PALAEONTOLOGY, Issue 6 2007
S. C. GHOSH
Abstract:, The fossilized larva of an aquatic beetle, Protodytiscus johillaensis gen. et sp. nov., is described from a ferruginous micaceous siltstone bed of the Permo-Triassic Parsora Formation of the South Rewa Gondwana Basin, Madhya Pradesh, India, and its systematic position and ordinal relationships within the coleopterous suborder Adephaga are discussed. Hitherto, the oldest known fossils of the hydradephagan superfamily Dytiscoidea have been Jurassic. The discovery of P. johillaensis extends the range of the Dytiscoidea back to the Permo-Triassic period. [source]

EFFECTS OF FIVE NEW COMPOUNDS ON THE LARVAL GROWTH AND DIGESTIVE PHYSIOLOGY OF THE ASIATIC CORN BORER, OSTRINIA FURNACALIS LARVAE

INSECT SCIENCE, Issue 3 2003
Jia He
Abstract Five new compounds were tested on the growth and antifeeding activity compared with toosendanin against fifth instar larvae Ostrinia furnacalis. The activities of two proteases, a weak alkaline trypsine-like enzyme and a chymotrypsin-like enzyme, in the midgut of Ostrinia furnacalis larvae were also measured. Experimental results suggest that when incorporated into an artificial diet at the concentration of 500mg/kg, the antifeeding activities of toosendanin, C19, C23, C24, C26, C28 were 51.16%, 57.61%, 4.28%, 51.08%, 36.73% and 51.67%, respectively, C19, C24, C28 had no significant difference with toosendanin. At 20mg/kg, the larval growth were remarkably suppressed by C19, C26, C28, the inhibition of C28 was close to toosendanin in 48 h. The two proteases were activated by toosendanin and C28 while they were inhibited in 48 h but activated in 24 h by C19, C24 and C26. In this paper, the related functions and mechanisms were discussed. [source]

External Features of the First Instar Larva of Damaster (Coptolabrus) jankowskii jankowskii (Coleoptera; Carabidae)

ENTOMOLOGICAL RESEARCH, Issue 2 2002
Jung Lark KIM
ABSTRACT Larval features of the carabid beetle, Damaster (Coptolabrus) jankowskii jankowskii (Oberthür) were investigated for the first time. For accomplishing the purpose, the adult beetles were collected by pitfall traps in the deciduous forest of Mt. Palgongsan, southern Korea. They have been reared under the laboratory condition of 16L: 8D at 20°C. The first instar larvae were obtained by isolating eggs after oviposition and were kept at the same condition. In the present study, external morphology of the first instar larva of this subspecies are described and its important character states and comparisons with the kin species are also discussed. [source]

Functional regeneration of the olfactory bulb requires reconnection to the olfactory nerve in Xenopus larvae

DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 1 2006
Jun Yoshino
Larvae of the South African clawed frog (Xenopus laevis) can regenerate the telencephalon, which consists of the olfactory bulb and the cerebrum, after it has been partially removed. Some authors have argued that the telencephalon, once removed, must be reconnected to the olfactory nerve in order to regenerate. However, considerable regeneration has been observed before reconnection. Therefore, we have conducted several experiments to learn whether or not reconnection is a prerequisite for regeneration. We found that the olfactory bulb did not regenerate without reconnection, while the cerebrum regenerated by itself. On the other hand, when the brain was reconnected by the olfactory nerve, both the cerebrum and the olfactory bulb regenerated. Morphological and histological investigation showed that the regenerated telencephalon was identical to the intact one in morphology, types and distributions of cells, and connections between neurons. Froglets with a regenerated telencephalon also recovered olfaction, the primary function of the frog telencephalon. These results suggest that the Xenopus larva requires reconnection of the regenerating brain to the olfactory nerve in order to regenerate the olfactory bulb, and thus the regenerated brain functions, in order to process olfactory information. [source]

Drosophila cdk5 is needed for locomotive behavior and NMJ elaboration, but seems dispensable for synaptic transmission

