Life tables of currant clearwing,Synanthedon tipuliformis (Lepidoptera: Sesiidae), in blackcurrant in Canterbury

Abstract

Survivorship curves and life tables for the 1971-75 generations of currant clearwing in an unsprayed blackcurrant (cv. 'Cotswold Cross') plantation and for the 1972-74 generations in a sprayed blackcurrant plantation (cvs 'Cotswold Cross' and 'Magnus') are presented. The key element in the life cycle is identified as adult survival, and the density dependence of the various mortalities is identified by various indices. The possible effects on population levels of currant clearwing of the proposed pruning management for mechanically harvested blackcurrants is discussed.     

The distribution and dispersion of life stages of currant clearwing,Synanthedon tipuliformis (Lepidoptera: Sesiidae), in blackcurrant

Abstract

The distribution of life stages of currant clearwing, Synanthedon tipuliformis (Clerck), in blackcurrant bushes was investigated on two plots during 1971–75. Three ways of expressing the distribution are examined, none of which is totally acceptable. Generally less than 10% of eggs are found on the current season's growth, and since wood of this age group represents over 50% of the available universe, the proportion of eggs laid on it is relatively low. The proportion of the larval population in the younger wood increases until just before pupation, when over 80% of the population is in the most recent 2 years' growth. The 1-year-old wood harbours 50% of the early larval population, and a use for this information in assessments of the effectiveness of insecticide trials against adults is suggested. The dispersion of eggs and larvae of S. tipuliformis is shown by a number of indices to be aggregated. The frequency distribution is adequately described by the negative binomial. A common k, k _c, of 0.66 (95% confidence limits 0.57–0.80) for the egg stage was valid, but the k _c for the larval stage of 1.28 (1.09–1.56) was only marginally valid.     

A sampling plan for population dynamics studies on currant clearwing,Synanthedon tipuliformis (Lepidoptera: Sesiidae)

Abstract

Sampling techniques for eggs, larvae, and pupae of the currant clearwing, Synanthedon tipuliformis (Clerck), attacking blackcurrant were developed, and their precision was evaluated. Reliable population estimates for the egg and early larval stages (standard error < 10%) were obtained by sampling one cane with at least two age groups of wood from the north and south halves of seven bushes in nine blocks. Similar precision was obtained for post-winter larvae from samples comprising three canes from each half of the bushes, but using this sampling scheme a lower precision (S.E.?25–30%) had to be accepted for overwintering mortality factors. The pupal population was estimated from the numbers of live larvae at the end of the post-winter feeding stage, and cross-checked from the number of emergence holes in the 1-year-old wood taken for egg sampling the following year. This procedure gave estimates of similar reliability to those for the egg and larval stages.     

Natural mortality of currant clearwing,Synanthedon salmachus (Lepidoptera: Sesiidae), in New Zealand

Abstract

In a wide-ranging survey of 11 blackcurrant blocks, mortality of currant clearwing, Synanthedon salmachus (L.), was found to range from 1.3% to 9.7% for larvae and from 5.3% to 23.0% for pupae. At least 51% of the mortality was caused by the fungal pathogens Beauveria bassiana, Paecilomyces farinosus, and Verticillium lecanii. One unidentified predatory carabid larvae was collected, and two parasites—Xanthocryptus novozealandicus and Diadegma sp.—were reared from clearwing larvae.     

The influence of amino acids and inorganic salts on feeding by larvae of Heteronychus arator (Coleoptera: Scarabaeidae)

Abstract

Twenty amino acids were offered at 2 concentrations to Heteronychus arator F. larvae in an agar/cellulose powder medium. In comparison with the plain medium, only 0.1M l-alanine, 0.01M l-aspartic acid, and 0.01M l-glutamic acid significantly stimulated feeding. A mixture of inorganic salts did not induce feeding when presented in the medium alone, nor did it affect the vigorous feeding response of larvae to 0.1M maltose.     

Changes in the karyotype of the cell line,DSIR-HA-1179, and a comparison with that of its parent insect,Heteronychus arator (F.) (Coleoptera: Scarabaeidae)

Abstract

Eighteen months after establishment of the primary cell culture, 36 metaphase nuclei of cell line DSIR-HA-1179, derived from the black beetle, Heteronychus arator (F.), had between 32 and 43 chromosomes; one cell contained 67 chromosomes. Structural abnormalities such as double minute chromosomes, ring and di- and tri-centric chromosomes were observed. Thirty-six months after establishment the chromosomes appeared to be similar, but the number of chromosomes per cell was much more variable (range, 12–73; 42 metaphase cells). The modal chromosome number of testicular tissues from H. arator was 2n = 20 — including an Xy pair — which is characteristic of the Scarabaeidae. The karyotype of DSIR-HA-1179 cells is unstable, with the number of chromosomes becoming more variable with continued propagation.     

