Search results for "Breed"
showing 10 items of 697 documents
Multiple aspects of plasticity in clutch size vary among populations of a globally-distributed songbird.
2013
Plasticity in life-history characteristics can influence many ecological and evolutionary phenomena, including how invading organisms cope with novel conditions in new locations or how environmental change affects organisms in native locations. Variation in reaction norm attributes is a critical element to understanding plasticity in life history, yet we know relatively little about the ways in which reaction norms vary within and among populations. We amassed data on clutch size from marked females in eight populations of house sparrows (Passer domesticus) from North America and Europe. We exploited repeated measures of clutch size to assess both the extent of within-individual phenotypic …
Prima nidificazione dell'Avocetta, recurvirostra avosetta, in Sicilia
1987
First breeding of Avocet, recurvirosta avosetta, in salt ponds in western Sicily
Interaction of climate change with effects of conspecific and heterospecific density on reproduction
2020
We studied the relationship between temperature and the coexistence of great tit Parus major and blue tit Cyanistes caeruleus, breeding in 75 study plots across Europe and North Africa. We expected an advance in laying date and a reduction in clutch size during warmer springs as a general response to climate warming and a delay in laying date and a reduction in clutch size during warmer winters due to density-dependent effects. As expected, as spring temperature increases laying date advances and as winter temperature increases clutch size is reduced in both species. Density of great tit affected the relationship between winter temperature and laying date in great and blue tit. Specifically…
Variation in clutch size in relation to nest size in birds
2014
© 2014 The Authors. Nests are structures built to support and protect eggs and/or offspring from predators, parasites, and adverse weather conditions. Nests are mainly constructed prior to egg laying, meaning that parent birds must make decisions about nest site choice and nest building behavior before the start of egg-laying. Parent birds should be selected to choose nest sites and to build optimally sized nests, yet our current understanding of clutch size-nest size relationships is limited to small-scale studies performed over short time periods. Here, we quantified the relationship between clutch size and nest size, using an exhaustive database of 116 slope estimates based on 17,472 nes…
Data from: Odor diversity decreases with inbreeding in the ant Hypoponera opacior
2016
Reduction in heterozygosity can lead to inbreeding depression. This loss of genetic variability especially affects diverse loci, such as immune genes or those encoding recognition cues. In social insects, nestmates are recognized by their odor, i.e. their cuticular hydrocarbon profile. Genes underlying hydrocarbon production are thought to be under balancing selection. If so, inbreeding should result in a loss of chemical diversity. We show here that cuticular hydrocarbon diversity decreases with inbreeding. Studying an ant with a facultative inbreeding lifestyle we found inbred workers to exhibit both a lower number of hydrocarbons and less diverse, that is, less evenly-proportioned profil…
Does risk of predation by mammalian predators affect the spacing behaviour of rodents? Two large-scale experiments.
2000
Predator-prey interactions between small mammals and their avian and mammalian predators have attracted much attention. However, large-scale field experiments examining small-mammal antipredatory responses under the risk of predation by mammals are rare. As recently pointed out, the scale of experiments may cause misleading results in studies of decision-making under predation risk. We studied the effect of small mustelid predators on the spacing behaviour of the gray-tailed vole (Microtus canicaudus) and the bank vole (Clethrionomys glareolus) in two separate field enclosure experiments. The experiments were conducted during the breeding season in North America and northern Europe, where s…
Phenotypic Flexibility in the Social Organization of Clethrionomys
1990
I review the flexibility of social organization and spacing behavior in Clethrionomys. This review is based on a 6-year comparative study and several experimental studies on cyclic populations of the bank vole, C. glareolus, in Central Finland. The social organization of Clethrionomys populations shows great flexibility during both the breeding and nonbreeding season, and is dependent on habitat patchiness, food availability, Predation, kinship, philopatry, and familiarity between individuals. The first three factors are most important in destabilizing a population, whereas the last three stabilize a population without exhausting its resources. Female territoriality can weaken in a producti…
A Comparative Study of Phenotypic Changes in Microtus Social Organization
1990
Monogamy, polygyny, and promiscuity have been found in populations of M. oeconomus and M. agrestis in different environmental situations in northern Finland. Thus the mating systems seem to be more variable both between and within species in Microtus than in Clethrionomys. Spacing behavior in Microtus caused a temporary decline in population density in mid-summer, but in Clethrionomys a decline occurred only in the beginning of the breeding season. Habitat quality affected spacing behavior in similar ways in Microtus and Clethrionomys but did not affect differences in breeding limitation. Despite the differences in population regulation, both Clethrionomys and Microtus populations cycle syn…
Genome structure in Sicilian cattle breeds
2014
Genomic technologies provide background information concerning genome structure in domestic animals. The aim of this work was to investigate the genetic structure and the patterns of linkage disequilibrium (LD) in two Sicilian local cattle breeds, Cinisara and Modicana. Genotypes from animals of Italian Holstein breed were also used to investigate the relationship among breeds. Structure software was used to analyze the genetic structure and assign the individuals to each cluster. The genetic relationship between individuals was estimated by Principal Components Analysis (PCA) of genetic distance. A standard descriptive LD parameter (r2) was obtained between adjacent SNPs and for all pairwi…
Jūras piekrastē ligzdojošo putnu ekoloģija
1997
Advisor: Jānis Priednieks