Search results for " Entomology"
showing 10 items of 285 documents
Escaping the evolutionary trap: Can size-related contest advantage compensate for juvenile mortality disadvantage when parasitoids develop in unnatur…
2021
Abstract The quality of hosts for a parasitoid wasp may be influenced by attributes such as host size or species, with high quality for successful development usually coincident with high quality for larger offspring. This is not always the case: for the Scelionid wasp Trissolcus basalis, oviposition in eggs of the Brown Marmorated Stink Bug, Halyomorpha halys, rather than of the normal host, the Southern Green Stink Bug, Nezara viridula, leads to lower offspring survival, but survivors can be unusually large. Adult female T. basalis engage in contests for host access. As larger contestants are typically favoured in contests between parasitoids, the larger size of surviving offspring may co…
NMR structure determination of (11E)-trinervita-1(14),2,11-triene, a new diterpene from sexual glands of termites
2005
Graphical Abstract Full-size image; International audience; Female alates of Nasutitermes ephratae termites from Guadeloupe and Nasutitermes sp. from Brazil produce a diterpene hydrocarbon of the molecular formula C20H30 as the main component of their tergal gland secretion. Analysis of NMR, IR, and mass spectra of the diterpene led to a structure of (11E)-trinervita-1(14),2,11-triene. Based on a comparison with the published oxygenated trinervitane skeleton from termites we prefer the enantiomer with absolute configurations (4R,7S,8R,15S,16S). The suggested structure is supported by ab initio quantum chemical calculation of 1H and 13C chemical shifts for the optimized geometry of the molec…
The defensive secretion of Eurycotis floridana (Dictyoptera, Blattidae, Polyzosteriinae): chemical identification and evidence of an alarm function
1997
0965-1748 doi: DOI: 10.1016/S0965-1748(97)00033-7; The defensive secretion of the cockroach Eurycotis floridana was believed to contain only (E)-2-hexenal. However, we have shown it consists of 40 components, of which 30 were tentatively identified. (E)-2-Hexenal, (E)-2-hexenol and (E)-2-hexenoic acid represented approximately 98% of the organic phase. The other 2% included 10 aldehydes, 10 alcohols, four acids, two lactones and one ether. Four compounds are novel insect exudates: 3-ethoxyhexanal, 3-hydroxyhexanal, [(E)-1-pentenyl]-4-propyl-1,3-dioxane and 3-[(E)-2-hexenoxyl-hexanal. In addition to its well-known allomonal function, we have demonstrated that the defensive secretion also act…
A new C12 alcohol identified as a sex pheromone and a trail-following pheromone in termites: the diene (Z,Z)-dodeca-3,6-dien-1-ol
2003
0028-1042 (Print) Journal Article; The diunsaturated C12 alcohol (Z,Z)-dodeca-3,6-dien-1-ol (dodecadienol) has been characterized by GC-MS and FTIR as a novel releaser pheromone in termites. This alcohol identified in Ancistrotermes pakistanicus (Termitidae, Macrotermitinae) possesses a double pheromonal function which again illustrates the chemical parsimony of termites compared with other social insects. In workers, dodecadienol elicits trail-following at a very low concentration (activity threshold at 0.1 pg/cm of trail); in male alates it induces trail-following at a low concentration (1-10 pg/cm) and sexual attraction at a higher concentration (about 1 ng). Traces of the monounsaturate…
Impact of the invasive painted bug, Bagrada hilaris on physiological traits of its host Brassica oleracea var botrytis
2017
Bagrada hilaris is a herbivorous insect native of Asia and Africa, which has invaded southern Europe and North America where it causes major damage to cole crops. Laboratory experiments were conducted to assess how the infestation of this invasive species damages the host Brassica oleracea var botrytis, and to evaluate the interaction between plant emission of volatile organic compounds (VOC) and B. hilaris adults. Plant responses to insect feeding were evaluated through changes in photosynthesis, stomatal conductance, VOC emission, and visual damage on leaves. The impact of B. hilaris was compared with that of Nezara viridula, a polyphagous species distributed worldwide. Plant VOC role in …
Diversity of subfamily Anacharitinae (Hymenoptera: Cynipoidea: Figitidae) in China with description of a new species of Xyalaspis Hartig, 1843
2016
Abstract The poorly known Anacharitinae fauna from China is studied. Two species of genus Aegilips Haliday, 1835 (which only had one species previously recorded there) are recorded in China. The genera Anacharis Dalman, 1823 and Xyalaspis Hartig, 1843 are recorded for the first time with two and four species present respectively. A new species of Xyalaspis, X. ribesi sp. n., is described. Diagnostic characters of the new species are illustrated, and data about biology, distribution and morphological variability of the Chinese Anacharitinae are discussed.
Importance of meteorological variables for aeroplankton dispersal in an urban environment
2016
Passive wind dispersal is one of the major mechanisms through which organisms disperse and colonize new areas. The detailed comprehension of which factors affect this process may help to preserve its efficiency for years to come. This is especially important in the current context of climate change, which may seriously alter weather regimes that drive dispersal, and is crucial in urban contexts, where biodiversity is dramatically threatened by pollution and fragmentation of natural patches. Despite its interest, the analysis of factors affecting aeroplankton dispersal in urban environments is rare in literature. We sampled aeroplankton community uninterruptedly every 4 hours from 17th May t…
Dispersal flight and colony development in the fungus-growing termites Pseudacanthotermes spiniger and P. militaris
2012
International audience; Pseudacanthotermes spiniger and P. militaris are two African fungus-growing termites (Termitidae, Macrotermitinae) which may become pests in disturbed agrosystems where they often live in sympatry. To study their development and their reproductive strategies, colonies of both species were reared in the laboratory for 20 and 17 years, respectively, after their foundation from reproductive pairs. The first steps of development were in great part similar in both species, although P. spiniger favoured the defence during the juvenile period, while P. militaris tended to favour a rapid development. While P. spiniger colonies did not produce alates until year 7 of colony li…
Integrative taxonomy demonstrates the unexpected synonymy between two predatory mite species: Cydnodromus idaeus and C. picanus (Acari: Phytoseiidae)
2011
Contact: tixier@supagro.inra.fr; Species of the mite family Phytoseiidae are well known as predators of mite pests all over the world. Their identification is thus of great interest for biological control. The specimens examined in this study belong to the species Cydnodromus idaeus (described from Brazil) and C. picanus (described from Chile). They were collected together on the same plant in Argentina. These species are mainly differentiated by the presence/absence of the dorsal solenostomes (gland openings) gd2. Some morphometric differences were observed between the Argentinian specimens and the type material of C. idaeus and C. picanus; however, they were not sufficient to support a sp…
(3Z,6Z,8E)-3,6,8-dodecatrien-1-ol : Sex pheromone in a higher fungus-growing termite, Pseudacanthotermes spiniger (Isoptera, Macrotermitinae)
1991
International audience; The female sex pheromone of the fungus-growing termitePseudacanthotermes spiniger (Termitidae, Macrotermitinae) was isolated from sternal glands of alates. The compound inducing attraction and excitation in males was identified as the (3Z,6Z,8E)-3,6,8-dodecatrien-1-ol by GC-MS, microhydrogenation, GC-FTIR, and NMR. This unsaturated alcohol is present in both sexes but in much higher quantities in females than in males (about 10 times). The hypothesis is suggested that this alcohol, which is detected at extremely low concentrations by the workers ofP. spiniger, may be used either as a trail-following pheromone or a sex pheromone according to concentrations and to targ…