ◽  
Dietary Choice ◽  
Niche Variation ◽  
Dietary Niche

The evolution and subsequent maintenance of sex has been debated for many years, and there are numerous aspects that remain poorly understood. When comparing sexual with asexual reproduction, there are many more apparent benefits to being asexual than sexual. The frozen niche variation (FNV) model describes how asexual clones can arise from a sexual population and how the two reproductive types can coexist. Herein we compared three sympatric populations of sexual and asexual fish (one sexual population, Poeciliopsis monacha, and two clonal populations, P. 2-monacha-lucida) to test the assumption of the FNV model that sexual populations have a broader dietary niche (as measured by gut contents analysis) than clonal populations. Individual sexual fish had similar dietary breadth when compared with clonal individuals. However, dietary breadth for sexual populations as a whole was broader than for either clonal population, indicating differences in between-individual dietary choice. Our results support the primary assumption of the FNV model and thereby provide a possible explanation for the maintenance of sexual reproduction in this clonal–sexual complex.

Feeding limitations in temperate anurans and the niche variation hypothesis

2017 ◽  
Vol 38 (4) ◽  
pp. 473-482 ◽  
Author(s):  
Carl S. Cloyed ◽  
Perri K. Eason
Keyword(s):  
Individual Variation ◽  
Niche Breadth ◽  
Rana Catesbeiana ◽  
Strong Support ◽  
Diet Breadth ◽  
Niche Variation ◽  
Gape Size ◽  
Dietary Niche ◽  
Niche Variation Hypothesis ◽  
Traditional Approaches

The niche variation hypothesis (NVH) states that populations with wider niches are more phenotypically variable. The NVH has important ecological and evolutionary implications but has been controversial since its inception. Recent interpretations have supported the NVH by directly comparing among-individual diet variation with population dietary niche breadth. Traditional studies of the NVH focused on morphological traits as proxies of niche variation, with contradictory results. Gape-limited predators may be relatively likely to show effects of morphological variation on diet breadth because gape size can strongly limit diet. We used five anurans to test NVH predictions, including three true frogs, Rana catesbeiana, R. clamitans, and R. sphenocephala, and two toads, Anaxyrus americanus and A. fowleri. We combined recent and traditional approaches by comparing both individual variation in diet and variation in gape width with dietary niche breadth. We found support for the NVH within two species of the three true frogs but not for either toad species, a difference likely driven by greater strength of the feeding limitation caused by gape width in the frogs. Toads had higher gape width to snout-vent length ratios, reducing the strength of the feeding limitation imposed by gape width. We found strong support for the NVH among species; species with more among-individual variation in diet and species with more variation in gape width had broader niches. Our results highlight the circumstances under which the NVH is applicable and demonstrate an example in which the NVH is supported through both traditional and recent interpretations.

scholarly journals Morphology and stable isotope analysis demonstrate different structuring of bat communities in rainforest and savannah habitats

2018 ◽  
Vol 5 (12) ◽  
pp. 180849 ◽  
Author(s):  
Ara Monadjem ◽  
Adam Kane ◽  
Peter Taylor ◽  
Leigh R. Richards ◽  
Grant Hall ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Niche Breadth ◽  
Isotope Analysis ◽  
Morphological Characters ◽  
Trophic Levels ◽  
Species Packing ◽  
Dietary Niche ◽  
The One ◽  
Ellipse Area

Bats play important ecological roles in tropical systems, yet how these communities are structured is still poorly understood. Our study explores the structure of African bat communities using morphological characters to define the morphospace occupied by these bats and stable isotope analysis to define their dietary niche breadth. We compared two communities, one in rainforest (Liberia) and one in savannah (South Africa), and asked whether the greater richness in the rainforest was due to more species ‘packing’ into the same morphospace and trophic space than bats from the savannah, or some other arrangement. In the rainforest, bats occupied a larger area in morphospace and species packing was higher than in the savannah; although this difference disappeared when comparing insectivorous bats only. There were also differences in morphospace occupied by different foraging groups (aerial, edge, clutter and fruitbat). Stable isotope analysis revealed that the range of δ 13 C values was almost double in rainforest than in savannah indicating a greater range of utilization of basal C 3 and C 4 resources in the former site, covering primary productivity from both these sources. The ranges in δ 15 N, however, were similar between the two habitats suggesting a similar number of trophic levels. Niche breadth, as defined by either standard ellipse area or convex hull, was greater for the bat community in rainforest than in savannah, with all four foraging groups having larger niche breadths in the former than the latter. The higher inter-species morphospace and niche breadth in forest bats suggest that species packing is not necessarily competitive. By employing morphometrics and stable isotope analysis, we have shown that the rainforest bat community packs more species in morphospace and uses a larger niche breadth than the one in savannah.

