Performance of irradiated Teia anartoides (Lepidoptera: Lymantriidae) in urban Auckland, New Zealand

The Australian moth Teia anartoides Walker has been the target of a major eradication program in Auckland, New Zealand. Information on cold torpor and dispersal was needed to help interpret catches of sterile and wild males in female-baited delta traps operated in a grid of up to 1,696 traps at 500-m spacings across the city. Laboratory experiments indicated male flight was enabled at temperatures above 17 degrees C (confirmed by field trapping of wild and recaptured moths). Male survival in the field or in field cages was determined to be limited to approximately 4 d. Sterilization of males for dispersal studies was achieved by exposing male pupae to either 160 or 100 Gy by using 1.25 MeV gamma rays from a Cobalt source, before release as fluorescent-dyed emerged adults. Dispersal was determined by recapture of males in the trapping grid of 1,696 delta traps baited with virgin female moths and placed at spacings of 50-500 m. Irradiated sterile males dispersed up to a maximum recorded distance of 4,500 m (160 Gy) and 10,000 m (100 Gy). At 100 Gy, the median dispersal distance was 300 m, with 90% of males dispersing 1,600 m or less.     

Effect of irradiation on female painted apple moth Teia anartoides (Lep., Lymantriidae) sterility and attractiveness to males

Abstract:  Live female painted apple moths are being used to monitor the distribution of this invasive species in Auckland as part of a major eradication effort, and the goal of this project was to develop a method to minimize the risk of unwanted live insect propagation from the trapping programme as a result of vandalism or 'eco-terrorism'. Female pupae were irradiated with a range of doses and their egg viability assessed, and also tested to determine the impact of irradiation on male moth catch in the field. Female painted apple moth pupae, irradiated at a range of doses from 100 to 500 Gy, were placed in cages in traps at 10 m spacings from non-irradiated females, near a central release site of irradiated males. Untreated control females alternated along orthogonal transects with irradiated females. The results indicated no significant effect of female irradiation on catch of males. There was no correlation between dose and catch, within the range of exposures tested. There was a very low hatch rate of eggs from females irradiated at all doses tested (100–500 Gy). These results suggest that irradiated females could be used in traps to reduce potential risks of deliberate spread of the unwanted organism by activists, without affecting the effectiveness of monitoring males.     

Field records of painted apple moth (Teia anartoides Walker: Lepidoptera: Lymantriidae) on plants and inanimate objects in Auckland, New Zealand

Abstract  As part of an eradication program, field searches were conducted to verify the geographical extent of the painted apple moth (PAM; Teia anartoides Walker: Lepidoptera: Lymantriidae) incursion and to determine which plants were being attacked. Most PAM were found on the wattle species, in particular Paraserianthes lophanta and Acacia mearnsii . Other species with large numbers of PAM included the native Corynocarpus laevigatus (karaka) and Avicennia marina (grey mangrove). The large number of PAM on these New Zealand species would not have been predicted from the known unrelated Australian hosts. The relatively high number of PAM found on inanimate objects demonstrated the mobility of PAM larvae and that plants upon which few larvae were found may not be suitable hosts for PAM.     

Radiation biology and inherited sterility in false codling moth (Lepidoptera: Tortricidae)

False codling moth, Cryptophlebia leucotreta (Meyrick), male and female mature pupae and newly emerged adults were treated with increasing doses of gamma radiation and either inbred or out-crossed with fertile counterparts. For newly emerged adults, there was no significant relationship between dose of radiation and insect fecundity when untreated females were mated to treated males (N female by T male). However, fecundity of treated females mated to either untreated (T female by N male) or treated males (T female by T male) declined as the dose of radiation increased. A similar trend was observed when mature pupae were treated. The dose at which 100% sterility was achieved in treated females mated to untreated males (T female by N male) for both adults and pupae was 200 Gy. In contrast, newly emerged adult males treated with 350 Gy still had a residual fertility of 5.2% when mated to untreated females, and newly emerged adult males that were treated as pupae had a residual fertility of 3.3%. Inherited effects resulting from irradiation of parental (P1) males with selected doses of radiation were recorded for the F1 generation. Decreased F1 fecundity and fertility, increased F1 mortality during development, and a significant shift in the F1 sex ratio in favor of males was observed when increasing doses of radiation were applied to the P1 males.     

