Showing papers on "Lepidoptera genitalia published in 1997"

Detecting the effects of climate change on Lepidoptera

Abstract: With the recent publication of the second report of the Intergovernmental Panel on Climate Change the evidence has become more convincing that not only is world climate changing but that these changes are likely to be caused by human activities. Climate change will have important implications for insect conservation and pest status. Under these circumstances it may be time to put more effort into investigating actual climate induced changes. The types of evidence required and available for such studies are discussed, with particular reference to the Lepidoptera. Preliminary results are presented on moth phenology from the Rothamsted Insect Survey which suggest that changes, consistent with climate change, can already be detected.

Visual determination of sex of diamondback moth larvae

Abstract: The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a major worldwide pest of cruciferous vegetables (Talekar and Shelton 1993). Male and female adults of this species can be accurately identified by visible differences in their external genitalia. According to Robertson (1939), the sex of pupae can also be identified, but, in our experience, this approach is more difficult. For some types of research, determination of larval sex would be useful. For example, one could determine sex-specific responses of larvae to a treatment by observing mortality, development rate, or behavior of male and female larvae separately. In studies requiring hybrid mating between different strains of diamondback moth (Tabashnik et al. 1992), one could isolate groups of male larvae separately from female larvae to avoid mating within a strain. Some lepidopteran larvae can be sexed by the gonads being visible through the cuticle of the fifth abdominal segment or by the position of external pits marking the location of the genital discs in the eighth and ninth abdominal segments (Stehr 1987). But, because of their small size, it is not practical to sex diamondback moth larvae by external pits and we have found no studies in which male and female larvae were identified by gonadal form. Herein we report that third- and fourth-instar larvae of diamondback moth can be sexed efficiently and reliably.

Recherche de souches naturelles du Bacillus thuringiensis dans différents biotopes, à travers le monde

Abstract: A screening programme to isolate new strains of the entomopathogenic bacteria Bacillus thuringiensis was undertaken on 4887 samples of various sources from 101 countries over the world: 1260 strains of the bacillus were isolated. Dust from mills and silos, as well as insects from nature, were more successful sources than soil samples, which emphasizes the diversity of biotopes where the bacillus is encountered. Electrophoretic characterization reveals the genetic variability of the species. An analysis of insecticidal properties of the isolated strains was performed on four insect species: Plutella xylostella (Lepidoptera: Plutellidae), Spodoptera littoralis (Lepidoptera: Noctuidae), Phaedon cochleariae (Coleoptera: Chrysomelidae), and Locusta migratoria or Schistocerca gregaria (Orthoptera: Acrididae). The most frequent strains (54%) were producing crystals constituted of proteins with molecular masses of 130–140 or 66 and 130–140 kDa and were toxic to Lepidoptera larvae. A significant number of strains ...

Recent shifts in phenology of Microlepidoptera, related to climatic change (Lepidoptera)

Abstract: One of the many effects of the warming of the global climate that have been predicted is an acceleration of the larval development of insects. Insect populations living in temperate climates generally have one or more generations per year, punctuated by the winter resting period. We hypothesised that a gradual shift in the timing of these generations to¬ wards an earlier date will take place. For this purpose we analysed the phenology of a large sample of the most common Microlepidoptera in The Netherlands. Our results show that during the period 1975 1994 the flight peak has shifted to a date 11.6 days on average earlier. This shift is primarily associated with a rise in spring temperatures. The phenological data are based on a large body of observations brought together at little cost by amateur recorders, and the results sug¬ gest a relatively inexpensive method of monitoring future climatic change. Tinea foundation, Institute of Systematics and Population Biology, University of Amsterdam, Plantage Middenlaan 64, 1018 DH Amsterdam, The Netherlands.

