Search results for "evolutionary ecology"

Small, beautiful and sexy: what rotifers tell us about ecology and evolution

2000

Adult coloration of the Bearded Vulture (Gypaetus barbatus) in the Pyrenees: relation to sex, mating system and productivity.

2021

Cosmetic coloration is not a common phenomenon among bird species. Adult Bearded Vultures Gypaetus barbatus typically show orange coloration in head, chest, belly and tarsus feathers that is the result of mud baths in ferruginous substrates. Several non-mutually exclusive visual signalling hypotheses can be proposed to explain this phenomenon. Coloration could be used to signal: (1) dominance towards conspecifics, with darker birds being dominant (status signalling hypothesis); (2) sex (gender signalling hypothesis) because females are usually more intensely coloured; (3) individual quality for mate choice (quality signalling hypothesis); or (4) different reproductive strategies between ind…

Time and energy constraints: reply to Nolet and Klaassen (2005)

2006

Jonathan M. Jeschke, (jonathan.jeschke@gmx.net), Laboratory of Ecological and Evolutionary Dynamics, Dept of Biological and Environmental Sciences, Univ. of Helsinki, P.O. Box 65, FI-00014 Helsinki, Finland; and Evolutionary Ecology Unit, Dept of Biological and Environmental Science, Univ. of Jyvaskyla, P.O. Box 35, FI-40014 Jyvaskyla, Finland. Michael Kopp, Dept Biologie II, Univ. of Munich, Grosshaderner Str. 2, DE-82152 Planegg-Martinsried, Germany. Ralph Tollrian, Biological Sciences, Ruhr-Universitat Bochum, Universitatsstr. 150, DE-44780 Bochum, Germany.

Chemical Cues Influence Pupation Behavior of Drosophila simulans and Drosophila buzzatii in Nature and in the Laboratory.

2012

International audience; In the wild, larvae of several species of Drosophila develop in heterogeneous and rapidly changing environments sharing resources as food and space. In this scenario, sensory systems contribute to detect, localize and recognize congeners and heterospecifics, and provide information about the availability of food and chemical features of environments where animals live. We investigated the behavior of D. simulans and D. buzzatii larvae to chemicals emitted by conspecific and heterospecific larvae. Our goal was to understand the role of these substances in the selection of pupation sites in the two species that cohabit within decaying prickly pear fruits (Opuntia ficus…

Spatially structured interactions between lobsters and lobster fishers in a coastal habitat: fine-scale behaviour and survival estimated from acousti…

2013

Fishing can have profound impacts on the ecology and evolution of marine populations. Understanding population-level changes ultimately depends on knowledge about individual survival and how it varies in time and space. We used acoustic tags and a network of receivers to monitor individual behaviour and fate of European lobster (Homarus gammarus) exposed to commercial and recreational trap fisheries on the Norwegian Skagerrak coast. In August 2011, 50 male lobsters above minimum legal size were tagged and monitored before and during the lobster fishing season. We also quantified the spatial and temporal variation in fishing activity. There was no significant effect of home-range size on th…

Life History Trade-Offs and Relaxed Selection Can Decrease Bacterial Virulence in Environmental Reservoirs

2012

Pathogen virulence is usually thought to evolve in reciprocal selection with the host. While this might be true for obligate pathogens, the life histories of opportunistic pathogens typically alternate between within-host and outside-host environments during the infection-transmission cycle. As a result, opportunistic pathogens are likely to experience conflicting selection pressures across different environments, and this could affect their virulence through life-history trait correlations. We studied these correlations experimentally by exposing an opportunistic bacterial pathogen Serratia marcescens to its natural protist predator Tetrahymena thermophila for 13 weeks, after which we meas…

Phage-driven loss of virulence in a fish pathogenic bacterium

2012

Parasites provide a selective pressure during the evolution of their hosts, and mediate a range of effects on ecological communities. Due to their short generation time, host-parasite interactions may also drive the virulence of opportunistic bacteria. This is especially relevant in systems where high densities of hosts and parasites on different trophic levels (e.g. vertebrate hosts, their bacterial pathogens, and virus parasitizing bacteria) co-exist. In farmed salmonid fingerlings, Flavobacterium columnare is an emerging pathogen, and phage that infect F. columnare have been isolated. However, the impact of these phage on their host bacterium is not well understood. To study this, four s…

Immune-mediated change in the expression of a sexual trait predicts offspring survival in the wild.

2011

9 pages; International audience; BACKGROUND: The "good genes" theory of sexual selection postulates that females choose mates that will improve their offspring's fitness through the inheritance of paternal genes. In spite of the attention that this hypothesis has given rise to, the empirical evidence remains sparse, mostly because of the difficulties of controlling for the many environmental factors that may covary with both the paternal phenotype and offspring fitness. Here, we tested the hypothesis that offspring sired by males of a preferred phenotype should have better survival in an endangered bird, the houbara bustard (Chlamydotis undulata undulata). METHODOLOGY/PRINCIPAL FINDINGS: We…

Ecologie évolutive de la malaria aviaire : approches expérimentales des relations entre Plasmodium relictum et le canari domestique

2010

Host-parasite interaction became one of the main topics of evolutionary sciences researches. One of the major issues raised by these studies is to understand why some parasites cause fatal diseases while others remain relatively mild to their hosts. In this challenge attempting to take up the evolutionary biologist and the medical sciences, we focused on avian malaria, and more specifically on its most common parasite: Plasmodium relictum. In performing experimental infections in domestic canaries (Serinus canaria), we wanted to understand what factors related to parasite and birds characteristics, could influence Plasmodium relictum virulence. We highlighted that factors such as infectious…

Ecological specialization to fluctuating resources prevents long-distance migratory raptors from becoming sedentary on islands

2013

[Background]: The adaptive transition between behavioral strategies, such as the shift from migratoriness to sedentariness, remains an outstanding question in evolutionary ecology. Density-dependent variation in the age of first breeding has been proposed as a feasible mechanism through which long-lived migratory birds with deferred sexual maturity should become sedentary to persist on islands. Although this pattern seems to hold for most raptors and herons, a few exceptions have been identified. One of these exceptions is the Eleonora's falcon, a long-distance migratory bird, which shows one of the most peculiar adaptations in the timing of reproduction and food requirements among raptors.…