An analysis of testicular morphology and spermatogenesis in the Heteroptera species Antiteuchus tripterus (Pentatomidae) revealed that these traits differ from that recorded for other species of the same family. The testes of A. tripterus have only six lobes, while other species of the same family typically have seven lobes, including a compound lobe, i.e., a lobe containing another in its lumen. A study of meiosis and sperm structure in the different lobes of A. tripterus revealed a conventional meiosis in the lobes numbered one to three. In lobe four, however, prophase I spermatocytes exhibit the morphological characteristics of the so called "diffuse" stage and are larger than those in lobes 1-3 in this and the remaining phases of meiosis. Thus, the resulting spermatids are not only larger but also their head is morphologically different. Lobe 5 exhibits characteristics known from other Pentatomidae species such as an uneven distribution of chromatin to the daughter cells, which give rise to cells of different sizes. This lobe forms spermatozoa of different sizes. Lobe 6, contained within lobe 5, differs from it by having larger cells at a stage similar to the so called "diffuse" and spermatid tails with cross divisions, which are not found in other lobes and unreported in the literature.
The mixture of volatile compounds emitted by Brassica oleracea var. sabauda changed significantly in response to feeding and/or oviposition by Murgantia histrionica (Heteroptera: Pentatomidae). Volatiles were collected from (1) healthy plants and those with (2) feeding punctures, (3) a combination of feeding punctures and oviposition, (4) feeding punctures and one hatched egg mass and (5) plants bearing only an egg mass. In the case of plants with feeding punctures or feeding punctures plus an egg mass, the volatiles were also collected at different time intervals after plants were subjected to these two treatments (0-24 h, 24-48 h and 48-72 h). Gas chromatographic and gas chromatograph-mass spectrometric analysis showed that the percent emission of several compounds changed significantly from plants subjected to the feeding and oviposition or just oviposition. Percentage of terpenes generally decreased after feeding and oviposition, although the percentage emission of (E)-β-caryophyllene from these plants and those with just feeding punctures significantly increased. Plants with just an egg mass emitted linalool de novo but not (E)-β-ocimene. The emission of jasmonates, mainly methyl jasmonate, increased from plants with feeding punctures plus an egg mass compared to those with only an egg mass. Higher percentages of the volatile glucosinolate derivatives (VGSs), mainly 4-methoxy-3-indolylacetonitrile, were emitted by plants with feeding punctures and an egg mass. The percentage emission of most of these compounds increased during the first 24 h after the treatment and then decreased over the next 24 h, except for methyl jasmonate, which remained high also 48-72 h later. The possible ecological roles of such volatiles in plant interactions with the second and third trophic levels are discussed.
a1_There are few studies on the morphology and meiosis in the testicles of Heteroptera, but are extremely important, especially for the family Pentatomidae, because in some species in this family meiosis in the testicular lobes results in the production of non-fertile spermatozoa. With the aim of improving the level of understanding of this phenomenon the morphology of the testes and spermatogenesis in 10 species of Pentatomidae were recorded and compared. All of them have testes covered by a pigmented peritoneal sheath. In some species the internal membrane or just inside the peritoneal sheath is pigmented. The pigmentation of both membranes varied. The pigmentation of both was either yellow, or the internal membrane was yellowish and the external one reddish. When the membrane is pigmented, the colour is red or yellow. The number of lobes varied from 3 to 7, with intermediate numbers of 4 and 6. The size and diameter of the lobes are similar in all the species studied, except Proxys albopunculatus, in which the diameter of the third and fifth is smaller than that of the other lobes. The behaviour of the cells during spermatogenesis was the same in all lobes of most species, except in P. albopunctulatus, in which the harlequin lobe is absent and the cells in lobes 4 and 6 exhibited characteristics different from those of cells in lobes 1-3 and 5. Chlorocoris complanatus and Loxa deducta (both Pentatominae) have a harlequin lobe (lobe 5). The chromosome complements recorded were: 2n = 12 (10A + XY) in Dichelops melacanthus and Edessa collaris, 2n = 14 (12A + XY) in C. complanatus, Edessa meditabunda, Ladeaschistus sp., Loxa deducta, P. albopunctulatus, Piezodorus guildinii and Thyanta perditor and 2n = 16 (14A + XY) in Edessa affinis. Thus, this study extends the knowledge of characteristics, such as the pigmentation of the peritoneal sheath, number of testicular lobes, the occurrence of meiotic cells in some, a2_testicular lobes, and the chromosome complements of the family Pentatomidae., and Hederson Vinícius De Souza, Aline Sumitani Murakami, Juliana De Moura, Elisângela Cristiane De Almeida, Inaiá Fernandes Gallego Marques, Mary Massumi Itoyama.
Proteinase activity in the midgut of the pentatomid stinkbug Podisus maculiventris was investigated. The optimal pH for adult and nymph proteolysis was pH 6.0 and pH 6.5, respectively. Proteinase activity was characterised using a range of diagnostic inhibitors. Activity of both adult and nymphal gut extracts, detected by the hydrolysis of Z-Phe-Arg-pNA, was inhibited to <20% of control levels by several inhibitors (e.g. E-64 and chicken egg white cystatin) associated with the inhibition of cysteine proteinases. The less specific inhibitor leupeptin reduced proteolytic activity to around 1.0% of the control values. In-gel analysis of the enzymes revealed that proteolytic activity was due to at least four proteinases, of ca. 30, 36, 50 and 110 kDa, which were all susceptible to E-64 inhibition. Salivary gland extracts gave maximal activity at pH 8.0 when tested for general proteolytic activity using fluorescent BODIPY-FL casein substrate, and showed moderate levels of inhibition when incubated with inhibitors of serine-, cysteine-, aspartic- and metallo-proteinases. Leupeptin and PMSF gave the highest levels of inhibition of salivary proteolytic activity, at ca. 50%, whilst the plant-derived inhibitors SKTI, CpTI and OC-1 did not inhibit proteolysis.