The male reproductive system of Costelytra zealandica (White)(Coleoptera: Scarabaeidae: Melolonthinae)

Abstract

The morphology and histology of the male internal reproductive organs of Costelytra zealandica show many similarities to other Scarabaeoidae, and are particularly close to other Melolonthinae and to Rutelinae. Testes follicles of C. zealandica have the usual structure for Melolonthinae with basal lobes surrounding the ends of the vasa efferentia. Epithelial cells of the vasa efferentia, vasa deferentia, and vesiculae seminales have similar densely basophilic cytoplasm but muscle layers are best developed around the latter. Accessory glands lack muscle and are not differentiated histologically into regions but do differ from their reservoirs. The ejaculatory duct has a cuticular intima and is differentiated into anterior and posterior regions. Both are surrounded by a muscular sheath which expands in the posterior region to enclose fluid. This forms a hydraulic mechanism for everting the internal sac during intromission. The parameres hook into the female’s genital chamber during copulation and have no pincer action. Probable homologies are listed between muscles of the external genitalia and anus of C. zealandica and other Scarabaeoidea.     

Inter- and intraspecific activities of compounds derived from sex pheromone glands of currant borer, Synanthedon tipuliformis (Clerck) (Lepidoptera: Sesiidae)

Gas chromatography and mass spectrometry analyses of crude sex pheromone gland extracts revealed that virgin Synanthedon tipuliformis (Clerck), currant borer (Lepidoptera: Sesiidae) females, produced 6 compounds, structurally related to sex pheromone components of clearwing moths. By comparison of retention times and mass spectra of natural products with corresponding properties of synthetic standards, these compounds were identified as: (2E,13Z)-octadeca-2,13-dien-1-yl acetate (E2,Z13-18:OAc), (3E,13Z)-octadeca-3,13-dien-1-yl acetate (E3,Z13-18:OAc), (13Z)-octadec-13-en-1-yl acetate (Z13-18:OAc), (2E,13Z)-octadeca-2,13-dien-1-ol (E2,Z13-18:OH), (13Z)-octadec-13-en-1-ol (Z13-18:OH) and octadecan-1-ol (18:OH) in the ratio 100:0.7:2.7:3.2:traces:traces. The first 3 compounds were previously known to occur in the sex pheromone gland extracts of currant borers, while the last 3 chemicals are now reported for the first time. Trapping tests carried out in the black currant field revealed that E2,Z13-18:OAc, when tested separately, attracted S. tipuliformis males, while addition of E3,Z13-18:OAc to the main component increased the effectiveness of E2,Z13-18:OAc over seven times. The attractiveness of 6 component lures did not differ significantly from the one of the binary mixture, confirming that E2,Z13-18:OAc and E3,Z13-18:OAc in the ratio100:0.7 are essential sex pheromone components of S. tipuliformis. Trapping tests carried out at the dwelling place of Synanthedon scoliaeformis (Borkhausen) (Lepidoptera: Sesiidae) revealed that, in addition to intraspecific synergistic effect, E3,Z13-18:OAc increased the specificity of the pheromone signal of S. tipuliformis, acting by intraspecific mode as an attraction antagonist against S. scoliaeformis males. By this way, it ensured the specificity of the sex attraction signal of the currant borer. Consequently, both compounds E2,Z13-18:OAc and E3,Z13-18:OAc have to be present in pheromone formulations used for monitoring and/or control of S. tipuliformis to avoid effecting non-target species. Other compounds identified from the sex pheromone gland of S. tipuliformis did not show any significant interspecific activity for males of S. scoliaeformis, however, they provide a basis to achieve specificity of a pheromone signal of S. tipuliformis and could act as attraction antagonists against other clearwing moth species which, like S. tipuliformis, employ E2,Z13-18:OAc as their sex pheromone component.     

