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Since in laboratory experiments a relationship between segment number and temperature in geophilomorph centipedes has been proven, we suggest that climatic variation in nature could have a direct effect on segment number. To address this hypothesis we examine the way in which local climatic factors in Sognefjord — air temperature and precipitation both changing along a longitudinal gradient — exert their effect on segment number in Geophilus flavus. Changes in G. flavus segment number along the climatic gradient are similar to that found in previous laboratory experiments with Strigamia maritima, but are even more pronounced. In G. flavus, a 1.5 difference in the mean segment number is found in populations that occur in Sognefjord along a temperature gradient of only about 1.4 °C. In contrast, several degrees centigrade were required to produce a similar increase in the mean segment number in laboratory experiments involving S. maritima.
We tested the usefulness of silicone casts for gathering morphological data from free-ranging wildlife by documenting the tracheobronchial anatomy of the Eurasian lynx (Lynx lynx). The silicone compound accurately reproduced the main aspects of the tracheobronchial branching but the demonstration of smaller airways was less accurate. Evaluation of air-inflated specimens and tracheobronchial casts showed that the right lung consisted of cranial, middle, caudal and accessory lobes, whereas the left lung was divided into cranial and caudal lobes. The left cranial lobe was further divided into cranial and caudal parts. The right cranial lobar bronchus was almost tracheal in location. The trachea had an average of 37 cartilages that showed a pattern of random anastomoses between adjacent cartilages. The silicone compound tested in this study holds promise for its use also under field conditions to gather quantitative morphological data.
The study of the spatial distribution of phenotypic and genetic diversity of pollinators has conservation implications since pollination is a key ecosystem function and a basis for the maintenance of biodiversity. The impact of landscape heterogeneity on the population structure of the important hoverfly pollinator, Eristalis tenax (Diptera, Syrphidae), was investigated. Allele frequencies at allozyme loci, wing traits (size and shape) and abdominal colour pattern were compared using samples from eight locations in the Durmitor National Park, Montenegro. These locations covered a broad range of altitudes and vegetation structures, from deciduous and coniferous forests to alpine meadows. From the conservation point of view, we investigated to what extent the localities in the Durmitor mountain range are connected. Results indicated a lack of population structure in the study area. A genetic clustering analyses based on Bayesian model revealed no resolution among samples, coinciding with FST estimates. Weak genetic differentiation was accompanied by wing size and shape similarity. In addition, there was an overlap between the levels of abdominal colour variation among samples supporting the negative association between gene flow and phenotypic divergence in E. tenax. We conclude that the surrounding landscape is of no relevance to the species movement capabilities. The availability of many sites for E. tenax and its strong dispersal capacity might make the study region a more or less continuous habitat for this species. Thus, our results may contribute to understanding the potential extent to which E. tenax can facilitate gene flow among isolated plant populations on Mt. Durmitor.
Costs of immunity are widely believed to play an important role in life history evolution, but many studies of ecological immunology have considered only single aspects of immunity. Young of altricial birds, while dependent primarily on innate immunity and maternally derived antibodies for immune defence, have to develop all components of the immune system which could generate resource-based trade-offs among different arms and between growth and immunity. We conducted a study on nestling pied flycatchers Ficedula hypoleuca in which we measured levels of natural antibodies (NAbs) and hemolysis, estimated serum immunoglobulin levels and obtained a specific measure of inflammation after inoculation of an antigen, phytohaemagglutinin (PHA). Thus we obtained independent estimates to explore the relationships among different arms of the immune system. We found that no immune variable measured was associated with any other variable at the individual and brood levels. This indicates that different aspects of immunity are independent and difficult to integrate in a general measure of immune response capacity in altricial nestling birds. We found that only NAbs was negatively associated with tarsus length at the age of 7 days, but not later. Thus, the evidence for resource-based trade-offs between nestling growth and immunity is weak in our study population.
It has long been known that there is an allometric relationship between metabolic rate (M) and body weight (W) of the form: M = M0Wb. However, the debate remains open regarding the value of b. Only recently research turned to the ecological implications of existing differences in metabolic scaling among taxa. Using a data set on forest soil invertebrates, we evaluated the influence of differences in intraspecific metabolic rate scaling on observed species biomass and abundance distributions. We found that absolute densities and biomass were correlated with the exponents of the intraspecific metabolic scaling. Evenness of the abundance distributions and species diversity were also moderately linked to b. These results suggest that the shape of the intraspecific metabolic-rate—body-size relationship affects interspecific biomass and abundance distributions. This emphasizes the importance of intraspecific variations in allometric scaling and indicates the need to take these variations into account when proposing models to explain these relationships.
Due to their reclusive nature, information on the population structure of many bat species is lacking or scarce. The pattern of small scale population genetic structure could reveal the degree of gene flow among colonies, and the evolutionary consequences of short-distance dispersal. In this study, we used nine microsatellite loci to assess the small-scale genetic population structure of Daubenton's bats in the Archipelago Sea comparing it to samples from sites elsewhere in Finland and Europe. The Archipelago Sea is a highly variable environment with possible dispersal barriers. Our results indicate a low level of population genetic structuring among the populations sampled. We found significant isolation by distance in both sexes, indicating a gradual increase of population differentiation across a large geographic scale. In Finland alone, isolationby-distance was also found, with high levels of gene flow among local populations. Isolation-by-distance was stronger in females, suggesting that males disperse longer distances.
We studied the effects of small-scale disturbance on breeding, forest passerine birds in an old-growth and managed boreal forests in northern Finland. Small-scale disturbance (< 2 ha) in an old-growth and managed forests originated from wind falls and small clear cuts. Continuous forest without gaps was used as a control for both management types (old-growth and managed forests). Passerines' response to disturbance was examined by estimating species richness and abundance of different ecological groups. Species richness and the total abundance of birds did not differ between gap and non-gap plots, neither did the abundance of most ecological groups. Management type or study year were the most important factors explaining abundances. Our results differ from studies conducted in temperate forests, mainly in North America, where small-scale disturbance have been found to increase avian diversity and abundance. Differences between boreal and temperate forests or in avian assemblages between continents may explain observed differences.
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