Identification of in vitro release products of corpora allata in female and male loreyi leafworms,Leucania loreyi

The in vitro release of juvenile hormones (JH) by female, and of JH acids (JHA) by male corpora allata (CA) ofLeucania loreyi was identified by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Separation and quantification were accomplished by HPLC and GC, respectively. JH II and JH III were the major components released by CA of females. Four JHA analogues were identified as the release products of male CA, i.e. JHA III, Iso-JHA II, JHA II and JHA I. JHA III and Iso-JHA II were reported for the first time as the major release products of CA of adult male Lepidoptera. Iso-JHA II is a new member of the insect juvenile hormone analogue family.     

Autoinhibition of juvenile hormone production. The case of the cockroachBlattella germanica (L.)

In 6-day-old females ofBlattella germanica, the activity of corpora allata (CA) was inhibited in vitro by juvenile hormone III (JH III). Effective doses (281.5 and 375.4 M in the medium) were somewhat higher than (although of the same order of magnitude as) the estimated intraglandular concentration of JH III at this age, and they induced about 45% inhibition of hormonal release and a significant intraglandular accumulation of JH III and methyl farnesoate. The results suggest that autoinhibitory mechanisms operate in the CA to constrain the upper limit of JH III production at the end of the gonadotrophic cycle.     

Phosphoramidon enhances allatostatin-mediated inhibition of juvenile hormone biosynthesis in the corpora allta of the cockroach,Diploptera punctata

Use of the enkephalinase inhibitor phosphoramidon in the in vitro radiochemical assay for juvenile hormone biosynthesis enhanced allatostatin-mediated inhibition of hormone production by corpora allata of the cockroach,Diploptera punctata. Significant increases in inhibition in day 2 virgin female CA by AST 1 (at 10^–7 M) and AST 4 (10^–8–10^–7 M) were observed in the presence of phosphoramidon (10^–5M or greater). No significant increases in inhibition were seen in CA from day 6 mated females with AST 4 (10^–9–10^–7M) and phosphoramidon combined. Phosphoramidon alone had no effect on JH biosynthesis. Analysis of allatostatin content of the CA, as determined by ELISA, revealed that addition of phosphoramidon to the medium increased the endogenous allatostatin conten in CA of virgin and mated females. The similarity in primary structure between allatostatins and enkephalin-like peptides and their similar distribution makes it probable that phosphoramidon acts by preventing breakdown of allatostatins within the CA.     

Expression and immunolocalisation of odorant-binding and chemosensory proteins in locusts

We have identified, cloned and expressed a new chemosensory protein (CSP) in the desert locust Schistocerca gregaria belonging to a third sub-class of these polypeptides. Polyclonal antibodies stained a band of 14 kDa, as expected, in the extracts of antennae and palps of the adults, but not in the 4th and 5th instars. In the related species Locusta migratoria, instead, the same antibodies cross-reacted only with a band of apparent molecular mass of 35 kDa in the extract of 1st–5th instars, but not in the adults. The recombinant protein binds the fluorescent probe N-phenyl-1-naphthylamine, but none of the compounds so far reported as pheromones for S. gregaria. The expression of the odorant-binding protein (OBP) and of CSPs of sub-classes I and II was also monitored in antennae, tarsi, palpi, wings and other organs of solitary and gregarious locusts in their nymphal and adult stages. OBP was found to be antenna specific, where it is expressed at least from the 3rd instar in both solitary and gregarious locusts. CSPs, instead, appear to be more ubiquitous, with different expression patterns, according to the sub-class. Immunocytochemistry experiments revealed that OBP is present in the sensillum lymph of sensilla trichodea and basiconica, while CSP-I and CSP-III were found in the outer sensillum lymph of sensilla chaetica and in the sub-cuticular space between epidermis and cuticle of the antenna. Sensilla chaetica on other parts of the body showed the same expression of CSP-I as those on the antenna.Received 11 Janury 2005; received after revision 21 February 2005; accepted 18 March 2005X. Jin and A. Brandazza contributed equally to this work.     