Kinetic organization of metaphase I bivalents in spermatogenesis of Lepidoptera and Trichoptera species with small chromosome numbers

Abstract: The fine structure of bivalents in metaphase I spermatocytes of two Lepidoptera species, Orgyia thyellina Butler (n = 11) and O. antiqua (L.) (n = 14) (Lymantriidae), and a Trichoptera species, Limnephilus decipiens (Kolenatý) (n = 10) (Limnephilidae) were studied using a series of ultrathin sections and transmission electron microscopy. The bulk of species in both orders possess a haploid chromosome number of about 30. Thus, the experimental species have relatively small chromosome numbers. This study showed that metaphase I bivalents in both Lepidoptera species are polykinetic; attachment of kinetochore microtubules is found scattered throughout the entire poleward chromosomal surface. The microtubules were inserted in material of medium electron density. A pair of distinct kinetochore plates, consisting of material of about the same electron density as the chromatin, was detected at each poleward chromosomal surface in metaphase I bivalents of the caddis-fly, L. decipiens. The observations suggest that DNA elements responsible for the organization of the kinetochores are dispersed throughout the chromosomes in the two Lepidoptera species, whereas they are narrowly clustered in the Trichoptera. Thus, karyotype evolution in the closely related Lepidoptera and the Trichoptera involved widely differing mechanisms.

Insect predation and seasonal seedfall of the Japanese beech, Fagus crenata Blume, in northern Japan

Abstract: The relationship between seasonal changes in seedfall pattern of the Japanese beech, Fagus crenata, and insect damage to the trees is discussed. Twenty-six lepidopteran species and one dipteran species were found during a 7-year study. Insect damage was classified into two categories: feeding by seed insects and feeding by foliage insects. The latter was speculated to occur by chance. Twenty-three lepidopteran species were identified as foliage feeders and, except for Venusia phasma, their densities were small. There were four seed insects: three Lepidoptera and one Diptera. Because Pseudopammene fagivora was the most abundant in all study plots, this seemed to be the most important insect species related to the seed survival of the Japanese beech. Insect damage was observed early in the season from the time of flowering until mid-June, except that by two seed insects, P. fagivora and an unidentified lepidopteran of the family Gelechiidae. Most of the seeds infested by insects fell by the end of July. Seedfall throughout the season should be investigated in order to fully understand the interaction between seed production and insect infestation.

Host specificity of cotesia rubecula and cotesia plutellae, parasitoids of white butterfly and diamondback moth

Abstract: Cotesia rubecula and Cotesia plutellae were assessed as potential biological control agents for white butterfly (Pieris rapae) and diamondback moth (Plutella xylostella), respectively, in New Zealand. Some literature records indicated a wider host range for C. plutellae compared with C. rubecula. The specificity of these parasitoids was evaluated by rearing collections of Lepidoptera from natural parasitoid habitats overseas, and by laboratory testing of their host preferences for related Lepidoptera and species from brassica habitats. C. rubecula showed strong preferences for white butterfly and developed in no other species. This parasitoid has now been released and its effectiveness and specificity are being confirmed in the field. Whereas C. plutellae demonstrated preferences for diamondback moth in oviposition rate and suitability for development, it was capable of developing in several other Lepidoptera in the laboratory. Current laboratory tests require very careful interpretation for predicting the field host range of species such as C. plutellae.

Evidence of competition in a herbivorous, gall-inhabiting moth (Lepidoptera) community

Abstract: The larvae of a number of Lepidoptera species inhabit galls induced by the rust fungus Ravenelia macowaniana on Acacia karroo in South Africa, and the community appears to fulfill the conditions required for interspecific competition. Therefore, the aim of this study was to determine if the predominantly polyphagous moth community utilizing this ephemeral, patchily distributed, yet high quality, resource, showed evidence of exploitative intraspecific and interspecific competition. The galls were found to be extensively utilized with over 93% of galls occupied and between 50- 80° of gall tissue consumed. Fewer than 0.6% of the larvae were parasitized. Significant, positive intra- and interspecific aggregation occurred in the galls and the mean number of species per gall was consistently greater than one. A threshold density of 13 individuals, representing a total moth biomass of 12.74 mg, was found above which body mass compensation occurred. Resources are therefore limited in the community. The species were positively associated as a result of a common habitat affinity. Species abundances also covaried positively in a common response to resource conditions. Resource limitation and 'non-specific' exploitative competition was thus found in the Lepidoptera community.

