Four species of Anagrus (A. breviphragma Soyka, A. incarnatus Haliday, A. fennicus Soyka and A. obscurus Foerster sensu Soyka), that live on Carex riparia Curtis (Cyperaceae) in uncultivated areas along the Po river in the Piacenza province in Italy were analysed using RAPD markers in order to investigate their genetic relationships. High levels of RAPD polymorphism were found in the genus Anagrus, which permitted the fingerprinting of the four species. Analysis of average genetic similarities within species and comparison with average values between species confirms that A. breviphragma, A. incarnatus, A. fennicus and A. obscurus represent four genetically distinct species. A dendrogram constructed from molecular data of single families clearly clustered the four species in different groups, their mutual position reflecting morphological and biological observations., Elisabetta Chiappini, Lucia Soressi, Corrado Fogher, Marco Zanirato, and Lit
The influence of host intrapatch spatial distribution on parasitoid host acceptance behavior was investigated with Trichogramma principium parasitizing eggs of grain moth, Sitotroga cerealella. Single females were placed in Petri dishes, each containing 60 host eggs arranged either as a compact patch or partitioned into 60 or 12 clusters each consisting of 1 or 5 eggs, respectively. Partitioned patches provoked parasitization more often than compact patches. The percentage of ovipositing females (i.e., females parasitizing at least one of 60 host eggs) increased with the number of clusters, while it was independent of the intercluster distance over intervals of 2.5-15 mm. The mean number of eggs parasitized by ovipositing females during 48 h was almost independent of the host egg spatial pattern. As a result, the rate of parasitization was higher when the hosts were sparsely distributed within a patch than when they were aggregated., Nataliya D. Voinovich, Taisiya Ya. Umarova, Sergey Ya. Reznik, and Lit
A. schneideri and A. grossulariae clones from southern Poland produced fertile hybrid eggs under experimental conditions. Established hybrid clones expressed normal parthenogenetic reproduction but bisexual generations were not obtained, though a few sexuales developed in some cases. Morphological features of A. schneideri and host-specificity of A. grossulariae tended to dominate in the majority of hybrid clones. Independent inheritance of the studied morphological characters and host specificity can therefore be presumed.
Present results do not exclude the possibility of natural hybridisation of studied aphid species. Natural crosses might cause taxonomic and currant pest management problems., Rimantas Rakauskas, and Lit
Insect peptidyl-dipeptidase A [angiotensin I - converting enzyme (ACE)] is a soluble single-domain peptidyl-dipeptidase that has many properties in common with the C-domain of mammalian somatic ACE and with the single-domain mammalian ACE. In agreement with a variety of insects, immunocytochemical studies reveal the presence of an ACE-like protein in Locusta migratoria. ACE-like immunoreactivity is present in neurosecretory cells of the pars intercerebralis. These cells have axons projecting into the nervus corporis cardiaci I and into the storage part of the corpus cardiacum, a neuroendocrine organ directly releasing into the aorta. The localisation of ACE in neurosecretory cells is consistent with its proposed role as a processing enzyme that is involved in the generation of active peptide hormones., Dirk Veelaert, Liliane Scoofs, Nathalie Macours, Anick Vandingenen, Arnold De Loof, Elwyn Isaac, Michel Salzet, Roger Huybrechts, and Lit
In view of the extremely high metabolic rates involved, insect flight offers a fascinating model system for studying metabolism during exercise, including its regulation by metabolic neurohormones. In our laboratory the African migratory locust, Locusta migratoria, well-known for its long-distance flights, is used as an internationally recognized model insect. The insect is mass-reared under controlled conditions; its size permits convenient handling in vivo and in vitro, while flight activity can be easily evoked. In addition, research on this pest insect may be of economical importance.
A survey of the energy metabolism during locust flight is presented in Fig. 1. Flight activity stimulates the neurosecretory adipokinetic cells in the glandular lobes of the corpus cardiacum, a neuroendocrine gland connected with the insect brain, to release peptide neurohormones, the adipokinetic hormones (AKHs). The target for these hormones is the fat body. Via signal transduction processes, the action of the hormones ultimately results in the mobilization of both carbohydrate and lipid reserves as fuels for flight. Carbohydrate (trehalose) is mobilized from glycogen reserves, implying hormonal activation of the key enzyme, fat body glycogen phosphorylase, by phosphorylation. Similarly, on the lipid side, sn-1,2-diacylglycerol (DAG) is mobilized from stored triacylglycerol (TAG), by hormonal activation of the fat body TAG lipase. The carbohydrate and lipid substrates are transported in the hemolymph to the contracting flight muscles. Carbohydrate provides most of the energy for the initial period of flight, whereas at a later stage, lipid substrate in the blood is increased and gradually takes over. The transport of DAG requires specific lipoprotein carriers (lipophorins) which differ in several respects from the lipoproteins in mammals, and act as a lipid shuttle.