Susceptibility of apple clearwing moth larvae,Synanthedon myopaeformis (Lepidoptera: Sesiidae) to Beauveria bassiana and Metarhizium brunneum

Apple clearwing moth larvae, Synanthedon myopaeformis (Lepidoptera: Sesiidae) were found to be susceptible to infection by two entomopathogenic fungi: an indigenous fungus isolated from S. myopaeformis cadavers and identified as Metarhizium brunneum (Petch); and Beauveria bassiana isolate GHA. In laboratory bioassays, larvae exhibited dose related mortality after exposure to both the M. brunneum and Beauveria bassiana with 7 day LC₅₀'s of 2.9×10⁵ and 3.4×10⁵ spores/mL, respectively. Larval mortalities caused by the two isolates at 1×10⁶ spores/mL were not significantly different and 73% of the M. brunneum-treated, and 76% of the B. bassiana-treated larvae were dead 7 days post treatment, with LT₅₀'s of 5.5 and 5.1 days, respectively.     

Late immature mortality is the major influence on reproductive success of African black beetle, Heteronychus arator (Fabricius) (Coleoptera: Scarabaeidae), in a Mediterranean-climate region of Australia

In field and laboratory studies, mortality of African black beetle, Heteronychus arator, in the winter-rainfall, Mediterranean-type climate region of south-western Australia was higher in the late immature stages during summer than in the early immature stages that occur during spring, a contrast to summer-rainfall climatic regions. Greatest mortality occurred around the pupal stage in contrasting soil types, despite drying differences in summer and supplementary watering in some plots. Sampling of natural populations confirmed experimental results that mortality in late immature stages is the major factor limiting H. arator populations under a Mediterranean-type climate. Inter-generation increase in H. arator abundance was uncommon, explaining the consistent abundance typically observed between years in south-western Australia. Random dispersal of newly emerged adults in autumn was inferred to restore uniformity in adult abundance between areas of varying favourability for immature survival.     

Efficacy of some insecticides against the small red belted clearwing borer, Synanthedon myopaeformis (Borkh.) (Lepidoptera: Sessiidae), in apple orchards in Jordan

Experiments were carried out in Ash-Shoubak on 10-year old apple trees, Malus domestica cv. Mondial Gala grafted on M26 that were infested with the small red belted clear wing moth. The efficacy of five insecticides was tested against this insect by either spraying or injecting the infested trees. The tested insecticides were; Comodor (imidaclorpid), Chlormezyl (chlorpyrifos & dimethoate), Avaunt (indoxacarb), Thvap (cyromazine) and Actellic (pyrimiphos-methyl). All of these insecticides were applied in 2003 and 2004 except that of Actellic that was applied only in 2004. Data on larval mortality have been observed after 2, 7 and 14 days of insecticides applications. Results showed that spraying or injecting Chlormezyl or Actellic resulted in a significant overall efficacy against the larvae of S. myopaeformis. It was also observed that injecting Comodor improved its overall efficacy against the insect.     

Effect of agronomic factors on the spatial distribution of greyback canegrub, Dermolepida albohirtum (Waterhouse) (Coleoptera: Scarabaeidae), in sugarcane in the Burdekin River Irrigation Area

Abstract A series of studies were undertaken examining the factors that impact on the spatial distribution of greyback canegrub infestations in sugarcane in the Burdekin region of Queensland. Historic records of damage by greyback canegrub showed that sugarcane blocks planted or harvested earlier than surrounding blocks were more likely to be damaged than blocks planted or harvested later. The derived hypothesis that sugarcane height may be the primary determinant of where damage occurs was confirmed in field studies. The tallest sugarcane blocks at the time of oviposition consistently had the highest grub populations. There was no difference in the distribution of damage between the cultivars Q96 and Q117 and the age of these crops also had no impact. The finding that sugarcane height is the primary determinant of where damage occurs on Burdekin farms opens the possibility of using it as a tool to manipulate where canegrubs oviposit and the development of a range of associated cultural control strategies.     

The early life history of kurosoi,Sebastes schlegeli (Scorpaenidae), in the Sea of Japan

