Showing papers on "Lepidoptera genitalia published in 1998"

Comparative evidence for the evolution of genitalia by sexual selection

Abstract: Rapid divergent evolution of male genitalia is one of the most general evolutionary trends in animals with internal fertilization; the shapes of genital traits often provide the only reliable characters for species identification1. Yet the evolutionary processes responsible for this pattern remain obscure. The long-standing lock-and-key hypothesis, still popular among taxonomists, suggests that genitalia evolve by pre-insemination hybridization avoidance; that is, hybrid inferiority drives the evolution of male genitalia with a proper mechanical fit to female genitalia. The sexual selection hypothesis2,3, in contrast, proposes that divergent evolution of genitalia is the result of sexual selection, brought about by variation in postinsemination paternity success among males. Here, by comparing pairs of related clades of insects that differ in mating system, I assess how the opportunity for postmating sexual selection affects the rate of divergent evolution of male genitalia. Genital evolution is more than twice as divergent in groups in which females mate several times than in groups in which females mate only once. This pattern is not found for other morphological traits. These findings provide strong empirical evidence in favour of a postmating sexual selection mechanism of genital evolution.

Wolbachia in two insect host–parasitoid communities

Abstract: Wolbachia form a group of intracellular bacteria that alter reproduction in their arthropod hosts. Two major phylogenetic subdivisions (A and B) of Wolbachia occur. Using a polymerase chain reaction assay we surveyed for the A and B group Wolbachia in 82 insect species from two temperate hostÐparasitoid communities (food webs) and a general collection of Lepidoptera caught at a light trap. One hostÐparasitoid community was based around leaf-mining Lepidoptera, and the other around Aphids. We found that: (i) 22.0% of insects sampled were infected with Wolbachia; and (ii) the prevalence and type (A or B) of Wolbachia infection differed significantly between communities and taxonomic groups. We obtained DNA sequences from the ftsZ gene for the group B Wolbachia found in six leaf-mining species and one of their parasitoids, as well as four of the Lepidoptera caught by a light trap. Taken together, the results of our survey and phylogenetic analyses of the sequence data suggest that hostÐparasitoid transfer of Wolbachia is not the major route through which the species we have examined become infected. In addition, the Wolbachia strains observed in five leaf-mining species from the same genus were not closely related, indicating that transfer between species has not occurred due to a shared feeding niche or cospeciation.

Larval Survival and Development of the Fall Armyworm (Lepidoptera: Noctuidae) on Normal and Transgenic Cotton Expressing the Bacillus Thuringiensis CryIA (c) δ-endotoxin

Abstract: Survival and development of fall armyworms, Spodoptera frugiperda (J. E. Smith), on leaves and bolls of normal (variety DP 5415) and transgenic cotton plants, Gossypium hirsutum L., expressing the Bacillus thuringiensis Berliner (Bt) CryIA(c) -endotoxin (variety NuCOTN 33B) were examined. No significant differences were observed in larval survival between the 2 varieties at 2, 4, 6, 8, 10, and 12 d after exposure. In addition, no significant differences were observed between varieties in the number of larvae that pupated and eclosed as adults. However, larval weights of fall armyworms were significantly higher at 6 and 12 d after exposure on DP 5415 leaves than NuCOTN 33B leaves, and time to pupation and adult eclosion were significantly shorter on DP 5415 leaves than on NuCOTN 33B leaves. No significant differences between varieties were observed for sex ratio, but neonate survival of the subsequent generation was significantly lower from insects reared on NuCOTN 33B.Larval survival to pupation and adult eclosion for larvae fed a combination of DP 5415 foliage (early instars) and bolls (late instars) were significantly higher than for larvae fed NuCOTN 33B foliage and bolls. The effects of a single generation selection of fall armyworms on NuCOTN 33B leaves were also measured. Fall armyworms originally reared on DP 5415 and NuCOTN 33B were fed either normal (DP 5690) or transgenic Bt cotton (NuCOTN 35B ) leaves. Larval survival at 2, 4, 6 d after exposure and adult survivorship were not significantly affected by 1 generation of rearing on transgenic Bt cotton. Single generation exposure to NuCOTN 33B did not affect larval weights of the subsequent generation when reared on transgenic Bt cotton.

