EJE, vol. 94 (1997), issue 3

Preface: The Sixth International Conference on Regulation of Insect Reproduction.


Eur. J. Entomol. 94 (3): 321, 1997


Juvenile hormone in insect reproduction - a paradox?


Eur. J. Entomol. 94 (3): 323-333, 1997

The insect corpus allatum hormone known as juvenile hormone (JH) was shown by Wigglesworth 60 years ago to play essential roles in repressing metamorphosis and in stimulating aspects of reproduction. Since then, its many actions in reproduction have been increasingly recognized, and it now appears that, in adult insects of most species, JH is a primary coordinator of reproductive processes. All tissues that are directly or indirectly involved in reproduction can be targets for JH action. In evolution, the reproductive role of JH probably preceded its metamorphic role. At the subcellular level, in adult locust fat body, JH induces the synthesis of factor(s)...

Gonadotrophic and morphogenetic effects of a juvenile hormone analog treatment and ovary presence on last instar male and female Diploptera punctata (Blattaria: Blaberidae)


Eur. J. Entomol. 94 (3): 335-348, 1997

Application of the juvenile hormone analog, 7S-hydroprene, to last instar female larvae of the viviparous cockroach Diploptera punctata on day 1 resulted in vitellogenesis in the basal oocytes of the larval ovary, a peak of juvenile hormone synthesis not seen in controls, as well as maintenance of juvenile characteristics in the instar following the molt. To investigate whether juvenile hormone analog and/or the developing ovary was responsible for such changes in juvenile hormone synthesis, the present study used 7S-hydroprene treatment on intact and ovariectomized last instar females and on last instar males with or without an adult or last...

Immunohistochemistry of the products of male accessory glands in several hemimetabolous insects and the control of their secretion in Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae)


Eur. J. Entomol. 94 (3): 349-360, 1997

Three antibodies against secretions of the male accessory glands of Tenebrio molitor react with specific regions of the male reproductive system in a damselfly, cockroach, cricket and the bug Pyrrhocoris apterus. Immunoreactivity was used to assess maturation of the system in the reproducing and diapausing P. apterus. In bugs reared continuously at 16 h photophase and 25°C (LD regimen), antigens detected with the PL 6.3 and PL 15.2 antibodies accumulate in the accessory glands and vas deferens (in case of PL 6.3 also in the testes) gradually during the last larval instar. The PL 3.4 antibody begins to react three days after adult...

Stick insect (Carausius morosus; Phasmatodea: Lonchodidae) brain extract contains multiple fractions with allatostatic activity


Eur. J. Entomol. 94 (3): 361-368, 1997

A first attempt to purify inhibitors of juvenile hormone biosynthesis from extracts of brains of the Indian stick insect, Carausius morosus, is reported here. A heterologous bioassay in the cricket, Gryllus bimaculatus, was used throughout the study. Separation of a prepurified extract using C-18 reversed-phase high performance liquid chromatography (RP-HPLC) resulted in a broad zone with biological activity. Upon re-chromatography of each of six active regions on a wide-pore C-18 column, the material separated in distinct peaks of biologically active fractions. Introducing a third purification step (C-8 column) resulted in a total of...

Factors regulating juvenile hormone and ecdysteroid biosynthesis in Gryllus bimaculatus (Ensifera: Gryllidae)


Eur. J. Entomol. 94 (3): 369-379, 1997

A family of neuropeptides (B-allatostatins) from the cricket, Gryllus bimaculatus, which had been purified on the basis of their ability to inhibit juvenile hormone III biosynthesis by cricket corpora allata and which showed high sequence homology with a class of myo-inhibiting peptides from locusts and butterflies, also effectively inhibit ovarian ecdysteroid biosynthesis, thus acting as ecdysiostatins. Within a 3 h in vitro incubation, ecdysteroid production was inhibited between 45 and 50% at 10-7-10-9 M Grb-AST B1 and B2, respectively. Grb-AST B3 and B4 were less effective in inhibiting ecdysteroid biosynthesis (inhibition...