Evaluation of dyes for marking painted apple moths (Teia anartoides Walker, Lep. Lymantriidae) used in a sterile insect release program

Abstract  Two methods of marking painted apple moth ( Teia anartoides Walker, Lepidoptera: Lymantriidae), internal and external dyes, were investigated for use with the sterile insect technique, to ensure that wild and released moths could be distinguished absolutely during the eradication program. Calco Red dye was used to mark all moths internally. It was added to artificial diet and was detectable in the adults. Dye was incorporated into the larval diet at four rates. No differences were observed in mortality of the larvae, fertility of the adult female or response of male moths to virgin females in a flight tunnel. Fluorescent powder dyes were used throughout the sterile insect program to identify irradiated moths, as well as their release location and colony. However, the powdered dyes reduced the ability of male moths to detect a component of the sex pheromone in electro-antennogram tests and to respond to a calling virgin female in flight tunnel trials. Field trials suggest that moths may subsequently overcome these negative effects and respond to female moths, as moths heavily coated in dye were recaptured.     

不同食料植物对棉古毒蛾生长发育和繁殖的影响

在恒温(28±1)℃、恒湿(80±5)%RH条件下,研究了莲雾、芒果、荔枝、龙眼、毛叶枣、木菠萝等6种食料植物对棉古毒蛾的生长发育和繁殖的影响。结果表明,棉古毒蛾能在这6种食料植物上完成其世代循环。其发育历期、雌蛹重、存活率、成虫繁殖力和寿命等,在6种寄主植物间均存在显著差异,其中莲雾和芒果是最适宜的寄主植物,荔枝和龙眼是不适宜的寄主植物。     

Inheritance of female flight in Lymantria dispar (Lepidoptera: Lymantriidae)

A clinal female flight polymorphism exists in the gypsy moth, Lymantria dispar L., where female flight diminishes from east to west across Eurasia. A Russian population where females are capable of sustained ascending flight and a North American population with females incapable of flight were crossed: parentals, reciprocal F(1) hybrids, double reciprocal F(2) hybrids, and all possible backcrosses to both the parental lines were compared. Heritabilities were estimated using a threshold model, female offspring on female parent regressions, and joint-scaling analyses. Heritability of female flight capability measured using a free flight test was at least 0.60, and variation in wing size, muscle strength, and flight behaviors contributed to the flight polymorphism. Relative wing size varied continuously and had a heritability of 0.70. Environmental variation accounted for >90% of the variation in female preflight weight and relative flight muscle strength, as estimated by an inverted female's ability to right herself. Preflight walking behavior and early deposition of eggs were each inherited through a single gene with two co-dominant alleles. There was no evidence for sex-linkage or maternal effects in female flight capability or associated traits. Continued vigilance to exclude and eradicate introductions of strains capable of female flight in North America is warranted even in areas where no females fly, because some of the alleles needed for full flight capability may not be present in the North American populations, and some flight capability is maintained in the hybrids that could increase the rate of spread of L. dispar.     

A revision of the genus Naroma (Lepidoptera: Lymantriidae)

A key is given to the four species of Naroma now recognised. The species are redescribed and their distribution is listed. The early stages of N.varipes and N.signifera are described by D.G.Sevastopulo.     

Effects of age and food source on secondary chemistry of larvae of Lymantria species (Lepidoptera: Lymantriidae)