Insects associated with purple loosestrife, Lythrum salicaria L., in Southern Manitoba

Abstract: In 1994 and 1995 insects were collected from several sites in southern Manitoba, where purple loosestrife, Lythrum salicaria L., is dominant. Collection techniques included the use of trap plants, sweep netting, vacuum sampling, and hand collecting. Insects from 38 families were collected and grouped into four general feeding guilds: herbivores, predators, omnivores, and fungivores. Herbivores that directly fed on L. salicaria included Galerucella nymphaeae Linne (Coleoptera: Chrysomelidae), Myzus lythri (Schrank) (Homoptera: Aphididae), Poecilocapsus lineatus (Fabricius) (Hemiptera: Miridae), Kleidocerys resedae (Panzer) (Hemiptera: Lygaeidae), Ametastegia glabrata (Fallen) (Hymenoptera: Tenthredinidae), Orgyia leucostigma (Smith) (Lepidoptera: Lymantriidae), Lophocampa maculata (Harris) (Lepidoptera: Lymantriidae), Spilosoma virginica (Fabricius) (Lepidoptera: Arctiidae), Simyra henrici (Grote) (Lepidoptera: Noctuidae), Dichomeris ligulella (Hubner) (Lepidoptera: Gelechiidae), Melanchrapicta (Harris) (Lepidoptera: Noctuidae), Hyles galli (Rottenburg) (Lepidoptera: Sphingidae), and Biston betularia cognataria (Gn) (Lepidoptera: Geometridae). These herbivores cannot severely limit the density of purple loosestrife in southern Manitoba and any interactions with the introduced agents should be minimal. The predatory stink bug, Apoecilus bracteatus Fitch (Hemiptera: Pentatomidae), was identified as a potentially important predator of the introduced biological control agents, Galerucella pusilla Duftschmidt and Galerucella calmariensis (L.) (Coleoptera: Chrysomelidae).

Mating disruption of diamondback moth (Lepidoptera: Plutellidae) and cabbage looper (Lepidoptera: Noctuidae) in cabbage using a blend of pheromones emitted from the same dispenser.

Abstract: Experiments were conducted in commercial plantings of cabbage in spring 1994 and 1995 to evaluate the efficacy of a blend of pheromones for diamondback moth, Plutella xylostella (Linnaeus), and cab...

The butterfly species (Insecta: Lepidoptera: Rhopalocera) of Kinabalu Park, Sabah

Abstract: Compiled records of 625 butterfly species from the area of Kinabalu Park in Sabah, Malaysia, on northwestern Borneo are presented in a systematic arrangement. The list is based on published records, unpublished specimen data, and field observations by the authors between 1993 and 1996. For each species, all recording locations within the park are listed including some localities adjacent to the present park boundaries. The results are interpreted through comparison with the entire butterfly fauna of the island, and with data from two other areas within northern Borneo (Brunei: Kuala Belalong; Sarawak: Gunung Mulu). The species recorded at Kinabaiu Park together represent 66.7% of the Bornean butterfly fauna, with Pieridae reaching 90.5% and Lycaenidae 53.2%. For all groups, the species numbers found in Kinabalu Park are considerably higher than those from any of the other Bornean locations, which is probably partly due to sampling effort. The importance of Mt. Kinabalu as a regional diversity hotspot for butterflies is stressed, and the need for more detailed studies with regard to conservation efforts is emphazised. Mount Kinabalu on Borneo, with Low's peak reaching 4,101 meters (13,455 feet), is the highest mountain in southeast Asia (between the Himalayas and New Guinea), and is widely known for its outstandingly diverse flora and fauna (Whitehead, 1893; Luping et al., 1978; Frahm et al., 1990; Wong & Phillipps, 1996). For a long time the mountain has attracted individual collectors, as well as scientific expeditions and research projects directed towards the study of insects, in particular butterflies (Moulton, 1913; Enriquez, 1927; Pendlebury & Chasen, 1932; Barlow et al., 1971; Zaidi & Kayau, 1995). The butterfly fauna of Mt. Kinabalu can therefore be regarded as comparatively well surveyed, and the area certainly represents one of the most visited localities by entomologists on the island of Borneo. A first butterfly list based on observations during an expedition to Mt. Kinabalu in 1965 has already been c. L. Hauser Staatliches Museum fUr Naturkunde, Rosenstein 1, D-70l9l Stuttgart, Germany. C. H. Schulze, K. Fiedler Department of Animal Ecology I, University of Bayreuth, D-95440 Bayreuth,

