Showing papers on "Lepidoptera genitalia published in 1994"

Accumulation of a chymotrypsin inhibitor in transgenic tobacco can affect the growth of insect pests

Abstract: A member of the potato proteinase inhibitor II (PPI II) gene family that encodes for a chymotrypsin iso-inhibitor has been introduced into tobacco (Nicotiana tabacum) usingAgrobacterium tumefaciens-mediated T-DNA transfer. Analysis of the primary transgenic plants (designated R0) confirmed that the introduced gene is being expressed and the inhibitor accumulates as an intact and fully functional protein. For insect feeding trials, progeny from the self-fertilization of R0 plants (designated R1) were used. Leaf tissue, either from transgenic or from control (non-transgenic) plants, was fed to larvae ofChrysodeixis eriosoma (Lepidoptera: Noctuidae, green looper),Spodoptera litura (F.) (Lepidoptera: Noctuidae) andThysanoplusia orichalcea (F.) (Lepidoptera: Noctuidae) and insect weight gain (increase in fresh weight) measured. Consistently,C. eriosoma larvae fed leaf tissue from transgenic plants expressing thePPI II gene grew slower than insects fed leaf tissue from non-transgenic plants or transgenic plants with no detectablePPI II protein accumulation. However, larvae of bothS. litura andT. orichalcea consistently demonstrated similar or faster growth when fed leaf tissue from transgenic plants compared with those fed non-transgenic plants. In agreement with the feeding trials, the chymotrypsin iso-inhibitor extracted from transgenic tobacco effectively retarded chymotrypsin-like activity measured inC. eriosoma digestive tract extracts, but not in extracts fromS. litura. We conclude, therefore, that for certain insects the use of chymotrypsin inhibitors should now be evaluated as an effective strategy to provide field resistance against insect pests in transgenic plants, but further, that a single proteinase inhibitor gene may not be universally effective against a range of insect pests. The significance of these observations is discussed with respect to the inclusion of chymotrypsin inhibitors in the composite of insect pest resistance factors that have been proposed for introduction into crop plants.

Sex-linked genes and species differences in Lepidoptera

Abstract: I review reports on the genetic basis for species differences in the Lepidoptera In the six best-studied species complexes, more than half of all ecological, behavioral, or physiological differences among species are controlled by X-linked genes Because Lepidoptera have about 30 pairs of chromosomes, this finding clearly indicates strong bias toward X-linkage of genes for species differences The proportion of X-linked species differences ranges from complete X-linkage in Colias butterflies, to almost none in Yponomeuta moths Four other complexes all have at least one X-linked gene that is crucial to species differences, including the Choristoneura fumiferana Clemens, Papilio glaucus L, and Papilio machaon L species groups, and Ostrinia nubilalis Hubner pheromone strains The mechanisms that account for this phenomenon are open to speculation Nonetheless, an interesting implication of disproportionate X-linkage is that reproductive isolation may frequently arise by selection on linkage complexes, rather than as a random byproduct of evolution in geographically isolated populations If confirmed, the bias toward X-linked species differences may also help efforts to find characters that distinguish host races and sibling species, as well as provide an avenue by which genes crucial to speciation can be more easily mapped and characterized at the molecular level

Egg Weight, Fecundity, and Longevity Are Increased by Adult Feeding in Ostrinia nubilalis (Lepidoptera: Pyralidae)

Abstract: Two experiments were conducted to assess the influence of sugar and protein foods for adult Ostrinia nubilalis (Hubner) females on selected reproductive parameters. Individuals were fed diets of sugar plus protein (fructose-egg-agar) in all possible combinations and diets with one of three sugars (glucose-agar, fructose-agar, sucrose-agar). Free water served as a control in both experiments. Diets with sugars significantly increased oviposition period, fecundity, and adult longevity. Total numbers of eggs and egg masses oviposited were significantly higher in females that received sugar diets. Weight of individual eggs remained constant for females that received a sugar diet but decreased by the 3rd d of oviposition for females that did not receive sugar. Adult nutrition may be an important factor in the population ecology of O. nubilalis .

