The light-brown apple moth,Epiphyas postvittana (Walker): 5. Variability of demographic characteristics in field populations of southeastern Australia.

Studies of population samples of the light-brown apple moth (LBAM), Epiphyas postvittana (Walker), collected along a 1500 km north-south transect in southeastern Australia, revealed significant differences in demographic performance between cohorts of different origins reared under uniform conditions in the laboratory. Mean sample values for survivorship and rate of pre-imaginal development, notably, were found to vary according to the latitude and mean January temperature of collection sites, suggesting that specialized forms had evolved in LBAM as an adaptive response to the characteristics of local environments. Underlying this general trend, however, great differences were recorded between samples from neighbouring populations, in actual values manifested for specific properties affecting demographic performance which would support the hypothesis that LBAM might currently be in the process of diversification throughout the area surveyed, as a consequence of environmental changes resulting from European settlement. General inferences are drawn from the present findings, concerning feasible objectives and procedures for the practical study of pest insects.     

The light-brown apple moth,Epiphyas postvittana (Walker) 2. Uneven sex ratios and a condition contributing to them in the field

Whereas populations of Epiphyas postvittana (Walker), the light-brown apple moth (LBAM), normally produced a slight preponderance of male adults in laboratory cultures, males tended consistently to be less abundant than females in samples drawn from Australian field populations. The sex ratio of the species was investigated with a view to explaining this fact. A condition, causing bisexually-reproducing females of LBAM to form viable progenies comprising mainly female individuals, was found to affect 7% of females in population samples from the south-eastern mainland of Australia, and 4% from Tasmania. A statistical model describing the distribution of the condition in field populations is given. The origin of the condition is unknown; the causative agent is believed to act by inducing the death of male embryos. The condition was only observed to be transmitted from mothers to daughters, of which some might produce apparently normal progenies, while others produced either all-female or predominantly-female progenies. The demographic performance of affected females differed from that of comparable ‘normal’ individuals only in fertility, which was significantly reduced. In a limited number of experiments, laboratory populations formed from field-collected samples containing affected females, which produced a proportion of males, could only be maintained through subsidies of males from non-affected stock. The present case was considered in relation to literature reports of similar conditions affecting a dipteron, a coleopteron, and a macrolepidopteron. In E. postvittana, it is surmised that the condition might contribute to optimizing the sex ratio of populations comprising affected individuals, thus increasing their adaptive fitness. A set of verifiable hypotheses are formulated concerning future trends in the condition's natural distribution and frequency.     

The light-brown apple moth,Epiphyas postvittana (Walker): 4. Studies on population dynamics and injuriousness to apples in the Australian Capital Territory

A population study of the light-brown apple moth (LBAM), Epiphyas postvittana (Walker), was pursued from 1963–64 to 1966–67 in a naturally-infested, unsprayed apple plantation near Canberra. The investigation covered the period of tree development leading up to and including, the production of the first substantial crop. The life history of LBAM and the occurrence of natural enemies were examined. The species did not produce seasonal series of identifiable generations, but individuals in all development stages tended to co-exist as cohorts of uncertain generation status. Whereas numbers of LBAM decreased gradually from 1963–64 to 1965–66, they rose again markedly in 1966–67, following the release in the study area of about 3,000 laboratory-reared moths. From periodic field surveys and complementary experiments, it was inferred that the population dynamics of LBAM in the study area consisted essentially in the production of excessive numbers of immature stages, which were reduced by natural enemies to much smaller cohorts of mature stages, determined by the ability of fruit trees to supply the LBAM's requisite food and shelter. It is argued that this ability, i.e. the carrying capacity for LBAM, decreased as the trees matured, and that the damage of LBAM in the crops of fully-bearing trees would have been negligible under the conditions prevailing in the study area. The probability of damage to fruits was directly proportional to the numbers of larvae and of fruits present, indicating that, unlike codling moth for instance, LBAM did not seek out fruits for attack, but struck them by chance encounter. The results of this life-system analysis are discussed in the light of Southwood & Comins’(1976) and Southwood's (1977a, b) generalizations on population dynamics, ecological strategies, and the status of pests. LBAM is believed to display all the characteristic features of an ‘intermediate strategist’ and an ‘intermediate pest’.     

Resistance to a nuclear polyhedrosis virus in the light-brown apple moth Epiphyas postvittana (Lepidoptera: Tortricidae)

Measurements were made of the relative susceptibility to a nuclear polyhedrosis virus of three populations of light-brown apple moth Epiphyas postvittana: a resistant laboratory strain (CAN), a susceptible laboratory strain (BAR), and a field population. CAN was found to be 50 times more resistant than BAR and 160 times more resistant than the field line. Experiments on hybrid crosses of resistant and susceptible strains showed that resistance is genetically determined. This serves as a warning of the possible selection of virus-resistant strains of insect pests, where viral insecticides are being used in the field.     

