Caterpillar-feeding induces large increases in foliar emissions of methanol, LOX volatiles and monoterpenes by Succisa pratensis.

Peñuelas J, Filella I, Stefanescu C, Llusià J (2005) Caterpillar-feeding induces large increases in foliar emissions of methanol, LOX volatiles and monoterpenes by Succisa pratensis. Geophysical Research Abstracts, Vol. 7, 05404 (p).

Caterpillars of Euphydryas aurinia (Lepidoptera: Nymphalidae) feeding on Succisa pratensis leaves induce large foliar emissions of methanol

Peñuelas J., Filella I., Stefanescu C., Llusià J. (2005) Caterpillars of Euphydryas aurinia (Lepidoptera: Nymphalidae) feeding on Succisa pratensis leaves induce large foliar emissions of methanol. New Phytologist. 167: 851-857.
Enllaç
Doi: 10.1111/j.1469-8137.2005.01459.x

Resum:

• A major new discovery made in the last decade is that plants commonly emit large amounts and varieties of volatiles after damage inflicted by herbivores, and not merely from the site of injury. However, analytical methods for measuring herbivore-induced volatiles do not usually monitor the whole range of these compounds and are complicated by the transient nature of their formation and by their chemical instability. • Here we present the results of using a fast and highly sensitive proton transfer reaction-mass spectrometry (PTR-MS) technique that allows simultaneous on-line monitoring of leaf volatiles in the pptv (pmol mol-1) range. • The resulting on-line mass scans revealed that Euphydryas aurinia caterpillars feeding on Succisa pratensis leaves induced emissions of huge amounts of methanol - a biogeochemically active compound and a significant component of the volatile organic carbon found in the atmosphere - and other immediate, late and systemic volatile blends (including monoterpenes, sesquiterpenes and lipoxygenase-derived volatile compounds). • In addition to influencing neighboring plants, as well as herbivores and their predators and parasitoids, these large emissions might affect atmospheric chemistry and physics if they are found to be generalized in other plant species. © New Phytologist (2005).

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Butterflies highlight the conservation value of hay meadows highly threatened by land-use changes in a protected Mediterranean area

Stefanescu C., Peñuelas J., Filella I. (2005) Butterflies highlight the conservation value of hay meadows highly threatened by land-use changes in a protected Mediterranean area. Biological Conservation. 126: 234-246.
Enllaç
Doi: 10.1016/j.biocon.2005.05.010

Resum:

Butterfly assemblages were used to characterize and evaluate the conservation value of the main habitat types in the Aiguamolls de l'Empordà Natural Park (north-eastern Spain), an important protected wetland area on the Mediterranean coast. Butterfly data were obtained from a number of transects walked as part of the Catalan Butterfly Monitoring Scheme, which uses a standardized methodology for monitoring butterflies. A Mantel test indicated a strong association between habitat types and the composition of butterfly assemblages and a principal component analysis ordinated individual butterfly species along a gradient from woodland to open areas, thereby indicating various degrees of shade tolerance. In addition, cluster analysis distinguished two main groups of habitats based on the similarities of their butterfly fauna: woodland and bramble clumps and a group of three different kinds of grasslands (traditionally hay meadows, pastures, and alfalfa fields). Hay meadows flooded in winter (the so-called closes) appeared always as the highest ranked habitat in terms of conservation evaluation: they have more butterflies and a slight tendency to harbor more and generally rarer species. This conclusion coincides with that of previous investigations that have indicated that the most diverse and rare plant communities in the whole Natural Park are present in the closes, and highlights the importance of traditionally managed hay meadows for wildlife. However, these hay meadows - one of the rarest habitats in the Mediterranean region - are in alarming decline and have become the most threatened habitat in this protected area: no longer profitable, we believe that the future of the closes will depend ultimately on the existence of agri-environmental schemes. © 2005 Elsevier Ltd. All rights reserved.

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