Flight activity in a pentatomid bug, Graphosoma lineatum, was measured under different photoperiodic conditions. Insects started flying 3 days after adult ecdysis and the percentage of flying adults became highest about 1 week after the ecdysis, regardless of the photoperiod. Under long day (18L : 6D), high flight activity was continued, whereas under short day (12L : 12D), most adults stopped flying when diapause was induced. In both photoperiods, a small number of adults showed flight of a long duration, longer than 30 minutes. Thus, no evidence was found relating the long flight to diapause. It is suggested that diapause adults of G. lineatum do not overwinter far from their breeding sites and thus there is no migration to hibernation sites. Also, the long flight is probably only a foraging flight, enabling the bugs to find their dispersed host plants.
This paper reports the results of a comparative laboratory analysis of the behavioural responses of the egg parasitoid Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae) to semiochemical cues from four species of pentatomid bugs, Nezara viridula (L.), Eurydema ventrale Klt., Murgantia histrionica Hahn. and Graphosoma semipunctatum F. (Heteroptera: Pentatomidae). In a Y-tube olfactometer, T. basalis was attracted by volatile chemicals from N. viridula, but not from other pentatomid species. In an open arena, the parasitoid reacted to chemical trails left on filter paper by all the species but most intensely to those left by N. viridula. However, upon encountering pentatomid eggs, T. basalis examined more intensely and probed more frequently the eggs of G. semipunctatum than those of the other species. The parasitoid only parasitized and emerged from eggs of G. semipunctatum and N. viridula; those of the other species were unsuitable. Therefore N. viridula is semiochemically confirmed to be a coevolved host (old association) of T. basalis, whereas G. semipunctatum may be a potential non-coevolved host (new association). The utility of these tests for defining a parasitoids' host specificity and in assessing the risk of non-target effects in biological control is discussed.
In Mormidea paupercula (n = 6 + XY in males), the presence of a CMA3-bright band in the telomeric regions on both sex chromosomes allowed the analysis of the kinetic activity of the sex univalents and XY pseudobivalent at the first and second meiotic divisions, respectively. The separation of the sister chromatids of the sex chromosomes occurs from a pair of telomeric regions (with or without a band), with opposite telomeric regions remaining associated with each other at meiosis I; the behaviour of both sex chromosomes differs, on the X chromosome both telomeric regions are similarly active, while on the Y chromosome the telomeric region without a band is more frequently active. At the second division, the most frequent associations in the pseudobivalent occur between the telomeric regions of both sex chromosomes with bands or without bands. Therefore, in both meiotic divisions, the same telomeric region on the sex chromosomes could lead the migration, in contrast to that observed usually in autosomal bivalents. These results provide evidence that the sex chromosomes of Heteroptera show more than one pattern of attachment to the spindle.
Photoperiodic responses and their adaptive significance were examined in Riptortus clavatus (Heteroptera: Alydidae), Plautia crossota stali, Dolycoris baccarum, Aelia fieberi, Nezara viridula, Nezara antennata, Graphosoma rubrolineatum, Dybowskyia reticulata, and Eurydema rugosum (Heteroptera: Pentatomidae) in the Kyoto-Osaka area, central Japan. All of these species overwinter as adults in diapause. Although they have similar feeding habits, their photoperiodic responses were quite different. Riptortus clavatus, P. c. stali, D. baccarum and N. viridula showed long-day photoperiodic responses with critical daylengths between 13 and 14 h, and were assumed to have three generations per year. The photoperiodic responses of the other five species were different both from those of the above species and from each other. These results suggested that A. fieberi and N. antennata produce two generations per year, and G. rubrolineatum, D. reticulata and E. rugosum have one or two generations per year. Nezara antennata showed a long-day-short-day photoperiodic response with summer adult diapause, which may avoid production of heat-susceptible nymphs in the hottest season. With the exception of N. antennata, the photoperiodic responses resulting in fewer generations were shown to be adaptations to dietary conditions in the field.
Volatiles and contact pheromones involved in the mating behaviour of the Painted bug, Bagrada hilaris Burmeister (Heteroptera: Pentatomidae), were investigated in behavioural and chemical experiments. Vertical open Y-shaped olfactometer bioassays showed that odour from males attract females but not males, while that from females did not attract either gender. Adult females were also attracted by hexane extracts of volatile compounds collected from males. In open arena bioassays, males displayed the characteristic steps of courtship behaviour in the presence of virgin females. Such courtship behaviour was displayed in the presence of females killed by freezing, but not in the presence of freeze-killed females washed with hexane. Gas chromatography-mass spectrometry (GC-MS) analysis of volatile compounds produced by cohorts of 20 B. hilaris adults and collected over 48 h showed that both males and females produce the compounds nonanal, decanal and (E)-2-octenyl acetate. Of these compounds males produce significantly more (E)-2-o-octenyl acetate, i.e. 186.74 ng and 67.53 ng for males and females respectively. These findings indicate this compound is possibly a long range volatile pheromone, and a complex lipophilic fraction of the adult cuticle possible contact pheromone involved in short range courtship behaviour.