DEVELOPMENTAL NEUROBIOLOGY, Issue 6 2009
Alexander E. Kissler
Abstract Cyclin-dependent kinase 5 (Cdk5) functions in postmitotic neuronal cells and play roles in cell differentiation, cell migration, axonal guidance, and synaptic function. Here, we demonstrate that Drosophila cdk5 is dispensable for adult viability and fertility, a feature that allows us to study its physiological function in the whole animal model. For the adult, cdk5 is needed for proper locomotion and flight performance. Larvae lacking cdk5 in the presynaptic tissue display abnormal crawling motion, and their neuromuscular junctions (NMJ) are elongated and contain a higher number of boutons that are smaller. As a result of these two counteracting effects, the total synaptic area/NMJ is similar to wild type, leading to normal synaptic transmission, indicating that a compensatory mechanism is capable of correcting the problem caused by the lack of cdk5. futsch, the Drosophila MAP1B homolog, is also involved in NMJ morphogenesis, and analysis of the NMJ phenotype of the double mutant futschK68; cdk5, indicates that cdk5 is epistatic to futsch in this process. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009 [source]

Climatic adaptation in an isolated and genetically impoverished amphibian population

ECOGRAPHY, Issue 4 2010
Germán Orizaola
The capacity of populations to respond adaptively to environmental change is essential for their persistence. Isolated populations often harbour reduced genetic variation, which is predicted to decrease adaptive potential, and can be detrimental under the current scenarios of global change. In this study, we examined climatic adaptation in larval life history traits in the pool frog Rana lessonae along a latitudinal gradient across the northern distribution area of the species, paying special attention to the isolated and genetically impoverished fringe populations in central Sweden. Larvae from eight populations within three geographic areas (Poland, Latvia and Sweden) were reared under three temperatures (19, 22 and 26°C) in a common garden laboratory experiment. We found clear evidence for latitudinal adaptation in R. lessonae populations, larvae from higher latitudes growing and developing faster than low-latitude ones. Larvae from the Swedish populations were able to compensate for the effects of cooler temperatures and a shorter growth season with genetically higher growth and development rates (i.e. countergradient variation) in the two higher temperature treatments, but there was no difference among the populations at the lowest temperature treatment, which is likely to be close to the temperature limiting growth in R. lessonae. Our results demonstrate that isolated and genetically impoverished populations can be locally adapted, and identify the Swedish fringe populations as a significant conservation unit adapted to the northern environmental conditions. [source]

Sabotaging behaviour and minimal latex of Asclepias curassavica incur no cost for larvae of the southern monarch butterfly Danaus erippus

ECOLOGICAL ENTOMOLOGY, Issue 4 2010
DANIELA RODRIGUES
1. The southern monarch, Danaus erippus, uses mainly Asclepias curassavica as its host in the Neotropics, a plant species bearing articulated anastomosing laticifers. When artificially severed, A. curassavica has been shown to release significantly less latex than other Asclepias species. 2. The present study tested the hypothesis that sabotaging behaviour changes during the ontogeny of D. erippus and recorded latex outflow of A. curassavica during sabotaging and feeding. Larvae displayed vein-cutting behaviour, which was initially observed in the second instar, became more pronounced in the third and fourth instars, and less frequent in the fifth instar. When present, latex outflow was never more than 1 µl at a time during either vein cutting or feeding, regardless of the instar. 3. Mandibular and midrib morphometrics revealed that larvae selected thicker midrib sites for severing as instars progressed; however, no correlation between mandibular size and midrib size severed was found within instars. 4. Costs of sabotaging behaviour and the effects of A. curassavica latex outflow on D. erippus larvae were also examined. Sabotaging behaviour did not incur growth costs for larvae, and only latex exudation volumes at least 10-fold greater than those observed due to D. erippus sabotaging or feeding, caused significantly higher larval mortality than controls. 5. Since latex outflow is minimal or non-existent in A. curassavica, sabotaging behaviour in D. erippus is mostly limited by morphological constraints and is probably driven by chemical stimulants rather than latex defence. In turn, latex does not constitute a major defence of A. curassavica against D. erippus. [source]

Crowding and disease: effects of host density on response to infection in a butterfly,parasite interaction

