نتایج جستجو برای: seasonal availability

تعداد نتایج: 208251  

Journal: :The Journal of experimental biology 2013
Lucy M Turner Simon G Webster Stephen Morris

There is a growing body of evidence implicating the involvement of crustacean hyperglycaemic hormone (CHH) in ionic homeostasis in decapod crustaceans. However, little is known regarding hormonally influenced osmoregulatory processes in terrestrial decapods. As many terrestrial decapods experience opposing seasonal demands upon ionoregulatory physiologies, we reasoned that these would make inte...

In recent years, Nigeria witnessed significant labour migration coupled with reduction in rural agricultural productivity. Youths abandoned farms for ventures with high returns and less drudgery in cities thus labour availability in peak agricultural seasons became scarce. The declining farm population constituting mostly women and old men are not capable of producing sufficient food for the no...

Journal: :The American naturalist 2008
Susan Lingle Alex Feldman Mark S Boyce W Finbarr Wilson

Variation in the temporal pattern of vulnerability can provide important insights into predator-prey relationships and the evolution of antipredator behavior. We illustrate these points with a system that has coyotes (Canis latrans) as a predator and two species of congeneric deer (Odocoileus spp.) as prey. The deer employ different antipredator tactics (aggressive defense vs. flight) that resu...

2017
Kasper Thorup Anders P Tøttrup Mikkel Willemoes Raymond H G Klaassen Roine Strandberg Marta Lomas Vega Hari P Dasari Miguel B Araújo Martin Wikelski Carsten Rahbek

Migratory birds track seasonal resources across and between continents. We propose a general strategy of tracking the broad seasonal abundance of resources throughout the annual cycle in the longest-distance migrating land birds as an alternative to tracking a certain climatic niche or shorter-term resource surplus occurring, for example, during spring foliation. Whether and how this is possibl...

2011
Qiong Zhou Ping Xie Jun Xu Xufang Liang Jianhui Qin Te Cao Feizhou Chen

We evaluated the seasonal variation in the contributions of planktonic and benthic resources to 11 littoral predators in eutrophic Lake Taihu (China) from 2004 to 2005. Seasonal fluctuations in consumer delta 13C and delta 15N were attributed to the combined impacts of temporal variation in isotopic signatures of basal resources and the diet shift of fishes. Based on a two-end-member mixing mod...

Journal: :Biological reviews of the Cambridge Philosophical Society 2012
Philipp Zerbe Marcus Clauss Daryl Codron Laurie Bingaman Lackey Eberhard Rensch Jürgen W Streich Jean-Michel Hatt Dennis W H Müller

Many ruminant species show seasonal patterns of reproduction. Causes for this are widely debated, and include adaptations to seasonal availability of resources (with cues either from body condition in more tropical, or from photoperiodism in higher latitude habitats) and/or defence strategies against predators. Conclusions so far are limited to datasets with less than 30 species. Here, we use a...

Journal: :Psychiatry (Edgmont (Pa. : Township)) 2008
Steven D Targum Norman Rosenthal

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