Telenomus cyamophylax n. sp. (Hymenoptera: Scelionidae) attacking eggs of the velvetbean caterpillar, Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae)

Abstract: Telenomus cyamophylax Polaszek, n. sp. is described from the eggs of the soybean pest velvetbean Anticarsia gemmatalis (Hubner) (Lepidoptera: Noctuidae) caterpillar. This new species belongs to the californicus-group sensu Johnson, 1984. Biological data, including one alternative host, are given.

Reproductive behavior of the female carob moth, (Lepidoptera: Pyralidae)

Abstract: Periodicities of the female reproductive behavior of the carob moth, Ectomyelois ceratoniae (Zeller), were investigated in regard to calling, mating, and oviposition Under varying photoperiods (16:8, 14:10, 12:12 L:D h), female carob moths initiated calling about the midpoint of the scotophase to which they were entrained resulting in a shift to later mean initiation times as the nocturnal period lengthened Matings were initiated during the fifth and sixth h of scotophase in a 169 L:D h light regime; this corresponded with the calling periodicity Carob moth females laid significantly more eggs in the first hour of scotophase (16:s L:D h) than in any other hour, after which oviposition declined significantly Oviposition was greatest from the third through sixth scotophase after which it decreased Oviposition periodicity was developed by the third scotophase, and peaked during the fourth

A new cell line from larval ovaries of Spodoptera Litura (F.) (Lepidoptera: Noctuidae)

