Populations at the warm edge of distribution are more genetically diverse, and at the same time are more susceptible to climate change. Between 1987-1996, we studied Tawny Owls in Israel, the species' global southern edge of distribution and a country undergoing a rapid land cover transformation for over a century. To assess the potential impacts of land cover transformation, we modelled the species' most suitable habitat and climate and analyzed how climate and habitat affected the nesting success and prey selection.
View Article and Find Full Text PDFStudies in Passerines have found that migrating species recruit more new neurons into brain regions that process spatial information, compared with resident species. This was explained by the greater exposure of migrants to spatial information, indicating that this phenomenon enables enhanced navigational abilities. The aim of the current study was to test this hypothesis in another order-the Columbiformes - using two closely-related dove species-the migrant turtle-dove () and the resident laughing dove (), during spring, summer, and autumn.
View Article and Find Full Text PDFNew neuronal recruitment in an adult animal's brain is presumed to contribute to brain plasticity and increase the animal's ability to contend with new and changing environments. During long-distance migration, birds migrating greater distances are exposed to more diverse spatial information. Thus, we hypothesized that greater migration distance in birds would correlate with the recruitment of new neurons into the brain regions involved with migratory navigation.
View Article and Find Full Text PDFWe report that two species of mouse-tailed bats (Rhinopoma microphyllum and R. cystops) hibernate for five months during winter in geothermally heated caves with stable high temperature (20°C). While hibernating, these bats do not feed or drink, even on warm nights when other bat species are active.
View Article and Find Full Text PDFEvidence suggests a possible correlation between learning abilities of adults and new neuronal recruitment into their brains. The hypothesis is that this brain plasticity enables animals to adapt to environmental changes. We examined whether there are differences in neuronal recruitment between resident and migrant birds.
View Article and Find Full Text PDFWe used a recent passerine phylogeny and comparative method to evaluate the macroevolution of body and egg mass, incubation and fledging periods, time to independence and time with parents of the main passerine lineages. We hypothesised that passerine reproductive traits are affected by adaptation to both past and present environmental factors and phenotypic attributes such as body mass. Our results suggest that the evolution of body and egg mass, time to independence, incubation and fledging times are affected by strong phylogenetic inertia and that these breeding traits are all affected by body mass.
View Article and Find Full Text PDFCompetition has long been assumed to be a major driver in regulating ecological communities. Intra-specific competition is considered to be maximal as members of the same species use the same ecological niches in a similar way. Many species of animals exhibit great physiological, behavioral, and morphological differences between sexes (sexual dimorphism).
View Article and Find Full Text PDFPrior to hibernation, mammals accumulate large amounts of fat in their bodies. In temperate mammalian species, hibernation is improved by increasing the levels of poly-unsaturated fatty acids (PUFA) in the body. The saturation of fatty acids (FA) in both white adipose tissue (WAT) and membrane phospholipids of mammals often reflects their diet composition.
View Article and Find Full Text PDFBackground: The native rodents of Australia are commonly divided into two groups based on the time of their colonization of the Sahulian continent, which encompasses Australia, New Guinea, and the adjacent islands. The first group, the "old endemics," is a diverse assemblage of 34 genera that are descended from a single colonization of the continent during the Pliocene. A second group, the "new endemics," is composed of several native Rattus species that are descended from a single colonization during the Pleistocene.
View Article and Find Full Text PDFWe studied the effect of various factors on body size variation of the Eurasian lynx in Norway, using data from 374 lynx collected between 1960 and 1976 and whose locality of capture, year of birth, sex, and age were known. Body size of lynx in Norway was mainly affected by sex and age. Female skull size (and by implication body size) was also positively affected by the availability of its main prey (roe deer) and by latitude, and negatively by the North Atlantic Oscillation (NAO).
View Article and Find Full Text PDFWe studied geographical and temporal body size trends among 169 adult museum specimens of the Eurasian otter (Lutra lutra) collected in Sweden between 1962 and 2008, whose sex, year of collection, and locality were known. Skull size and body mass increased significantly in relation to the year of collection, and skull size (but not body mass) was significantly and negatively related to latitude, contrasting Bergmann's rule and the trend found for Norwegian otters. Latitudinal differences in body size between the two countries may be due to differences in food availability.
