A nonpeptide agonist of the invertebrate receptor for SchistoFLRFamide (PDVDHVFLRFamide), a member of a subfamily of insect FMRFamide-related peptides.

We describe a nonpeptide mimetic analog of an invertebrate peptide receptor. Benzethonium chloride (Bztc) is an agonist of the SchistoFLRFamide (PDVDHVFLRFamide) receptors found on locust oviducts. Bztc competitively displaces [125I-labeled Y1]SchistoFLRFamide binding to both high- and low-affinity receptors of membrane preparations. Bztc mimics the physiological effects of SchistoFLRFamide on locust oviduct, by inhibiting myogenic and induced contractions in a dose-dependent manner. Bztc is therefore recognized by the binding and activation regions of the SchistoFLRFamide receptors. This discovery provides a unique opportunity within insects to finally target a peptide receptor for the development of future pest management strategies.

Molecular cloning of insect pro-phenol oxidase: a copper-containing protein homologous to arthropod hemocyanin.

Pro-phenol oxidase [pro-PO; zymogen of phenol oxidase (monophenol, L-dopa:oxygen oxidoreductase, EC 1.14.18.1)] is present in the hemolymph plasma of the silkworm Bombyx mori. Pro-PO is a heterodimeric protein synthesized by hemocytes. A specific serine proteinase activates both subunits through a limited proteolysis. The amino acid sequences of both subunits were deduced from their respective cDNAs; amino acid sequence homology between the subunits was 51%. The deduced amino acid sequences revealed domains highly homologous to the copper-binding site sequences (copper-binding sites A and B) of arthropod hemocyanins. The overall sequence homology between silkworm pro-PO and arthropod hemocyanins ranged from 29 to 39%. Phenol oxidases from prokaryotes, fungi, and vertebrates have sequences homologous to only the copper-binding site B of arthropod hemocyanins. Thus, silkworm pro-PO DNA described here appears distinctive and more closely related to arthropod hemocyanins. The pro-PO-activating serine proteinase was shown to hydrolyze peptide bonds at the carboxyl side of arginine in the sequence-Asn-49-Arg-50-Phe-51-Gly-52- of both subunits. Amino groups of N termini of both subunits were indicated to be N-acetylated. The cDNAs of both pro-PO subunits lacked signal peptide sequences. This result supports our contention that mature pro-PO accumulates in the cytoplasm of hemocytes and is released by cell rupture, as for arthropod hemocyanins.

Polyomavirus VP1 phosphorylation: coexpression with the VP2 capsid protein modulates VP1 phosphorylation in Sf9 insect cells.

The polyomavirus virion has an outer capsid comprised of 72 pentamers of the VP1 protein associated with the minor virion proteins, VP2 and VP3, and the viral minichromosome. To investigate the interaction between VP1 and VP2/VP3, we mapped VP1 phosphorylation sites and assayed VP1 recognition by anti-peptide antibodies after coexpression of VP1 with VP2 or VP3 by using recombinant baculovirus vectors. VP1, expressed either alone or with VP3, was phosphorylated on serine residues, which are not modified during polyomavirus infection of mouse cells. When VP1 was coexpressed with VP2, the nonphysiologic serine phosphorylation of VP1 was decreased, and a tryptic peptide containing Thr-63, a site modified during virus infection of mouse cells, was phosphorylated. An anti-peptide antibody directed against the VP1 BC loop domain containing Thr-63 recognized VP1 expressed alone but not VP1 coexpressed with VP2 or VP3. The change in phosphorylation resulting from coexpression of two structural proteins identifies the potential of the baculovirus system for studying protein-protein interactions and defines a functional role for the VP1-VP2 interaction.

Activation of mammalian retinoid X receptors by the insect growth regulator methoprene.

We report that methoprene and its derivatives can stimulate gene transcription in vertebrates by acting through the retinoic acid-responsive transcription factors, the retinoid X receptors (RXRs). Methoprene is an insect growth regulator in domestic and agricultural use as a pesticide. At least one metabolite of methoprene, methoprene acid, directly binds to RXR and is a transcriptional activator in both insect and mammalian cells. Unlike the endogenous RXR ligand, 9-cis-retinoic acid, this activity is RXR-specific; the methoprene derivatives do not activate the retinoic acid receptor pathway. Methoprene is a juvenile hormone analog that acts to retain juvenile characteristics during insect growth, preventing metamorphosis into an adult, and it has been shown to have ovicidal properties in some insects. Thus, a pesticide that mimics the action of juvenile hormone in insects can also activate a mammalian retinoid-responsive pathway. This finding provides a basis through which the potential bioactivity of substances exposed to the environment may be reexamined and points the way for discovery of new receptor ligands in both insects and vertebrates.