Abstract: Dear Editor: Lepidopteran cell lines are finding application in the fields of agriculture and biotechnology (10). Therefore, there is a need to develop additional lepidopteran cell lines as substrate for recombinant baculoviruses and for baculovirus-expressed proteins (2,6). The insect cell line extensively used in baculovirus-expression-vectorstudies is from Spodoptera frugiperda (9). Cell lines from a few other species of Spodoptera are also established (1,3,5), but no published report is yet available of a cell line from larval tissue of Spodoptera litura. In this report we describe the establishment of and characterize a new cell line derived from the larval ovaries of the tobacco cutworm, S. litura (F.). An S. litura colony was maintained in the laboratory from the eggs, larvae, and pupae collected from farms growing cauliflower, in and around Pune. The larvae were fed the leaves of castor plants; the moths were identified by scientists of the Agricultural College, Pune. Twenty-one primary cultures from male and female larval gonads of the S. litura moth were initiated, but only one culture from larval ovaries developed into a cell line. The procedure described by Vaughn (9) was followed with slight modification. The growth medium was Grace's medium (4) supplemented with lactalbumin hydrolysate (0.3%), yeastolate (0.3%), and 20% fetal bovine serum (FBS). Penicillin (50 U/ml), streptomycin (100 ~g/ml), and gentamicin (40 ~g/ ml) were also added to the medium initially but were omitted once the culture became established. The culture was incubated at 28 ° C and fed with 50% fresh medium once in 7-10 d. During early passages, many muhicellular vesicles were observed in the culture, and a few patches of firmly attached cells could also be seen. In about 31/2 too. the first passage was made. However, steady growth of cells was observed only after 91/2 too. in vitro. The culture is being maintained in 50-ml Nunclon plastic culture flasks with 3 ml medium and is subcultured at 5-7-d intervals by trypsinizing with 0.1% trypsin in Rinaldini's salt solution (7). The split ratio has increased from 1:2 at early passage levels to 1:6 at Passage 79. The culture was initiated on September 29, 1992, and is designated NIV-SU-992. It is at passage level 101 (May 27, 1996) and can be called an established cell line. The culture can be cryopreserved in liquid nitrogen and revived successfully. It can also be stored at 13 ° C for a month without any significant loss of cell viability. The culture is free of bacterial and fungal contaminants. Tests for the presence of mycoplasma have not been done. Two types of cell growth patterns were observed, the monolayer and the multicellular vesicles. In the monolayer (Passage 10) three cell types were observed: epithelial-like cells (94%), fibroblast-like cells (5%), and giant cells (1%) (Fig. I A). The epithelial-like cells were oval or polygonal, ranging from 18 to 45 ~m in diameter and formed well-attached cell sheets. The fibroblast-like cells were slender and spindle-shaped, the length varying from 30 to 135 gm. Giant cells were of various sizes ranging from 60 to 150 p.m in diameter. Following a similar procedure, we established a second cell line (NIV-SU-893) from pupal ovaries of S. litura. The culture was initiated on August 12, 1993, and steady growth of cells was observed from 31/2 mo. onwards, unlike 91/2 too. for the larval cell line. The culture is at Passage 103 (August 10, 1996) and has three cell types: epithelial-like cells (91%), fibroblast-like cells (7%), and giant cells (2%). These cells grow loosely attached to the glass or plastic flask and are dispersed by just pipetting, unlike the larval cell line which cannot grow in glass flasks and requires trypsinization. The chromosome number of the NIV-SU-893 cell line is very high, i.e., 41200 and above. In most lepidopteran cell lines, round or spindle-shaped cells predominate; they are loosely attached to the culture flask and can be easily dispersed with a Pasteur pipette. Round cells vary from 10 to 20 p.m in diameter. Differences in size of spindle-shaped cells are often observed and range from about 34 ~m long in Chilo suppressalis to 86.3-123.7 ~m long in Trichoplusia hi. Only a few cell lines show epithelial-like cells that remain firmly attached to the culture vessel and require trypsinization, e.g., Choristoneurafumiferana (pupal ovaries), Heliothia virescens (pupal ovaries), and Manduca sexta (minced neonatal larvae). Most of the cells of the NIV-SU-992 cell line are also firmly attached epithelial-like cells (94%) that require trypsinization. Cells (Passage 10) were given hypotone treatment and stained with Giemsa for karyological studies. The cells showed numerous small, round chromosomes; the centromere could not be located, which is typical of lepidopteran chromosomes (Fig. 1 B). Their number varied from 40 to 95. About 46% of the ceils had 50-54 chromosomes and 5% of the cells had more than 90 chromosomes (Fig. 2). Thus, all three cell types in this cell line varied in size, percentage of each cell type, and chromosome number. We determined the chromosome number of S. litura male larval gonads: 61% of the metaphase cells showed 30 chromosomes, whereas the remaining cells had 28--31 chromosomes. The growth curve of the cell line was determined at Passages 14 and 65. Cells were grown in belco tubes and kept over 14 d without the growth medium being changed. We removed two tubes daily and counted only viable cells which we stained with trypan blue. After the 3rd d of seeding, logarithmic growth started and continued to the 10th d; by the 14th d most of the cells had degenerated. The population doubling time during the logarithmic phase of growth was 48 h. The maximum cell population of 5.5 and 12 million cells per milliliter was observed on the 10th d at Passages 14 and 65, respectively. The culture did not grow in RPMI, MEM, and Leibovitz L-15 media but could be adapted to grow in Mitsuhashi and Maramorosch