The dimensionality of ecological networks

Eklof A., Jacob U., Kopp J., Bosch J., Castro-Urgal R., Chacoff N.P., Dalsgaard B., de Sassi C., Galetti M., Guimaraes P.R., Lomascolo S.B., Martin Gonzalez A.M., Pizo M.A., Rader R., Rodrigo A., Tylianakis J.M., Vazquez D.P., Allesina S. (2013) The dimensionality of ecological networks. Ecology Letters. 16: 577-583.
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Doi: 10.1111/ele.12081

Resum:

How many dimensions (trait-axes) are required to predict whether two species interact? This unanswered question originated with the idea of ecological niches, and yet bears relevance today for understanding what determines network structure. Here, we analyse a set of 200 ecological networks, including food webs, antagonistic and mutualistic networks, and find that the number of dimensions needed to completely explain all interactions is small (

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Floral advertisement scent in a changing plant-pollinators market

Filella I., Primante C., Llusia J., Martin Gonzalez A.M., Seco R., Farre-Armengol G., Rodrigo A., Bosch J., Penuelas J. (2013) Floral advertisement scent in a changing plant-pollinators market. Scientific Reports. 3: 0-0.
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Doi: 10.1038/srep03434

Resum:

Plant-pollinator systems may be considered as biological markets in which pollinators choose between different flowers that advertise their nectar/pollen rewards. Although expected to play a major role in structuring plant-pollinator interactions, community-wide patterns of flower scent signals remain largely unexplored. Here we show for the first time that scent advertisement is higher in plant species that bloom early in the flowering period when pollinators are scarce relative to flowers than in species blooming later in the season when there is a surplus of pollinators relative to flowers. We also show that less abundant flowering species that may compete with dominant species for pollinator visitation early in the flowering period emit much higher proportions of the generalist attractant β-ocimene. Overall, we provide a first community-wide description of the key role of seasonal dynamics of plant-specific flower scent emissions, and reveal the coexistence of contrasting plant signaling strategies in a plant-pollinator market.

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Nest marking behavior and chemical composition of olfactory cues involved in nest recognition in Megachile rotundata

Guedot C., Buckner J.S., Hagen M.M., Bosch J., Kemp W.P., Pitts-Singer T.L. (2013) Nest marking behavior and chemical composition of olfactory cues involved in nest recognition in Megachile rotundata. Environmental Entomology. 42: 779-789.
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Doi: 10.1603/EN13015

Resum:

In-nest observations of the solitary bee, Megachile rotundata (F.), revealed that nesting females apply olfactory cues to nests for nest recognition. On their way in and out of the nest, females drag the abdomen along the entire length of the nest, and sometimes deposit fluid droplets from the tip of the abdomen. The removal of bee-marked sections of the nest resulted in hesitation and searching behavior by females, indicating the loss of olfactory cues used for nest recognition. Chemical analysis of female cuticles and the deposits inside marked nesting tubes revealed the presence of hydrocarbons, wax esters, fatty aldehydes, and fatty alcohol acetate esters. Chemical compositions were similar across tube samples, but proportionally different from cuticular extracts. These findings reveal the importance of lipids as chemical signals for nest recognition and suggest that the nest-marking cues are derived from a source in addition to, or other than, the female cuticle. © 2013 Entomological Society of America.

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