Saló d'Actes Laboratori de Natura,
Museu de Ciències Naturals
Passeig Picasso s/n, Barcelona
Dilluns, 11 d’abril 2011.
17:00 – 19:00h
Björn Rogell
Population Biology Dept., Evolutionary Biology Centre, Uppsala. Sweden
The effect of drift and selection on life-history traits among managed and natural populations of sea trout Salmo trutta.
Several endangered or economically important populations are today managed by ex-situ rearing. If the ex-situ rearing conditions induces adaptive changes of traits, this management strategy may be harmful for the part of the population facing native selection pressures. In Sweden the sea trout (Salmo trutta) is managed by rearing parts of the populations in hatchery between the egg and the smolting stage that is released into the stream. Here we employ a QST-FST approach to investigate local adaptations in survival until, and size at, the smolting stage across managed and unmanaged populations of the sea trout. We found evidence for local adaptations in survival and size with the managed populations having a larger probability for survival and a larger size. The results indicate that different management strategies may
induce local adaptations in life history traits.
Josefin Sundin
Animal Ecology Dept., Evolutionary Biology Centre, Uppsala. Sweden
Sexual signalling in a changing environment
Stable as well as variable environments are becoming increasingly unpredictable because of human induced environmental change. In order to persist, both opportunists and specialists respond to these changes. We use pipefish as our study organism, which is a group of sex-role reversed, highly specialized marine fish. Pipefish have evolved in close relation to seagrass, which they mimic in colour, shape and behaviour. Their vision system is very sophisticated, with eyes that can be moved independent of each other. Pipefish are dependent on vision when they feed, but also during courtship and mating. Seagrass meadows are exposed to human induced changes, amongst all in the form of eutrophication and over fishing, which leads to phytoplankton blooms and extreme growth of filamentous algae. Water turbidity reduces visibility and such changes may in turn affect animal behaviour as well as evolutionary processes that are dependent on visual stimuli. We have shown that pipefish strongly avoids this new environment if possible, but in the case of no choice we show the effects of turbidity on the genetic mating system, mate choice and search, as well as reproductive success.
Mårten Hjernquist
Animal Ecology, Evolutionary Biology Centre, Uppsala. Sweden
Reproductive decisions in a variable environment: Patterns of sex allocation, paternity and the use of public information in the socially monogamous Collared Flycatcher (Ficedula albicollis).
The environment is often variable and heterogeneous and the fitness return of a reproductive decision will vary between environments. Moreover, it can be costly to gather personal or firsthand information about the environment, especially for long distance migrants. The collared
flycatchers breeding on the island of Gotland in the Baltic Sea are long distance migratory passerine birds which form socially monogamous pairs. About 35 % of all broods contains offspring that has been fathered by another male then the social father resulting in about 15-20 % extrapair young (EPY) over all. In some areas sex ratios are also biased. These reproductive decisions are associated to male ornamentation, density of breeding birds, territory and habitat quality as well as interactions between them. Information about environmental characteristics is also acquired by observing other resident species reproductive decisions that are inadvertently advertised as cues for habitat quality.
Mirjam Amcoff
Animal Ecology Dept., Evolutionary Biology Centre, Uppsala. Sweden
Sensory exploitation in the swordtail characin
Mate choice plays an important role in sexual selection. But why should an individual choose to mate with one individual over another? This is especially intriguing in cases where choosy individuals only gain indirect benefits from the mate and where the trait used as a criterion for the choice is clearly costly to its bearer. The sensory exploitation hypothesis offers an interesting explanation to the evolution of mate preferences by suggesting that sexual preferences may arise as side effects of preferences that are under direct selection (natural or sexual) in another context. The swordtail characin (Corynopoma riisei) is a fish species in which the males display a flag-like ornament, growing from the operculum, which has been proposed to work as a food mimic. Using this species as a model I, together with my supervisor associate professor, Niclas
Kolm, have been testing the prediction that changes in natural selection should, through sensory exploitation, lead to changes in sexual selection. Using direct experimental manipulations, we have found evidence supporting the hypothesis that the preference for this ornament has evolved through sensory exploitation by acting as a food mimic and that females respond to the ornament as if it was food. Moreover, we show a high plasticity in female preference for male ornaments that is linked to environmental variation.
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