The male pheromone of the old house borerHylotrupes bajulus (L.) (Coleoptera: Cerambycidae): Identification and female response

We report here the identification of the long-range, male-produced sex pheromone of the Old house borerHylotrupes bajulus. Chemical analysis of hexane extracts obtained by surface extraction from dissected prothoracic glands and from headspace samples of the two sexes, revealed male-specific compounds: (3R)-3-hydroxy-2-hexanone, 2-hydroxy-3-hexanone, the diastereomeric diols (2R, 3R)-2,3-hexanediol and (2S, 3R)-2,3-hexanediol, 2,3-hexanedione, as well as 1-butanol.In wind tunnel bioassays we tested the influence of these male-specific compounds from the prothoracal glands on the behaviour of unmated and mated females. Specific behavioural sequences of the tested females (activity, running behaviour, searching, cleaning, flying, extension of ovipositor) were recorded. Unmated females were attracted by male beetles, headspace extracts of males, synthetic blends of the major pheromone compounds as well as by the components (3R)-3-hydroxy-2-hexanone, and the diastereomeric diols. Hexane, female beetles and 2,3-hexanedione did not attract unmated females. The reactions of mated females to male beetles and headspace samples did not differ significantly from those of the controls.The results of the bioassays show that the two-stage premating behaviour is initiated by emission of a long-range sex pheromone from the male prothoracal glands, which functions as an activator, attractant, and possibly aphrodisiac for unmated females.     

Control of corpus allatum activity inDiploptera punctata: roles of the pars intercerebralis and pars lateralis

Summary Control of the corpora allata (CA) ofDiploptera punctata is maintained by at least 2 factors. The glands are directly inhibited by an allatostatin arriving at the CA via the nervi corporis cardiaci I (NCC I). Destruction of the putative source (median neurosecretory cells, MNC) of the allatostatin by radio-frequency (RF) cautery relieved the inhibition imposed on the CA of virgin females, and the glands became active. Similarly, destruction of the lateral neurosecretory cells (LNC) also relieved the inhibition. We propose that the LNC stimulated the MNC to release allatostatin. RF-cautery did not result in the activation of CA of pregnant or ovariectomized females. Activation of the CA may therefore require not only absence of the inhibitory factor but also the presence of a stimulatory one (perhaps from the ovary).     

Infection of frog tadpoles (Amphibia) by insect parasitic nematodes (Rhabditida)

Summary Infective stage juveniles ofNeoaplectana carpocapsae (Steinernematidae) andHeterohabditis heliothidis (Heterorhabditidae) were able to penetrate through the alimentary tract of young tadpoles ofHyla regilla (Hylidae) andXenopus laevis (Pipidae) and enter the body cavity. Some infectives ofN. carpocapsae were able to release their symbiotic bacterium,Xenorhabdus nematophilus inside the host and in two cases, the nematodes developed into adult females before they perished. Tadpole mortality was associated with foreign bacteria entering the penetration holes made by the invading nematodes. The infective stage juveniles of both nematodes frequently encountered a host defense reaction upon reaching the tadpole's infective stage juveniles of both nematodes frequently encountered a host defense reaction upon reaching the tadpole's coelom.     

Intrapopulational genetic variation in the hybridization betweenDrosophila melanogaster females andD. simulans males

Summary Intrapopulational variation on interspecific crossing ability betweenD. melanogaster andD. simulans has been measured. When themelanogaster females andsimulans males were crossed, hybridization ranged from 3 to 34%, the female component of variation being more important than the male component. This point is discussed in relation with the role played by each sex in sexual isolation.     

Alkaloidal oviposition stimulants for a danaid butterfly,Ideopsis similis L., from a host plant,Tylophora tanakae (Asclepiadaceae)

Chemicals releasing oviposition by an Asclepiadaceae feeder,Ideopsis similis, were identified from a host plant,Tylophora tanakae. A strong positive response was evoked by a methanolic extract of the plant, which proved to contain multiple stimulants. A mixture of two phenanthroindolizidine alkaloids, (+)-isotylocrebrine and (–)-7-demethyltylophorine, isolated from organic fractions, elicited significant ovipositional responses from females.     

Determination of diel periodicity of sex pheromone release in three species of Lepidoptera by ‘closed-loop-stripping’

Summary By means of closed-loop-stripping and subsequent GC analyses the diel periodicity of release of (Z)-11-hexadecenyl acetate, (E)-8-dodecenyl acetate, and (Z)-9-tetradecenyl acetate, the main constituents of the respective sex pheromone blends ofMamestra brassicae, Cryptophlebia leucotreta andSpodoptera sunia females, was determined.Pheromones, 64. For the 63rd contribution we have taken from: Szöcs, G., Toth, M., Bestmann, H. J., Vostrowsky, O., Heath, R. R., and Tumlinson, J. H., Z. Naturforsch.42c (1987) 165; Pheromones, 62: Bestmann et al.¹³.     

