scholarly journals The bite force–gape relationship as an avenue of biomechanical adaptation to trophic niche in two salmonid fishes

2020 ◽  
Vol 223 (20) ◽  
pp. jeb223180
Author(s):  
Elska B. Kaczmarek ◽  
Nicholas J. Gidmark
Keyword(s):  
Skeletal Muscles ◽  
Oncorhynchus Tshawytscha ◽  
Pink Salmon ◽  
Sympatric Species ◽  
Trophic Niche ◽  
Bite Force ◽  
Optimal Length ◽  
Length Relationship ◽  
Maximum Gape ◽  
Feeding Systems

ABSTRACTAll skeletal muscles produce their largest forces at a single optimal length, losing force when stretched or shortened. In vertebrate feeding systems, this fundamental force–length relationship translates to variation in bite force across gape, which affects the food types that can be eaten effectively. We measured the bite force–gape curves of two sympatric species: king salmon (Oncorhynchus tshawytscha) and pink salmon (Oncorhynchusgorbuscha). Cranial anatomical measurements were not significantly different between species; however, peak bite forces were produced at significantly different gapes. Maximum bite force was achieved at 67% of maximum gape for king salmon and 43% of maximum gape for pink salmon. This may allow king salmon to use greater force when eating large or elusive prey. In contrast, pink salmon do not require high forces at extreme gapes for filter feeding. Our results illustrate that the bite force–gape relationship is an important ecophysiological axis of variation.

scholarly journals Diet and life history reduce interspecific and intraspecific competition among three sympatric Arctic cephalopods

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Alexey V. Golikov ◽  
Filipe R. Ceia ◽  
Rushan M. Sabirov ◽  
Georgii A. Batalin ◽  
Martin E. Blicher ◽  
...  
Keyword(s):  
Intraspecific Competition ◽  
Climate Changes ◽  
Barents Sea ◽  
Marine Species ◽  
Sympatric Species ◽  
Habitat Utilization ◽  
Trophic Niche ◽  
The Arctic ◽  
The Barents Sea ◽  
Isotope Analyses

AbstractTrophic niche and diet comparisons among closely sympatric marine species are important to understand complex food webs, particularly in regions most affected by climate change. Using stable isotope analyses, all ontogenetic stages of three sympatric species of Arctic cephalopods (genus Rossia) were studied to assess inter- and intraspecific competition with niche and diet overlap and partitioning in West Greenland and the Barents Sea. Seven traits related to resource and habitat utilization were identified in Rossia: no trait was shared by all three species. High boreal R. megaptera and Arctic endemic R. moelleri shared three traits with each other, while both R. megaptera and R. moelleri shared only two unique traits each with widespread boreal-Arctic R. palpebrosa. Thus all traits formed fully uncrossing pattern with each species having unique strategy of resource and habitat utilization. Predicted climate changes in the Arctic would have an impact on competition among Rossia with one potential ‘winner’ (R. megaptera in the Barents Sea) but no potential ‘losers’.

Coexistence of morphologically similar bats (Vespertilionidae) on Madagascar: stable isotopes reveal fine-grained niche differentiation among cryptic species

2014 ◽  
Vol 31 (2) ◽  
pp. 153-164 ◽  
Author(s):  
Melanie Dammhahn ◽  
Claude Fabienne Rakotondramanana ◽  
Steven M. Goodman
Keyword(s):  
Stable Isotopes ◽  
Deciduous Forest ◽  
Niche Differentiation ◽  
Sympatric Species ◽  
Trophic Niche ◽  
Trophic Levels ◽  
Seasonal Migration ◽  
Similar Species ◽  
Fine Grained ◽  
Hair Samples

Abstract:Based on niche theory, closely related and morphologically similar species are not predicted to coexist due to overlap in resource and habitat use. Local assemblages of bats often contain cryptic taxa, which co-occur despite notable similarities in morphology and ecology. We measured in two different habitat types on Madagascar levels of stable carbon and nitrogen isotopes in hair (n = 103) and faeces (n = 57) of cryptic Vespertilionidae taxa to indirectly examine whether fine-grained trophic niche differentiation explains their coexistence. In the dry deciduous forest (Kirindy), six sympatric species ranged over 6.0‰ in δ15N, i.e. two trophic levels, and 4.2‰ in δ13C with a community mean of 11.3‰ in δ15N and −21.0‰ in δ13C. In the mesic forest (Antsahabe), three sympatric species ranged over one trophic level (δ15N: 2.4‰, δ13C: 1.0‰) with a community mean of 8.0‰ δ15N and −21.7‰ in δ13C. Multivariate analyses and residual permutation of Euclidian distances in δ13C–δ15N bi-plots revealed in both communities distinct stable isotope signatures and species separation for the hair samples among coexisting Vespertilionidae. Intraspecific variation in faecal and hair stable isotopes did not indicate that seasonal migration might relax competition and thereby facilitate the local co-occurrence of sympatric taxa.

Comparison of the effect of salmon gonadotropin administered by pellet implantation or injection on sexual development of juvenile male pink salmon (Oncorhynchus gorbuscha)

1978 ◽  
Vol 56 (1) ◽  
pp. 86-89 ◽  
Author(s):  
Colin N. MacKinnon ◽  
Edward M. Donaldson
Keyword(s):  
Body Weight ◽  
Chinook Salmon ◽  
Sexual Development ◽  
Oncorhynchus Tshawytscha ◽  
Pink Salmon ◽  
Mitotic Division ◽  
Oncorhynchus Gorbuscha ◽  
Juvenile Male ◽  
Time Intervals ◽  
Pink Salmon Oncorhynchus Gorbuscha

In juvenile male pink salmon complete maturity was induced by September in the year of hatching by both pellet implantation (once per 3 weeks) and injection (thrice weekly) of 1.0μg of chinook salmon (Oncorhynchus tshawytscha) gonadotropin per gram body weight. Time of onset of mitotic division of spermatogonia and rate of spermatogenesis were accelerated in the precociously mature testes. Similar doses of salmon gonadotropin injected at longer time intervals (once per week and once per 2 weeks) resulted in slower maturation.

