Chitin synthesis in larval and pupal epidermis of the Indian meal moth,Plodia interpunctella (Hübner), and the greater wax moth,Galleria mellonella (L.)

The level of chitin synthesis was determined in whole last-instar larvae and in pupae of Plodia interpunctella, and in epidermal tissue from similar stages of Galleria mellonella. The incorporation of radiolabelled N-acetyl-d-glucosamine into chitin was used to measure synthesis. Chitin production was similar in both species with peaks of synthesis occurring at the beginning of the last larval instar, in prepupae, in white pupae and prior to adult emergence. P. interpunctella also exhibited an additional small increase at mid-instar. Exposure of larval epidermis of P. interpunctella to 20-hydroxyecdysone in vitro stimulated chitin synthesis, but only after a 24 hr lag period subsequent to exposure to the hormone. This hormonal stimulation of chitin synthesis was inhibited by actinomycin-D and cycloheximide which suggested that 20-hydroxyecdysone-stimulated production of chitin depended on synthesis of RNA and protein. Comparison of the synthesis of chitin in epidermis of G. mellonella with previously published ecdysone titres, indicated that chitin production in vivo is preceded by an elevated ecdysone titre.     

Anatomy of the neurosecretory cells in the cerebral and subesophageal ganglia of the female European corn borer moth,Ostrinia nubilalis (Hübner) (Lepidoptera: Pyralidae)

The anatomy of the neurosecretory cells in the brain-subesophageal ganglion complex of female European corn borer moth Ostrinia nubilalis (Lepidoptera: Pyralidae) was studied using histological and cobalt backfilling techniques. Histological staining revealed the presence of 2 median and one lateral neurosecretory cell groups in the brain. These brain neurosecretory cells are made up of mainly type A cells with a few type B cells in the median group. Three type C neurosecretory cell clusters occupy the apparent mandibular, maxillary, and labial neuromeres at the ventral median aspect of the subesophageal ganglion. Axonal pathways of the neurosecretory cell groups were delineated by retrograde cobalt filling from the corpora cardiaca. Fibers of the 3 brain neurosecretory cell groups merged to form a distinct axonal tract that exits the brain via the fused nervi corporis cardiaci-1 + 2. Cobalt backfilling from the corpora cardiaca filled 4 groups of cell bodies in the subesophageal ganglion. The presence in the subesophageal ganglion of extensive dendritic arborizations derived from the brain suggests interactions between neurosecretory cell groups in the 2 head ganglia.     

Gap junctions between germ and somatic cells in the testis of the moth,Anagasta küehniella (Insecta: Lepidoptera)

Summary Heterocellular gap junctions were demonstrated in germ cysts of the moth Anagasta küehniella (Lepidoptera). They conjoin peripheral germ cells of a cyst and cells of their envelope. Their morphology differs according to the developmental stage of the germ cell involved. While gap junctional profiles are flat in cysts of gonia, in cysts of early spermatocytes they appear as button-like structures, the germ cell indenting the corresponding cyst cell. In cysts of late spermatocytes and of young spermatids, they are very numerous and often located at the extremity of conical protrusions of the germ cell. On the germ cell side, cytoplasmic microfilaments are associated with the junctional differentiation. Gap junctions are observed as being pinched off from the surface of the spermatids and, correspondingly, gap vesicles are found in the cyst cells. This, together with the fact that gap junctions are not found at later stages of development, suggests that internalization of the gap junctions might take place before elongation of the spermatids. The potential importance of these germsomatic cell gap junctions is evaluated in light of recent physiological findings obtained by other authors on the oocyte-cumulus system and also in relation with some particularities in the development of the male germ cells in Lepidoptera.     

Changing dynamics of the pine beauty moth (Panolis flammea) in Britain: the loss of enemy free space?