Mating attempts between the Scarlet Tiger Moth,Callimorpha dominula L., and the Cinnabar Moth,Tyria jacobaeae L. (Lepidoptera: Arctiidae), involve a common sex pheromone composition

It has been suggested that a common sex pheromone composition may account for interspecific sexual interactions observed with certain moths in the Arctiidae. In this study, it is demonstrated that the sex pheromones released by females of the Scarlet Tiger Moth,Callimorpha dominula L., and the Cinnabar Moth,Tyria jacobaeae L., have similar activities and elute at the same retention time on analysis by coupled gas chromatography (GC)-electrophysiology with males from each species. Peak enhancement on GC, chiral GC and coupled GC-mass spectrometry using authentic compounds show that the sex pheromone for bothC. dominula andT. jacobaeae is (3Z,6Z,9S,10R)-9,10-epoxyheneicosa-3,6-diene.     

Aggregated oviposition byChymomyza amoena (Diptera: Drosophilidae)

Summary Aggregated oviposition byChymomyza amoena in Virginia and Michigan has been shown to be due to egg clustering, females attracted to fruits on whichC. amoena females have already oviposited, and to variation in fruit attractiveness. Negative binomialk values support behavioral similarities among females of this rarely seen species in both states. Discovery ofC. amoena in Europe may indicate that this larval overwintering drosophilid has a Holarctic distribution.The research in Virginia during summer 1986, conducted at Mt. Lake Biological Station, was supported by a fellowship from the University of Virginia. Thanks are gratefully extended to all property owners in Virginia and Michigan for allowing me to collect fruits and to Blaine Cole, Director and J.J. Murray, Chairman of the Biology Dept., University of Virginia for research space in 1986 and 1987. R. N. Band constructed the figures. Comments from reviewers have been helpful.     

Ansamitocin P-3, a maytansinoid,fromClaopodium crispifolium andAnomodon attenuatus or associated actinomycetes

Summary Guided by cytotoxicity, ansamitocin P-3, a maytansinoid, was isolated in very low yield from two members of the moss family Thuidiaceae,Claopodium crispifolium (Hook.) Ren & Card. andAnomodon attenuatus (Hedw.) Hueb. Ansamitocin P-3 showed potent cytotoxicity against the human solid tumor cell lines A-549, HT-29. A possible basis for the occurrence of this compound in mosses is discussed.Presented at the XV International Symposium on Natural Product Chemistry, Monterrey (Mexico) April 28–30, 1988 and at the International Research Congress on Natural Products, Park City (Utah, USA) in July 1988.Acknowledgments. This work was supported by grant No. CA 33326 from the NCI, NIH, USA. K.S. is the recipient of support from the Anandha-Mahidol Foundation, Thailand. The 470 MHz NMR instrument was available through the Purdue University Biochemical Magnetic Resonance Laboratory supported by NIH grant No. RR1077 from the Biotechnology Resources Program of the Division of Research Resources. Special thanks are due to the Purdue Cell Culture Laboratory for in vitro testing data and to Dr M. Antoun forC. crispifolium extraction. The animal testing data are the results of screening performed under the auspices of the Developmental Therapeutics Program, Division of Cancer Treatment, the NCI.     

Oviposition stimulants of aCitrus-feeding swallowtail butterfly,Papilio xuthus L

Summary A methanolic extract ofCitrus unshiu induces oviposition by females of aCitrus-feeding swallowtail butterfly,Papilio xuthus L. The chemical factors responsible for stimulating oviposition were isolated and characterized as 5-hydroxy-N-methyltryptamine, adenosine, vicenin-2, narirutin, hesperidin and rutin. An artificial blend of these six components elicited significant oviposition behavior, apparently identical to that induced by contact with intactCitrus leaves.     

Residual influences on fecundity in drosophilid species

Summary A residual influence of males and females on oviposition has been examined in 7 drosophilids. There was evidence for oviposition deterrence inDrosophila funebris, with males as well as females producing the inhibitory effect. In contrast, male residues stimulated oviposition inZaprionus tuberculatus. Male residues also stimulated oviposition and appeared to serve as an aggregation cue inD. melanogaster.     