The Unique Structure of Lepidopteran Spindles

Abstract: Publisher Summary This chapter focuses on spindle architecture in Lepidoptera. The variability in spindle structure is illustrated by describing meiosis as well as mitosis in both sexes. Lepidoptera chromosomes are unusually small, and light microscopy has not contributed much to knowledge of chromosome structure in this group. Although observations are limited to a few species, fine structure studies suggest that Lepidoptera chromosomes represent a type intermediate between monokinetic and holokinetic chromosomes. Four different spindle types have been identified in Lepidoptera. These are somatic and gonial mitoses, female meiosis I, and divisions in eupyrene and apyrene spermatocytes. Though smaller, the spindles of spermatogonia and somatic tissues of Lepidoptera resemble those of mammalian cells. Meiosis I in female Lepidoptera is achiasmatic. Eupyrene spindles of Lepidoptera, which give rise to fertile spermatozoa, usually show a prominent spindle envelope and a rich intraspindle membrane system. Apyrene spindles, which produce sterile sperm, possess fewer membranes and microtubules (MTs) than the spindles of the “sheathed nuclear division.” Segregation of the chromatin is highly irregular in the apyrene line. The idea is advanced that the evolution of the sheathed nuclear division contributed to the development of double spermatogenesis in Lepidoptera. The acetylation status of MTs in mitotic and eupyrene meiotic spindles and its implications for MT behavior are described in the chapter.

Mortality of Helicoverpa zea (Lepidoptera: Noctuidae) Eggs in Cotton as a Function of Oviposition Sites, Predator Species, and Desiccation

Abstract: Predation rates of Helicoverpa zea (Boddie) eggs on cotton plants were determined by placing 32P-labeled moth eggs on different types of plant structures throughout the vertical strata of cotton plants. There was a slight trend for predation rates to be greater toward the top of the plants. Egg predation rates were higher on mainstem and fruiting branch terminals, and on blooms than on other plant parts. Similar predation rates (=75%) were observed on abaxial and adaxial leaf surfaces. Seasonal predation rates averaged 81.7 and 81.4 in 1982 and 1983, respectively. Rates began high each year (81.8–100%) and slowly decreased toward the end of the growing season when rates ranged from 55 to 80%. Predation by sucking predators ranged from 14.2–37.0% Orius tristicolor (White), O. insidiosus (Say), Geocoris punctipes (Say), and Pseudatomoscelis seriatus (Reuter) were the most important. Chewing predators accounted for 0.8–22.9% of the predation. Solenopsis invicta (Buren) was observed removing more eggs from plants than any other predator species. Ground based predators added significantly to egg predation. Mortality rates of eggs dislodged to the soil surface were also investigated. Nearly 90% of eggs placed on the soil surface were predated in <48h. Eggs that escaped predation but that were exposed to high midday soil temperatures (e.g., 45.5°C) died of exposure. Larvae safely eclosed from eggs placed in shaded locations near the plant bases.

Responses of gypsy moth (Lepidoptera: Lymantriidae) and forest tent caterpillar (Lepidoptera: Lasiocampidae) to transgenic poplar, Populus spp., containing a Bacillus thuringiensis d-endotoxin gene

Abstract: Transgenic Populus plants (clone NC5339) expressing a Bacillus thuringiensis d -endotoxin gene significantly reduced feeding and weight gain by gypsy moth, Lymantria dispar (L.), and the forest tent caterpillar, Malacosoma disstria Hubner. Forest tent caterpillar larvae also experienced significant mortality following exposure to the transgenic d -endotoxin. Gypsy moths were better able to recover after transfer to artificial diet than were forest tent caterpillars. Transgenic leaves deterred feeding by both species in behavioral choice tests. Four additional transformants contained, but did not express the d -endotoxin gene. Results are discussed in terms of efficacy, plant deployment strategies, ecosystem stability, and tree improvement.