1 The pine beauty moth Panolis flammea has two main host plants in Britain: Pinus sylvestris (Scots pine), which is the ancestral food plant where the insect is never abundant enough to cause tree mortality, and Pinus contorta (lodgepole pine), an introduced host tree that has experienced periodic widespread tree mortality due to this pest.
2 We review the recent literature, published mostly after the year 2000, regarding the impact of natural enemies on the population dynamics of P. flammea in Britain.
3 The natural enemies of P. flammea are more diverse and abundant in Scots pine habitat than in lodgepole pine habitat and some of them show differential selection for P. flammea larvae in Scots pine habitat over those located in lodgepole pine habitat.
4 It is concluded that the difference in the population dynamics of this insect in the two different habitats was probably the result of the P. flammea finding enemy-free space in lodgepole pine habitat.
5 Recent evidence on the diversity and impact of natural enemies on lodgepole pine has demonstrated that they currently have a much more significant impact on this pest than they did in the 1970s and 1980s, when outbreaks were frequent.     

Binding specificity of OBPs in the yellow peach moth Conogethes punctiferalis (Guenée)

Odorant-binding proteins (OBPs) are translators of the external chemical signals, which are critical for maintaining insect life. However, few OBPs were reported in the yellow peach moth (YPM), Conogethes punctiferalis (Guenée). In the current study, five OBPs (CpunOBP1, CpunOBP2, CpunOBP7, CpunPBP2 and CpunPBP4) were expressed and purified from the antennae of the YPM. The results showed that the proteins encoded by five CpunOBPs had six conserved cysteine residues, which were typical structural features of classic OBPs. Moreover, the fluorescence competitive binding assays indicated that the binding affinity of five CpunOBPs to the selected YPM female sex pheromones, host plant volatiles and Penicillium-inoculated apple volatiles was obviously different. The binding affinities of CpunOBP1 and CpunOBP2 with β-ionone were the strongest. CpunOBP7 could bind with 12 host plant volatiles but was unable to interact with any one of the three tested female sex pheromones. CpunPBP2 and CpunPBP4 exhibited the highest binding affinity to female sex pheromone trans-10-hexadecenal among 30 tested compounds. In conclusion, these results suggest the functional differentiation of the CpunOBPs in recognizing sex pheromones, host plant volatiles and fungus-infected host plant volatiles, which will provide new insights into selecting target proteins for YPM biocontrol.     

Did biological control cause extinction of the coconut moth, Levuana iridescens, in Fiji?

In 1925, J.D. Tothill and two colleagues set out to manage Levuana iridescens, the coconut moth of Fiji, using biological control. By 1930, they had succeeded so completely that this pest of the copra crop had been reduced to almost undetectable levels by the tachinid fly, Bessa remota, introduced from Malaya, and they had summarized their campaign in a thoroughly documented and well-illustrated monograph. The example of the coconut moth is presented in the modern literature as the first and best documented extinction of a species due to scientific biological control. The program has been severely criticized because the moth was unique, beautiful, and considered endemic to Fiji. Thus, this program is also portrayed as an example of the highly controversial practice of neoclassical biological control. However, a careful reexamination of this event discloses that the moth was likely not native to Fiji, appeared to be spreading through the Fijian Archipelago, and might have spread to other island groups in the South Pacific. Also, L. iridescens is probably not extinct. Collateral damage, that is, non-target impacts, did occur as native zygaenid moths have been attacked by the tachinid, and they may be extinct. The reasons for the control campaign of L. iridescens were not primarily economic. Tothill and colleagues were trying to protect copra so that ethnic Fijian culture, so dependent on the coconut palm threatened by L. iridescens, could be sustained. Hence, this control program represents a difficult clash of values: preservation of insect biodiversity versus preservation of indigenous Pacific Islander cultures. A strategy to search for L. iridescens populations is proposed and development of biological control of B. remota, using hyperparasitoids, is possible, but would require careful evaluation since it might release L. iridescens from suppression, have non-target impacts on native tachinids, and lack an economic motivation.     

Prothoracicotropic hormone — like activity in the embryonated eggs of gypsy moth,Lymantria dispar (L.)