ECOLOGICAL ENTOMOLOGY, Issue 5 2009
ELIZABETH LINDSEY
Abstract. 1. Hosts experiencing frequent variation in density are thought to benefit from allocating more resources to parasite defence when density is high (,density-dependent prophylaxis'). However, high density conditions can increase intra-specific competition and induce physiological stress, hence increasing host susceptibility to infection (,crowding-stress hypothesis'). 2. We studied monarch butterflies (Danaus plexippus) and quantified the effects of larval rearing density on susceptibility to the protozoan parasite Ophryocystis elektroscirrha. Larvae were inoculated with parasite spores and reared at three density treatments: low, moderate, and high. We examined the effects of larval density on parasite loads, host survival, development rates, body size, and wing melanism. 3. Results showed an increase in infection probability with greater larval density. Monarchs in the moderate and high density treatments also suffered the greatest negative effects of parasite infection on body size, development rate, and adult longevity. 4. We observed greater body sizes and shorter development times for monarchs reared at moderate densities, and this was true for both unparasitised and parasite-treated monarchs. We hypothesise that this effect could result from greater larval feeding rates at moderate densities, combined with greater physiological stress at the highest densities. 5. Although monarch larvae are assumed to occur at very low densities in the wild, an analysis of continent-wide monarch larval abundance data showed that larval densities can reach high levels in year-round resident populations and during the late phase of the breeding season. Treatment levels used in our experiment captured ecologically-relevant variation in larval density observed in the wild. [source]

Seed weevils living on the edge: pressures and conflicts over body size in the endoparasitic Curculio larvae

ECOLOGICAL ENTOMOLOGY, Issue 3 2009
RAÚL BONAL
Abstract 1.,Body size in parasitic insects can be subjected to contrasting selective pressures, especially if they complete their development within a single host. On the one hand, a larger body size is associated with a higher fitness. On the other hand, the host offers a discrete amount of resources, thus constraining the evolution of a disproportionate body size. 2.,The present study used the weevil Curculio elephas as a study model. Larvae develop within a single acorn, feeding on its cotyledons, and larval body size is strongly related to individual fitness. 3.,The relationship between larval and acorn size was negatively exponential. Larval growth was constrained in small acorns, which did not provide enough food for the weevils to attain their potential size. Larval size increased and levelled off in acorns over a certain size (inflexion point), in which cotyledons were rarely depleted. When there were more than one larva per acorn, a larger acorn was necessary to avoid food depletion. 4.,The results show that C. elephas larvae are sometimes endoparasitic, living on the edge of host holding capacity. If they were smaller they could avoid food depletion more easily, but the fitness benefits linked to a larger size have probably promoted body size increase. The strong negative effects of conspecific competition may have possibly influenced female strategy of laying a single egg per seed. 5.,Being larger and fitter, but always within the limits of the available host sizes, may be one main evolutionary dilemma in endoparasites. [source]

Variation in food availability influences prey-capture method in antlion larvae

ECOLOGICAL ENTOMOLOGY, Issue 5 2008
EFRAT ELIMELECH
Abstract 1.,Larvae of a Myrmecaelurus sp. are unique among antlions because they have two prey-capture methods; they either ambush prey at the surface, or dig pit traps that prey fall in to. It was hypothesised that larvae will use the capture method that maximises their net rate of energy gain, which will be influenced by food availability (encounter rate) and by past energy inputs (body condition). 2.,Costs were estimated by measuring resting and activity metabolic rates and determining the duration of pit maintenance at various encounter rates with ants that served as prey. Benefits were estimated from the energy gained per ant captured at different encounter rates. 3.,Net energy gained was higher with a pit than without one, and was influenced more by the differences in prey capture rate between the two capture methods, and less by the differences in energy costs associated with each method. The proportion of larvae that constructed pits was higher when they were in intermediate body condition than when in good or in poor body condition. 4.,Thus, the use of one capture method or the other depends on a combination of the influences of past net energy gain and the antlion's most recent change in encounter rate with prey. Ambushing without a pit may serve as a default when physiological constraints limit the larvae's ability to invest in pit construction and maintenance, or when larvae are sated, and saving the energy of pit construction and maintenance is worthwhile. [source]

Resistance and tolerance to herbivory in Salix cordata are affected by different environmental factors

ECOLOGICAL ENTOMOLOGY, Issue 5 2005
Kevin P. Macdonald
Abstract., 1.,Effects of sand burial and nutrients on the ability of sand-dune willow (Salix cordata) to tolerate or resist herbivory by the beetle Altica subplicata were evaluated in field experiments. 2.,To assess tolerance, all combinations of sand burial (none, 50%), nutrients (presence, absence), and beetles (presence, absence) were applied to caged plants and growth responses to herbivory were measured. Sand burial increased plant growth rate, but decreased S. cordata's tolerance to herbivory. Although nutrients increased growth, tolerance to herbivory was unaffected. 3.,To assess resistance, plants were exposed to all combinations of sand burial and nutrients, and then to natural beetle colonisation. The presence of nutrients, but not sand burial, significantly increased the percentage of plants with beetles, for both adults and larvae. This decreased resistance to beetles of plants grown with added nutrients occurred only in the absence of sand burial. 4.,The performance and preference of beetles were examined in laboratory experiments. Larvae developed faster and had increased pupation success on plants with nutrients added. Beetles also showed a marginally significant feeding preference for leaves grown with added nutrients. Thus, S. cordata tolerance to herbivory was affected by sand burial, whereas resistance, preference, and performance were affected by nutrient level. [source]