Influence of tree hollow characteristics on the diversity of saproxylic insect guilds in Iberian Mediterranean woodlands

Saproxylic diversity assessment is a major goal for conservation strategies in woodlands and it should consider woodland composition and configuration at site and tree level as key modelling factors. However, in Mediterranean woodlands little is known about the relation with the environmental factors that structure their assemblages, especially those linked to tree hollow microhabitats. We assessed the diversity of Syrphidae (Diptera) and Coleoptera saproxylic guilds that co-occurred in tree hollows located in three different Iberian Mediterranean woodlands in the Cabañeros National Park (Spain). Furthermore, we evaluated how differences in tree hollow microenvironmental variables (understood as the physical and biotic characteristics of a hollow and tree individual) influenced saproxylic guild diversity both within and among woodland sites. We found that woodland sites that provided greater heterogeneity of trees and hollow microhabitats determined higher saproxylic guild diversity. Nevertheless, certain species or even complete guilds can be favoured in woodlands where some hollow microhabitats predominate as a consequence of historical tree management. In general, hollow volume was the main determining factor for saproxylic guild richness and abundance in woodland sites, and large hollow volume was usually related to higher diversity, which highlighted the importance of multi-habitat hollow trees. Moreover, saproxylic guilds also responded to other different microenvironmental variables, which indicated different ecological preferences among guilds. The conservation of saproxylic insects in Iberian Mediterranean areas must be addressed to protect woodland sites that provide high diversity and large numbers of tree hollow microhabitats, and practices to enhance microhabitat heterogeneity should even be encouraged.

Association Patterns in Saproxylic Insect Networks in Three Iberian Mediterranean Woodlands and Their Resistance to Microhabitat Loss

The assessment of the relationship between species diversity, species interactions and environmental characteristics is indispensable for understanding network architecture and ecological distribution in complex networks. Saproxylic insect communities inhabiting tree hollow microhabitats within Mediterranean woodlands are highly dependent on woodland configuration and on microhabitat supply they harbor, so can be studied under the network analysis perspective. We assessed the differences in interacting patterns according to woodland site, and analysed the importance of functional species in modelling network architecture. We then evaluated their implications for saproxylic assemblages’ persistence, through simulations of three possible scenarios of loss of tree hollow microhabitat. Tree hollow-saproxylic insect networks per woodland site presented a significant nested pattern. Those woodlands with higher complexity of tree individuals and tree hollow microhabitats also housed higher species/interactions diversity and complexity of saproxylic networks, and exhibited a higher degree of nestedness, suggesting that a higher woodland complexity positively influences saproxylic diversity and interaction complexity, thus determining higher degree of nestedness. Moreover, the number of insects acting as key interconnectors (nodes falling into the core region, using core/periphery tests) was similar among woodland sites, but the species identity varied on each. Such differences in insect core composition among woodland sites suggest the functional role they depict at woodland scale. Tree hollows acting as core corresponded with large tree hollows near the ground and simultaneously housing various breeding microsites, whereas core insects were species mediating relevant ecological interactions within saproxylic communities, e.g. predation, competitive or facilitation interactions. Differences in network patterns and tree hollow characteristics among woodland sites clearly defined different sensitivity to microhabitat loss, and higher saproxylic diversity and woodland complexity showed positive relation with robustness. These results highlight that woodland complexity goes hand in hand with biotic and ecological complexity of saproxylic networks, and together exhibited positive effects on network robustness.

The insect book : a popular account of the bees, wasps, ants, grasshoppers, flies and other North American insects exclusive of the butterflies, moths and beetles, with full life histories, tables and bibliographies /

Bibliography.

1987 insect pest management guide : home, yard, and garden /

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Insect injuries to the seed and root of Indian corn /

Caption title.

Insect prevention and control in plants processing dry milk /

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1979 insect pest management guide : home, yard, and garden.

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1979 insect pest management guide : livestock and livestock barns.

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Insect control by radiation and radiosotopes : a literature search /

This bibliography contains one hundred and one selected references on the uses of radiation and radioisotopes in entomology. These references were selected from the scientific literature published since 1961. An index to the insects studied is included.