Summary Prothoracicotropic hormone (PTTH)-like activity was obtained from embryonated eggs of the gypsy moth, Lymantria dispar. Activity was detected using an in vitro prothoracic gland stimulation bioassay. Doseresponse kinetics of crude extract revealed a 4-fold activation range with a maximum activation of 35-fold. Nearly 70% of the activity was sensitive to denaturation by heat or organic solvent extraction. Heat and organic solvent-stable activity is due to a protein. Dose-response kinetics suggest the presence of a small molecular weight PTTH with pre-hatch eggs providing a rich source of the hormone.Abbreviations Ar activation ratio - ED ₅₀ 50 percent effective dose - eq equivalent - HPLC high performance liquid chromatography - PC prothoracic gland - PTTH prothoracicotropic hormone - RIA radioimmuno assay - TFA trifluoroacetic acid     

A target-specific feeding toxicity of β(1) integrin dsRNA against diamondback moth, Plutella xylostella

Integrin is a cell-surface protein consisting of α and β heterodimers. A predicted amino acid sequence of an integrin subunit of the diamondback moth, Plutella xylostella, was highly homologous to other lepidopteran β1 subunits and possessed essential functional domains. The β1 integrin of P. xylostella (βPx1) was expressed in all developmental stages of P. xylostella. It was also expressed in all tested tissues including hemocyte, fat body, gut, and epidermis of last instar. When βPx1 expression was suppressed by injection of dsRNA specific to βPx1 (dsRNA(βPx1)), the treated larvae exhibited significant suppression in immune response and also suffered significant larval mortality. When dsRNA(βPx1) was orally fed to young larvae, it suppressed the expression of aPx1 and resulted in a significant mortality. By contrast, a dsRNA specific to β1 subunit of Spodoptera exigua gave little adverse effects on βPx1 expression and larval development when it was treated by injection or oral administration, though these two genes showed 71% sequence homology. These results suggest a target-specific RNA interference of dsRNA(βPx1), which causes significant mortality to P. xylostella by feeding treatment.     

Utilization of blueberry by the lappet moth, Streblote panda Hübner (Lepidoptera: Lasiocampidae): survival, development, and larval performance

The lappet moth, Streblote panda Hübner [1820] (Lasiocampidae), is a common species found in blueberry, Vaccinium spp. (Ericaceae) fields of Western Andalusia. The biology of this species as well as the extent to which its larvae can use and survive on blueberry is unknown. In this study, the suitability to larvae of several blueberry cultivars was studied. Larvae were grown under controlled laboratory conditions on excised foliage of six blueberry cultivars. Survival, development, and food use were determined for first and fifth instars. According to our results, blueberry has become an alternative host plant for S. panda in southwestern Andalusia. Low growth rates and efficiencies of use of food were observed. Lower gross efficiency of growth was found for larvae fed blueberry 'Sharpblue', despite a higher apparent digestibility of this cultivar. Larvae reared on this cultivar had the highest mortality, increased developmental time, and used a greater part of metabolism for maintenance. Herbivore pressure may be increased with the widespread planting of the most suitable cultivars 'Misty' and 'O'Neal', whereas 'Sharpblue' and'Climax' seem to be the least suitable host plants. These data provide useful information for planning and managing blueberry orchards in the presence of S. panda populations.     

Molecular phylogenetics of the moth genus Omiodes Guenée (Crambidae: Spilomelinae), and the origins of the Hawaiian lineage

The moth genus Omiodes (Crambidae) comprises about 80 species and has a circumtropical distribution, with the type species, O. humeralis, occurring in Central America. In Hawaii, there are 23 native species currently placed in Omiodes, but this classification has been disputed, and they were previously placed in various other genera. We used molecular phylogenetic analyses to assess the monophyly of Omiodes as a whole, and specifically of the Hawaiian species, as well as their geographic origins and possible ancestral host plants. Mitochondrial (COI) and nuclear (wingless, EF1α, CAD, and RPS5) DNA was sequenced for Omiodes from Hawaii, South America, and Australasia, along with many other putative outgroup spilomeline genera. Phylogenies were estimated using maximum likelihood and Bayesian inference, and various taxon and character datasets. With the exception of two paleotropical species (O. basalticalis and O. odontosticta, whose placement was unresolved) all Hawaiian, paleotropical and neotropical Omiodes, including the type species, fell within a well-supported, monophyletic clade. Although the center of diversity for Omiodes is in the Neotropics, its center of origin was ambiguous, due to poor resolution of the basal splits between paleotropical and neotropical Omiodes. Very low genetic divergence within the Hawaiian Omiodes suggests a relatively recent colonization of the Hawaiian Islands. Phylogenies constructed using all codon positions were poorly resolved at intergeneric levels, and did not reveal a sister taxon for Omiodes, but phylogenies constructed using only first and second codon positions suggested a close relationship with Cnaphalocrocis. The monophyly of several other spilomeline genera is also discussed.     