Parasitism and ant protection alter the survival of the lycaenid Hemiargus isola

ECOLOGICAL ENTOMOLOGY, Issue 2 2003
Jennifer A. Weeks
Abstract. 1. Although the majority of lycaenid,ant associations is facultative, few studies have documented the protection benefits provided by ants to lycaenids that are tended facultatively (Pierce & Easteal, 1986; Peterson, 1993). 2. Larvae of Hemiargus isola (Lepidoptera: Lycaenidae) feeding on Dalea albiflora are tended facultatively by several species of ant. In 1999 and 2000, the levels of parasitism and the identities of attendant ants were determined for larvae of H. isola. In addition, the presence of ants was manipulated experimentally to determine the efficacy of protection provided by attendant ants to H. isola. 3. Lycaenids were parasitised by a braconid wasp, Cotesia cyaniridis (Riley), and a tachinid fly, Aplomya theclarum (Scudder). In 1999 and 2000, 62 and 65% of larvae were parasitised; the percentage of the population parasitised did not differ significantly between years. In both 1999 and 2000, parasitism by the braconid wasp C. cyaniridis accounted for >,99% of all parasitism events. 4. Four species of ant, Crematogaster sp., Dorymyrmex sp., Forelius sp., and Formica sp., were associated with 88,99% of the tended lycaenids collected in both 1999 and 2000. For both years, there was a single, numerically dominant species associated with >80% of the tended larvae collected, but the identity of this numerically dominant ant differed between years. 5. Experimental exclusion of ants from D. albiflora plants resulted in 78% larval mortality as a result of parasitism, nearly twice that of larvae that were tended by ants on unmanipulated plants. [source]

A minimalist approach to the effects of density-dependent competition on insect life-history traits

ECOLOGICAL ENTOMOLOGY, Issue 4 2002
Philip Agnew
Abstract ,1. Due to its effects on the phenotypic and genotypic expression of life-history traits, density-dependent competition is an important factor regulating the growth of populations. Specifically for insects, density-dependent competition among juveniles is often associated with increased juvenile mortality, delayed maturity, and reduced adult size. 2. The aim of the work reported here was to test whether the established phenotypic effects of density-dependent competition on life-history traits could be reproduced in an experimental design requiring a minimal number of individuals. Larvae of the mosquito Aedes aegypti were reared at densities of one, two, or three individuals per standard Drosophila vial and in six different conditions of larval food availability. This design required relatively few individuals per independent replicate and included a control treatment where individuals reared at a density of one larva per vial experienced no density-dependent interactions with other larvae. 3. Increased larval densities or reduced food availability led to increased larval mortality, delayed pupation, and the emergence of smaller adults that starved to death in a shorter time (indicating emergence with fewer nutritional reserves). 4. Female mosquitoes were relatively larger than males (as measured by wing length) but males tended to survive for longer. These differences increased as larval food availability increased, indicating the relative importance of these two traits for the fitness of each sex. The role of nutritional reserves for the reproductive success of males was highlighted in particular. 5. This minimalist approach may provide a useful model for investigating the effects of density-dependent competition on insect life-history traits. [source]

A comparison of the host-searching efficiency of two larval parasitoids of Plutella xylostella