scholarly journals Diet Composition and Feeding Strategies of the Stone Marten (Martes foina) in a Typical Mediterranean Ecosystem

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Dimitrios E. Bakaloudis ◽  
Christos G. Vlachos ◽  
Malamati A. Papakosta ◽  
Vasileios A. Bontzorlos ◽  
Evangelos N. Chatzinikos
Keyword(s):  
Diet Composition ◽  
Niche Breadth ◽  
Interference Competition ◽  
Mediterranean Ecosystem ◽  
Feeding Strategies ◽  
Stone Marten ◽  
Martes Foina ◽  
Dietary Niche ◽  
Individual Specialisation ◽  
The Individual

Stone martens (Martes foina) are documented as generalist throughout their distributional range whose diet composition is affected by food availability. We tested if this occurs and what feeding strategies it follows in a typical Mediterranean ecosystem in Central Greece by analysing contents from 106 stomachs, seasonally collected from three different habitats during 2003–2006. Seasonal variation in diet and feeding strategies was evident and linked to seasonal nutritional requirements, but possibly imposed by strong interference competition and intraguild predation. Fleshy fruits and arthropods predominated in the diet, but also mammals and birds were frequently consumed. An overall low dietary niche breadth (BA=0.128) indicated a fruit specialization tendency. A generalised diet occurred in spring with high individual specialisation, whereas more animal-type prey was consumed than fruits. A population specialization towards fruits was indicated during summer and autumn, whereas insects were consumed occasionally by males. In those seasons it switched to more clumped food types such as fruits and insects. In winter it selectively exploited both adult and larvae insects and partially fruits overwinter on plants. The tendency to consume particular prey items seasonally reflected both the population specialist behaviour and the individual flexibility preyed on different food resources.

scholarly journals Drought but not population density influences dietary niche breadth in white-tailed deer in a semiarid environment

Ecosphere ◽  
2014 ◽  
Vol 5 (12) ◽  
pp. art162 ◽  
Author(s):  
Donald J. Folks ◽  
Kory Gann ◽  
Timothy E. Fulbright ◽  
David G. Hewitt ◽  
Charles A. DeYoung ◽  
...  
Keyword(s):  
Population Density ◽  
Niche Breadth ◽  
Semiarid Environment ◽  
Dietary Niche

Optimal foraging constrains macroecological patterns: body size and dietary niche breadth in lizards

2008 ◽  
Vol 17 (5) ◽  
pp. 670-677 ◽  
Author(s):  
Gabriel C. Costa ◽  
Laurie J. Vitt ◽  
Eric R. Pianka ◽  
Daniel O. Mesquita ◽  
Guarino R. Colli
Keyword(s):  
Body Size ◽  
Optimal Foraging ◽  
Niche Breadth ◽  
Dietary Niche

scholarly journals A theoretical test of the DNA repair hypothesis for the maintenance of sex in eukaryotes

1991 ◽  
Vol 58 (2) ◽  
pp. 157-165 ◽  
Author(s):  
Eörs Szathmáry ◽  
Szilvia Kövér
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Essential Feature ◽  
Genetic System ◽  
Sexual Population ◽  
Maintenance Of Sex ◽  
Successful Establishment ◽  
Heterozygous Form ◽  
Theoretical Test ◽  
Double Strand Dna

SummaryThe DNA repair hypothesis for the maintenance of sex states that recombination is necessary for the repair of double-strand DNA damage. In a closed (mitotic) genetic system crossing-over generates homozygosity. This reduces fitness if deleterious recessive alleles become expressed. Thus, outcrossing is required to restore heterozygosity destroyed by recombination. The repair hypothesis is tested by comparing outcrossing sexuality with a hypothetical parthenogenic strategy (the Prudent Reparator) which destroys as little heterozygosity during repair as possible. In the Prudent Reparator, repair of double-strand DNA damage results in a small amount of homozygosity due to gene conversion only, since this process does not render outside markers homozygous. Diploidy, deleterious recessives, multiplicative fitness and linkage equilibrium in mutation-selection balance are assumed. The average fitness of this population increases, and complementation (i.e. masking of recessives in heterozygous form) decreases with the rate of damage per locus. The equilibrium fitness of the Prudent Reparator can be well above that of the sexual population. A lower complementation ability of parthenogens may not be an impenetrable barrier to their successful establishment if the invader's genome is relatively uncontaminated by mutant alleles: there are always such genotypes in the sexual population. Thus, the Prudent Reparator could solve the problem of repairing damage as well as that of invading an existing outcrossing population. As we do not see this strategy widely adopted instead of sexuality, the repair hypothesis is likely to miss some essential feature of the evolution of sex.