Does aggregation behavior of codling moth larvae,Cydia pomonella,increase the risk of parasitism by Mastrus ridibundus?

Mastrus ridibundus is a specialist hymenopteran parasitoid that parasitizes last-instar larvae or prepupae of the codling moth, Cydia pomonella. Foraging females eavesdrop on an aggregation pheromone produced by cocooning larvae. We investigated whether larvae that cocoon in aggregation experience a greater rate of parasitism than larvae that cocoon in isolation. In wind tunnel experiments, 10 larvae in aggregations were more readily located by female M. ridibundus than 10 larvae well separated from each other. Similarly, aggregations of 30 larvae were more attractive to female M. ridibundus than those of 3 larvae. In cage experiments, larval cocooning in aggregation or isolation had no effect on the mean rate of parasitism and the mean number of eggs deposited per parasitized host. In Petri-dish experiments, the location of larvae within an aggregation significantly affected their rate of parasitism, with those in the center of an aggregation completely shielded from parasitism. Our data suggest that aggregation behavior by C. pomonella larvae does not appear to increase the rate of parasitism. The increased risk of aggregated larvae to be detected by M. ridibundus is likely offset by diluted parasitism risk and structural refugia effects that larvae in aggregation experience. As an egg-limited parasitoid, female M. ridibundus can parasitize on average only one larva in an aggregation, with the likelihood of parasitism for each larva being inversely proportional to the number of larvae in that aggregation.     

Heterosis in the flour moth,Ephestia kühniella

Four lines of Ephestia kühniella each homozygous for one of three different allozyme alleles at the Est-2 locus and two alleles at the Adh locus were crossed in order to study the extent of somatic, reproductive and adaptive heterosis in F₁ hybrids in comparison with the mean performance of the simultaneously reared inbred parent lines. With regard to adult weight and wing length (somatic heterosis) hybrids exhibit maximally 20% (males 10%) and 9% heterosis, respectively. As concerns the production of eggs and hatched larvae (reproductive heterosis) hybrids exceed the parental mean by 90% and 200%. Adaptive heterosis is realized by a shorter development period of the hybrids (maximally by 30%) as well as by significant lower variance of all metrical characters studied. In the F₂ the degree of heterosis diminishes. There is neither an excess of heterozygotes among the segregating allozyme genotypes nor superior performance of the heterozygotes concerning any one of the traits studied. Therefore, it is concluded that the pronounced heterosis in F₁ is not a single-gene-heterosis operating at the Est-2 and the Adh-locus.     

The roles of the Chantransia phase of Lemanea (Lemaneaceae,Batrachospermales, Rhodophyta) and of the ‘Mushroom’ phase of Himanthalia (Himanthaliaceae,Fucales, Phaeophyta)

Summary

The life cycle of the Batrachospermales (freshwater florideophyte red such as Batrachospermum, Lemanea) is a shortened variant of the ‘normal’ marine florideophyte life cycle. The perennial Chantransia diploid phase is microscopic and encrusting. Each winter it produces one or more semi-erect haploid gametophytes by vegetative meiosis. Gamete production and fertilization is followed by production of diploid carposporophytes; these produce diploid carpospores which disperse, and regenerate the Chantransia phase. The question of the extent to which the Chantransia phase contributes resources to the gametophyte was approached by physiological-hydrodynamic modelling. These computations suggest that the photosynthetic rates in situ on an area basis are 20 times greater for the gametophyte than the Chantransia phase; this agrees with the observed ratios of peak biomass. The conclusion is that the Chantransia phase has a negligible role in provisioning the growing gametophyte, and that the role of the Chantransia phase is to occupy space with living biomass throughout the year, including exposure at summer drawdown, and (perhaps) by dispersal via production of monospores. A similar conclusion is arrived at on the basis of biomass data for the role of the perennial ‘mushroom’ phase of the semelparous marine Fucalean brown alga Himanthalia elongata in relation to the short-lived but much larger reproductive receptacles.     