The hymenopteran parasitoids of light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae) in Australia

Abstract  Epiphyas postvittana (Walker) is a serious pest of a number of horticultural crops including grapes in Australia and New Zealand. This study brings together information on the parasitoid complex associated with E. postvittana that previously was fragmented and largely inaccessible. We include species reared during a 3-year study of the parasitoids of E. postvittana in the vineyards of the Coonawarra region, South Australia, material from several Australian agricultural insect collections and records from the literature. An illustrated key is presented for 25 species of parasitoids and hyperparasitoids associated with E. postvittana , along with information on the taxonomy, identification, distribution and biology of each species. Taxa newly recorded from this host are Perilampus sp. (Perilampidae), and six species of Ichneumonidae: Euceros sp., Labium sp., Netelia sp., Plectochorus sp., Temalucha minuta (Morley) and Eriborus epiphyas sp. n., the latter species being described in full.     

A proteinase inhibitor from Nicotiana alata inhibits the normal development of light-brown apple moth, Epiphyas postvittana in transgenic apple plants

Insecticidal proteins are a potential resource to enhance resistance to insect pests in transgenic plants. Here, we describe the generation and analysis of the apple cultivar ‘Royal Gala’ transgenic for Nicotiana alata (N. alata) proteinase inhibitor (PI) and the impact of this PI on the growth and development of the Epiphyas postvittiana (light-brown apple moth). A cDNA clone encoding a proteinase inhibitor precursor from N. alata (Na-PI) under the control of either a double 35S promoter or a promoter from a ribulose-1,5-bisphosphate carboxylase small sub-unit gene (rbcS-E9 promoter) was stably incorporated into ‘Royal Gala’ apple using Agrobacterium-mediated transformation. A 40.3 kDa Na-PI precursor protein was expressed and correctly processed into 6-kDa proteinase inhibitors in the leaves of transgenic apple lines. The 6-kDa polypeptides accumulated to levels of 0.05 and 0.1% of the total soluble protein under the control of the rbc-E9 promoter and the double 35S promoter, respectively. Light-brown apple moth larvae fed with apple leaves expressing Na-PI had significantly reduced body weight after 7 days of feeding and female pupae were 19–28% smaller than controls. In addition, morphological changes such as pupal cases attached to the wing, deformed wings, deformed body shape, and pupal cases and curled wings attached to a deformed body were observed in adults that developed from larvae fed with apple leaves expressing Na-PI, when compared to larvae fed with the non-transformed apple leaves.     

Periodicity of sex pheromone biosynthesis, release and degradation in the lightbrown apple moth, Epiphyas postvittana (Walker)

Pheromone titer in moths is a product of three processes occurring in or at the surface of the pheromone gland: biosynthesis, release, and intraglandular degradation, of pheromone. Changes in titers of sex pheromone, the fatty acyl pheromone analog (FAPA), and tetradecanoate, a pheromone biosynthetic intermediate, were studied in detail in the lightbrown apple moth, Epiphyas postvittana (Walker). Although changes in the pheromone titers in a day were relatively small, with the peak titer being 2-3 times greater than that at the trough, pheromone titer did show a distinct diel periodicity. Titer of the FAPA showed a similar, but less variable, diel pattern, but tetradecanoate titer showed little or no diel pattern. The pattern of pheromone titer suggested that females biosynthesize pheromone at two different rates during the photoperiod: a high rate during the latter half of the photophase and most of the scotophase, which is associated with a high pheromone titer, and a low rate throughout the first half of the photophase, which is associated with a low titer. Consistent with data on commencement of copulation, pheromone was released from the second hour of the scotophase through to the eighth hour. Pheromone release rate during this period appeared to be similar to the rate of pheromone biosynthesis. In contrast to the other two processes, pheromone degradation did not appear to have a diel pattern. Females decapitated at different times of the photoperiod showed a similar decline in pheromone titer, consistent with the reaction kinetics being first order in pheromone titer.     

Study of single sensillum responses to pheromone in the light-brown apple moth, Epiphyas postvittana, using an averaging technique

ABSTRACT. A technique is described for averaging the electrophysiological responses of single olfactory sensilla when repeatedly stimulated with the same odour. This enables measurements of electrophysiological responses to be interpreted in a way not normally possible because of the highly variable nature of the individual responses of sensory cells. When the antennal receptors of males of Epiphyas postvittana are stimulated with a single pheromone component, it is shown that the responses contain sufficient information to detect readily both the onset and removal of a stimulus and also a doubling or halving in the concentration of the pheromone. Significant changes in the spontaneous activity of cells following stimulation are also described.     