Location of a lepidopteran specificity region in insecticidal crystal protein CryIIA from Bacillus thuringiensis.

Abstract: The Bacillus thuringiensis insecticidal crystal protein CryIIA has both high mosquito activity and gypsy moth activity; in contrast CryIIB, which is 87% homologous, displays no mosquito activity and has a three-fold lower gypsy moth activity. The regions responsible for specificity against gypsy moth (Lymantria dispar) and mosquito (Aedes aegypti) larvae were located by introducing MluI and XhoI sites into homologous positions within the putative domain II of both cryIIA and cryIIB genes, which divided almost equally the respective second domains into three regions. Taking advantage of naturally occurring NheI and NarI sites that border the putative domain II, a set of seven chimeric proteins were produced by exchanging all combinations of those regions between CryIIA and CryIIB. Analysis of the toxicity of these chimeric proteins demonstrated that the lepidopteran and dipteran specificity regions of CryIIA were not colinear. While the specificity region of CryIIA against mosquito larvae involved region 1 and probably also region 2, the specificity region of CryIIA against gypsy moth larvae was located within region 2.

Response of Spodoptera exigua and S. eridania (Lepidoptera: Noctuidae) Males to Synthetic Pheromone and S. exigua Females

Abstract: The seasonal occurrence of the beet armyworm, Spodoptera exigua (Hubner), and the southern armyworm, Spodoptera eridania (Cramer), was monitored over a 2-year period using International Pheromones, Ltd. Moth Traps® baited with rubber septa impregnated with pheromone blends identified from conspecific females and also with pheromone emitted by live female beet armyworm moths. The pheromone blend for beet armyworm was (Z)-9-tetradecen-1-ol (2.5%), (Z,E)-9,12-tetradecadien-1-ol acetate (87.2%), and (Z)-11-hexadecen-1-ol acetate (10.3%). The pheromone blend used for southern armyworm was (Z)-9-tetradecen-1-ol acetate (55.78%), (Z,E)-9,12-tetradecadien-1-ol acetate (21.23%), (Z,E)-9,11-tetradecadien-1-ol acetate (8.67%), and (Z)-11-hexadecen-1-ol acetate (14.32%). Although subtropical in habit, both species apparently can survive in North-Central Florida even when temperatures drop below freezing for several days. The response of male southern armyworm moths to traps baited with beet armyworm females was remarkably similar to that recorded for southern armyworm males to their synthetic pheromone. This response was consistent over two years.

Summer diapause in the polymorphic life cycle of the noctuid moth Mamestra brassicae

Abstract: The southern life cycle of Mamestra brassicae (Lepidoptera: Noctuidae) is characterized by two phenologically contrasting forms of pupal diapause. In the strain from Kagoshima (southern Japan, 31.5 °N) at 25 °C, summer diapause was prevalent in 14.5 h or longer days, and winter diapause in 13 h or shorter days. Nondiapause development occurred only to a limited extent in intermediate days. The direction of changes in daylength affected the number of long days required for 50% induction of summer diapause: the required day number was 10 in transfers from long day (LD, 15 h) to short day (SD, 11 h) but only 5 in the reverse transfer. Conversely, the induction of winter diapause required fewer days in transfers from LD to SD than in the reverse. Summer diapause required a smaller number of inductive light cycles than did winter diapause. The larvae were more sensitive to the summer-diapause-inducing effect of LD experienced from the middle extending into the second half of larval life than in the early or late stages of development.

Antipodes Island Lepidoptera

Abstract: The Lepidoptera of Antipodes Island are described, together with biological and ecological information on many species. Twenty‐two species are now recorded, of which 20 are believed to be breeding there. One of these is a world‐wide domestic species, while four are considered to be endemic to the island. Close faunal relationships are demonstrated with the moth fauna of Bounty, Chatham and the South Island of New Zealand. The total list of Lepidoptera for the subantarctic islands south of New Zealand is updated and discussed. The seasonality, dependence on disturbed areas and diurnal activity of the moth fauna are commented on. The status of the megaherb Senecio antipodus, defoliated by magpie moth larvae, is discussed. The presence of mice on the island, and their possible effect on invertebrates, is discussed and a recommendation made that they be eradicated. Coleoptera and Mollusca collected are listed in an appendix.