scholarly journals Dietary plasticity of North American herbivores: a synthesis of stable isotope data over the past 7 million years

2021 ◽  
Vol 288 (1948) ◽  
Author(s):  
Melissa I. Pardi ◽  
Larisa R. G. DeSantis
Keyword(s):  
Stable Isotope ◽  
North American ◽  
Tooth Enamel ◽  
Local Level ◽  
Habitat Preferences ◽  
Dietary Behaviour ◽  
The Past ◽  
Dietary Breadth ◽  
Dietary Plasticity ◽  
Dietary Niche

Palaeoecological interpretations are based on our understanding of dietary and habitat preferences of fossil taxa. While morphology provides approximations of diets, stable isotope proxies provide insights into the realized diets of animals. We present a synthesis of the isotopic ecologies ( δ 13 C from tooth enamel) of North American mammalian herbivores since approximately 7 Ma. We ask: (i) do morphological interpretations of dietary behaviour agree with stable isotope proxy data? (ii) are grazing taxa specialists, or is grazing a means to broaden the dietary niche? and (iii) how is dietary niche breadth attained in taxa at the local level? We demonstrate that while brachydont taxa are specialized as browsers, hypsodont taxa often have broader diets that included more browse consumption than previously anticipated. It has long been accepted that morphology imposes limits on the diet; this synthesis supports prior work that herbivores with ‘grazing’ adaptions, such as hypsodont teeth, have the ability to consume grass but are also able to eat other foods. Notably, localized dietary breadth of even generalist taxa can be narrow (approx. 30 to 60% of a taxon's overall breadth). This synthesis demonstrates that ‘grazing-adapted’ taxa are varied in their diets across space and time, and this flexibility may reduce competition among ancient herbivores.

Observations on feeding habits of the common dolphinfish, Coryphaena hippurus (Linnaeus 1758) from the western Bay of Bengal

2021 ◽  
Vol 34 ◽  
pp. 24
Author(s):  
Shubhadeep Ghosh ◽  
Satishkumar Mamidi ◽  
Manas Hoshalli Munivenkatappa ◽  
Prathibha Rohit ◽  
Abdussamad Eruppakkottil Median ◽  
...  
Keyword(s):  
Bay Of Bengal ◽  
Prey Species ◽  
Niche Breadth ◽  
Feeding Habits ◽  
Weight Ratio ◽  
Primary Study ◽  
Feeding Intensity ◽  
Coryphaena Hippurus ◽  
Dietary Niche ◽  
Western Bay Of Bengal

Coryphaena hippurus is a large pelagic species and constitutes an important by-catch in drift gillnet, trolling and long-line fishing gears operated along the Bay of Bengal, northeastern Indian Ocean. The present study, first from the region, is aimed at deciphering the feeding dynamics from 1150 individuals collected from 2017 to 2019. 32.17% of the fishes had empty stomachs or was with food traces, 45.57% had partially-full stomachs and 22.26% had full stomachs. The feeding intensity was inferred through stomach filling and predator-prey weight ratio, which was higher in May and lower in January, and increasing as increase in the fish size. Coryphaena hippurus is considered a piscivorous pelagic predator as pelagic teleosts contribute more than half of the prey species. Major prey species were big-eye scad (27.3%), squid (10.3%), crabs (9.3%), Indian mackerel (7.2%), Indian scad (5.9%), whitebaits (5.7%) and sardines (5.4%). Scads and crabs were abundantly preyed during summer and winter, while clupeids and engraulids in monsoon; however, no significant variations were observed in prey composition between sizes. Trophic Level was 4.22 ± 0.15 and Levins Standardized Niche Breadth Index was 0.30. Dietary niche breadth was higher during summer (0.48) and monsoon (0.33) and in fishes measuring 60.0–74.9 cm (0.51) and below 45.0 cm (0.48) indicating generalised feeding. This primary study from Bay of Bengal is the first comprehensive report on trophodynamics for the species and would contribute to its management using trophic interactions.

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