Search results for "social science"

Emigration speed and the production of sexuals in colonies of the ant Temnothorax crassispinus under high and low levels of disturbance

2015

A nest relocation is costly for social insects, and involves hazards. Emigrations were studied in Temnothorax crassispinus ant colonies, which inhabit ephemeral nest sites, and which frequently change their nests. In a laboratory experiment, ant colonies from one group were forced to change their nest sites 10 times over a ca. 3-month period, whilst colonies from the second group were forced to adopt this practice twice (on the beginning of May, and in the second half of July). Colonies of the ant from both the groups reduced their total emigration duration. However, the duration of the transport phase remained unchanged. In the case of colonies with higher level of disturbance, there was n…

Iridescent (angle-dependent reflectance) properties of dorsal coloration in Podarcis muralis (Laurenti, 1768)

2016

Iridescence is a visual property of those surfaces that change in colour with viewing angle. Iridescence has been rarely reported in reptiles, but some snakes and lizards show this type of coloration. Here we study the effect of different angles of light incidence and observation on the spectrophotometrically assessed reflectance of dorsal coloration in the lizard Podarcis muralis. The results demonstrate clear angle dependence of several colour parameters. In particular, different angles of light incidence and observation result in changes in hue of more than 30 nm. This suggests that lizard dorsal coloration may be perceived, depending on viewing geometry, as being of different colours by…

Spatio‐temporal patterns of tree growth as related to carbon isotope fractionation in European forests under changing climate

2019

Aim The aim was to decipher Europe‐wide spatio‐temporal patterns of forest growth dynamics and their associations with carbon isotope fractionation processes inferred from tree rings as modulated by climate warming. Location Europe and North Africa (30‒70° N, 10° W‒35° E). Time period 1901‒2003. Major taxa studied Temperate and Euro‐Siberian trees. Methods We characterize changes in the relationship between tree growth and carbon isotope fractionation over the 20th century using a European network consisting of 20 site chronologies. Using indexed tree‐ring widths (TRWi), we assess shifts in the temporal coherence of radial growth across sites (synchrony) for five forest ecosystems (Atlantic…

Predators' consumption of unpalatable prey does not vary as a function of bitter taste perception

2020

Many prey species contain defensive chemicals that are described as tasting bitter. Bitter taste perception is, therefore, assumed to be important when predators are learning about prey defenses. However, it is not known how individuals differ in their response to bitter taste, and how this influences their foraging decisions. We conducted taste perception assays in which wild-caught great tits (Parus major) were given water with increasing concentrations of bitter-tasting chloroquine diphosphate until they showed an aversive response to bitter taste. This response threshold was found to vary considerably among individuals, ranging from chloroquine concentrations of 0.01 mmol/L to 8 mmol/L.…

Does beak coloration of male blackbirds play a role in intra and/or intersexual selection?

2002

In many bird species, males may show brightly coloured traits and variance in male mating success may be explained by female preference and/or competition between males favouring the most coloured males. Male beak coloration has been suggested to play an important role in the pairing pattern of European blackbirds. Here, we investigate female preference and male-male interactions in relation to male beak coloration in this species. We used a field experiment to measure female and male responses toward stuffed decoys showing either of two beak coloration representing the extremes of the natural variation from yellow to orange. Decoys were situated on the centre of plots and behaviours of mal…

2019

Assessing the added value of the recent declaration on unregulated fishing for sustainable governance of the central Arctic Ocean

2016

Accepted manuscript version. Published version available at https://doi.org/10.1016/j.marpol.2016.01.013. Accepted manuscript version, licensed CC BY-NC-ND 4.0. The ‘Declaration concerning the prevention of unregulated high seas fishing in the central Arctic Ocean’ signed by the Arctic 5 nations, limits unregulated high seas fishing in the central part of the Arctic Ocean, and holds potential social, economic and political impacts for numerous stakeholders. In this paper, the four Interim Measures in the Declaration are discussed and what value these measures bring beyond the existing international agreements is explored. It is found that even though the Declaration fills a gap in the manag…

Mechanisms of reciprocity and diversity in social networks: a modeling and comparative approach

2018

Individual-based computer models show that different mechanisms, proximity-based or emotional bookkeeping, can lead to reciprocation. By comparing social networks from different computer models with those of empirical data, we show that the models’ social networks bear limited resemblance with some features of the observed social networks. This indicates that additional social processes (third-party awareness) may be needed in these models to represent more accurately the social behavior and interaction patterns observed in group-living animals.

Population abundance, structure and movements of the European pond turtle, Emys orbicularis (Linnaeus 1758) based on capture-recapture data in a Veni…

2021

A freshwater turtle monitoring programme along the inland margins of the Venice lagoon was initiated in 2019 in collaboration with the World Wild Fund for Nature (WWF-Italy). From a total of 336 European pond turtles (Emys orbicularis) captured and marked, 97 freshwater turtles were recaptured at least once (28.9% return rate) providing important information on population size, structure and movements of mature individuals within the study area. The population size was estimated with capture-recapture method (Capture-Mark-Recapture-CMR) at 1009.4 ± 365.2 pond turtles, with a mean density of 252.3 ± 91.3 ind./ha. The analysis of the movements showed that the average distance covered intra-wa…

Parameter identification and state estimation of a microalgae dynamical model in sulphur deprived conditions: Global sensitivity analysis, optimizati…

2014

International audience; In this article, a dynamic model describing the growth of the green microalgae Chlamydomonas reinhardtii , under light attenuation and sulphur‐deprived conditions leading to hydrogen production in a photobioreactor is presented. The strong interactions between biological and physical phenomena require complex mathematical expressions with an important number of parameters. This article presents a global identification procedure in three steps using data from batch experiments. First, it includes the application of a sensitivity function analysis, which allows one to determine the parameters having the greatest influence on model outputs. Secondly, the most influentia…