Search results for "agon"

Susceptibility of Grapholita molesta (Busck, 1916) to formulations of Bacillus thuringiensis, individual toxins and their mixtures.

2016

The Oriental fruit moth, Grapholita molesta (Lepidoptera: Tortricidae), is a major pest of fruit trees worldwide, such as peach and apple. Bacillus thuringiensis has been shown to be an efficient alternative to synthetic insecticides in the control of many agricultural pests. The objective of this study was to evaluate the effectiveness of B. thuringiensis individual toxins and their mixtures for the control of G. molesta. Bioassays were performed with Cry1Aa, Cry1Ac, Cry1Ca, Vip3Aa, Vip3Af and Vip3Ca, as well as with the commercial products DiPel® and XenTari®. The most active proteins were Vip3Aa and Cry1Aa, with LC50 values of 1.8 and 7.5ng/cm2, respectively. Vip3Ca was nontoxic to this …

Changing of the guard: mixed specialization and flexibility in nest defense (Tetragonisca angustula)

2019

Abstract Task allocation is a central challenge of collective behavior in a variety of group-living species, and this is particularly the case for the allocation of social insect workers for group defense. In social insects, both benefits and considerable costs are associated with the production of specialized soldiers. We asked whether colonies mitigate costs of production of specialized soldiers by simultaneously employing behavioral flexibility in nonspecialist workers that can augment defense capabilities at short time scales. We studied colonies of the stingless bee Tetragonisca angustula, a species that has 2 discrete nest-guarding tasks typically performed by majors: hovering guardin…

Aspartic Proteinase from Barley Seeds is Related to Animal Cathepsin D

1991

In contrast to the well-characterized mammalian aspartic proteinases, plant aspartic proteinases have received little attention so far. Aspartic proteinase activity has been detected, for example, in resting seeds of scots pine (Salmia et al., 1978), soybean (Bond & Bowles, 1983), barley and wheat (Morris et al., 1985) as well as in leaves of orange (Garcia-Martinez & Moreno, 1986) and barley (Kervinen et al., 1990). Aspartic proteinases have been purified from the seeds of rice (Doi et al., 1980), cucumber, squash (Polanowski et al 1985) and wheat (Dunaevsky et al., 1989) as well as from the leaves of tomato (Rodrigo et al., 1989). The plant aspartic proteinases have been reported to enhan…

Stream restorations with meanders increase dragonfly and damselfly diversity and abundance, including an endangered species.

2021

10 pages; International audience; This study presents examples of successful restoration projects for biodiversity conservation. In West France, the Pinail National Nature Reserve is a protected wetland interspersed with more than 6000 ponds. This wetland is inhabited by 50 species of Odonata and thus is a key biodiversity area for damselflies and dragonflies conservation. In the past, when the limestone was exploited, the streams of the plateau were artificially channeled rectilinearly, running to the Vienne River. Eventually streams were blocked by biomass and sediments resulting in water flowing mainly underground. In 2011, two restoration projects dug and recreated lost habitats such as…

Mineral phase in shell repair of Manila clam Venerupis philippinarum affected by brown ring disease.

2011

14 pages; International audience; The mineral phase of shell repair in the Manila clam Venerupis philippinarum affected by brown ring disease (BRD) was characterised at various scales and at various stages of shell repair by confocal Raman microspectrometry and scanning electron microscopy. Spherulitic and quadrangular aragonite microstructures associated with polyene pigments were clearly observed. Von Kossa staining showed that at the beginning of shell repair, hemocytes are filled with insoluble calcium carbonate salts in all fluids and then are transported toward the extrapallial fluids and the repair sites. Our analyses suggest that after a Vibrio tapetis attack and BRD deposit some cl…

The shell matrix of the pulmonate land snail Helix aspersa maxima.

2012

12 pages; International audience; In mollusks, the shell mineralization process is controlled by an array of proteins, glycoproteins and polysaccharides that collectively constitute the shell matrix. In spite of numerous researches, the shell protein content of a limited number of model species has been investigated. This paper presents biochemical data on the common edible land snail Helix aspersa maxima, a model organism for ecotoxicological purposes, which has however been poorly investigated from a biomineralization viewpoint. The shell matrix of this species was extracted and analyzed biochemically for functional in vitro inhibition assay, for amino acid and monosaccharides composition…

Protist predation can select for bacteria with lowered susceptibility to infection by lytic phages

2015

Background: Consumer-resource interactions constitute one of the most common types of interspecific antagonistic interaction. In natural communities, complex species interactions are likely to affect the outcomes of reciprocal co-evolution between consumers and their resource species. Individuals face multiple enemies simultaneously, and consequently they need to adapt to several different types of enemy pressures. In this study, we assessed how protist predation affects the susceptibility of bacterial populations to infection by viral parasites, and whether there is an associated cost of defence on the competitive ability of the bacteria. As a study system we used Serratia marcescens and i…

2018

Odonate (damselfly and dragonfly) species richness and species occupancy frequency distributions (SOFDs) were analyzed in relation to geographical location in standing waters (lakes and ponds) in Fennoscandia, from southern Sweden to central Finland. In total, 46 dragonfly and damselfly species were recorded from 292 waterbodies. Species richness decreased to the north and increased with waterbody area in central Finland, but not in southern Finland or in Sweden. Species occupancy ranged from 1 up to 209 lakes and ponds. Over 50% of the species occurred in <10% of the waterbodies, although this proportion decreased to the north. In the southern lakes and ponds, none of the species occurred …

The plasticity of breeding system in arid-adapted Zygophylloideae

2019

Abstract The assurance of reproductive success is an important challenge for arid-adapted plants. Self-compatibility is suggested as a mechanism to compensate for the inadequate breeding opportunities in extreme environments. Zygophylloideae is an arid-adapted subfamily which has successfully radiated in different ranges of arid habitats. In order to study the significance of selfing for the reproductive success of the Zygophylloideae, we calculated pollen ovule ratios (P/O) and conducted bagging experiments for autogamy and xenogamy in eleven representative members of Zygophylloideae and three species of the sister subfamilies Tribuloideae and Larreoideae. Our results revealed an extremely…

Sexual antagonism for testosterone maintains multiple mating behaviour

2011

Summary 1. The persistence of multiple mating remains one of the fundamental questions in evolutionary biology. In theory, multiple mating is predicted to improve female fitness cumulatively through direct and ⁄ or genetic benefits. However, intra-locus sexual conflicts may potentially constrain or even eliminate these benefits owing to the gender load imposed by sexually antagonistic selection. 2. Here, we tested whether sexually antagonistic selection can maintain the variance in multiple mating behaviour of bank voles (Myodes glareolus) by manipulating the hormone testosterone through artificial selection in the laboratory. Among mammals, testosterone is a sexually dimorphic fitness-rela…