Are the metabolomic responses to folivory of closely related plant species linked to macroevolutionary and plant–folivore coevolutionary processes?

The debate whether the coevolution of plants and insects or macroevolutionary processes (phylogeny) is the main driver determining the arsenal of molecular defensive compounds of plants remains unresolved. Attacks by herbivorous insects affect not only the composition of defensive compounds in plants but also the entire metabolome. Metabolomes are the final products of genotypes and are constrained by macroevolutionary processes, so closely related species should have similar metabolomic compositions and may respond in similar ways to attacks by folivores. We analyzed the elemental compositions and metabolomes of needles from three closely related Pinus species with distant coevolutionary histories with the caterpillar of the processionary moth respond similarly to its attack. All pines had different metabolomes and metabolic responses to herbivorous attack. The metabolomic variation among the species and the responses to folivory reflected their macroevolutionary relationships, with P. pinaster having the most divergent metabolome. The concentrations of terpenes were in the attacked trees supporting the hypothesis that herbivores avoid plant individuals with higher concentrations. Our results suggest that macroevolutionary history plays important roles in the metabolomic responses of these pine species to folivory, but plant–insect coevolution probably constrains those responses. Combinations of different evolutionary factors and trade‐offs are likely responsible for the different responses of each species to folivory, which is not necessarily exclusively linked to plant–insect coevolution.     

Taphonomic signature of golden eagles (Aquila chrysaetos) on bone prey remains

Abstract

The golden eagle (Aquila chrysaetos) is one of the most important birds of prey in the Northern Hemisphere. This raptor is used to building large nests in high cliffs to which they return for several breeding years accumulating important amounts of their prey skeletal remains. This makes the golden eagle one of the major predators able to accumulate faunal remains in archaeological sites. Despite this fact, the taphonomic signature of golden eagles has not been properly characterized. Here we present the analysis of ingested and non-ingested faunal remains predated and accumulated by this raptor in two different nesting areas from the Iberian Peninsula. Results show how the faunal taxonomic record may vary depending on the ecological zone. Leporids and terrestrial carnivores are the best represented. The observed anatomical representation, breakage and bone surface modification patterns are discussed for different taxa. The taphonomic pattern varies depending on the type of prey and the origin of skeletal materials (non-ingested vs. pellets). Finally, after comparing our results with marks left by other predators, several characteristic features are noted to recognise golden eagles as agents of animal bones accumulations in the fossil record.     

Forest Type Influences Population Densities of Nocturnal Lemurs in Manompana,Northeastern Madagascar

Forest loss, fragmentation, and anthropization threaten the survival of forest species all over the world. Shifting agriculture is one of these threatening processes in Madagascar. However, when its cycle is halted and the land is left to regenerate, the resulting growth of secondary forest may provide a viable habitat for folivorous and omnivorous lemur species. We aimed to identify the response of nocturnal lemurs to different successional stages of regenerating secondary, degraded mature, and mature forest across a mosaic-type landscape. We surveyed four nocturnal lemur species (Avahi laniger, Microcebus cf. simmonsi, Allocebus trichotis, and Daubentonia madagascariensis) in four forest types of varying habitat disturbance in northeastern Madagascar. We estimated densities in mature and regenerating secondary forest for the eastern woolly lemur (Avahi laniger) and mouse lemur (Microcebus cf. simmonsi), two sympatric species with folivorous and omnivorous diets respectively. We did not estimate densities of Allocebus trichotis and Daubentonia madagascariensis owing to small sample size; however, we observed both species exclusively in mature forest. We found higher population densities of A. laniger and M. cf. simmonsi in secondary than in mature forest, showing the potential of regenerating secondary forest for lemur conservation. Several environmental factors influenced the detectability of the two lemur species. While observer and habitat type influenced detection of the eastern woolly lemur, canopy height and vine density influenced detection of mouse lemurs. Understanding how different species with different diets interact with anthropogenically impacted habitat will aid future management decisions for the conservation of primate species.     

Nanosecond dynamics of horse heart apocytochrome c in aqueous solution as studied by time-resolved fluorescence of the single tryptophan residue (Trp-59)

The time-resolved fluorescence emission characteristics of the single tryptophan residue (Trp-59) of horse heart apocytochrome c--the precursor of the intramitochondrial cytochrome c--were studied in aqueous solution. The total fluorescence intensity decay measured over the whole emission spectrum was analyzed as a sum of three or four exponentials by the nonlinear least-squares method, the last model always providing a slight but significant decrease in the chi 2 values. Maximum entropy analysis, recently developed for time-resolved fluorometry (Livesey et al., 1987; Livesey & Brochon, 1987), strongly suggests the existence of a distribution including at least four separate classes of lifetimes. The center values were around 0.1-0.2, 1, 3, and 5 ns, in agreement with the lifetime values obtained by nonlinear least-squares regression analysis. As a function of the emission wavelength, these values remained constant within the experimental error, whereas a redistribution of the fractional amplitudes was observed: the contributions of the short components increased in the blue edge region of the emission spectrum. Temperature increase led essentially to a redistribution of the fractional amplitudes, affecting mostly that of the 5-ns component, which almost totally disappeared at high temperature (35-40 degrees C). The lifetime values were not significantly affected except for the 3-ns component, which decreased by about 15% in the temperature range studied. Such observations strongly suggest that the protein exists under different conformational substates in thermal equilibrium. Time-resolved fluorescence anisotropy measurements evidenced the existence of fast internal rotation of the Trp residue. An average maximum restricted angle of rotation of around 55 degrees was calculated. A second internal motion, slower by 1 order of magnitude, corresponding likely to a local motion of the peptide chain involving the Trp-59 residue, was detected on the anisotropy decay curve. Finally, the longest correlation time (5 ns) should correspond to the average rotation of the overall protein. Its value doubled as a function of the protein concentration, revealing an association process leading most likely to a dimer in the concentration range studied (2-139 microM). The flexibility of the peptide chain was more restrained in the associated than in the monomeric form, but the fast internal rotation of the Trp residue was not.     

Sex differences in growth rates of Yellow-legged Gull Larus michahellis chicks

Capsule: Chick growth rates was sex-dependent in an Atlantic Yellow-legged Gull Larus michahellis population.

Aims: To describe the growth rate of Yellow-legged Gull chicks and sex-associated variations, and obtain a discriminant function to sex them using morphological data.

Methods: Fifty-two Yellow-legged Gull chicks from a colony in northern Iberia were measured for body mass, head and bill length, tarsus length and three other bill-length associated variables, from the hatching date up to the age of 36 days. Birds were sexed using DNA analysis.

Results: Using logistic models, chick growth rates was observed to be similar between the sexes, while the asymptote was higher among males for the majority of the variables. Discriminant analyses showed that the variable head+bill was very reliable to predict the sex of >80% of chicks at an early developmental stage, and 100% of chicks if combined with tarsus length and two more bill-length associated variables at the age of 35 days.

Conclusions: This is the first study using a discriminant analysis to sex Yellow-legged Gull chicks, and also the first to describe the growth function for the species. The growth rate varied between sexes because males showed higher asymptote values within the growth function.