Search results for "Larva"
showing 10 items of 632 documents
High-NaCl perception in drosophila melanogaster
2014
Salt is a fundamental nutrient that is required for many physiological processes, including electrolyte homeostasis and neuronal activity. In mammals and Drosophila, the detection of NaCl induces two different behaviors: low-salt concentrations provide an attractive stimulus, whereas high-salt concentrations are avoided. We identified the gene called serrano (sano) as being expressed in the sensory organs of Drosophila larvae. A transgenic reporter line showed that sano was coexpressed with Gr66a in a subset of gustatory neurons in the terminal organ of third-instar larvae. The disruption of sano gene expression in gustatory neurons led to the specific loss of high-salt concentration avoida…
Experimental increase of worker diversity benefits brood production in ants
2021
Background The reproductive division of labor of eusocial insects, whereby one or several queens monopolize reproduction, evolved in a context of high genetic relatedness. However, many extant eusocial species have developed strategies that decrease genetic relatedness in their colonies, suggesting some benefits of the increased diversity. Multiple studies support this hypothesis by showing positive correlations between genetic diversity and colony fitness, as well as finding effects of experimental manipulations of diversity on colony performance. However, alternative explanations could account for most of these reports, and the benefits of diversity on performance in eusocial insects stil…
Chemical Cues Influence Pupation Behavior of Drosophila simulans and Drosophila buzzatii in Nature and in the Laboratory.
2012
International audience; In the wild, larvae of several species of Drosophila develop in heterogeneous and rapidly changing environments sharing resources as food and space. In this scenario, sensory systems contribute to detect, localize and recognize congeners and heterospecifics, and provide information about the availability of food and chemical features of environments where animals live. We investigated the behavior of D. simulans and D. buzzatii larvae to chemicals emitted by conspecific and heterospecific larvae. Our goal was to understand the role of these substances in the selection of pupation sites in the two species that cohabit within decaying prickly pear fruits (Opuntia ficus…
Hastifolins A-G, antefeedant neo-clerodane diterpenoids from Scutellaria hastifolia
2010
From the aerial parts of Scutellaria hastifolia, family Lamiaceae (Labiatae), seven neo-clerodane diterpenoids (hastifolins A-G) were isolated. The products are similar to the known scuteparvin and are characterized by being trans-cinnamoyl derivatives. Structures and stereochemistry were determined by intensive NMR investigation. Six of the products form three pairs of epimers at C-13. Hastifolins A-C showed significant antifeedant activity.
Fascioliasis transmission by Lymnaea neotropica confirmed by nuclear rDNA and mtDNA sequencing in Argentina
2009
Fascioliasis is widespread in livestock in Argentina. Among activities included in a long-term initiative to ascertain which are the fascioliasis areas of most concern, studies were performed in a recreational farm, including liver fluke infection in different domestic animal species, classification of the lymnaeid vector and verification of natural transmission of fascioliasis by identification of the intramolluscan trematode larval stages found in naturally infected snails. The high prevalences in the domestic animals appeared related to only one lymnaeid species present. Lymnaeid and trematode classification was verified by means of nuclear ribosomal DNA and mitochondrial DNA marker sequ…
INHIBITION OF FATTY ACID DESATURASES INDrosophila melanogasterLARVAE BLOCKS FEEDING AND DEVELOPMENTAL PROGRESSION
2016
International audience; Fatty acid desaturases are metabolic setscrews. To study their systemic impact on growth in Drosophila melanogaster, we inhibited fatty acid desaturases using the inhibitor CAY10566. As expected, the amount of desaturated lipids is reduced in larvae fed with CAY10566. These animals cease feeding soon after hatching, and their growth is strongly attenuated. A starvation program is not launched, but the expression of distinct metabolic genes is activated, possibly to mobilize storage material. Without attaining the normal size, inhibitor-fed larvae molt to the next stage indicating that the steroid hormone ecdysone triggers molting correctly. Nevertheless, after moltin…
Dietary rescue of altered metabolism gene reveals unexpected [i]Drosophila[/i] mating cues
2015
Running title: Dietary rescue of metabolic mutation and reproduction; To develop and reproduce, animals need long-chain Mono and PolyUnsaturated Fatty Acids (MUFAs; PUFAs). Although some UFAs can be synthesized by the organism, others must be provided by the diet. The gene desat1, involved in Drosophila melanogaster UFA metabolism, is necessary for both larval development and for adult sex pheromone communication. We first characterized desat1 expression in larval tissues. Then, we found that larvae in which desat1 expression was knocked down throughout development died during the larval stages when raised on standard food. By contrast pure MUFAs or PUFAs, but not saturated FAs, added to th…
Glucocorticoid receptor (DlGR1) is expressed in pre-larval and larval stages of the teleost fish Dicentrarchus labrax.
2008
Glucocorticoid hormone receptors (GR), members of the nuclear hormone receptor superfamily, are ligand-dependent transcription factors expressed in various tissues by binding to specific DNA sequences. Since glucocorticoids have a role in maintaining the homeostatic status in fish, we previously cloned and sequenced a GR (DlGR1) of adult Dicentrarchus labrax; we also showed mRNA expression (in situ hybridization) and tissue immunohistochemical localization of DlGR1 in several organs. This work has now been extended to the examination of the expression, tissue distribution, and cytolocalization of DlGR1 in larval developmental stages by similar methods to those used for the adult organs. The…
Relationships between absence of functional swimbladder, calculosis and larval mortality in hatcheryreared gilthead sea bream, Sparus aurata L.
1993
Abstract. The relationship between absence of functional swim-bladder, calculosis and larval mortality of hatchery-reared sea bream, Sparus aurata L., was observed. There was a temporal variation in the main causes of mortality, i.e. not inflated swim-bladder appears to be the main cause up to the 47th day, and the presence of calculi around the 55th day. Histological sections, semi-quantitative analysis and scanner electron microscope photographs were carried out.
Seasonal changes in predator community switch the direction of selection for prey defences
2014
Insect communities consist of aposematic species with efficient warning colours against predation, as well as abundant examples of crypsis. To understand such coexistence, we here report results from a field experiment where relative survival of artificial larvae, varying in conspicuousness, was estimated in natural bird communities over an entire season. This takes advantage of natural variation in the proportion of naive predators: naivety peaks when young birds have just fledged. We show that the relative benefit of warning signals and crypsis changes accordingly. When naive birds are rare (early and late in the season), conspicuous warning signals improve survival, but conspicuousness b…