Constitutive and herbivore-induced monoterpenes emitted by Populus × euroamericana leaves are key volatiles that orient Chrysomela populi beetles

Chrysomela populi beetles feed on poplar leaves and extensively damage plantations. We investigated whether olfactory cues orientate landing and feeding. Young, unexpanded leaves of hybrid poplar emit constitutively a blend of monoterpenes, primarily ( E )- β -ocimene and linalool. This blend attracts inexperienced adults of C. populi that were not previously fed with poplar leaves. In mature leaves constitutively emitting isoprene, insect attack induces biosynthesis and emission of the same blend of monoterpenes, but in larger amount than in young leaves. The olfactometric test indicates that inexperienced beetles are more attracted by adult than by young attacked leaves, suggesting that attraction by induced monoterpenes is dose dependent. The blend does not attract adults that previously fed on poplar leaves. Insect-induced emission of monoterpenes peaks 4 d after the attack, and is also detected in non-attacked leaves. Induced monoterpene emission is associated in mature leaves with a larger decrease of isoprene emission. The reduction of isoprene emission is faster than photosynthesis reduction in attacked leaves, and also occurs in non-attacked leaves. Insect-induced monoterpenes are quickly and completely labelled by ¹³C. It is speculated that photosynthetic carbon preferentially allocated to constitutive isoprene in healthy leaves is in part diverted to induced monoterpenes after the insect attack.     

Long-Distance Dispersal of a Rescued Wolf From the Northern Apennines to the Western Alps

ABSTRACT By using Global Positioning System technology, we documented the long-distance dispersal of a wolf (Canis lupus) from the northern Apennines in Italy to the western Alps in France. This is the first report of long-distance dispersal of wolves in the human-dominated landscapes of southern Europe, providing conclusive evidence that the expanding wolf population in the Alps originates from the Apennine source population through natural recolonization. By crossing 4 major 4-lane highways, agricultural areas, and several regional and provincial jurisdictions, the dispersal trajectory of wolf M15 revealed a single, narrow linkage connecting the Apennine and the Alpine wolf populations. This connectivity should be ensured to allow a moderate gene flow between the 2 populations and counteract potential bottleneck effects and reduced genetic variability of the Alpine wolf population. The case we report provides an example of how hard data can be effective in mitigating public controversies originating from the natural expansion and recolonization processes of large carnivore populations. In addition, by highlighting the connectivity between these 2 transboundary wolf populations, we suggest that documenting long-distance dispersal is particularly critical to support population-based, transboundary management programs.     

Influence of diel behaviour in the morphology of decapod natantia

Natantia is a group of decapod species showing morphologically convergent adaptations for swimming behaviour (i.e. the shrimps and prawns morphotype). Different categories are identified in relation to water column or seabed zones where the diel behaviour takes place (i.e. pelagic and nektobenthic submorphotypes). In the present study, we hypothesized a morphological convergence in different pelagic and nektobenthic species based on common nocturnal or diurnal behaviour. We analysed the pattern of morphological variation in 56 Atlanto-Mediterranean species by measuring biometric and morphometric (i.e. landmarks) characters. We also extensively reviewed the literature, recompiling information on species diel behaviour and type of displacement. That information was organized in different grouping variables and their categories: Diel-Behaviour (categories: Diurnal and Nocturnal); Sub-Morphotype (categories: Nektobenthic and Pelagic); and Classification-Status (categories: Penaeidea or Caridea). Soft independent modelling of class analogy analysis was performed per each variable to group species in each category and consequently obtain a morphological model of reference. The results obtained indicate that species sharing the same type of diel behaviour present morphological convergence in characters located in the cephalothorax and rostrum areas. Differences in the size of eyes were not related to nocturnal or diurnal rhythms but to the type of displacement (i.e. pelagic and nektobenthic). The results were interpreted assuming that visual predators exert a morphological selection on natantia depending on the presence o absence of environmental light when animals are active.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 517–532.     

Ecophenotypic variation and phylogenetic inheritance in first lower molar shape of extant Italian populations of Microtus (Terricola) savii (Rodentia)

Seventeen extant populations of Microtus (Terricola) savii have been investigated for correlations of first lower molar shape to climatic variables by means of geometric morphometrics, and controlling for phylogenetic inheritance. Comparative methods revealed that climatic variables and phylogeography provide a very similar contribution to variation in first lower molars morphology, whereas tooth size does not appear to be affected by climatic conditions. Climate‐related changes have been recognized in the anteroconid portion of the tooth. This indicates that molar tooth variation is strongly influenced by climatic conditions, although in a complex way. Calabrian populations, often ascribed to Microtus (Terricola) brachycercus, form a distinct cluster, in agreement with the most recent genetic analyses. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 632–647.     

Fast response of Scots pine to improved water availability reflected in tree‐ring width and δ13C

Drought‐induced forest decline, like the Scots pine mortality in inner‐Alpine valleys, will gain in importance as the frequency and severity of drought events are expected to increase. To understand how chronic drought affects tree growth and tree‐ring δ¹³C values, we studied mature Scots pine in an irrigation experiment in an inner‐Alpine valley. Tree growth and isotope analyses were carried out at the annual and seasonal scale. At the seasonal scale, maximum δ¹³C values were measured after the hottest and driest period of the year, and were associated with decreasing growth rates. Inter‐annual δ¹³C values in early‐ and latewood showed a strong correlation with annual climatic conditions and an immediate decrease as a response to irrigation. This indicates a tight coupling between wood formation and the freshly produced assimilates for trees exposed to chronic drought. This rapid appearance of the isotopic signal is a strong indication for an immediate and direct transfer of newly synthesized assimilates for biomass production. The fast appearance and the distinct isotopic signal suggest a low availability of old stored carbohydrates. If this was a sign for C‐storage depletion, an increasing mortality could be expected when stressors increase the need for carbohydrate for defence, repair or regeneration.     

CO2 emissions from biomass combustion for bioenergy: atmospheric decay and contribution to global warming

Carbon dioxide (CO₂) emissions from biomass combustion are traditionally assumed climate neutral if the bioenergy system is carbon (C) flux neutral, i.e. the CO₂ released from biofuel combustion approximately equals the amount of CO₂ sequestered in biomass. This convention, widely adopted in life cycle assessment (LCA) studies of bioenergy systems, underestimates the climate impact of bioenergy. Besides CO₂ emissions from permanent C losses, CO₂ emissions from C flux neutral systems (that is from temporary C losses) also contribute to climate change: before being captured by biomass regrowth, CO₂ molecules spend time in the atmosphere and contribute to global warming. In this paper, a method to estimate the climate impact of CO₂ emissions from biomass combustion is proposed. Our method uses CO₂ impulse response functions (IRF) from C cycle models in the elaboration of atmospheric decay functions for biomass‐derived CO₂ emissions. Their contributions to global warming are then quantified with a unit‐based index, the GWP_bio. Since this index is expressed as a function of the rotation period of the biomass, our results can be applied to CO₂ emissions from combustion of all the different biomass species, from annual row crops to slower growing boreal forest.