Search results for "Red"

Alternative prey can change model-mimic dynamics between parasitism and mutualism

2003

Classical (conventional) Mullerian mimicry theory predicts that two (or more) defended prey sharing the same signal always benefit each other despite the fact that one species can be more toxic than the other. The quasi-Batesian (unconventional) mimicry theory, instead, predicts that the less defended partner of the mimetic relationship may act as a parasite of the signal, causing a fitness loss to the model. Here we clarify the conditions for parasitic or mutualistic relationships between aposematic prey, and build a model to examine the hypothesis that the availability of alternative prey is crucial to Mullerian and quasi-Batesian mimicry. Our model is based on optimal behaviour of the pr…

Changing winter conditions in the boreal forest : the effects of fluctuating temperature and predation risk on activity and physiological stress leve…

2016

Due to global climate change, the winter conditions in the North are predicted to change, as the time with an intact insulating snow cover gets shorter or disappears altogether. For small mammals, this could cause exposure to strong temperature fluctuations and increased predation risk, inducing severe stress and leading to alterations in the physical condition and behavior. To test this, we exposed bank voles (Myodes glareolus) to different temperature regimes and cues of predator threat under laboratory conditions. The test animals experienced either a stable but cool temperature regime resembling the stable conditions under snow cover, or an unstable temperature regime with cold nights a…

Phenology of Emergence by Mediterranean Sympatric Cave-Dwelling Bats During Their Breeding Period

2017

The emergence of cave-dwelling bats can be influenced by multiple variables, such as diurnal predator evasion, energetic requirements, and prey abundance. This work aimed to determine emergence patterns of cave-dwelling bat species from roosts over the April–July 2013 period in the Valencian Community (East Spain) by infrared camera and acoustic recordings. We observed that Miniopterus schreibersii left earliest followed by the Myotis myotis/blythii group and Myotis capaccinii and finally Myotis escalerai. This pattern of emergence was observed in four roosts with no significant differences. Miniopterus schreibersii tended to display quicker flight in open areas, compared to the Myotis genu…

Male mating success and risk of predation in a wolf spider: a balance between sexual and natural selection?

1998

1.  Traits that benefit males through sexual selection are simultaneously expected to impair males by provoking costs through natural selection. If we consider the two male fitness components, mating success and viability, then we may expect that the increase in male mating success resulting from a larger trait size will be counterbalanced by an increase in viability costs. 2.  We studied the benefits and costs of male mate searching and sexual signalling activity in the wolf spider Hygrolycosa rubrofasciata. In the field, males search females actively and court them by drumming dry leaves with their abdomen. Females have been shown to prefer males with high drumming rate. Male moving and e…

Deceiving predators: linking distraction behavior with nest survival in a ground-nesting bird

2016

Gene expression levels influence amino acid usage and evolutionary rates in endosymbiotic bacteria

2005

International audience; Most endosymbiotic bacteria have extremely reduced genomes, accelerated evolutionary rates, and strong AT base compositional bias thought to reflect reduced efficacy of selection and increased mutational pressure. Here, we present a comparative study of evolutionary forces shaping five fully sequenced bacterial endosymbionts of insects. The results of this study were three-fold: (i) Stronger conservation of high expression genes at not just nonsynonymous, but also synonymous, sites. (ii) Variation in amino acid usage strongly correlates with GC content and expression level of genes. This pattern is largely explained by greater conservation of high expression genes, l…

A miniature world in decline. European Red List of Mosses, Liverworts and Hornworts

2019

AimThis Red List is a summary of the conservation status of the European species of mosses, liverworts and hornworts, collectively known as bryophytes, evaluated according to IUCN’s Guidelines for Application of IUCN Red List Criteria at Regional Level. It provides the first comprehensive, region-wide assessment of bryophytes and it identifies those species that are threatened with extinction at a European level, so that appropriate policy measures and conservation actions, based on the best available evidence, can be taken to improve their status.ScopeAll bryophytes native to or naturalised in Europe (a total of 1,817 species), have been included in this Red List. In Europe, 1,796 species …

Numerical response of predators to large variations of grassland vole abundance and long‐term community changes

2020

Abstract Voles can reach high densities with multiannual population fluctuations of large amplitude, and they are at the base of predator communities in Northern Eurasia and Northern America. This status places them at the heart of management conflicts wherein crop protection and health concerns are often raised against conservation issues. Here, a 20‐year survey describes the effects of large variations in grassland vole populations on the densities and the daily theoretical food intakes (TFI) of vole predators based on roadside counts. Our results show how the predator community responded to prey variations of large amplitude and how it reorganized with the increase in a dominant predator…

Diversity of foraging strategies and responses to predator interference in seed-eating carabid beetles

2019

12 pages; International audience; The prediction of pest regulation by multi-predator communities often remains challenging because of variable and opposite effects of niche complementarity and predator interference. Carabid communities are regulating weeds in arable fields and include a mix of species ranging from granivores to predators that are obligate omnivores. It is not clear from field studies whether granivore and obligate omnivore species either contribute equally or are complementary in the process of weed suppression, and little is known about the impact of potential predator interference within carabid communities on weed suppression. We compared the weed seed foraging strategy…

Habitat fragmentation and anthropogenic factors affect wildcat Felis silvestris silvestris occupancy and detectability on Mt Etna

2019

International audience; Knowledge of patterns of occupancy is crucial for planning sound biological management and for identifying areas which require paramount conservation attention. The European wildcat Felis silvestris is an elusive carnivore and is classified as ‘least concern' on the IUCN red list, but with a decreasing population trend in some areas. Sicily hosts a peculiar wildcat population, which deserves conservation and management actions, due to its isolation from the mainland. Patterns of occupancy for wildcats are unknown in Italy, and especially in Sicily. We aimed to identify which ecological drivers determined wildcat occurrence on Mt Etna and to provide conservation actio…