Genetic population structure of the winter moth (Operophtera brumata L.)(Lepidoptera, Geometridae) in a fragmented landscape

Abstract: Genetic population structure of the winter moth ( Operophtera brumata L.) (Lepidoptera, Geometridae) in a fragmented landscape

Laboratory Assessment of the Effects of Bacillus thuringiensis on Native Lepidoptera

Abstract: The effect of 2 formulations of Bacillus thuringiensis subsp. kurstaki (Foray 48B and Dipel 8AF) was evaluated on 42 species of native Lepidoptera in laboratory bioassays using instars that are present in the field at the time of gypsy moth suppression applications. Mortality was significant for 27 of the 42 species evaluated against Foray 48B, and 8 of 14 species evaluated against Dipel 8AF. Susceptible species were noted in 5 of 6 families assayed—Papilionidae, Nymphalidae, Geometridae, Lasiocampidae, Saturniidae, and Noctuidae. The 1 species treated in the Lymantriidae family was not susceptible to B. thuringensis . Treated individuals that survived for a week were likely to reach adulthood. Intrageneric differences in susceptibility to B. thuringiensis were recorded among 8 species of Catocala and 3 species of Lithophane assayed. Of the 18 species assayed as 1st or 2nd instars, mortality was significant, usually exceeding 95%. By contrast, 9 of 11 species not susceptible to B. thuringiensis were assayed as penultimate or ultimate instars. However, species susceptible to B. thuringiensis were found in both early and late instars.

Bacillus thuringiensis isolates from the Philippines: habitat distribution, δ-endotoxin diversity, and toxicity to rice stem borers (Lepidoptera: Pyralidae)

Abstract: Bacillus thuringiensis Berliner isolates were detected in 57% of 801 samples of rice grain dust, soil, rice field arthropods, and miscellaneous habitats (rice straw compost and mammal faeces) collected at 100 sites in the Philippines. The collection yielded 3950 isolates of B. thuringiensis (8.7 isolates/positive sample). Grain dust from rice mills was the richest source (63% of the samples were positive, with 10.2 isolates/positive sample), followed by rice field arthropods, soil, and miscellaneous habitats. Polyclonal antibodies to six δ-endotoxin groups (Cry1A, Cry1B, Cry1C, Cry1D, Cry1E, and Cry3A) were used in enzyme-linked immunosorbent assays (ELISA) to characterize the toxins produced by each isolate. Subsamples of isolates representing the diversity of isolate sources and δ-endotoxin profiles were bioassayed against the yellow stem borer, Scirpophaga incertulas (Walker) and striped stem borer, Chilo suppressalis (Walker). Eighteen isolates highly toxic to both species were selected for characterization of δ-endotoxin genes by polymerase chain reaction (PCR) with primers specific to 14 genes or gene subfamilies, and Western blotting with Cry2A antibodies. At least two novel δ-endotoxin genes, related to cry1B and cry1F, were detected by DNA sequencing of PCR products.

Courtship Behavior in Empyreuma affinis Roths. (Lepidoptera, Arctiidae, Ctenuchinae): Acoustic Signals and Tympanic Organ Response