This review is focused on three interrelated topics, covering recent data on the biosynthesis and release of the AKHs, their signal transduction mechanisms in the fat body cells, and the changes in the lipophorin system induced by the AKHs during flight., Dick J. Van Der Horst, Wil J.A. Van Marrewijk, Henk G.B. Vullings, Jacques H.B. Diederen, and Lit
The monophyly of the subgenus Leptempis Collin of the genus Empis L. is established on the basis of a male hypopygial character, and the possibility of a close relationship between the subgenera Leptempis Collin, Planempis Frey and Kritempis Collin is discussed. Seven new species belonging to Empis (Leptempis) rustica-group are described from France, Germany, Greece and Spain: E. (L.) abdominalis sp. n., E. (L.) lamellata sp. n., E. (L.) multispina sp. n., E. (L.) pandellei sp. n., E. (L.) lamellimmanis sp. n., E. (L.) sinuosa sp. n. and E. (L.) trunca sp. n. A key to the E. (L.) rustica-group is presented., Christophe Daugeron, and Lit
The profile of hemolymph ecdysteroid was studied in the gram pod borer, Helicoverpa armigera, during larval-pupal transformation. The changes closely correspond to the developmental events occurring at metamorphosis. Two insect growth regulators, plumbagin and azadirachtin, significantly depleted the content and altered the profile of ecdysteroids at crucial stages, when applied at ED50 doses. The activity profiles of two fat body lysosomal enzymes, acid phosphatase and b-galactosidase, were also significantly affected by the insect growth regulators. It is suggested that plumbagin and azadirachtin treatments primarily modify the ecdysteroid titer, which in turn leads to changes in lysosomal enzyme activity causing overt morphological abnormalities during the metamorphic molt., Arulappan Josephrajkumar, Bhattiprolu Subrahmanyam, Srinivasan, and Lit
A revision of species of the genus Macroscytus Fieber distributed in Madagascar and adjacent islands is presented. Four previously known species [M. fryeri Distant, M. lobatus Signoret, M. madagascariensis (Signoret), M. privignus Horváth] are redescribed, and lectotypes are designated for three of them. Four new species (M. mayottensis sp. n., M. simulans sp. n., M. tamatavei sp. n., and M. viettei sp. n.) are described and compared with their congeners. A key to all species of the genus known from Madagascar and adjacent islands is also provided., Jerzy A. Lis, and Lit
The effects of 5 pmols of adipokinetic hormone (Lom-AKH-I) on both the locomotion and mobilization of lipids were studied in 10-day-old diapausing adult females of the short-winged (brachypterous) morph of Pyrrhocoris apterus (L.). The results revealed that AKH stimulation of locomotion in this bug is wing-morph independent. The stimulatory effect of AKH on locomotion was shown to be positively correlated with its effect on lipid mobilization., Radomír Socha, Dalibor Kodrík, Rostislav Zemek, and Lit
The presence of adipokinetic activity in crude extracts of corpora cardiaca (CC) from the butterfly (Vanessa cardui L., Nymphalidae) was demonstrated by bioassay and Mas-AKH was revealed as the major adipokinetic hormone (AKH) by use of two different technologies of sequence elucidation: HPLC separation of the peptide followed by Edman degradation and Q-TOF mass spectrometry. In contrast to the time- and material-consuming conventional methods of peptide purification and sequencing, substantial structural data of the peptide were confirmed - post factum - from one pCC (pair of CC) by Q-TOF mass spectrometry. Only males of our laboratory colony showed a significant lipid increase in the haemolymph after injection of either crude CC extract (1 pCC equivalent) or 10 pmol of synthetic peptide., Gabriele Köllisch, Peter D. Verhaert, Matthias W. Lorenz, Roland Kellner, Gerd Gäde, Klaus H. Hoffmann, and Lit