ECOLOGICAL ENTOMOLOGY, Issue 1 2002
Xin-Geng Wang
Summary 1. A host specialist parasitoid is thought to have greater efficiency in locating hosts or greater ability to overcome host defence than a generalist species. This leads to the prediction that a specialist should locate and parasitise more hosts than a generalist in a given arena. The work reported here tested these predictions by comparing the host-searching behaviour of Diadegma semiclausum (a specialist) and Cotesia plutellae (an oligophagous species), two parasitoids of larval Plutella xylostella. 2. Both parasitoids employed antennal search and ovipositor search when seeking hosts but D. semiclausum also seemed to use visual perception in the immediate vicinity of hosts. 3. Larvae of P. xylostella avoided detection by parasitoids by moving away from damaged plant parts after short feeding bouts. When they encountered parasitoids, the larvae wriggled vigorously as they retreated and often hung from silk threads after dropping from a plant. 4. These two parasitoids differed in their responses to host defences. Diadegma semiclausum displayed a wide-area search around feeding damage and waited near the silk thread for a suspended host to climb up to the leaf, then attacked it again. Cotesia plutellae displayed an area-restricted search and usually pursued the host down the silk thread onto the ground. 5. Diadegma semiclausum showed a relatively fixed behavioural pattern leading to oviposition but C. plutellae exhibited a more plastic behavioural pattern. 6. The time spent by the two parasitoids on different plants increased with increasing host density, but the time spent either on all plants or a single plant by D. semiclausum was longer than that of C. plutellae. Diadegma semiclausum visited individual plants more frequently than C. plutellae before it left the patch, and stung hosts at more than twice the rate of C. plutellae. 7. The results indicated that the host-location strategies employed by D. semiclausum were adapted better to the host's defensive behaviour, and thus it was more effective at detecting and parasitising the host than was C. plutellae. [source]

Plants, gall midges, and fungi: a three-component system

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2008
Odette Rohfritsch
Abstract Larvae of gall midges (Diptera: Cecidomyiidae) induce the activation of plant cells, partial cell lysis, and differentiation of nutritive tissue. Specialized nutritive tissue is essential for larval development and plays a key role in gall organization. Midges of the tribes Lasiopterini and Asphondyliini, however, do not induce nutritive tissues as part of the formation of their galls. Instead, these ,ambrosia galls' contain fungal mycelia that line the interior surface of the chambers. The fungi not only provide Lasiopterini with nutrition, they also penetrate the stems, induce the lysis of the middle lamella of host cells, and open a channel to the vascular bundles. Larvae of Lasioptera arundinis (Schiner) (Lasiopterini) follow the fungus and feed on its mycelium along with adjoining stem cells of Phragmites australis (Cav.) Trin. (Poaceae). Eggs together with fungal conidia are deposited by the imago on the host. Asphondyliini use a needle-like ovipositor to introduce fungal conidia and eggs into the organs they attack. Larvae of Schizomyia galiorum Kieffer (Asphondyliini) are unable to initiate the gall or to develop in the flowers of Galium mollugo L. (Rubiaceae) without their fungal associate. In this article, I provide an overview of oviposition behaviour in the Asphondyliini, as well as descriptions of the ovipositor and the female post-abdominal segments. Gall formation by Lasiopterini and Asphondyliini and the role of associated fungi are discussed, as is the role of the fungus as an inquiline or an organizer of gall tissues and a nutritive device. [source]

Trade-offs in oviposition choice?

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2007
Food-dependent performance, defence against predators of a herbivorous sawfly
Abstract The sawfly Athalia rosae L. (Hymenoptera: Tenthredinidae) is a feeding specialist on plant species of the Brassicaceae, which are characterised by secondary metabolites, called glucosinolates. The larvae can take up the respective glucosinolates of their hosts and concentrate them in their haemolymph to protect themselves against predators. Oviposition preferences of naïve females were tested for three species, Sinapis alba L., Brassica nigra (L.) Koch, and Barbarea stricta Andrz., and were related to larval performance patterns. Larvae were reared on either one of these plants and it was investigated how host-plant quality influences both the developmental times and growth of larvae (bottom-up) and the defence efficiency against predators (top-down). Innately, almost all adult females avoided B. stricta for oviposition and clearly preferred B. nigra over S. alba. On average, larvae developed best on B. nigra. Female larvae reached similar final body masses on all host-plant species, but males reared on S. alba were slightly lighter. The developmental time of larvae reared on B. stricta was significantly longer than on the other two plants. However, larvae reared on B. stricta were best protected against the predatory wasp Polistes dominulus Christ (Hymenoptera: Vespidae). The wasps rejected these larvae most often, while they attacked larvae reared on S. alba most frequently. Thus, larvae feeding on B. stricta theoretically run a higher risk of predation due to a prolonged developmental time, but in practice they are better protected against predators. Overall, oviposition preferences of A. rosae seem to be more influenced by bottom-up effects on larval performance than by top-down effects. [source]