Abstract: Correspondence to: M.V. Sanderford Field and laboratory observations of the mating behavior ofEmpyreuma affinis show that ultrasonic signals consistently produced by the males and occasionally by the females are a distinctive feature of the courtship of this insect. The sounds produced by males and females show a significant sexual dimorphism, most dramatically in their modulation cycle rates. Moreover, males produce two distinct types of emissions that differ in modulation cycle rate. Electrophysiological recordings of spike activity at the tympanic nerve of males and females were carried out, and the responses to prerecorded intraspecific acoustic signals emitted during courtship behavior are shown. The results predict that the main informational content of these signals is in the modulation cycle rate, which is followed faithfully by the receptor cells. In 1864 Laboulbene suggested that acoustic signals play a role in the reproductive behavior of the Arctiidae [1]. Peter [2] later described the use of sound by a day-flying Alpine arctiid moth in its mating behavior, and more recently ultrasonic emissions associated with reproductive behavior have been described for an additional three arctiid species [3, 4]. The first ctenuchine moth to be implicated in acoustic mating behavior was Empyreuma affinis (E. pugione, in earlier references), the “scarlet-winged wasp moth,” a day-flying moth endemic to the Caribbean [5–7]. Since the initial (1983) publication on the ears and sound emission organs of E. affinis [8, 9] additional information has been gathered revealing characteristics which appear to adapt it for acoustic intraspecific communication: (a) Males and females produce sounds with striated and partially denuded tymbals which resemble those of other acoustically active arctiids [10]. (b) The acoustic signals of E. affinis consist of ultrasonic clicks composed of frequencies from 14 to 64 kHz with a major peak at 34 kHz [11] with signal sound pressure levels approaching 80 dB at 2 cm [10]. (c) Audiograms of the A1 and A2 receptor cells of males and females show a close frequency match of auditory sensitivity with the power spectrum of the sound emitted, and an overlap of the Q10 dB bandwidth of sound reception and emission [11]. (d) The auditory organ of this species can detect directional information over an intensity range of at least 60 dB [11]. Also behavioral studies [12] have shown that the time spent in courtship behavior and mating was significantly reduced when either the male or female was deafened. These data suggest that E. affinis engages in acoustic courtship communication, and that both sexes emit acoustic signals during courtship [13]. Our results confirm that sound emission in males (in all the successful matings observed) and in females (in some cases) is indeed present during its courtship. Audition in moths has been often studied in the context of bat/moth interactions [14–17]. Acoustic stimuli resembling bat echolocation signals, and in a few cases natural bat cries have been used to stimulate the tympanic organs [18–21] or central auditory neurons of moths [22]. The use of conspecific moth sounds to evoke tympanal responses has been limited [18, 23, 24]. We here show the responses of lepidopteran auditory receptors to intraspecific acoustic courtship signals.

Protozoan free colonies of lepidoptera

Abstract: A method for the establishment and maintenance of colonies of Lepidoptera which are free of contamination with protozoa is provided The colonies consists of individuals capable of breeding and producing viable, noncontaminated butterflies

Food habits of sympatric insectivorous bats in southern Kyushu, Japan

Abstract: Five species of bats, Myotis nattereri, M. macrodactylus, Miniopterus fuliginosus, Rhinolophus ferrumequinum and R. cornutus were found to forage in the same habitats in southern Kyushu, Japan. M. nattereri fed mainly on Lepidoptera, Coleoptera, Diptera and Araneae, the proportions of each of these in the diet fluctuating seasonally, however, Lepidoptera and Coleoptera, especially, were consumed selectively. Their available prey items ranged in body length from 5-13 mm in length. M. macrodactylus preyed mainly on Diptera, Trichoptera and Lepidoptera, that were larger (7-20 mm) than those eaten by M. nattereri. Small or medium-sized Lepidoptera constituted the bulk of M. fuliginosus' diet in summer. R. ferrumequinum fed chiefly on larger Diptera, Coleoptera and Lepidoptera measuring 8-45 mm in body length, and clearly selected beetles despite these being relatively few in the trap samples. Lepidoptera and Diptera measuring 7-23 mm were important dietary components for R. cornutus, and despite their abundance being relatively low in summer moths were selectively preyed upon. These five bat species selectively hunted particular prey species in addition to taking food opportunistically. Through differences in both foraging-site and in prey selection, they seem to be able to coexist in the same habitat.

