Special Issue: Molecular Ecology, Physiology and Biochemistry of Insects 3.0.

With the outstanding work of Sir Vincent B [...

IDENTIFICATION OF THE FGL-AMIDE ALLATOSTATIN GENE OF THE PRIMITIVE TERMITE Mastotermes darwiniensis AND THE WOODROACH Cryptocercus darwini.

Allatostatins with the C-terminal ending Tyr/Phe-Xaa-Phe-Gly-Leu/Ile-amide (FGLa/ASTs) are widespread neuropeptides with multiple functions. The gene encoding the FGLa/AST polypeptide precursor was first isolated from cockroaches and since then could be identified in many insects and crustaceans. With its strictly conserved regions in combination with variable regions the gene seems to be a good candidate for phylogenetic analyses between closely and distantly related species.

SECRETION OF LIPASES IN THE DIGESTIVE TRACT OF THE CRICKET Gryllus bimaculatus.

Little is known concerning the sites and the ratios of the lipase secretions in insects, therefore we undertook an examination of the lipase secretion of fed and unfed adult female Gryllus bimaculatus. The ratio of triacylglyceride lipase, diacylglyceride lipase, and phosphatidylcholine lipase secreted by fed females in the caecum and ventriculus is 1:1.4:0.

Effects of Pharmacological Agents on Ecdysteroid Synthesis in vitro in Ovaries and Abdominal Integument from Female Adult Crickets, Gryllus bimaculatus de Geer (Ensifera, Gryllidae).

In female adults of Gryllus bimaculatus, ovaries as well as the abdominal integument produce free and conjugated ecdysteroids in vitro (Hoffmann et al., 1992). The aim of the current study was to determine the influence of various potential ecdysteroid biosynthesis effectors (RH 5849, KK 42, diflubenzuron, ketoconazole, azadirachtin, acetylenic and allenic cholesteryl derivatives B1, B6, AL2), and also of the protein synthesis inhibitor cycloheximide, on net release of moulting hormones in vitro by the adult ecdysteroid sources.

Neuropeptides affecting the transfer of juvenile hormones from males to females during mating in Spodoptera frugiperda.

In the polyandric moth, Spodopterafrugiperda, juvenile hormone (JH) is transferred from the male accessory reproductive glands (AG) to the female bursa copulatrix (BC) during copulation (see Hassanien et al., 2014). Here we used the RNA interference technique to study the role of allatoregulating neuropeptides in controlling the synthesis and transfer of JH during mating.

Functional activity of allatotropin and allatostatin in the pupal stage of a holometablous insect, Tribolium castaneum (Coleoptera, Tenebrionidae).

Allatotropin (AT) and allatostatin (AS) neuropeptides are known to regulate the biosynthesis of juvenile hormones (JH) in insects. Furthermore, they possess myoregulatory and other activities in a wide range of insect species. The genome of Tribolium castaneum encodes two AS and one AT precursors.

Regulation of amylase, cellulase and chitinase secretion in the digestive tract of the two-spotted field cricket, Gryllus bimaculatus.

The secretion of amylase and cellulase in Gryllus bimaculatus is determined by increased food intake, whereby shortly after molting food consumption increases. About half of the standing amylase concentration (activity) in the endothelial cells can be secreted within 30 min. The peak of amylase and cellulase secretion that occurs in the photophase is related to the feeding peak in the previous scotophase.

Putative-farnesoic acid O-methyltransferase (FAMeT) in medfly reproduction.

A gene potentially involved in juvenile hormone (JH) biosynthesis was previously identified in Ceratitis capitata as the putative-farnesoic acid O-methyltransferase (FAMeT). Since JH is involved in insect reproduction, we silenced the putative-FAMeT expression by RNA interference in Ceratitis capitata to evaluate its implication in egg production. FAMeT gene expression was knocked down in females and males after eclosion and in 1- and 2-day-old females.

Neuropeptide regulators of the juvenile hormone biosynthesis (in vitro) in the beetle, Tenebrio molitor (Coleoptera, Tenebrionidae).

The genome of Tribolium castaneum encodes two allatostatin [AS type B; W(X)(6)Wamide and AS type C; PISCF-OH] and one allatotropin (AT) precursor, but no AS type A (FGLamide) (Tribolium Genome Sequencing Consortium, 2008: Nature 452:949-955). Here we studied the activity (in vitro) of peptides derived from these precursors on the synthesis/release of juvenile hormone (JH) III. The corpora cardiaca-corpora allata (CC-CA) complexes of adult females of another tenebrionid beetle, the mealworm Tenebrio molitor, were used.

Exogenous and endogenous protease inhibitors in the gut of the fall armyworm larvae, Spodoptera frugiperda.

