Search results for "TSH"

Factors Affecting Male Song Evolution in Drosophila montana

2005

D. montana (a species of the D. virilis group) has spread over the northern hemisphere, populations from different areas showing both genetic and phenotypic divergence. The males of this species produce an elaborate courtship song, which plays a major role both in species recognition and in intraspecific mate choice. The genetic architecture and physical constraints, as well as the importance of the signal for species recognition, set boundaries within which this signal can vary. Within these limits, courtship song parameters may change, depending on the males' physical condition and on the environment they inhabit. Females are likely to affect song evolution by exerting directional selecti…

2015

Insects encounter a vast repertoire of chemicals in their natural environment, which can signal positive stimuli like the presence of a food source, a potential mate, or a suitable oviposition site as well as negative stimuli such as competitors, predators, or toxic substances reflecting danger. The presence of specialized chemoreceptors like taste and olfactory receptors allow animals to detect chemicals at short and long distances and accordingly, trigger proper behaviors towards these stimuli. Since the first description of olfactory and taste receptors in Drosophila fifteen years ago, our knowledge on the identity, properties, and function of specific chemoreceptors has increased expone…

Ocean acidification affects fish spawning but not paternity at CO2 seeps

2016

Fish exhibit impaired sensory function and altered behaviour at levels of ocean acidification expected to occur owing to anthropogenic carbon dioxide emissions during this century. We provide the first evidence of the effects of ocean acidification on reproductive behaviour of fish in the wild. Satellite and sneaker male ocellated wrasse (Symphodus ocellatus) compete to fertilize eggs guarded by dominant nesting males. Key mating behaviours such as dominant male courtship and nest defence did not differ between sites with ambient versus elevated CO2 concentrations. Dominant males did, however, experience significantly lower rates of pair spawning at elevated CO2 levels. Despite the higher r…

Ekfrasen som begivenhet

2021

Sammendrag Ekfrasebegrepet har vært gjenstand for mye diskusjon de siste tiårene. Denne artikkelen viser hvordan det har blitt lansert flere forslag til hvordan man kan legge bak seg en snever forståelse av møtet mellom tekst og bilde som en form for representasjon. Samtidig vises det hvordan løsningsforslagene virker sterkt fragmenterende og at de baserer seg på avgrensete perioder. I denne artikkelen lanseres begrepet «ekfrastisk begivenhet» som en alternativ formulering for å fange en bredere, kontekstuell forståelse av fenomenet. Samtidig innføres også begrepet «begivenhetshorisont» for å artikulere hvordan viktige institusjonelle og romlige premisser for ekfrasen har endret seg gjennom…

Alcohol boosts pheromone production in male flies and makes them sexier

2020

The attraction of Drosophila melanogaster towards byproducts of alcoholic fermentation, especially ethanol, has been extensively studied 1–4. However, the adaptive value of this behavior has not been elucidated. Previous studies have suggested anthropomorphic interpretations of D. melanogaster behavior towards alcohols 5,6. Here, we instead assert that there exists a simple yet vital biological rationale for alcohol contact and consumption by these insects. We show that exposure to alcohols, especially methanol, results in an immediate amplification of fatty acid ester pheromone levels, which in turn elevates the probability that a male will successfully compete for a female during courtshi…

Regulation of cuticular hydrocarbon profile maturation by Drosophila tanning hormone, bursicon, and its interaction with desaturase activity

2016

International audience; Shortly after emergence the exoskeleton (cuticle) of adult insects is rapidly expanded, hardened (sclerotized), and pigmented (melanized). In parallel with this process, the oenocytes, which are large polyploid cells located below the abdominal epidermis, secrete onto the cuticle a cocktail of cuticular hydrocarbons (CHs) and waxes. These improve the waterproofing of the cuticle, and also provide important chemosensory and pheromonal cues linked with gender, age, and species differentiation. The hardening and pigmentation of the new cuticle are controlled by the neurohormone, bursicon, and its receptor, encoded by the DLGR2 receptor, rickets (rk); by contrast, little…

Sexual selection for genetic quality: disentangling the roles of male and female behaviour

2009

According to the good genes model of sexual selection, females choose males of good heritable genetic quality to obtain offspring with high fitness. However, better mating success of high-quality males can also be brought about by direct interference competition between males, or simply through elevated activity of high-quality males. We examined the roles of different processes leading to sexual selection for genetic quality in Drosophila montana. We manipulated genetic quality of male flies by inducing mutations with ionizing radiation. We then recorded the effects of inherited heterozygous mutations on several aspects of mating behaviour of males and females in two experiments. We found …

Eugen Alt † 17./29. April 1891: Erinnerungsblätter für seine Freunde

1891

Gotiskajā šriftā

Commercial sharks under scrutiny: Baseline genetic distinctiveness supports structured populations of small-spotted catsharks in the Mediterranean Sea

2023

The present study, based on microsatellite markers, describes a population genetic analysis of the small-spotted catshark Scyliorhinus canicula (Linnaeus, 1758), representing one of the most abundant and commonly caught cartilaginous fishes in the Mediterranean Sea and adjacent areas. The analyses were performed to unravel the genetic features (variability, connectivity, sex-biased dispersal) of their relative geographic populations, both at the small (around the coast of Sardinia, Western Mediterranean Sea) and at a larger spatial scale (pan-Mediterranean level and between the Atlantic Ocean and the Mediterranean Sea). Individual clustering, multivariate and variance analyses rejected the …

Gertrude Bonnin on Sexual Morality

2021

This paper examines attitudes to sexual morality held by the Yankton Dakota author and activist Gertrude Bonnin (1876–1938), better known by her penname Zitkála-Šá (Red Bird in Lakota). Bonnin’s concerns encompass several themes: the victimization of Indian women, disintegration of Native courtship rituals, sexual threats posed by peyote use, and the predatory nature of Euro-American men. This critique as a whole — in which a ‘white invasion,’ in her words, leads to a corruption of Native sexuality — sometimes produces inconsistencies, particularly regarding Bonnin’s statements on the alleged sexual perils of peyote. Her investigations into the Oklahoma guardianship scandals of the 1920s, h…