Search results for "SEL"
showing 10 items of 14031 documents
Vessel noise pollution as a human threat to fish: assessment of the stress response in gilthead sea bream (Sparus aurata, Linnaeus 1758)
2016
This study examined the effects of boat noise pollution on the stress indices of gilthead sea bream (Sparus aurata, Linnaeus 1758). To assess the stress response in these fish, biometric values and plasma parameters such as ACTH, cortisol, glucose, lactate, haematocrit, Hsp70, total protein, cholesterol, triglycerides and osmolarity were analysed. After acclimatization of the animals, the experiment was carried out in a tank fitted with underwater speakers where the fish were exposed to sound treatments (in duplicate) consisting of: 10 days of no sound (control treatment; the animals were only exposed to the experimental tank’s background noise) and 10 days of noise derived from original re…
Energetic costs of size and sexual signalling in a wolf spider
1998
A prerequisite for honest handicaps is that there are significant condition–dependent costs in the expression of sexual traits. In the wolf spider Hygrolycosa rubrofasciata (Ohlert), sexual signalling (drumming) is costly in terms of increased mortality. Here we investigated whether this mortality may be caused by increased energy expenditure. During sexual signalling, metabolic rate was 22 times higher than at rest and four times higher than when males were actively moving. Metabolic rate per unit mass was positively related to absolute body mass during sexual signalling but not during other activities. This positive relationship is novel to any studies of metabolic rates. Indeed, it seems…
Cost-effective forest conservation and criteria for potential conservation targets: a Finnish case study
2008
International audience; Selecting reserves for forest biodiversity maintenance is often done by setting criteria for components of structural elements of biodiversity, such as a volume of decaying wood. We tested how the different threshold values for the components of structural elements affect the cost-effective site selection. Using Finnish National Forest Inventory information and remote sensing data, we determined a habitat quality index and economic value for each site in Satakunta region in Finland. Moreover, we defined several sets of potential conservation targets using alternative criteria for the habitat quality index developed for the Finnish case study. These figures were used …
Functional responses of intertidal bivalves to repeated sub-lethal, physical disturbances
2019
In coastal habitats, physical disturbances of benthic organisms can be caused by natural events like wave-born objects and human activity like trampling, and these disturbances can be sub-lethal (e.g., resulting in the organism's displacement). We know little of how sessile organisms respond to physical disturbances such as displacements. Using Mytilaster minimus, a mussel that is native to the Mediterranean Sea, we tested how byssus production and oxygen uptake rates changed in response to different frequencies of disturbance events (10-60 events h-1). Mussels increased oxygen uptake rates but not byssus production with increasing disturbance frequencies (50-60 events h-1). Our results sho…
Extended haplodiploidy hypothesis
2019
P.R., M.P., and H.H. were supported by Academy of Finland (grant 258385 to M.P., grant 135970 to H.H., and 252411 to the Centre of Excellence in Biological Interactions), P.R. also by the Royal Society Newton International Fellowship, and H.H. also by the Kone Foundation. Evolution of altruistic behavior was a hurdle for the logic of Darwinian evolution. Soon after Hamilton formalized the concept of inclusive fitness, which explains how altruism can evolve, he suggested that the high sororal relatedness brought by haplodiploidy could be why Hymenopterans have a high prevalence in eusocial species, and why helpers in Hymenoptera are always female. Later it was noted that in order to capitali…
Male health status, signalled by courtship display, reveals ejaculate quality and hatching success in a lekking species.
2010
8 pages; International audience; Summary 1. The information content of secondary sexual traits and the benefits gathered by choosy females are at the heart of sexual selection theory. Indicator models of sexual selection assume that secondary sexual traits reflect the phenotypic/genetic quality of their bearers and that females gather benefits from choosing these high-quality males. 2. Here, we tested the idea that courtship display reflects the health status in a bird species with a lek-based mating system, the houbara bustard (Chlamydotis undulata undulata). A group of males was treated with the lipopolysaccharide (LPS) of the cell wall of the bacterium Escherichia coli during the seasona…
Correlational selection on pro- and anti-inflammatory effectors.
2012
9 pages; International audience; Parasites impose a permanent threat for hosts. As a consequence, immune defenses are important for host fitness. However, the immune response can also produce self-damage and impair host fitness if not properly regulated. Effectors that up- and downregulate the immune response should, therefore, evolve in concert, and be under the action of correlational selection. To address this issue, we assessed the shape of the selection operating on pro- and anti-inflammatory effectors following an inflammatory challenge in laboratory mice. We found that selection acts on the combination of these two traits as individuals that produced large amount of pro-inflammatory …
Can number and size of offspring increase simultaneously?--a central life-history trade-off reconsidered.
2011
Abstract Background To maximize their fitness, parents are assumed to allocate their resources optimally between number and size of offspring. Although this fundamental life-history trade-off has been subject to long standing interest, its genetic basis, especially in wild mammals, still remains unresolved. One important reason for this problem is that a large multigenerational pedigree is required to conduct a reliable analysis of this trade-off. Results We used the REML-animal model to estimate genetic parameters for litter size and individual birth size for a common Palearctic small mammal, the bank vole (Myodes glareolus). Even though a phenotypic trade-off between offspring number and …
Island selection on mammalian life-histories: genetic differentiation in offspring size
2008
Abstract Background Since Darwin's pioneering work, evolutionary changes in isolated island populations of vertebrates have continued to provide the strongest evidence for the theory of natural selection. Besides macro-evolutionary changes, micro-evolutionary changes and the relative importance of natural selection vs. genetic drift are under intense investigation. Our study focuses on the genetic differentiation in morphological and life-history traits in insular populations of a small mammal the bank vole Myodes glareolus. Results Our results do not support the earlier findings for larger adult size or lower reproductive effort in insular populations of small mammals. However, the individ…
The Bruce effect revisited: is pregnancy termination in female rodents an adaptation to ensure breeding success after male turnover in low densities?
2017
Pregnancy termination after encountering a strange male, the Bruce effect, is regarded as a counterstrategy of female mammals towards anticipated infanticide. While confirmed in caged rodent pairs, no verification for the Bruce effect existed from experimental field populations of small rodents. We suggest that the effect may be adaptive for breeding rodent females only under specific conditions related to populations with cyclically fluctuating densities. We investigated the occurrence of delay in birth date after experimental turnover of the breeding male under different population composition in bank voles (Myodes glareolus) in large outdoor enclosures: one-male–multiple-females (n = 6 p…