Light brown apple moth (Epiphyas postvittana) (Lepidoptera: Tortricidae) colonization of California

In response to the confirmed detection of the light brown apple moth, Epiphyas postvittana, in California, approximately 53,000 pheromone-baited Jackson traps were deployed and more than 246,000 males were caught (February 2007–February 2010). Approximately 46,000 manually entered catch records were corrected for errors and converted into catch per trap per day. As empty trap data (zeros) were not recorded, we added zeros between first and last catch for each trap based on the stated servicing period (~30,000), before analyzing for trends. Residual data error rate was estimated as 1.5 %. San Francisco and Santa Cruz counties had relatively high trap catches immediately upon trap set, and remained the leading population centers, while most other counties showed a more general trend of a slow build-up in catch over time (12 counties). An exponential increase in trap catch was observed in four counties with sufficient data. The pattern of spread indicated natural, as well as anthropogenic-assisted spread rates, with populations appearing well ahead of the invasion front. This jump dispersal is probably due to movement of host plants, unsurprising since eggs of this polyphagous moth are readily laid on foliage. There was evidence of seasonality in spread, probably linked to the phenology of the insect. There was a positive relationship between catch and known host tree preference, suggesting that trap placement in preferred hosts could add sensitivity to future surveys. Recommendations include the improved provision of data acquisition by telecommunications, standardization of data input, more archiving, and frequent analysis of trap catches. The rapid rate of population growth demonstrated in two counties and spread across many others supports the hypothesis of the recent arrival of E. postvittana in California.     

浅析潜在外来入侵物种——苹浅褐卷蛾

苹浅褐卷蛾Epiphyas postvittana原产澳大利亚,是澳大利亚西南部、新西兰、英国及美国多种经济作物的重要害虫,目前尚未在全球范围广泛分布。由于其地理分布范围窄、寄主植物广泛、形态鉴定困难、能够对农作物造成较大的经济危害以及具有遗传多样性等特点,目前已被多数国家列为检疫对象并提出严格的检疫要求。而2007年该虫在美国加州地区的定殖使得研究人员对该虫能够造成的危害程度引起了再次的关注。在我国,该虫也被列为对外检疫对象,但是相关报道相对较少。作为检疫性害虫,对其相关信息的综合掌握是进一步进行有害生物风险分析的基础和保障。本文详细描述了苹浅褐卷蛾的地理分布、寄主范围、发生为害与环境条件的相互关系等,以期为该虫进行进一步风险分析及对其的检疫措施的制定和实施提供重要的信息与依据。     

Interactions between male moths of the lightbrown apple moth, Epiphyas postvittana (Walker) (Lep.: Tort.), landing on synthetic sex pheromone sources in a wind-tunnel

Abstract. This study was designed to determine whether landings of males of Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae) on synthetic sex pheromone sources are influenced by other males which have preceded them in flying to and landing on the sources. The investigation comprised two separate experiments. In one, using a single pheromone source, insects released singly were compared with insects released in groups of three, and in the other, insects released in groups of five were presented with a choice between two identical sources. The resolution for changes in attractancy was higher in the choice experiment which demonstrated an increase in attraction for a source on which males had already landed and remained whilst the new male flew towards it. A single resident insect increased the source attractancy by a factor of 1.40 and a pair of insects by 1.77 compared with an empty source. With the single sources the data exhibited the same trend but the result was rendered not significant by an insufficient amount of data, although approximately equal times were allocated to each experiment. To achieve a significant result with the single sources at least 6 times as much data would need to be collected.     

Reduction in responsiveness of male light-brown apple moths, Epiphyas postvittana, to sex pheromone following pulsed pre-exposure to pheromone components

ABSTRACT. A combination of two sex pheromone compounds is required to elicit sexual response in males of Epiphyas postvittana. Sequential exposure to the two compounds failed to elicit sexual response in males, but a pre-exposure sequence of alternated pulses of the two compounds did habituate males to the same extent as did pulsed pre-exposures to the compounds combined.     

Differences between single cell responses to different components of the sex pheromone in males of the lightbrown apple moth (Epiphyas postvittana)

ABSTRACT. Single cell responses, elicited by each of three components of the pheromone blend of the lightbrown apple moth, Epiphyas postvittana (Walker) (Lepidoptera, Tortricidae), exhibit significant differences in disadaptation rates and effect of stimulation on the spontaneous generation of spikes upon removal of the stimulus. The major component has a disadaptation rate of a few seconds and a sustained effect on the rate of spontaneous spike generation upon removal of the stimulus. Faster disadaptation rates and sharp reduction in the spike rate upon removal of stimulus, were observed for one minor component, 12: Ac, and suggests a likely role in close-range orientation to the female. The second minor component produces two types of response, one of which resembles the major component. The other, more common response, exhibits a very slow rate of disadaptation, of the order of minutes. This characteristic also may have some bearing on search strategies.     

Morphogenetic and physiological effects of a juvenile hormone analogue on the light brown apple moth,Epiphyas postvittana (Lepidoptera: Tortricidae)

Abstract

The juvenile hormone analogue ZR-619—ethyl 11-methoxy-3,7,11-trimethyl-(2E,4E-dodecadienethiolate) —produced morphological and physiological effects when fed via artificial diet to larvae of Epiphyas postvittana (Walker). Morphological effects included changes in larval head and antennal structures after instar V (supernumerary instars); deformation of pupal and adult structures, particularly in genitalia and wings; and development of individuals with varying mixtures of larval and pupal structures. Physiological effects included prolongation of larval life, increase in larval weight, increase in larval instars, and decrease in fecundity. Effects were directly related to dosage concentrations.