Search results for "Instar"
showing 10 items of 56 documents
First Descriptions of Larva and Pupa of Bagous claudicans Boheman, 1845 (Curculionidae, Bagoinae) and Systematic Position of the Species Based on Mol…
2019
In this paper, the mature larva and pupa of Bagous claudicans are described and illustrated for the first time. Measurements of younger larval instars are also given. The biology of the species is discussed in association with larval morphology and feeding habits. Overall larval and pupal morphological characters of the genus Bagous are presented. Confirmation of the larva identification as Bagous claudicans species was conducted by cytochrome oxidase I (COI) sequencing. DNA barcoding was useful for specimen identification of larval stages. The systematic position of the species within the Bagous collignensis-group, based on morphological and molecular results, is also discussed.
Biology and Behaviour of Cirrospilus diallus and Cirrospilus pictus, Parasitoids of Phyllocnistis citrella
2005
International audience; Studies were carried out on some biological and behavioral aspects of Cirrospilus diallus Walker and Cirrospilus pictus (Nees) (Hymenoptera: Eulophidae) in relation to their host, the citrus leafminer (CLM), Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae). Adults of both species fed with sugar lived on average 4.45 +/- 0.19 days, whereas adults provided with honey survived on average 40.62 +/- 1.97 days. Rates of host mortality due to parasitoid stings without oviposition were as high as 31.25 and 37.73% for C. pictus and C. diallus, respectively. Both species showed arrhenotokous parthenogenesis. Sex ratios of parasitoids emerging from the 2nd and 3rd …
Chemical Composition and Broad-Spectrum Insecticidal Activity of the Flower Essential Oil from an Ancient Sicilian Food Plant, Ridolfia segetum
2021
Several species of the family Apiaceae are aromatic herbs that produce essential oils usable on an industrial scale for pharmaceutical, cosmetic, and food purposes. In particular, some essential oils, such as green insecticides for example, may replace synthetic insecticides, keeping most of their efficacy and avoiding environmental pollution or human poisoning. In the present study, we explored the insecticidal potential of Ridolfia segetum (L.) Moris essential oil (EO) against three different pests: Culex quinquefasciatus Say, Musca domestica L., and Spodoptera littoralis (Boisduval). For this purpose, the EO was obtained by hydrodistillation of flowers and its composition was achieved by…
Males of the tortricid moth Amorbia cuneana (Walsingham, 1879) shed their genital spines inside the female during copulation
2018
Abstract The genitalia of most insect species are composed of several structures whose functions are poorly understood in many cases. The deciduous genital spines (deciduous cornuti, DC) found on the endophallus of many species of Lepidoptera are a clear example of this problem. We performed two experimental studies with the western avocado leafroller Amorbia cuneana (Tortricidae), aimed at answering some basic questions about the biology of DC. We found that the number of DC shows positive allometry with male forewing length, indicating that larger males have disproportionally more DC than smaller males. Males, with very few exceptions, shed virtually all their DC in their first copulation…
Rapid induction of immune density-dependent prophylaxis in adult social insects.
2009
The innate immune system provides defence against parasites and pathogens. This defence comes at a cost, suggesting that immune function should exhibit plasticity in response to variation in environmental threats. Density-dependent prophylaxis (DDP) has been demonstrated mostly in phase-polyphenic insects, where larval group size determines levels of immune function in either adults or later larval instars. Social insects exhibit extreme sociality, but DDP has been suggested to be absent from these ecologically dominant taxa. Here we show that adult bumble-bee workers ( Bombus terrestris ) exhibit rapid plasticity in their immune function in response to social context. These results sugges…
The relative abundance of hemocyte types in a polyphagous moth larva depends on diet.
2016
7 pages; International audience; Hemocytes are crucial cells of the insect immune system because of their involvement in multiple immune responses including coagulation, phagocytosis and encapsulation. There are various types of hemocytes, each having a particular role in immunity, such that variation in their relative abundance affects the outcome of the immune response. This study aims to characterize these various types of hemocytes in larvae of the grapevine pest insect Eupoecilia ambiguella, and to assess variation in their concentration as a function of larval diet and immune challenge. Four types of hemocytes were found in the hemolymph of 5th instar larvae: granulocytes, oenocytoids…
Production performance and economic traits of silkworms (Bombyx mori L., 1758) fed with mulberry tree leaves (Morus alba, var. Ichinose) significantl…
2019
Abstract Production performance of silkworm (Bombyx mori L., 1758) play a pivotal role in sericulture industry and good quality cocoon represents the economic driver of farms. Silkworms are monophagus insects and differences between cocoon characteristics may depend both on mulberry tree leaves quality as well as on genetic selection of hybrid lines. While a huge work was carried out to identify the best feeding sources to optimize yields, genetic types of silkworms with desirable production and economic traits were studied to a limited extent to date. This experimental feeding trial was carried out using a commercial variety of mulberry tree leaves (Morus alba var. Ichinose) to feed a tota…
Ontogeny of Heterocypris bosniaca (Ostracoda: Cyprididae): description of postembryonic instars and rediscovery of the neglected A-9 stage
2013
Despite being the most common and widespread family of Ostracoda in fresh water, the Cyprididae are still poorly known with respect to species ontogeny. The full series of eight juvenile instars has been described in detail for just five of the approximately 1000 living species, and only in one case did this include the earliest A-9 stage. We aimed to fill this gap with a morphological study of the post-embryonic development of Heterocypris bosniaca Petkowski, Scharf and Keyser, 2000, a species with unusual morphological traits within the genus, including putatively paedomorphic characters such as valves without tubercles and the narrow calcified inner lamella on both valves. Inside the egg…
Synthesis and characterization of some dibutylbis{5-[(E)-2-(aryl)-1-diazenyl]-2-hydroxybenzoato}tin(IV) compounds. Toxicity studies of di- and tri-or…
2003
The preparation and spectroscopic characterization of some complexes of the type Bu2Sn(LH)2 (LH = 5-[(E)-2-(aryl)-1-diazenyl]-2-hydroxybenzoate) are reported. On the basis of spectroscopic evidence (1H, 13C, 119Sn NMR, IR and 119mSn Mossbauer) the compounds were judged to adopt the usual dicarboxylato structural type with a skew trapezoidal arrangement. This was further confirmed by X-ray crystallography in the case of Bu2Sn(L5H)2 (L5H = 5-[(E)-2-(4-chlorophenyl)-1-diazenyl]-2-hydroxybenzoate). Toxicity studies of the di- and tri-organotin compounds on the second larval instar of Aedes aegypti mosquito larvae are reported. Copyright © 2003 John Wiley & Sons, Ltd.
Comparing the acute response to cadmium toxicity of nauplii from different populations ofArtemia
2002
The lethal responses to cadmium of instar II nauplii from eight populations of Artemia belonging to the species Artemia franciscana, Artemia salina, Artemia persimilis, and Artemia parthenogenetica have been compared. Generalized linear models were used to fit mortality. The model indicates that there is a relationship between species, type of population, and mortality rate. The two populations of A. franciscana were the most sensitive to cadmium toxicity (median lethal concentration, LC50, of 93.3-142 mg/L), while the population of A. persimilis was the most resistant (LC50 of 284 mg/L). Differences in the phenotypic variability in each population were assessed through the slope of the mor…