A dose-dependent inhibition of endogenous trypsin and aminopeptidase occurs in the lumen of Spodoptera frugiperda after feeding L6 larvae exogenous inhibitors soybean trypsin inhibitor (SBTI), tosyl-L-lysine chloromethyl ketone-HCl (TLCK), or bestatin, respectively, for 3 days. TLCK inhibits trypsin in tissue extracts and in secretions more strongly than SBTI. The aminopeptidase released into the lumen (containing the peritrophic membrane) is strongly inhibited by bestatin, but the membrane-bound enzyme is not.

Control of the release of digestive enzymes in the larvae of the fall armyworm, Spodoptera frugiperda.

There is a basal level of enzyme activity for trypsin, aminopeptidase, amylase, and lipase in the gut of unfed larval (L6) Spodoptera frugiperda. Trypsin activity does not decrease with non-feeding, possibly because of the low protein levels in plants along with high amino acid requirements for growth and storage (for later reproduction in adults). Therefore, trypsin must always be present so that only a minimal protein loss via egestion occurs.

Energetics of embryonic development: effects of temperature on egg and hatchling composition in a butterfly.

Phenotypic plasticity may allow an organism to adjust its phenotype to environmental needs. However, little is known about environmental effects on offspring biochemical composition and turnover rates, including energy budgets and developmental costs. Using the tropical butterfly Bicyclus anynana and employing a full-factorial design with two oviposition and two developmental temperatures, we explore the consequences of temperature variation on egg and hatchling composition, and the associated use and turnover of energy and egg compounds.

Juvenile hormone titres and winged offspring production do not correlate in the pea aphid, Acyrthosiphon pisum.

Pea aphids, Acyrthosiphon pisum, reproduce parthenogenetically and are wing-dimorphic such that offspring can develop into winged (alate) or unwinged (apterous) adults. Alate induction is maternal and offspring phenotype is entirely determined by changes in the physiology and environment of the mother. Juvenile hormones (JHs) have been implicated in playing a role in wing differentiation in aphids, however until recently, methods were not available to accurately quantify these insect hormones in small insects such as aphids.

Effects of temperature on reproductive output, egg provisioning, juvenile hormone and vitellogenin titres in the butterfly Bicyclus anynana.

Environmentally induced phenotypic plasticity is common in nature. Hormones, affecting multiple traits and signaling to a variety of distant target tissues, provide a mechanistic link between environments, genes and trait expression, and may therefore well be involved in the regulation phenotypic plasticity. Here, we investigate whether in the tropical butterfly Bicyclus anynana temperature-mediated plasticity in egg size and number, with fewer but larger eggs produced at lower temperatures and vice versa, is under control of juvenile hormone, and whether different temperatures cause differences in egg composition.

Adult nutrition and butterfly fitness: effects of diet quality on reproductive output, egg composition, and egg hatching success.

Background: In the Lepidoptera it was historically believed that adult butterflies rely primarily on larval-derived nutrients for reproduction and somatic maintenance. However, recent studies highlight the complex interactions between storage reserves and adult income, and that the latter may contribute significantly to reproduction. Effects of adult diet were commonly assessed by determining the number and/or size of the eggs produced, whilst its consequences for egg composition and offspring viability were largely neglected (as is generally true for insects).

RNA interference with the allatoregulating neuropeptide genes from the fall armyworm Spodoptera frugiperda and its effects on the JH titer in the hemolymph.

The juvenile hormone (JH) titer was measured by liquid chromatography-mass spectrometry (LC-MS) with electrospray ionization (ESI). Three JH homologs, the JH I-III were detected in various amounts in larvae, prepupae and virgin adult females of Spodoptera frugiperda. In penultimate larvae, the JH II and III titers were relatively high, but decreased continuously during the 3 days of that stage, whereas JH I was detectable at low amounts only on the first 2 days.

Effects of the NMDA receptor antagonist MK-801 on female reproduction and juvenile hormone biosynthesis in the cricket Gryllus bimaculatus and the butterfly Bicyclus anynana.

Apart from regulating insect development, juvenile hormones (JHs) play an important role in insect reproduction, where they initiate vitellogenin synthesis and regulate the uptake of yolk by the ovary. JH synthesis is a tightly regulated process controlled by neurons and peptidergic neurosecretory cells. One of the known stimulatory regulators of JH biosynthesis is glutamate, and its N-methyl-d-aspartate (NMDA) receptor has been recently found in the cockroach Diploptera punctata.

The adipokinetic hormones in the fall armyworm, Spodoptera frugiperda: cDNA cloning, quantitative real time RT-PCR analysis, and gene specific localization.

Small neuropeptides of the adipokinetic/red pigment-concentrating hormone (AKH/RPCH) family regulate energy metabolism in insects. Within lepidopterans, the nonapeptide Manduca sexta AKH (Manse-AKH) represents a widely occurring AKH, whereas the decapeptide Helze-HrTH (at first isolated from Helicoverpa zea) seems to be restricted to moths. Here we report the identification of the Manse-AKH-like Spofr-AKH 1 and the Helze-HrTH-like Spofr-AKH 2 prohormone precursors from the fall armyworm, Spodoptera frugiperda.