Genetic analysis of larval survival and larval growth of two populations of Leptinotarsa decemlineata on tomato

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2001
Wenhua Lu
Abstract The genetics of adaptation to tomato in Leptinotarsa decemlineata (Say) were investigated in reciprocal F1, F2, and backcross populations generated from crosses between beetles from a tomato adapted population and from a population that was poorly adapted to tomato. Larvae from the parent and test populations were reared on tomato for four days, after which survivorship and larval weights were recorded. Most results indicate that differences in larval growth and survival on tomato between the parent populations are largely determined by autosomal, polygenic mechanisms, the inheritance of which involves a significant dominance component. However, results from F2 crosses are not consistent with this conclusion. A significant difference in larval weights, but not in survival, between reciprocal F1 populations in an analysis of combined data from four separate experiments suggests that maternal cytoplasmic effects may contribute to differences in larval performance on tomato between the adapted and unadapted populations. The unusual results obtained from F2 crosses in this study are not atypical of results from previous studies of the genetics of adaptation to host plants by the Colorado potato beetle. Host plant adaptation by Colorado potato beetles may therefore involve unusual genetic mechanisms that are not easily assessed by classical Mendelian analysis. [source]

Effects of crowding on populations of Aedes albifasciatus larvae under laboratory conditions

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2000
Raquel M. Gleiser
Abstract Aedes (Ochlerotatus) albifasciatus (Macquart 1838) (Diptera: Culicidae) is a neotropical flood water mosquito, incriminated as the main vector of the western equine encephalitis virus, and which affects beef and milk production in central Argentina. The short time required to hatch and develop from egg to adult, usually in temporary pools, suggests a strategy which allows for exploitation of transient pools, thus evading predation and interspecific competition. Under these conditions intra specific competition could represent a major density-dependent source of larval mortality, but the relative importance of density-dependent regulation of mosquito populations has generated controversy. Therefore we examined the effects of larval density on basic population characteristics of Ae. albifasciatus in the laboratory. Larvae were obtained by synchronous hatching of eggs laid by field-trapped females. Emerging larvae (L1) were used to build cohorts of different initial densities, kept in plastic trays with 400 ml of distilled water, and food supplied daily during the first 10 days (0.1 g per larvae day,1). Age-specific development time and specific and relative mortality were estimated, and their relation to initial larval density was assessed through linear and non-linear regressions and correlation analysis. First hatching was registered 3 h after flooding the eggs. Higher levels of pre-adult mortality were detected in groups with higher densities. Specific mortality and average time to enter a stage of L1 to L3 could directly be related to initial larval density, but no significant relations were found for L4 and pupae. Results suggest that crowding could be a factor capable of regulating the density of natural populations of Ae. albifasciatus. [source]

The lethal effects of gamma irradiation on larvae of the Huhu beetle, Prionoplus reticularis: a potential quarantine treatment for New Zealand export pine trees

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 3 2000
Philip J. Lester
Abstract Gamma irradiation was investigated as a possible method for disinfestation of huhu beetle larvae, Prionoplus reticularis White, in Pinus radiata D. Don. Larvae of four representative size classes were irradiated at six doses, and the lethal dose (LD99) calculated from mortality data 3 days and 10 days post treatment. All larval size classes showed a similar sensitivity to gamma irradiation and required 3677 Gray (Gy) and 2476 Gy for a LD99 3 and 10 days post-treatment, respectively. The penetration of gamma irradiation into pine wood was found to be lowest in freshly cut logs, and decreased linearly at a rate of 0.698 Gy mm,1 of wood. The penetration was greatest in wood that had been stored for 2 years, and decreased 0.512 Gy mm,1 of wood. These results are likely to be correlated with wood moisture content. Gamma irradiation appears to be a potential alternative method to fumigation for quarantine treatment of P. reticularis. [source]

Purification and cDNA Cloning of Lysozyme II from Cabbage Butterfly, Artogeia rapae Larvae

