Search results for "RED"
showing 10 items of 23890 documents
The roles of temperature, nest predators and information parasites for geographical variation in egg covering behaviour of tits (Paridae)
2020
Abstract Aim: Nest building is widespread among animals. Nests may provide receptacles for eggs, developing offspring and the parents, and protect them from adverse environmental conditions. Nests may also indicate the quality of the territory and its owner and can be considered as an extended phenotype of its builder(s). Nests may, thus, function as a sexual and social signal. Here, we examined ecological and abiotic factors—temperature, nest predation and interspecific information utilization—shaping geographical variation in a specific nest structure—hair and feather cover of eggs—and its function as an extended phenotype before incubation in great (Parus major) and blue tits (Cyanistes …
Is in vitro micrografting a possible valid alternative to traditional micropropagation in Cactaceae? Pelecyphora aselliformis as a case study
2016
Several taxa of Cactaceae are endangered by overcollection for commercial purposes, and most of the family is included in the Convention on International Trade in Endangered Species of Fauna and Flora (CITES). Micropropagation may play a key role to keep the pressure off wild populations and contribute to ex situ conservation of endangered taxa. One of the limits of micropropagation is the species-specific requirement of plant regulators for each taxon and sometimes even for different genotypes. With the micrografting technique the rootstock directly provides the scion with the necessary hormonal requirements. In this paper we present data on in vitro grafting of Pelecyphora aselliformis Eh…
Species specificity of trail pheromones of fungus-growing termites from northern Vietnam
2001
Trail-following pheromones were studied in four fungus-growing termites from northern Vietnam: Macrotermes annandalei, M. barneyi, Odontotermes hainanensis and O. maesodensis. From bioassays, we suggest that trail pheromones of these species are composed of a common or anony-mous signal, as well as species-specific signals. The anonymous signal has been identified by GC-MS as (Z)-dodec-3-en-1-ol for each species from extracts of sternal glands and from solid phase microextraction of the surface of their sternal gland. This compound is secreted in much higher quantities (up to 1.4 ng/worker) than dodecatrienol, another anonymous signal of trail-following in termites. (Z)-dodec-3-en-1-ol is a…
Filling gaps: closing the life cycle of the endangered Mediterranean limpet Patella ferruginea Gmelin, 1791 (Gastropoda, Patellidae)
2020
Several reproductive issues and the larval development of the ferruginous limpet, Patella ferruginea Gmelin, 1791, an endangered species endemic from the western Mediterranean Sea, were studied to fill gaps in the knowledge of its life cycle. Average diameter of mature oocytes was 141.83 μm and mean oocyte density in the ovary was 283,800 oocytes/gram. No significant correlations were found between both oocyte diameter or density and female shell length. Female fecundity (number of oocytes per gonad) was significantly correlated with shell length and varied between 189,200 oocytes in a 40.0 mm female and 5,019,200 oocytes in an 86.4 mm female. However, there was considerable variability, in…
Risk assessment for Iberian birds under global change
2013
Conservation priority areas and programs are often established without consideration of future changes in species distributions. However, global change is expected to threaten the persistence of several species while offering opportunities for range expansion to others. In this study, building on previous work, we develop and implement an approach to classify bird species according to their degree of exposure and vulnerability to future climate and land-use change, including climatically driven changes in vegetation. To examine species exposure to environmental changes, we first fitted environmental envelope models and projected then into the future under scenarios of climate, land use and …
Factors affecting population dynamics of Eurasian woodcocks wintering in France: assessing the efficiency of a hunting-free reserve
2005
International audience; The Eurasian woodcock Scolopax rusticola is a migratory bird of major importance for hunting, which is susceptible to habitat loss and the stochastic effects of severe winter weather. Conservation issues mostly concerned regulation of hunting, but the efficiency of hunting-free reserves has never been investigated. We studied causes of mortality and survival probabilities of 98 radio-tagged woodcocks in a reserve with no hunting and in an adjoining hunting area in Brittany (France). Predation, mostly by mammalian predators on fields at night, was similar among adults and yearlings, while hunting mortality was more important in yearlings. Overall winter survival proba…
Enforced monoandry over generations induces a reduction of female investment into reproduction in a promiscuous bird.
2021
Abstract While uncovering the costs and benefits of polyandry has attracted considerable attention, assessing the net effect of sexual selection on population fitness requires the experimental manipulation of female mating over generations, which is usually only achievable in laboratory populations of arthropods. However, knowing if sexual selection improves or impairs the expression of life‐history traits is key for the management of captive populations of endangered species, which are mostly long‐lived birds and mammals. It might therefore be questionable to extrapolate the results gathered on laboratory populations of insects to infer the net effect of sexual selection on populations of …
Species loss leads to community closure
2008
Global extinction of a species is sadly irreversible. At a local scale, however, extinctions may be followed by re-invasion. We here show that this is not necessarily the case and that an ecological community may close its doors for re-invasion of species lost from it. Previous studies of how communities are assembled have shown that there may be rules for that process and that limitations are set to the order by which species are introduced and put together. Instead of focusing on the assembly process we randomly generated simple competitive model communities that were stable and allowed for two to 10 coexisting species. When a randomly selected single species was removed from the communit…
Lake eutrophication and brownification downgrade availability and transfer of essential fatty acids for human consumption
2016
Article
Gray plumage color is more cryptic than brown in snowy landscapes in a resident color polymorphic bird
2020
Abstract Camouflage may promote fitness of given phenotypes in different environments. The tawny owl (Strix aluco) is a color polymorphic species with a gray and brown morph resident in the Western Palearctic. A strong selection pressure against the brown morph during snowy and cold winters has been documented earlier, but the selection mechanisms remain unresolved. Here, we hypothesize that selection favors the gray morph because it is better camouflaged against predators and mobbers in snowy conditions compared to the brown one. We conducted an online citizen science experiment where volunteers were asked to locate a gray or a brown tawny owl specimen from pictures taken in snowy and snow…