Search results for "Study"
showing 10 items of 15483 documents
Population asynchrony alone does not explain stability in species‐rich soil animal assemblages: The stabilizing role of forest age on oribatid mite c…
2020
The importance of microbial and plant communities in the control of the diversity and structure of soil animal communities has been clarified over the last decade. Previous research focused on abiotic factors, niche separation and spatial patterns. Significant gaps still exist in our knowledge of the factors that control the stability of these communities over time. We analysed a 9-year dataset from the national Long-term Ecological Research Network of Latvia. We focused on 117 oribatid species from three Scots pine forests of different age (40, 65 and150 years) and structure. For each forest type, 100 samples were collected each year, providing very high replication and long time series fo…
Latitudinal clines in the timing and temperature‐sensitivity of photoperiodic reproductive diapause in Drosophila montana
2020
Reproductive diapause is a primary mechanism used by arthropods to synchronize their life cycle with seasonal changes in temperate regions. Our study species, Drosophila montana, represents the northern insect species where flies enter reproductive diapause under short day conditions and where the precise timing of diapause is crucial for both survival and offspring production. We have studied clinal variation in the critical day length for female diapause induction (CDL) and their overall susceptibility to enter diapause (diapause incidence), as well as the temperature sensitivity of these traits. The study was performed using multiple strains from four latitudinal clines of the species – …
Conservation implications of change in antipredator behavior in fragmented habitat: Boreal rodent, the bank vole, as an experimental model
2015
Abstract Habitat fragmentation is known to cause population declines but the mechanisms leading to the decline are not fully understood. Fragmentation is likely to lead to changes in predation risk, which may cause behavioral responses with possible population level consequences. It has recently been shown that the awareness of predator presence, resulting in a fear response, strongly affects behavior and physiology of the prey individuals. Costs arising from fear may be as important for the prey population size as the direct killing of prey. We tested how predation risk in the form of scent of a specialist predator, the least weasel (Mustela nivalis nivalis), affects bank vole (Myodes glar…
Genetic analysis of organoleptic quality in fresh market tomato. 1. Mapping QTLs for physical and chemical traits
2001
Improving organoleptic quality is an important but complex goal for fresh market tomato breeders. A total of 26 traits involved in organoleptic quality variation were evaluated, in order to understand the genetic control of this characteristic. A recombinant inbred line (RIL) population was developed from an intraspecific cross between a cherry tomato line with a good overall aroma intensity and an inbred line with a common taste but with bigger fruits. Physical traits included fruit weight, diameter, color (L,a,b), firmness and elasticity. Chemical traits were dry matter weight, titratable acidity, pH, and the contents of soluble solids, sugars, lycopene, carotene and 12 aroma volatiles. R…
Do peahens not prefer peacocks with more elaborate trains?
2008
Ever since Darwin (1871), the peacock’s train has been cited as the icon of an extravagant conspicuous secondary sexual trait that has evolved through female mate choice. However, Takahashi et al. (2008) recently challenged this idea. They monitored female mate choice during 7 years in a feral peafowl, Pavo cristatus, population in Japan and found no correlation between male mating success and three morphological train traits. They concluded that ‘combined with previous results, our findings indicate that the peacock’s train is not currently the universal target of female choice’ and proposed ‘that the peacock’s train is an obsolete signal for which female preference has already been lost o…
New national and regional bryophyte records, 44
2015
Syntrichia norvegica is a circumpolar arctic- montane species (Smith, 2004), rare at lower altitudes and in southern Europe (Frey et al., 2006). It is known from several south-eastern European countries (Sabovljevic et al., 2008) and now it is recorded for the first time in Croatia. Regarding its conservation status, S. norvegica is red listed in Great Britain (EN), Czech Republic (CR), Slovakia (VU), Bulgaria (NT), Hungary (DD), Romania (VU) and Estonia (VU) (Hodgetts, 2014). It was found in the northern Velebit Mountains, in an area with the most outstanding and extreme karst relief, with steep slopes, perpendicular rocks, screes and deep dolines. The locality is situated in the Pinus mug…
Genetic structure of a European forest species, the edible dormouse ( Glis glis ): a consequence of past anthropogenic forest fragmentation?
2019
International audience; The genetic structure of forest animal species may allow the spatial dynamics of the forests themselves to be tracked. Two scales of change are commonly discussed: changes in forest distribution during the Quaternary, due to glacial/interglacial cycles, and current fragmentation related to habitat destruction. However, anthropogenic changes in forest distribution may have started well before the Quaternary, causing fragmentation at an intermediate time scale that is seldom considered. To explore the relative role of these processes, the genetic structure of a forest species with narrow ecological preferences, the edible dormouse (Glis glis), was investigated in a set…
Acoustic signalling in a wolf spider: can signal characteristics predict male quality?
2000
While there has been considerable interest in female choice for male sexual signals, there have been few studies of the underlying information that different aspects of the signal calls convey. Such studies, however, are essential to understand the significance of signals as honest handicaps, arbitrary Fisherian traits and/or in species recognition. We studied the somewhat exceptional system of audible drumming in the wolf spider Hygrolycosa rubrofasciata. We estimated the repeatabilities of signal components, the levels of between-male variance, the symmetry of the signal, the correlations between different aspects of drumming and their correlations with body weight. While in other taxa th…
Is a change in juvenile hormone sensitivity involved in range expansion in an invasive beetle?
2015
Introduction: It has been suggested that rapid range expansion could proceed through evolution in the endocrinological machinery controlling life-history switches. Based on this we tested whether the Colorado potato beetle, Leptinotarsa decemlineata, which has rapidly expanded its range across latitudinal regions in Europe, and shows photoperiodic adaptation in overwintering initiation, has different sensitivities to juvenile hormone (JH) manipulation along a latitudinal gradient. Results: A factorial experiment where beetles were reared either under a long or short day photoperiod was performed. Hormone levels were manipulated by topical applications. An allatostatin mimic, H17, was used t…
Genetic structure of a greenhouse population of the spider mite Tetranychus urticae: spatio-temporal analysis with microsatellite markers.
2002
International audience; The genetic structure of a greenhouse population of the mite Tetranychus urticae was studied by the analysis of five microsatellite loci. Genetic variation was compared during a crop season between periods of population foundation and rapid population increase and was investigated in two consecutive years. The population displayed significant heterozygote deficiency at all the sampling periods. However, inbreeding tended to decrease with increasing density (FIS coefficient between 0.13 and 0.25). No significant genetic differentiation between samples was found either at a spatial scale within the greenhouse or at a temporal scale between two growing seasons (FST betw…