Induction of precocious sexual development in female pink salmon (Oncorhynchus gorbuscha)

1973 ◽  
Vol 51 (5) ◽  
pp. 493-500 ◽  
Author(s):  
James D. Funk ◽  
Edward M. Donaldson ◽  
Helen M. Dye
Keyword(s):  
Body Weight ◽  
Chinook Salmon ◽  
Sexual Development ◽  
Oncorhynchus Tshawytscha ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Ovarian Maturation ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Large Numbers ◽  
Estradiol 17Β

Acceleration of ovarian maturation was achieved in immature pink salmon (Oncorhynchus gorbuscha) with injections of chinook (spring) salmon (Oncorhynchus tshawytscha) gonadotropin alone, and in combination with estradiol 17β. Oocytes containing yolk globules were evident in fish treated three times per week with 1.0 μg/g body weight salmon gonadotropin in combination with 1.5 μg/g body weight estradiol 17β for 126 days. After 168 days they were also seen in salmon treated with the same dosage of salmon gonadotropin alone. Estradiol 17β alone, at a dosage of 15 μg/g body weight, or in combination with salmon gonadotropin, inhibited vitellogenesis. Formation of oocytes 2 mm in diameter required [Formula: see text] months of treatment with 1.0 μg/g body weight salmon gonadotropin in combination with 1.5 μg/g body weight estradiol 17β, and 9 months of injections with 1.0 μg/g body weight gonadotropin alone. Few large yolky oocytes were developed by any of the treatments. Large numbers of preovulatory corpora atretica were observed in all treated fish.Only a small amount of histochemically demonstrable Δ5-3β hydroxysteroid dehydrogenase activity was present in ovaries from pink or chinook salmon juveniles treated for 3 months with various dosages of salmon gonadotropin.

scholarly journals Optimal length, calcium sensitivity and twitch characteristics of skeletal muscles from mdm mice with a deletion in N2A titin

2019 ◽  
Vol 222 (12) ◽  
pp. jeb200840 ◽  
Author(s):  
Anthony L. Hessel ◽  
Venus Joumaa ◽  
Sydney Eck ◽  
Walter Herzog ◽  
Kiisa C. Nishikawa
Keyword(s):  
Skeletal Muscles ◽  
Calcium Sensitivity ◽  
Optimal Length ◽  
Twitch Characteristics

Fast Deformation of Skeletal Muscle Using Constraint Functions

2010 ◽  
Vol 139-141 ◽  
pp. 903-907
Author(s):  
Xiu Xia Liang
Keyword(s):  
Deformation Process ◽  
Skeletal Muscles ◽  
Muscle Force ◽  
Musculoskeletal Model ◽  
Passive Force ◽  
Fast Speed ◽  
Fast Approach ◽  
Length Relationship ◽  
Anatomical Properties ◽  
The Cost

In this paper, we propose a fast approach to simulate the dynamic behavior of skeletal muscles based on bio-mechanical and anatomical properties. In contrast to physically accurate deformation, this simulation achieves faster and better simulation of skeletal muscles, with the cost of unnoticeable visual accuracy. Internal constrains are generated to conserve linear and angular momentum which is essential for cloth self-collision. Deformation constraints are defined by using the muscle force-length relationship serve as Control Axial Curve, which constrainedly generates the active and passive force of the muscles to drive skeletal motion during the deformation process. This approach generates realistic visual effect, and manages the deformation of muscles on the basis of the bio-mechanical properties with fast speed. We have demonstrated the simulation by creating a musculoskeletal model of the upper limb.

scholarly journals Quantifying trophic niche spaces of small mammals using stable isotopes (δ15N and δ13C) at two scales across Alaska

2015 ◽  
Vol 93 (7) ◽  
pp. 579-588 ◽  
Author(s):  
A.P. Baltensperger ◽  
F. Huettmann ◽  
J.C. Hagelin ◽  
J.M. Welker
Keyword(s):  
Interspecific Competition ◽  
Small Mammals ◽  
Species Interactions ◽  
Species Turnover ◽  
Niche Overlap ◽  
Sympatric Species ◽  
Trophic Niche ◽  
Isotopic Niche ◽  
Climate Conditions ◽  
Hair Samples

Changing climate conditions are causing global distribution shifts, resulting in altered food webs and novel species assemblages in terrestrial systems. How diets of sympatric small mammals overlap and whether this may translate into competitive exclusion among new species interactions remains largely unknown. Monitoring niche overlap in changing arctic and boreal communities can assist in forecasting interspecific competition and species turnover. We quantified the isotopic niche spaces of small mammals, which may reflect dietary niche spaces, at study sites along two megatransects spanning Alaska. Field sampling resulted in the capture of 724 small mammals belonging to 12 species of rodent (10 Arvicolinae and 2 Sciuridae) and 6 species of shrew (genus Sorex L., 1758). We created dietary mixing models based on hair samples for four rodent species using stable isotope (δ15N and δ13C) analyses in R. We also modeled isotopic niche ellipses and quantified niche overlap among species at small and large scales. A varied combination of fungi and herbaceous plants composed the diets of most species. Fundamental niche spaces overlapped considerably between sympatric species statewide, but realized niche spaces were largely segregated at individual sites. We conclude that some degree of dietary plasticity served to partition niche spaces and minimize interspecific competition, allowing sympatric species to co-exist.

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