Limiting the cost of mutualism: the defensive role of elongated gynophore in the leafflower–moth mutualism

Mutualisms are interactions from which both partners benefit but may collapse if mutualists’ costs and benefits are not aligned. Host sanctions are one mechanism whereby hosts selectively allocate resources to the more cooperative partners and thereby reduce the fitness of overexploiters; however, many mutualisms lack apparent means of host sanctions. In mutualisms between plants and pollinating seed parasites, such as those between leafflowers and leafflower moths, pollinators consume subsets of the seeds as larval food in return for their pollination service. Plants may select against overexploiters by selectively aborting flowers with a heavy egg load, but in many leafflower species, seeds are fully eaten in some fruits, suggesting that such a mechanism is not present in all species. Instead, the fruits of Breynia vitis-idaea have stalk-like structures (gynophore) through which early-instar moth larvae must bore to reach seeds. Examination of moth mortality in fruits with different gynophore lengths suggested that fruits with longer gynophore had higher moth mortality and, therefore, less seed damage. Most moth mortality occurred at the egg stage or as early larval instar before moths reached the seeds, consistent with the view that gynophore functions to prevent moth access to seeds. Gynophore length was unaffected by plant size, extent of moth oviposition, or geography; thus, it is most likely genetically controlled. Because gynophores do not elongate in related species whose pollinators oviposit directly into the ovary, the gynophore in B. vitis-idaea may have evolved as a defense to limit the cost of the mutualism.     

Effect of a test meal,duodenal acidification,and tetragastrin on the plasma concentration of β-endorphin-like immunoreactivity in man

The effects of various test materials on plasma β-endorphin-like immunoreactivity (β-EpLI) were investigated in man using a specific radioimmunoassay developed by the authors. Plasma β-EpLI was determined after extraction by the acid/acetone method (recovery 73±5%). The intraassay and interassay coefficients of variation were 5.0% and 7.6%, respectively. The plasma concentrations of human β-EpLI in normal subjects were 11.6±4.0 pmol/l for men (n=23) and 10.7±4.8 pmol/l for women (n=27). Ingestion of a test meal (150 g of Campbell's condensed meat soup) resulted in a biphasic rise in plasma β-EpLI from the basal level of 4.4±1.0 pmol/l to 29.2±1.9 pmol/l after 5 min and 24.8±6.7 pmol/l after 90 min. Intraduodenal infusion of 115 ml of 0.1 M HCl over 10 min increased the plasma β-EpLI level from 8.7±0.5 pmol/l to 15.5±0.4 pmol/l at 10 min after the start of infusion, but the level rapidly returned to the initial value after the end of the infusion. Intramuscular injection of 4 μg/kg body weight of tetragastrin markedly stimulated gastric acid output and β-EpLI release, but pretreatment with 10 mg of histamine H₂ receptor antagonist inhibited the gastric acid output and plasma β-EpLI release induced by tetragastrin.These results indicate that β-EpLI release is stimulated by ingestion of meat soup, duodenal acidification and tetragastrin administration. It is suggested that gastric acid participates, at least in part, in postprandial release of β-EpLI, probably from the gastrointestinal tract.     

Redescription of Skrjabinodon medinae (García-Calvente, 1948) (Nematoda: Pharyngodonidae) from the cloaca of Podarcis pityusensis (Bosca, 1883) (Sauria: Lacertidae) of the Balearic Islands (Spain)

Pharyngodon medinae García-Calvente, 1948 (Nematoda: Pharyngodonidae) is redescribed from Podarcis pityusensis (Bosca, 1883) (Sauria: Lacertidae) of the Balearic Islands (Spain) and confirmed as a member of the genus Skrjabinodon Inglis, 1968. A systematic review of S. medinae and closely related species is also given. Parathelandros canariensis is referred to Skrjabinodon as a new combination and Parathelandros Magzoub et al., 1980 is dismissed as a junior homonym of Parathelandros Baylis, 1930.     

Brumptomyia angelae, a new species of Phlebotominae (Diptera, Psychodidae) of the Atlantic forest of the state of Paraná, Brazil

The male of Brumptomyia angelae, sp. nov., a new species of Phlebotominae (Diptera, Psychodidae) of the Atlantic forest of the state of Paraná, Brazil, is described and illustrated. This new taxon is closely related to Brumptomyia ortizi Martins, Silva & Falc?o 1971, Brumptomyia nitzulescui (Costa Lima, 1932), and Brumptomyia troglodytes (Lutz, 1922). The male genitalia of these three latter species have also been drawn.