Species variation in the response of tsetse flies (Glossina spp.; Diptera: Glossinidae) to parturition hormone


Eur. J. Entomol. 94 (3): 381-383, 1997

Parturition hormone, present in the uterus of several species of Glossina, causes expulsion of the uterine content in neck-ligated, pregnant females of Glossina morsitans, thus eliciting either parturition or abortion. Uteri of all six tsetse species tested (G. morsitans, G. austeni, G. brevipalpis, G. palpalis, G. fuscipes, G. pallidipes) contain parturition hormone activity, and neck-ligated females of G. morsitans, G. austeni, G. palpalis and G. pallidipes all respond to the hormone by giving birth. Though uterine extracts of both G. brevipalpis and G....

Lipid synthesis by ovaries and fat body of Aedes aegypti (Diptera: Culicidae)


Eur. J. Entomol. 94 (3): 385-391, 1997

Synthesis of fatty acids by the ovaries of Aedes aegypti was demonstrated by incubating ovaries in tritiated water. Mostly phospholipids were synthesized, however, in mature oocytes the vast majority of lipids are triacylglycerol. 80% of the fatty acids synthesized in vitro were saturated while in the mature oocytes 70% of the fatty acids are unsaturated. These results suggest that lipids synthesized in the oocytes contribute only a minor portion of the lipid complement of the egg and that most of the oocyte lipids are taken up from external sources. The amount of lipid synthesized in vitro by the ovaries was extremely small, less than 1/1000...

Nuclear bodies from cricket and mealworm oocytes contain splicing factors of pre-mRNA


Eur. J. Entomol. 94 (3): 393-407, 1997

A comparison of nuclear structures of the germinal vesicles from an insect with panoistic ovarioles (cricket Acheta domesticus) with that of an insect with meroistic ovarioles (mealworm Tenebrio molitor) was carried out. Immunocytochemistry revealed that spheres from cricket oocyte nuclei contained small nuclear RNP (snRNP) and fibrillarin - protein which may be involved in pre-rRNA processing. Additionally, coilin-related protein was revealed in cricket spheres. In the mealworm germinal vesicles, two types of nuclear bodies containing snRNP were identified. Only one of these types of nuclear bodies contained SC35 splicing factor. In...

Host-parasitoid relationship of Ceratitis capitata (Diptera: Tephritidae) and Coptera occidentalis (Hymenoptera: Proctotrupoidea: Diapriidae) under host heavy metal stress


Eur. J. Entomol. 94 (3): 409-420, 1997

The development and fecundity of Ceratitis capitata Wiedemann (Diptera: Tephritidae) and the host-parasitoid relationship of C. capitata and its pupal endoparasitoid, Coptera occidentalis (Muesebeck) (Hymenoptera: Proctotrupoidea: Diapriidae) were investigated under conditions in which the host was stressed by heavy metal ingestion. C. capitata larvae (from first instar to pupation) were fed diets that were separately contaminated with three metals; each contaminant was applied at four concentrations that differed by a factor of 2. The lowest concentrations were as follows: copper 100 µg/g, cadmium 25 µg/g and...

Cytogenetic analysis of some aradid species (Heteroptera: Aradidae)


Eur. J. Entomol. 94 (3): 421-424, 1997

Known sex chromosome mechanisms in Aradidae are XX : XY or compound X(XnY). The present paper adds data obtained from studying testes of adults and stage IV and V larvae of four aradid species. The number of chromosomes and their behaviour during spermatogenesis (in Aradinae for the first time) were documented and illustrated: Aradus cinnamomeus Panter -2n = 35 (32 + X1X2Y); Aradus corticalis corticalis (L.) -2n = 28 (26 + XY); Aradus conspiculus Herrich-Schaffer 2n = 28 (26 + XY); Aneurus avenius Dufour -2n = 27 (24 + X1X2Y). Mechanisms which could have played a role...