Field Tests of Synthetic Sex Pheromone of the Apple Leafminer Moth, Phyllonorycter ringoniella

Abstract: The apple leafminer moth, Phyllonorycter ringoniella, is becoming a more serious insect pest on apple trees with four to five generations a year in Korea. In order to devise a forecasting method for more accurate estimation of their numbers and development timing, the sex attractant was studied. Various ratios, from 10:0 to 0:10, of the two components, (Z)-10-tetradecenyl acetate (Z10–14:Ac) and (E,Z)-4,10-tetradecadienyl acetate (E4,Z10–14:Ac), identified from the sex pheromone gland (Jung and Boo, 1997), were tested for attractivity in terms of behavioral response (taxis, approach, and landing) against P. ringoniella males in a wind tunnel. The lure with Z10–14:Ac/E4,Z10–14:Ac in a ratio of 4:6 elicited the highest response in two (taxis and approach) measurement categories. For eliciting landing behavior, the two blends of 5:5 and 4:6 were best. The single component, Z10–14:Ac, elicited taxis behavior, but a combination of two chemicals was needed for eliciting all three behaviors. In the field, male attraction to various lure mixtures in Pherocon IC traps was usually greater than attraction to virgin females. The best field activity was in the lure baited with a 4:6 ratio of Z10–14:Ac and E4,Z10–14:Ac. Similar results were obtained from tests conducted in a net house. This optimum ratio for attracting P. ringoniella males in Korea is different from those reported in Japan (10:3) or China (7:3 to 6:4). The isomer E10–14:Ac neither improved nor depressed the number of catches when added at up to 10% of the total mixture to lures of the two components in the 4:6 ratio. The attractivity of the lures increased with higher amounts of the pheromones, up to 10 μg in the wind-tunnel experiment and 5 mg in the apple orchard. The number of males captured was not significantly different among traps installed at 0.3, 1.5, or 2 m above the ground, or among wing, delta, or water traps. A rubber septum dispenser impregnated with 1 mg of the 4:6 mixture maintained its field attractivity for up to eight weeks.

Japanese species of the subfamily oecophyllembiinae réal et balachowsky (lepidoptera : gracillariidae), with descriptions of a new genus and eight new species

Abstract: KUMATA, T. 1998. Japanese species of the subfamily Oecophyllembiinae Real et Balachowsky (Lepidoptera: Gracillariidae), with descriptions of a new genus and eight new species. Ins. matsum. n. s. 54: 77 131,27 figs. (11 text-figs., 16 pIs.). The subfamily Oecophyllembiinae is redefined to receive the genera Metriochroa Braun (= Oecophyllembius Silvestri), Cryphiomystis Meyrick, Guttigera Diakonoff, Prophyllocnistis Davis and Eumetriochroa (gen. nov.) on the basis of the hind wing venation and the larval thoracic spiracles. So far as the larvae of eight species belonging to this subfamily are examined, thoracic spiracles are not opened on the prothorax, but on the mesothorax at the anterolateral areas in both the sap-feeding and spinning morphs. The thoracic spiracles opened on the mesothorax in lepidopterous larvae may be a new discovery to the entomological science. Four species of Eumetriochroa, two of Metriochroa and two of Cryphiomystis are dealt with in this paper, and all the species are new to science. Larvae of Japanese species are all leaf-miners on various arboreal plants mainly belonging to the families Rubiaceae or Oleaceae. Photographs of the moths and leaf-mines, and also drawings of the wing venations and genitalia, are given for all the species. Larval photographs are also provided for some species to show the thoracic spiracles. A tentative list of the world species of the subfamily is given in Appendix I, and a list of food plants of these species is also given in Appendix ll. Author's address. 45-16, Bunkyodai-Minamirnati, Ebetu City, Hokkaido, 069-0835 Japan.

INSECTICIDAL ACTIVITY OF MELIACEOUS SEED EXTRACTS AGAINST Crocidolomia binotalis ZELLER (LEPIDOPTERA: PYRALIDAE)

