Dissecting biological invasions.

Sol D (2010) Dissecting biological invasions. Trends in Ecology and Evolution 25: 133

Large-brained mammals live longer

González-Lagos C., Sol D., Reader S.M. (2010) Large-brained mammals live longer. Journal of Evolutionary Biology. 23: 1064-1074.
Enllaç
Doi: 10.1111/j.1420-9101.2010.01976.x

Resum:

Many mammals have brains substantially larger than expected for their body size, but the reasons for this remain ambiguous. Enlarged brains are metabolically expensive and require elongated developmental periods, and so natural selection should have favoured their evolution only if they provide counterbalancing advantages. One possible advantage is facilitating the construction of behavioural responses to unusual, novel or complex socio-ecological challenges. This buffer effect should increase survival rates and favour a longer reproductive life, thereby compensating for the costs of delayed reproduction. Here, using a global database of 493 species, we provide evidence showing that mammals with enlarged brains (relative to their body size) live longer and have a longer reproductive lifespan. Our analysis supports and extends previous findings, accounting for the possible confounding effects of other life history traits, ecological and dietary factors, and phylogenetic autocorrelation. Thus, these findings provide support for the hypothesis that mammals counterbalance the costs of affording large brains with a longer reproductive life. © 2010 The Authors. Journal Compilation © 2010 European Society For Evolutionary Biology.

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Predecir el éxito de las especies invasoras.

Vall-llosera M, Sol D (2010) Predecir el éxito de las especies invasoras. Investigación y Ciencia 405: 2-3.

Ant versus bird exclusion effects on the arthropod assemblage of an organic citrus grove

Piñol J., Espadaler X., Cañellas N., MartíNez-Vilalta J., Barrientos J.A., Sol D. (2010) Ant versus bird exclusion effects on the arthropod assemblage of an organic citrus grove. Ecological Entomology. 35: 367-376.
Enllaç
Doi: 10.1111/j.1365-2311.2010.01190.x

Resum:

Predation-exclusion experiments have highlighted that top-down control is pervasive in terrestrial communities, but most of these experiments are simplistic in that they only excluded a single group of predators and the effect of removal was evaluated on a few species from the community. The main goal of our study was to experimentally establish the relative effects of ants and birds on the same arthropod assemblage of canopy trees. We conducted 1-year long manipulative experiments in an organic citrus grove intended to quantify the independent effects of bird and ant predators on the abundance of arthropods. Birds were excluded with plastic nets whereas ants were excluded with sticky barriers on the trunks. The sticky barrier also excluded other ground dwelling insects, like the European earwig Forficula auricularia L. Both the exclusion of ants and birds affected the arthropod community of the citrus canopies, but the exclusion of ants was far more important than the exclusion of birds. Indeed, almost all groups of arthropods had higher abundance in ant-excluded than in control trees, whereas only dermapterans were more abundant in bird-excluded than in control trees. A more detailed analysis conducted on spiders also showed that the effect of ant exclusion was limited to a few families rather than being widespread over the entire diverse spectrum of spiders. Our results suggest that the relative importance of vertebrate and invertebrate predators in regulating arthropod populations largely depends on the nature of the predator-prey system. © 2010 The Authors. Journal compilation © 2010 The Royal Entomological Society.

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Evolutionary divergence in brain size between migratory and resident birds

Sol D., Garcia N., Iwaniuk A., Davis K., Meade A., Boyle W.A., Székely T. (2010) Evolutionary divergence in brain size between migratory and resident birds. PLoS ONE. 5: 0-0.
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Doi: 10.1371/journal.pone.0009617

Resum:

Despite important recent progress in our understanding of brain evolution, controversy remains regarding the evolutionary forces that have driven its enormous diversification in size. Here, we report that in passerine birds, migratory species tend to have brains that are substantially smaller (relative to body size) than those of resident species, confirming and generalizing previous studies. Phylogenetic reconstructions based on Bayesian Markov chain methods suggest an evolutionary scenario in which some large brained tropical passerines that invaded more seasonal regions evolved migratory behavior and migration itself selected for smaller brain size. Selection for smaller brains in migratory birds may arise from the energetic and developmental costs associated with a highly mobile life cycle, a possibility that is supported by a path analysis. Nevertheless, an important fraction (over 68%) of the correlation between brain mass and migratory distance comes from a direct effect of migration on brain size, perhaps reflecting costs associated with cognitive functions that have become less necessary in migratory species. Overall, our results highlight the importance of retrospective analyses in identifying selective pressures that have shaped brain evolution, and indicate that when it comes to the brain, larger is not always better. © 2010 Sol et al.

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