View Article and Find Full Text PDFBiol Rev Camb Philos Soc
May 2011
Geographical and temporal variations in body size are common phenomena among organisms and may evolve within a few years. We argue that body size acts much like a barometer, fluctuating in parallel with changes in the relevant key predictor(s), and that geographical and temporal changes in body size are actually manifestations of the same drivers. Frequently, the principal predictors of body size are food availability during the period of growth and ambient temperature, which often affects food availability.
View Article and Find Full Text PDFNaturwissenschaften
April 2009
In many ant species, nuptial flight tends to be short in time and assumed to be synchronous across a large area. Here, we report that, in the upper Jordan Valley, northern Israel, massive nuptial flights of Carpenter ants (Camponotus sp.) occur frequently throughout the summer, and their alates form up to 90% of the diet of the greater mouse-tailed bat (Rhinopoma microphyllum) during this period.
View Article and Find Full Text PDFThe lynx Lynx canadensis is a common predator in the boreal forests of North America. Its population fluctuates during a 9- to 11-year cycle in synchrony with the population size of its main prey, the snowshoe hare Lepus americanus. Using adult museum specimens, we studied changes in skull (and hence body) size of the lynx in Alaska during the second half of the 20th century.
View Article and Find Full Text PDFVector Borne Zoonotic Dis
February 2007
The transmission of harmful pathogens during commercial air flights is an increasing health concern. A potential, yet relatively overlooked source of zoonotic infectious diseases involves collisions of birds and bats with aircraft and long distance transport of their carcasses. We report a case of aerial transportation of the remains of an African fruit bat over three continents, following a collision with an aircraft, and demonstrate the relative ease with which zoonotic pathogens, such as rabies virus or other viruses associated with bats, may cross national boundaries and continents even.
View Article and Find Full Text PDFUsing museum data of adult specimens whose sex, age, and locality are known, we studied temporal and geographical body size trends among the otter, Lutra lutra, in Norway. We found that body size of the otters increased during the last quarter of the twentieth century, and suggest that this trend is related to increased food availability from fish farming and possibly also to energy saving due to elevated sea temperatures. Birth year and death year explained 38.
View Article and Find Full Text PDFPatterns of ecotypic variation constitute some of the few 'rules' known to modern biology. Here, we examine several well-known ecogeographical rules, especially those pertaining to body size in contemporary, historical and fossil taxa. We review the evidence showing that rules of geographical variation in response to variation in the local environment can also apply to morphological changes through time in response to climate change.
View Article and Find Full Text PDFLatitudinal trends in body size have been explained as a response to temperature- or water-related factors, which are predictors of primary production. We used the first principal component calculated from three body parameters (weight, body length and the greatest length of the skull) of a sample of mammals from Israel and Sinai to determine those species that vary in size geographically, and whether such variation is related to annual rainfall, average minimum January temperature and average maximum August temperature. We used a conservative approach to discern the effects of precipitation and temperature by applying sequential regression.
View Article and Find Full Text PDFWe studied characteristics of the Syrian woodpecker (Dendrocopos syriacus) cavities in the field and a laboratory model, and rates of gas exchange in the laboratory. Night temperature of occupied cavities is 4.3 degrees C higher than empty ones, representing energy savings of approximately 24%.
View Article and Find Full Text PDFThe reproductive rates of about 50 species of Australian rodents were studied by calculating allometric equations for the relationships between female body weight, litter size, length of gestation and weaning periods as well as age of sexual maturity.Members of the subfamily Hydromyinae, which invaded Australia 5-10 million years ago, are characterised by small litters, long gestation and weaning periods and late maturity. The opposite is true for the Murinae (Rattus and Mus) which invaded Australia during the Pleistocene.
View Article and Find Full Text PDFSupplemental food, in the form of millet seed, was provided to half of an island Song Sparrow population during the 1978-1979 winter to test if winter food influenced: (1) overwinter survival; (2) winter wights; (3) breeding density in 1979 and (4) 1979 breeding performance.Territorial males were most dominant at feeders and may have restricted access of young to feeders. Young females were most subordinate at feeders.
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