Larval and juvenile stages of kurosoi,Sebastes schlegeli, are described and illustrated from wild specimens. Some ecological aspects of larvae and juveniles are also described. Notochord flexion occurred between 5.6–7.5 mm SL. Transformation occurred between 13–20 mm SL. Preflexion and flexion larvae ofS. schlegeli can be distinguished from similar larvae by the pigmentation of the dorsal and ventral midlines of the tail and absence of pigmentation on the ventral portion of the rectum. After notochord flexion, the dorsal and lateral regions in both larvae and pelagic juveniles were heavily pigmented, suggesting adaptation for neustonic life style. Larvae and juveniles were caught at many coastal stations, but did not occur in cooler offshore waters. Larvae smaller than 20 mm SL inhabited surface waters. Until ca. 40 mm SL, juveniles inhabited mainly surface waters (without drifting seaweed), but also used other habitats, such as the drifting seaweed, and near the sea bed. Small larvae (<7 mm SL) fed mainly on copepod nauplii. Larger larvae fed on calanoid copepodites andEvadne nordmanni. Pelagic juveniles fed mainly on fish eggs, with fish larvae also being important food items for some individuals. Most food items taken by juveniles that were associated with drifting seaweed were eggs with attaching filaments (Cololabis saira andHyporhamphus sajori), suggesting that the high density of such food items both attracts and keeps juveniles around drifting seaweed.     

Early life history of kitsune-mebaru,sebastes vulpes (scorpaenidae), in the sea of japan

The larval and juvenile stages of kitsune-mebaru,Sebastes vulpes, based on 50 wild specimens collected in, the Sea of Japan, are described and illustrated, and some ecological aspects of the early life history (feeding, horizonal distribution and habitat shift) included. Preflexion larvae became extruded between 3.9–4.6 mm body length (BL) and notochord flexion occurred between 4.7–7.1 mm BL. Transformation from postflexion larvae to pelagic juventiles occurred between 13–17 mm BL. Compared with other rockfish species,S. vulpes is deep-bodied, throughout both larval and, juvenile stages. Larval and juvenileS. vulpes inhabit mainly coastal water surface layer (usually on the continental shelf), but do not occur offshore region (northwest of Oki Islands). Although someS. vulpes juveniles are associated with drifting seaweed, such clumps are not indispensable habitats for any stages. Surface-to-benthie migration of juveniles occurs at about 25 mm BL. Preflexion and flexion larvae feed mainly on copepod nauplii, and postflexion, transforming larvae and pelagic juveniles mainly on calanoid copepodites (Parracalanus parvus).     

Biology and Host Specificity of Chamaesphecia mysiniformis (Lepidoptera: Sesiidae), a Potential Biological Control Agent of Marrubium vulgare (Lamiaceae) in Australia

The biology of the rhizophagous clearwing moth Chamaesphecia mysiniformis Rambur and its specificity to Marrubium vulgare L. (Lamiaceae) (horehound), a serious introduced weed in southern Australia, were studied in France. Adults emerged in late spring during the morning and began mating on the same day, usually in the mid to late afternoon. Eggs were laid among flower clusters, with females laying an average of 96 2.41 (range, 1-268) with an overall hatch success of 79%. In no-choice, host-specificity tests, first instar larvae attacked only four species of Marrubium, along with Ballota nigra L. and Stachys arvensis L. This high level of specificity and the high mortality of the target plant in its native range make this moth a promising biological control agent of horehound in Australia.     

The life history and biology of Diceratocephala boschmai (Platyhelminthes; Temnocephalida), an ectosymbiont on the redclaw crayfish Cherax quadricarinatus

Adults of the temnocephalan Diceratocephala boschmai, an ectocommensal on the crayfish Cherax quadricarinatus, deposited eggs on the host carapace. After 15 to 20 days at 28 °C, the eggs hatched into ciliated miniature adults with undeveloped reproductive organs, that remained attached to the host alongside the eggs. They grew and became gravid within 53 to 70 days if they were not dislodged. Most oviposited on the host on which they had hatched. Although larval temnocephalans have been described from in vitro work, this is the first temnocephalan life history to be described in vivo.Juvenile worms frequently changed their position on the carapace. Adult worms were sedentary just prior to, and during oviposition, and were frequently found at the base of the large chelae, the ventral surface of the antennae and antennules, and at the base of the walking legs. The ventral margins of the abdomen, the mouthparts, and the interorbital-rostral area were secondarily inhabited.It was calculated using an indirect regression that adult Diceratocephala boschmai survived on average 91 days when removed from the host but they did not produce eggs in vitro. On the host, adult worms lived an average of 48 days after the commencement of oviposition.Abbreviations C cilia - E eyespot - Es ejaculatory sac - Ex excretory canal - G gut - Gl glands - I intertentacular flange - M muscular peduncle - O ovary - P penis - Pg pharyngeal glands - Ph pharynx - R rhabdites - S seminal vesicle - T tentacles - Te testes - U uterus - Vd vas deferens - Vit vitelline glands