scholarly journals Evidence for Dietary Niche Separation Based on Infraorbital Foramen Size Variation among Subfossil Lemurs

2010 ◽  
Vol 81 (6) ◽  
pp. 330-345 ◽  
Author(s):  
Magdalena N. Muchlinski ◽  
Laurie R. Godfrey ◽  
Kathleen M. Muldoon ◽  
Lydia Tongasoa
Keyword(s):  
Size Variation ◽  
Niche Separation ◽  
Infraorbital Foramen ◽  
Dietary Niche

Review of Data on Diets of Beaked Whales: Evidence of Niche Separation and Geographic Segregation

2003 ◽  
Vol 83 (3) ◽  
pp. 651-665 ◽  
Author(s):  
C.D. MacLeod ◽  
M.B. Santos ◽  
G.J. Pierce
Keyword(s):  
Prey Species ◽  
Stomach Contents ◽  
Published Data ◽  
Niche Separation ◽  
Beaked Whale ◽  
Important Prey ◽  
Wide Range ◽  
Dietary Niche ◽  
Beaked Whales ◽  
Fish Remains

This study reviewed published data on dietary preferences of beaked whales (Ziphiidae) from stomach contents analysis. Detailed data were only available for three of the six beaked whale genera (Hyperoodon, Mesoplodon and Ziphius). Stomach samples of these three beaked whale genera primarily contained cephalopod and fish remains, although some also contained crustaceans. Mesoplodon spp. were found to contain the most fish, with some species containing nothing but fish remains, while the southern bottlenose whale (Hyperoodon planifrons) and Cuvier's beaked whale (Ziphius cavirostris) rarely, if ever, contained fish. Of cephalopods identified, Histioteuthid, Gonatid, Cranchiid and Onychoteuthid species usually contributed most to prey numbers and biomass for all beaked whale genera. There was a wide range of species and families of cephalopods recorded from stomach contents, with no obvious preference for bioluminescent prey species, vertical migrating prey species or prey species with specific body compositions. Whales of the genus Mesoplodon generally contained smaller prey, such as cephalopods under 500 g in weight, compared with other beaked whales. Hyperoodon and Ziphius frequently contained much larger cephalopods with many important prey species having a mean weight of over 1000 g. This suggests that Mesoplodon occupies a separate dietary niche from Hyperoodon and Ziphius, which may be an example of niche segregation. In contrast, Hyperoodon and Ziphius appear to occupy very similar dietary niches but have geographically segregated distributions, with Hyperoodon occupying cold-temperate to polar waters and Ziphius occupying warm-temperate to tropical waters.

Spatial and Size Variation in Dietary Niche of a Non-native Freshwater Fish

2021 ◽  
Vol 109 (2) ◽  
Author(s):  
Phillip J. Haubrock ◽  
Paride Balzani ◽  
Inga Hundertmark ◽  
Ross N. Cuthbert
Keyword(s):  
Freshwater Fish ◽  
Size Variation ◽  
Dietary Niche

scholarly journals The Influence of Seasonal Availability of Young Leaves on Dietary Niche Separation in Two Ecologically Similar Folivorous Lemurs

2021 ◽  
pp. 1-12
Author(s):  
Marco Campera ◽  
Michela Balestri ◽  
Fiona Besnard ◽  
Megan Phelps ◽  
Faniry Rakotoarimanana ◽  
...  
Keyword(s):  
Food Availability ◽  
Niche Separation ◽  
Feeding Time ◽  
Activity Levels ◽  
Lowland Rain Forest ◽  
Phenological Data ◽  
Dietary Shift ◽  
Young Leaves ◽  
Dietary Niche ◽  
The Rich

Traditional socio-ecological models consider that folivorous primates experience limited feeding competition due to the low quality, high abundance, and even distribution of leaves. Evidence from several folivorous species that experience similar constraints to frugivores does not support this hypothesis. The sympatric lemur genera <i>Avahi</i> (Indriidae) and <i>Lepilemur</i> (Lepilemuridae) are good models to understand how food availability constrains folivores since they are both nocturnal, folivorous, and have a comparable body mass. Here we investigate how two nocturnal folivorous primates, <i>Avahi meridionalis</i> and <i>Lepilemur fleuretae</i>, living in the lowland rain forest of Tsitongambarika, South-East Madagascar, partition their dietary niche and are influenced by seasonality of young leaves. To account for food availability, we collected annual phenological data on 769 trees from 200 species. We also collected behavioural data on 5 individuals per lemur species from August 2015 to July 2016 via continuous focal sampling. We found the phenological profile to be seasonal with peaks of leaf flushing, flowering, and fruiting occurring in the austral summer. The two species showed limited dietary overlap (37% rich period, 6% lean period), and <i>A. meridionalis</i> showed higher feeding time and longer daily distances travelled during the rich period. <i>Lepilemur fleuretae</i> showed a dietary shift during the lean period, relying more on mature leaves (73.3% during the lean period, 13.5% during the rich period) but maintaining similar activity levels between seasons. The time spent feeding on food items by <i>A. meridionalis</i> was positively correlated with the nitrogen content and negatively correlated with polyphenols during the rich period. We highlighted a clear effect of the seasonality of young leaves on the diet, nutritional content, activity patterns, and daily distances travelled by two folivorous species, which can be linked to nutrient balancing and time-minimising versus energy-maximising strategies.