Abstract: Acetone seed extracts of 21 species of Meliaceae were evaluated for their insecticidal activity against second-instar larvae of Crocidolomia binotalis Zeller by a leaf-residue feeding method. The larvae were fed extract-treated broccoli leaves for 2 days, then were maintained on untreated leaves until the fourth-instar stage. Records were kept in regard to the area of leaves eaten during the 2-day feeding treatment, daily larval mortality, and developmental time of surviving larvae from instar II to instar IV. The seed extract of Aglaia harmsiana, Azadirachta indica (neem) and Dysoxylum mollissimum at a concentration of 0.25 percent exhibited a strong insecticidal activity against C. binotalis larvae (95-100 percent mortality), those of Aglaia odoratissima and Trichilia trijuga showed a fairly strong activity (78 percent and 87 percent mortality), whereas the activity of other extracts varied from inactive to moderately active (0-73 percent mortality). The active extracts generally exhibited the three kinds of effects, i.e. antifeedant, insecticidal and developmental derangement, at similar levels. The active extracts at 0.25 percent inhibited feeding by C. binotalis larvae on treated leaves by 78.4-96.6 percent and prolonged the developmental time from instar II to instar IV by 2.2-4.2 days as compared with controls. Further studies are needed to identify insecticidal compounds in the said active extracts, excepts neem which has been exhaustively studies.

Insect-Plant Interactions — Metabolism of Plant Compounds to Pheromones and Allomones by Lepidoptera and Leaf Beetles

Abstract: Pyrrolizidine alkaloids are taken up from plants by various butterflies and moths belonging to the Danainae, Ithomiinae, and Arctiidae, which use them for defence and for the production of male pheromones. A complex distribution scheme of these plant alkaloids by the insect has been established in some species. The transformations involved include conversion into insect alkaloids, metabolism to male pheromones, and transfer of alkaloids from males to females and further into eggs. While these lepidoptera selectively sequester certain compounds from plants in a complex pattern, the leaf beetle Chrysomela lapponica follows a different strategy. Glycosidically bound alcohols present in leaves of their hostplants are liberated and transformed into esters, which are used for defence. Related beetles rely on host-derived single compounds such as salicyl aldehyde or de novo synthesized iridoid monoterpenes. Several aspects of these insect-plant relations, including biosynthetic transformations of plant compounds by the insects, are discussed herein.

First record of Strongygaster triangulifera (Loew) (Diptera : Tachinidae) as a parasitoid of Harmonia axyridis (Pallas) (Coleoptera : Coccinellidae) in Western North America

Abstract: The parasitic tachinid fly Strongygaster triangulifera (Loew) is widely distributed in North America (Stone et al. 1965). It parasitizes several Coleoptera and sometimes species of other orders such as Lepidoptera, Dermaptera, and Hemiptera (Sabrosky and Braun 1970). Existing records of S. triangulifera found in coccinellid hosts are from eastern North America. One describes low parasitization levels (<1%) in two indigenous species, Coccinella trifasciata perplexa Mulsant and Coleomegilla maculata lengi Timberlake, in Ontario, Canada (Smith 1960). The other existing record describes fluctuating parasitization levels (3.0–31.1% in 1993 and 0–6.5% in 1994) in the exotic species Harmonia axyridis (Pallas) in North Carolina and Virginia (Nalepa et al. 1996).

Low Intrinsic Rate of Natural Increase in BT-resistant Population of Diamondback Moth, Plutella xylostella (L.) (Lepidoptera: Yponomeutidae).

Abstract: 大阪府岸和田市神於町のハウス栽培のクレソンから採集した抵抗性個体群に対して薬剤無淘汰で感受性を回復させた感受性個体群KS,ならびにKSに対してBT剤で淘汰して高度な抵抗性を発達させた抵抗性個体群KRを作出し,両者を25°C, 16L:8Dの条件下で人工飼料,ダイコンの子葉,クレソンの3種類の餌により飼育した.BT剤(トアロー®水和剤CT)に対するLC50値は,KSが1.14ppm, KRが25,200ppmであった.KRはKSに比べ,孵化率が低く,孵化から羽化までの期間が長く,同期間の生存率が低く,成虫の生存期間が短く,産卵数が少なかった.岸和田個体群ではBT抵抗性と適応度がトレードオフの関係にあり,特に抵抗性個体の孵化から羽化までの発育期間が長いため,実験室内でBT剤に対する感受性が回復しやすいと考えられた.