Search results for "evolution"

Native egg parasitoids recorded from the invasive Halyomorpha halys successfully exploit volatiles emitted by the plant–herbivore complex

2017

When an accidentally introduced pest establishes in the invaded area, native natural enemies may adapt to the new host. A decade after the accidental introduction of the brown marmorated stink bug, Halyomorpha halys, in Europe, two generalist native egg parasitoids, the eupelmid Anastatus bifasciatus and the encyrtid Ooencyrtus telenomicida, have been recorded from this invasive agricultural pest in the field. Both species are able to complete development to the adult stage within the new host. Trissolcus basalis (Platygastridae = Scelionidae), which is not associated with H. halys in the field, was reared from freeze-killed sentinel eggs placed on soybean plants in central Italy. We tested…

Beta diversity of stream insects differs between boreal and subtropical regions, but land use does not generally cause biotic homogenization

2021

Made available in DSpace on 2021-06-25T10:17:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-03-01 Previous studies have found mixed results regarding the relationship between beta diversity and latitude. In addition, by influencing local environmental heterogeneity, land use maymodify spatial taxonomic and functional variability among communities causing biotic differentiation or homogenization. We tested 1) whether taxonomic and functional beta diversities among streams within watersheds differ between subtropical and boreal regions and 2) whether land use is related to taxonomic and functional beta diversities in both regions.Wesampled aquatic insects in 100 subtropical (Brazil…

Monuments Unveiled: Genetic Characterization of Large Old Chestnut (Castanea sativa Mill.) Trees Using Comparative Nuclear and Chloroplast DNA Analys…

2020

Large old trees are extraordinary organisms. They not only represent a historical, landscape and environmental heritage of inestimable value, but they also witness a long history of environmental changes and human interventions, and constitute an as yet poorly known reserve of genetic variability which can be considered a great resource for management programs of forest species. This is the first genetic study on Italian, large, old chestnut trees (Castanea sativa Mill.). Ninety-nine trees were surveyed and analysed. For each tree, more than one sample from canopy and root suckers was collected to test for the genetic integrity of the individuals. All samples were genotyped using nine nucle…

Sex ratio at mating does not modulate age fitness effects in Drosophila melanogaster

2019

Abstract Understanding the effects of male and female age on reproductive success is vital to explain the evolution of life history traits and sex‐specific aging. A general prediction is that pre‐/postmeiotic aging processes will lead to a decline in the pre‐ and postcopulatory abilities of both males and females. However, in as much the sexes have different strategies to optimize their fitness, the decline of reproductive success late in life can be modulated by social context, such as sex ratio, in a sex‐specific manner. In this study, we used Drosophila melanogaster to investigate whether sex ratio at mating modulates age effects on male and female reproductive success. As expected, male…

Long-term carbon stock recovery in a neotropical-logged forest

2019

AbstractThis article assesses the effect of different logging levels on loss of above-ground biomass and the contribution of different ecological groups of species in the long-term recovery of C st...

2018

Assessing the potential of marine Natura 2000 sites to produce ecosystem‐wide effects in rocky reefs: A case study from Sardinia Island (Italy)

2019

A number of policy measures have been adopted to cope with ongoing ocean degradation. Marine protected areas (MPAs) are among them. MPAs and their coverage have increased worldwide, including in EU waters. Natura 2000 (Nat2000) sites are at the core of the EU biodiversity conservation strategy and have been established to protect habitats and species included in two EU directives. Besides their specific objectives, their potential to contribute to an ecosystem-wide conservation and their complementarity with other national and supranational initiatives (e.g. nationally established MPA networks, the Marine Strategy Framework Directive, the Convention on Biological Diversity Ecosystem-Based A…

Temporal variability in detritus resource maintains diversity of bacterial communities

2008

Competition theory generally predicts that diversity is maintained by temporal environmental fluctuations. One of the many suggested mechanisms for maintaining diversity in fluctuating environments is the gleaner-opportunist trade-off, whereby gleaner species have low threshold resource levels and low maximum growth rates in high resource concentration while opportunist species show opposite characteristics. We measured the growth rates of eight heterotrophic aquatic bacteria under different concentrations of chemically complex plant detritus resource. The growth rates revealed gleaner-opportunist trade-offs. The role of environmental variability in maintaining diversity was tested in a 28-…

Forest responses to last-millennium hydroclimate variability are governed by spatial variations in ecosystem sensitivity.

2020

Forecasts of forest responses to climate variability are governed by climate exposure and ecosystem sensitivity, but ecosystem model projections and process representations are under-constrained by data at multidecadal and longer timescales. Here, we assess ecosystem sensitivity to centennial-scale hydroclimate variability, by comparing dendroclimatic and pollen-inferred reconstructions of drought, forest composition and biomass for the last millennium with five ecosystem model simulations. In both observations and models, spatial patterns in ecosystem responses to hydroclimate variability are strongly governed by ecosystem sensitivity rather than climate exposure. Ecosystem sensitivity was…

Benthic mats offer a potential subsidy to pelagic consumers in tundra pond food webs

2014

We quantified the potential nutritional contribution of benthic mats to pelagic consumers in tundra ponds using three approaches. (1) We compared benthic and pelagic habitats based on their algal biomass and community composition and assessed the dietary quality in terms of fatty acid (FA) concentrations in both habitats. The algal community compositions differed significantly between habitats. Both benthic and pelagic habitats contained saturated and unsaturated FAs, but on average there were more FAs relative to carbon in the pelagic habitat (44 6 29 m gm g C21) than the benthic habitat (23 6 18 m gm g C21) across all studied ponds. (2) We quantified the contribution of benthic mats to th…