Haemolymph and osmeterial secretions of caterpillars of Lymantria monacha (Linnaeus) and L. concolor Walker were analysed by gas chromatography/mass spectrometry for low molecular weight secondary metabolites. The similarities of their chemical compositions were determined by means of cluster analysis techniques in order to characterize possible chemical variations related to developmental stage or food of the larvae. For this purpose, two dissimilarity coefficients (Euclidean distances, Canberra metrics) and four clustering methods (UPGMA, WPGMA, WPGMC, single linkage) were combined. The patterns of secondary compounds obtained from the haemolymph and osmeterial secretions studied did not differ statistically significantly between two groups of L. monacha larvae fed with either larch, Larix decidua Mil., or Norway spruce, Picea abies (L.), indicating no relevant influence of plant chemistry. However, haemolymph of penultimate instar larvae of L. concolor fed on Rhododendron contained a mixture of compounds differing statistically significantly from that of last instar caterpillars. The total compositions of the corresponding gland secretions were statistically identical though the presence/amounts of individual compounds varied. This suggested that the haemolymph composition reflected changing physiological requirements of the successive instars, whereas the composition of the defensive mixtures remained comparatively constant, possibly due to a constant spectrum of potential enemies. A more pronounced age-dependence of larval chemistry was shown by a similar analysis of data from various developmental stages of L. dispar (Linnaeus) and one of its food plants. This analysis suggested plant composition affected the secondary chemistry of early larval instars of L. dispar. The results are discussed in terms of the roles of secondary metabolites in defence against natural enemies.     

Shifts in developmental diet breadth of Lymantria xylina (Lepidoptera: Lymantriidae)

The moth Lymantria xylina Swinhoe (1903) (Lepidoptera: Lymantriidae) is a major defoliator of hardwood and fruit trees in Taiwan. Although the plants identified as host plants of L. xylina usually refer to plants used as food or as shelter, most of the host plant identifications have not considered the role of these hosts on larval development. This study investigated various instars feeding on different plants to assess the developmental diet breath of L. xylina. Forty-seven plant species, belonging to 25 families were used in feeding trials. Various bioassays, including first instar survival and long-term feeding trials, indicated the most suitable host plants for the different developmental stages. Results of the first instar survival trial indicated that first instars could survive only on 13 of the tested plant species. In addition, first instars could only successfully grow to pupa on seven of these 13 test plants species. To assess the developmental diet breath shifts of this moth, 38 plant species (excluding those nine plant species that the first instars did not feed upon) were fed to third and fifth instars in long-term feeding trials. Survival to pupa was noted on 12 and 13 test plant species for the third and fifth instars, respectively. In short, we found that the larvae performed differently when fed on various host plants and that the host plant range increased with the larval stage. Therefore, it is necessary to adjust the host plant range of this moth and to consider host plant breadth together with the developmental stages of caterpillars.     

Effects of gamma radiation on development, sterility, fecundity, and sex ratio of Dermanyssus gallinae (DeGeer) (Acari: Dermanyssidae)

Protonymphal Dermanyssus gallinae were irradiated with 0.50, 0.75, 1.0, 3.0, and 6.0 krad of gamma radiation and subsequently monitored regarding their developmental, feeding, and mating success. Also, sex ratios of adults treated as protonymphs were recorded as were sex ratios of embryos and F1 adults produced by these adults. Doses up to 1.0 krad did not prevent development of treated protonymphs to the adult stage or stop mating. Three krad reduced the number of treated protonymphs attaining adulthood and 6.0-krad treatment prevented all mites from developing to the adult stage. Egg (embryo) production was normal for mites treated with 0.50 krad, but significantly curtailed by doses of 0.75 krad and greater. Radiation doses used in this study did not appear to affect the normal variable sex ratios observed in untreated mites.     

寄主植物对乌桕黄毒蛾取食量及生长发育的影响

【目的】研究乌桕黄毒蛾Euproctis bipunctapex(Hampson)对5种不同科寄主植物(天仙果Ficus erecta var.beecheyana、拐枣Hovenia acerba、苦槠Castanopsis sclerophylla、杨梅Myrica rubra和杜英Elaeocarpus decipiens)叶片的取食量以及不同寄主植物对乌桕黄毒蛾生长发育和繁殖的影响。【方法】在恒定条件[温度(26±1)℃,相对湿度80%,光周期12L︰12D]下,设置5个处理组,每处理分别投喂不同寄主植物叶片,测定取食量、幼虫历期、存活率、繁殖力等指标。【结果】乌桕黄毒蛾对不同寄主植物的取食量差异显著,苦槠饲喂组最高(2 588.15 mg),杜英饲喂组最低(1 971.33 mg);但对不同植物的日取食量总体趋势相同,随时间呈指数增长,4龄起进入暴食期,4龄、5龄和6龄幼虫取食量占总取食量的80.68%~85.91%。取食不同寄主植物的乌桕黄毒蛾生长发育差异显著,天仙果饲喂组的个体幼虫历期(34.35 d)最短,存活率(60.20%)最高,产卵量(281.33粒/雌)最多,而杜英饲喂组的个体幼虫历期(41.36d)最长,存活率(38.78%)最低,产卵量(215.83粒/雌)较少。【结论】乌桕黄毒蛾虫害防治适期是4龄之前,苦槠和杨梅受乌桕黄毒蛾取食最多,天仙果是乌桕黄毒蛾生长发育的最适寄主植物。     