Dietary niche separation of rodents and shrews in an African savanna

Biotropica ◽  
2018 ◽  
Vol 50 (3) ◽  
pp. 541-550 ◽  
Author(s):  
Ngawo Namukonde ◽  
Chuma Simukonda ◽  
Jörg U. Ganzhorn
Keyword(s):  
Niche Separation ◽  
African Savanna ◽  
Dietary Niche

Elevated nest predation risk promotes offspring size variation in birds with prolonged parental care.

2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser
Keyword(s):  
Predation Risk ◽  
Reproductive Cycle ◽  
Perceived Risk ◽  
Nest Predation ◽  
Bird Species ◽  
Size Variation ◽  
Egg Laying ◽  
Offspring Size ◽  
Natural Predation ◽  
Risk Spreading

Predation of offspring is the main cause of reproductive failure in many species, and the mere fear of offspring predation shapes reproductive strategies. Yet, natural predation risk is ubiquitously variable and can be unpredictable. Consequently, the perceived prospect of predation early in a reproductive cycle may not reflect the actual risk to ensuing offspring. An increased variance in investment across offspring has been linked to breeding in unpredictable environments in several taxa, but has so far been overlooked as a maternal response to temporal variation in predation risk. Here, we experimentally increased the perceived risk of nest predation prior to egg-laying in seven bird species. Species with prolonged parent-offspring associations increased their intra-brood variation in egg, and subsequently offspring, size. High risk to offspring early in a reproductive cycle can favour a risk-spreading strategy particularly in species with the greatest opportunity to even out offspring quality after fledging.

High-Temperature Synthesis of CdSe-Based Core/Shell, Core/Shell/Shell, and Core/Graded-Shell Nanoplatelets for Stable and Efficient Narrowband Emitters

2019 ◽  
Author(s):  
Aurelio A. Rossinelli ◽  
Henar Rojo ◽  
Aniket S. Mule ◽  
Marianne Aellen ◽  
Ario Cocina ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Temperature ◽  
Equilibrium Shape ◽  
Size Variation ◽  
Crystal Defects ◽  
Atomic Scale ◽  
Quantum Yields ◽  
Core Shell ◽  
Compositional Gradient ◽  
High Quality

<div>Colloidal semiconductor nanoplatelets exhibit exceptionally narrow photoluminescence spectra. This occurs because samples can be synthesized in which all nanoplatelets share the same atomic-scale thickness. As this dimension sets the emission wavelength, inhomogeneous linewidth broadening due to size variation, which is always present in samples of quasi-spherical nanocrystals (quantum dots), is essentially eliminated. Nanoplatelets thus offer improved, spectrally pure emitters for various applications. Unfortunately, due to their non-equilibrium shape, nanoplatelets also suffer from low photo-, chemical, and thermal stability, which limits their use. Moreover, their poor stability hampers the development of efficient synthesis protocols for adding high-quality protective inorganic shells, which are well known to improve the performance of quantum dots. <br></div><div>Herein, we report a general synthesis approach to highly emissive and stable core/shell nanoplatelets with various shell compositions, including CdSe/ZnS, CdSe/CdS/ZnS, CdSe/Cd<sub>x</sub>Zn<sub>1–x</sub>S, and CdSe/ZnSe. Motivated by previous work on quantum dots, we find that slow, high-temperature growth of shells containing a compositional gradient reduces strain-induced crystal defects and minimizes the emission linewidth while maintaining good surface passivation and nanocrystal uniformity. Indeed, our best core/shell nanoplatelets (CdSe/Cd<sub>x</sub>Zn<sub>1–x</sub>S) show photoluminescence quantum yields of 90% with linewidths as low as 56 meV (19.5 nm at 655 nm). To confirm the high quality of our different core/shell nanoplatelets for a specific application, we demonstrate their use as gain media in low-threshold ring lasers. More generally, the ability of our synthesis protocol to engineer high-quality shells can help further improve nanoplatelets for optoelectronic devices.</div>

Documenting Intraspecfic Genome Size Variation in Soybean

Crop Science ◽  
2004 ◽  
Vol 44 (1) ◽  
pp. 261 ◽  
Author(s):  
A. Lane Rayburn ◽  
D. P. Biradar ◽  
R. L. Nelson ◽  
R. McCloskey ◽  
K. M. Yeater
Keyword(s):  
Genome Size ◽  
Size Variation ◽  
Genome Size Variation
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