Diurnal patterns of adult activity of four orchard pests (Lepidoptera: Tortricidae) measured by timing trap and actograph.

Abstract: An aclograph using ultrasound was constructed to evaluate adult behavior of' lour tOI\"tricid moths: Cydia pomonella (L.l, Agryrotaenia citrano (Leonard), Pandemis pyl'llsana (Kearrott), and Chorislolle\"ra rosaceano (Harris). Studies were conducted to compare the timing of male and female moth activity in the adograph using simulated dusk and sunrise periods with the liming of male captures in pheromone-baited traps at 60­ min intervals. For all four species, the timing of acti\\'iLy measUl'cd for males and females in the adograph was similar to the liming of catch of male moths in the field. Peak periods of adult activity and male moth catch were 0-1 h after dusk for Cydia pomonella, 3-5 h after dusk for Argyrotaenia citrano, 0-2 h afler dusk for Charislancura rosaceana, and 0-1 after dusk for Pandemis pyrusana. For both sexes of all species, except female Chorl:sloneura rosacea,1/.n, activity levels of both sexes in the actograph increased allhe onset of sunrise. This was particularly pronounced for Cydio. pomonella. In the actogl'aph, females of Argyrotaelli.(l citrano. and Choristoneura rosaceallCl had an elevated level of activity prior to the simulated dusk period. Future studies with the actog'raph are planned to evaluate the effect of pheromone blend and concentration on the activity patterns of both sexes of these species.

Taxonomische Bearbeitung der westpaläarktischen Arten der Gattung Leucoptera Hübner, ‘1825’, s. 1. (Lepidoptera, Lyonetiidae) ‘Taxonomic revision of the westpalaearctic species of the genus Leucoptera Hübner, ‘1825’, s. I. (Lepidoptera, Lyonetiidae)’

Abstract: The genus Leucoptera Hbn., s. l., including Paraleucoptera Heinr., Proleucoptera Bsk. and Perileucoptera Silv. contains up to now 20 known species, distributed in the Western Palaearctic Region. The species are examined and taxonomically revised. Four species are newly described: L. andalusica n. sp. from Spain, L. karsholti n. sp. from Marokko, L. nieukerkeni n. sp. and L. thessalica n. sp. from Greece. The diagnostic characters of all species are outlined. A homologisation of the structures of the male genitalic apparatus is proposed. Keys to the species are provided and all species and their genitalia are described and illustrated. Four new synonymies are established and four lectotypes are designated. The distributional range of each species is mapped for the West Palaearctic Region. Aspects of the subgeneric division of the group are proposed and shortly discussed.

Diet of Sorex cinereus, the masked shrew, in relation to the abundance of Lepidoptera larvae in northern Ontario

Abstract: -We examined the diet of Sorex cinereus (masked shrew) and abundance of Lepidoptera larvae over 3 yr. Shrews and Lepidoptera larvae were sampled in a 40-yr-old jack pine (Pinus banksiana) plantation near Gogama, Ontario, Canada. Shrews consumed a higher proportion of Lepidoptera larvae when Lepidoptera larvae were more abundant on low shrubs, herbs, and ground level. Sorex cinereus showed a functional response to changes in the abundance of Lepidoptera larvae. These larvae were the primary food of shrews, and juveniles consumed higher proportions than adults. This may explain the high abundance, large litter size and juvenile recruitment of shrews reported previously for the same plantation during 1985.

Immunoglobulins against insect tissue

Abstract: The present invention provides a composition and method of protecting plants otherwise susceptible to infestation by insects of the orders Lepidoptera and Coleoptera.