Irradiation of adult Epiphyas postvittana (Lepidoptera: Tortricidae): egg sterility in parental and F1 generations

Adult Epiphyas postvittana Walker were irradiated using a Cobalt 60 source to determine the dose needed to achieve complete egg sterility of mated female moths, and egg sterility of female moths mated to F1 generation males. Adult male and female E. postvittana were irradiated at 100, 200, 250, and 300 Gy and their fertility (when crossed with normal moths) was compared with nonirradiated moths. Viable progeny (determined by egg hatch) were found at doses of 100 and 200 Gy, but very little at 250 and 300 Gy. In particular, there was no survival of female progeny into the F1 generation. Males irradiated at 250 and 300 Gy had very low egg eclosion rates (2.25 and 1.86% at 250 and 300 Gy, respectively) when mated with normal females. The F2 generation from those male progeny had a mean percent hatched of < 1.02%. Based on our results, a dose of 250-300 Gy is recommended for irradiation of E. postvittana adults used for sterile insect technique (SIT) if sterility of parental moths is the desired outcome. Our data also suggests that inclusion of F1 hybrid sterility rather than parental generation sterility into programs using the SIT may allow for doses lower than what we have reported, especially during initial phases of an eradication program where increase fitness of moths might be desirable. Further research is needed to verify the use of F1 hybrid sterility in light brown apple moth SIT programs.     

Long-term effects of methoxyfenozide on the adult reproductive processes and longevity of Spodoptera exigua (Lepidoptera: Noctuidae)

The long-term effects of methoxyfenozide on the longevity and reproductive processes of beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), adults were assessed after exposure by ingestion. Methoxyfenozide significantly reduced adult male longevity compared with females by 1.1 and 1.5 d at 75 and 150 mg (AI)/liter, respectively. Fecundity decreased by >60% with both concentrations at 72 and 96 h after treatment, but at 48 h, no significant effect was observed. The carbohydrate, protein, and lipid content in the eggs were determined as representatives of the biochemical effects of methoxyfenozide associated with the disruption of reproductive processes. The content of carbohydrates in the eggs laid 48 h at treatment was similar to that of controls, but it increased by approximately 1.5 and 2-fold in eggs laid after 72 and 96 h, respectively, compared with controls (15 microg per egg). Protein content was reduced approximately 2.5 and approximately 3-fold for each treatment concentration, respectively, compared with the controls (25 and 23 microg per egg for 75 and 150 mg [AI]/liter, respectively) in eggs collected 72 and 96 h after treatment. Lipid content significantly decreased by approximately 1.6-fold in both treatment concentrations in eggs collected at 48 and 96 h after treatment compared with the controls (24 and 21 microg per egg for 48 and 96, respectively), but it was similar to controls (approximately 19 microg per egg) at 72 h (approximately 15 microg per egg) for both concentrations. The biochemical effects of methoxyfenozide on S. exigua egg formation detected in this work are consistent with the reduction in fertility observed, as reported previously.     

Programmed cell death in the wing of Orgyia leucostigma (Lepidoptera: Lymantriidae)

Programmed cell death is an integral and ubiquitous phenomenon of development that is responsible for the reduction of wing size in female moths of Orgyia leucostigma (Lymantriidae). Throughout larval and pupal life, cells of the wing epithelium proliferate and interact to form normal imaginal discs and pupal wings in both sexes. But at the onset of adult development, most cells in female O. leucostigma wings degenerate over a brief, 2-day period. Lysosomes and autophagic vacuoles appear in cells of the wing epithelium shortly after it retracts from the pupal cuticle. Hemocytes actively participate in removing the resulting cellular debris. By contrast, epithelial cells in wings of developing adult males of O. leucostigma do not undergo massive cell death. Wing epithelium of female pupae transferred to male pupal hosts behaves autonomously in this foreign environment. By pupation, cells of the female wing apparently are committed to self-destruct even in a male pupal environment. Normal interactions among epithelial cells within the plane of a wing monolayer as well as between the upper and lower monolayers of the wing are disrupted in female O. leucostigma by massive cell degeneration. Despite this disruption, the remaining cells of the wing contribute to the formation of a diminutive, but reasonably proportioned, adult wing with scales and veins.     