Malarial parasites complete sporogony in axenic mosquitoes

Summary To obtain sporogonic stages of malaria free from microbial contaminants for in vitro studies,Anopheles stephensi were reared under sterile conditions using a mosquito cell line as larval food. The adult females, kept in sterile humidified containers and allowed to engorge on parasitemic hamsters, supported the sporogonic development of the rodent malarial parasitePlasmodium berghei. In 10 experiments, the proportion of infected mosquitoes varied from 0 to 92%, and the geometric mean number of oocysts per female mosquito from 2.5 to 58,6, with a range of 1 to 548. The average number of salivary gland sporozoites per infected mosquito was determined by direct sporozoite counts in the pooled homogenate of the thoraces of all female mosquitoes. In five experiments, it varied from 2.7×10³ to 9.0×10³. The sterile sporozoites, harvested on day 19 or 20 after the infective blood meal, were as infective for rodents as nonsterile ones.Supported in part by Public Health Service research grant AI 18345 from the National Institute of Allergy and Infectious Diseases, by a grant from the Agency of International Development DSPE-5542-G-SS-3042-00, and by a Charles and Johanna Busch award.     

Juvenile hormone and reproduction in the cricket. II. Effect of rearing temperature on corpus allatum activity (in vitro) in adult females

Summary In the Mediterranean field cricket,Gryllus bimaculatus, reproduction is controlled by temperature and the corpus allatum (CA) hormone JH III. In CA of females reared at 24°12°C(168 h) (high reproduction rate) a first peak in JH III synthesis is reached about 4 days earlier than in those of 20°C females (low reproduction rate). Furthermore, in 20°C animals CA activity is low during the entire oviposition period, whereas at 24°12°C high CA activity is found during this period of adult life. The results indicate a stimulation of CA activity and reproduction by thermoperiods around a constant low temperature.Supported by the DFG (SFB 87 A 4).     

Phosphoramidon enhances allatostatin-mediated inhibition of juvenile hormone biosynthesis in the corpora allata of the cockroach, Diploptera punctata.

Use of enkephalinase inhibitor phosphoramidon in the in vitro radiochemical assay for juvenile hormone biosynthesis enhanced allatostatin-mediated inhibition of hormone production by corpora allata of the cockroach, Diploptera punctata. Significant increases in inhibition in day 2 virgin female CA by AST 1 (at 10(-7) M) and AST 4 (10(-8)-10(-7) M) were observed in the presence of phosphoramidon (10(-5) M or greater). No significant increase in inhibition were seen in CA from day 6 mated females with AST 4 (10(-9)-10(-7) M) and phosphoramidon combined. Phosphoramidon alone had no effect on JH biosynthesis. Analysis of allatostatin content of the CA, as determined by ELISA, revealed that addition of phosphoramidon to the medium increased the endogenous allatostatin content in CA of virgin and mated females. The similarity in primary structure between allatostatins and enkephalin-like peptides and their similar distribution makes it probable that phosphoramidon acts by preventing breakdown of allatostatins within the CA.     

Behavior and catecholamine levels: comparative study of gregarious insects, solitary insects, and those treated with carbon dioxide in Locusta migratoria (Insecta, Orthoptera)]

The dopamine (DA) and noradrenaline (NA) was measured in Locusta migratoria for 3 groups of individuals showing differences in their motility: gregarious are very active, solitary and animals in chronic treatment by CO2 (1 mn/day) show a very low motility. NA is present in small amounts (0,120-0,250 microng/g) in the 3 groups without significant differences. On the contrary, the quantity of DA is 5 times greater in gregarious than in the 2 other groups (1,78 and 0,31-0,39 microng/g). Thus it is suggested that DA is related to motility and must play its own role of a neurochormone, distinct from that of a metabolic intermediary between DOPA and NA. The question of a relationship between the metabolism of catecholamine and melanization is open.     

Why isPyrrhocoris apterus insensitive to precocene II?

Summary Precocene II (P II) was applied to the adult females of 2 Pyrrhocorid bugs —Pyrrhocoris apterus (insensitive to P II) andDysdercus cingulatus (sensitive to P II)-subjected to allatectomy and intraspecific or interspecific reimplantations of corpus allatum (CA). The failure of P II to inhibit ovarian development inP. apterus appears to be caused by both a low sensitivity to P II of the CA itself and unknown anti-precocene mechanisms outside the CA.Precocene II was kindly supplied by Zoecon.