Radiation biology and inherited sterility of light brown apple moth (Lepidoptera: Tortricidae): developing a sterile insect release program

The radiation biology of two geographically isolated populations of the light brown apple moth [Epiphyas postvittana (Walker)] was studied in Australia and New Zealand as an initiation of a SIT/F1 sterility program. Pharate and < or = 2 d pre-emergence pupae were exposed to increasing radiation doses up to a maximum dose of 300 Gy. Fertility and other life history parameters were measured in emerging adults (parental) and their progeny (F1-F3 adults). Parental fecundity was significantly affected by increasing irradiation dose in pharate pupae only. For both populations, parental egg fertility declined with increasing radiation. This was most pronounced for the irradiated parental females whose fertility declined at a higher rate than of irradiated males. At 250 Gy, females < or = 2 d preemergence pupae produced few larvae and no adults at F1. No larvae hatched from 250 Gy-irradiated female pharate pupae. At 300 Gy, males still had residual fertility of 2-5.5%, with pharate pupae being the more radio-sensitive. Radiation-induced deleterious inherited effects in offspring from irradiated males were expressed as increased developmental time in F1 larvae, a reduction in percent F1 female survival, decreased adult emergence and increased cumulative mortality over subsequent generations. Males irradiated at > or = 150 Gy produced few but highly sterile offspring at F1 and mortality was > 99% by F2 egg.     

Effects of rearing density on larval growth and activity of digestive enzymes in Lymantria dispar L. (Lepidoptera: Lymantriidae)

Density dependent responses of 4th, 5th and 6th instar gypsy moth larvae were studied at the level of larval mass, midgut loading and activities of three digestive enzymes (alpha-amylase, trypsin and leucine aminopeptidase). High density significantly reduced larval mass while midgut loading (expressed as relative midgut mass) did not change except in the 5th instar where it was increased at high density. Specific amylase and leucine aminopeptidase activities were not affected by crowding. Specific trypsin activity was on average higher in crowded than in isolated larvae. High density also affected the correlations between midgut protein content and activities of two proteolytic enzymes suggesting differences in regulatory mechanisms of insect digestion. The importance of these changes for survival under stressful conditions is discussed.     

一日龄粘虫不同时长吊飞对生殖及寿命的影响

【目的】本研究旨在阐明羽化后1日龄粘虫Mythimna separata(Walker)的飞行潜力以及飞行对成虫生殖和寿命的影响,从而进一步解析粘虫的迁飞行为特征。【方法】利用室内昆虫飞行磨计算机数据采集系统,研究了羽化后1日龄粘虫吊飞6、9和12 h的飞行能力差异,以及不同时长吊飞后粘虫的生殖参数和成虫寿命的变化情况。【结果】结果表明,1日龄雌雄蛾均具有一定的飞行能力,但当吊飞时间超过9 h之后,成虫的飞行时间、距离和速度均不再显著上升。除吊飞12 h成虫的飞行速度外,其它处理雌雄蛾的飞行能力之间无显著差异。羽化后1日龄不同时长吊飞对粘虫的生殖均有显著的促进作用,但随着吊飞时间的延长,这种促进作用显著降低。6、9和12 h吊飞处理均导致成虫产卵前期显著缩短,但仅吊飞6和9 h成虫的产卵量和产卵历期显著高于对照。吊飞12 h成虫的产卵量和产卵历期则显著低于吊飞6和9 h的成虫,并和对照差异不显著。吊飞12 h后,雌雄成虫寿命均显著缩短。【结论】羽化后1日龄飞行显著促进粘虫的生殖,但随着飞行时间的延长,飞行对生殖的促进效应显著减弱。