ENTOMOLOGICAL RESEARCH, Issue 4 2005
BANG In Seok
ABSTRACT Last instar larvae of cabbage butterfly Artogeia rapae respond to injection of bacteria with a set of inducible antibacterial peptides/proteins. The inducible peptides/proteins are related to the known hinnavins (I and II) and lysozymes (I and II). The lysozyme II has been isolated by heat treatment, cation exchange, and reversed-phase chromatography from immunized hemolymph of last instar larvae. The lysozyme II gene of A. rapae was isolated and its nucleotide sequence was determined by the RACE-PCR from immunized fat body with E. coli. It has an open reading frame of 414 bp nucleotide corresponding to 138 amino acids including an 18 amino acid signal sequence. The molecular weight and the isoelectric point of Artogeia lysozyme II without a signal peptide were 13,649.38 Da and 9.11, respectively. It is great similarity with Manduca lysozyme among other lepidopteran. [source]

A Taxonomic Study on the Larvae of the Genus Pyrrhalta Joannis (Coleoptera: Chrysomelidae: Galerucinae) from Korea

ENTOMOLOGICAL RESEARCH, Issue 4 2004
Jin Young PARK
ABSTRACT Last instar larvae of Pyrrhalta annulicornis, P. fuscipennis, P. humeralis, P. lineola and P. maculicollis are described and illustrated for the first time in Korea. Their taxonomic remarks, tubercle patterns and a key are also given. [source]

Life history and host specificity of the Japanese flea beetles Trachyaphthona sordida and T. nigrita (Coleoptera: Chrysomelidae), potential biological control agents against skunk vine, Paederia foetida (Rubiaceae), in the southeastern parts of the United States and Hawaii

ENTOMOLOGICAL SCIENCE, Issue 2 2008
Chie OKAMOTO
Abstract Skunk vine, Paederia foetida (Rubiaceae), is native to Asia and has been recognized as an invasive weedy vine of natural areas in Florida and Hawaii. Two insects, Trachyaphthona sordida and Trachyaphthona nigrita (Coleoptera: Chrysomelidae) from Japan are being considered as potential biological control agents against skunk vine. To gather fundamental information on their biology, we carried out field surveys and laboratory experiments in Kyushu, southern Japan, between 2003 and 2006. We found that T. sordida is commonly distributed in Kyushu and T. nigrita is restricted to the southern parts of Kagoshima Prefecture on the southern part of Kyushu. These species are fundamentally univoltine and adults appear in late April to early July. Trachyaphthona sordida overwinters as mature larvae and T. nigrita as mature larvae or rarely as adults. Larvae of both species feed on fine roots of P. foetida in the field and Serissa foetida (Rubiaceae) under rearing conditions, and they appear to have tribe-level host specificity in their host range. On the basis of these results, we suggest that both species are suitable as biological control agents. [source]

Survivorship and growth in the larvae of Luehdorfia japonica feeding on old leaves of Asarum megacalyx

ENTOMOLOGICAL SCIENCE, Issue 4 2007
Aya HATADA
Abstract Although the papilionid butterfly Luehdorfia japonica, usually lays eggs on new leaves of the host plant (Asarum sp.; Aristolochiaceae), eggs of the butterfly were frequently found on old leaves of Asarum megacalyx in Suyama, Tokamachi, Niigata prefecture. Larvae hatched on new leaves and those hatched on old leaves did not show significant differences in their survival rate in the field. In laboratory breeding, about 90% of larvae that were fed old leaves survived and developed normally to the pupal stage. Their growth rate, however, was slightly lower than those that were fed new leaves. No nutritional differences were found between the old and new leaves. The reason why oviposition on the old leaves was so frequent and why larvae that hatched on old leaves could survive in the study area is discussed. [source]

Microhabitat and rhythmic behavior of tiger beetle Callytron yuasai okinawense larvae in a mangrove forest in Japan

ENTOMOLOGICAL SCIENCE, Issue 3 2007
Aya SATOH
Abstract Mangrove forests are regularly flooded by tides at intervals of approximately 12.4 h (tidal rhythm). Larvae of the tiger beetle Callytron yuasai okinawense in a mangrove forest made shallow burrows in mounds up to 1 m in height constructed by the mud lobster Thalassina anomala. No larval burrows were observed on the forest floor, which was very muddy even during low tide. Some larvae plugged the burrow openings before they were submerged at high tide. The mean interval between consecutive burrow plugging events was 12.37 h, which is similar to the period of tidal cycles. Nine out of 30 larvae plugged the burrow openings even when the burrows did not become submerged. Plugging behavior may be governed by an endogenous biological clock, or may be a response to exogenous information about tidal level (e.g. moisture seeping through the ground). [source]

Moths boring into Ficus syconia on Iriomote Island, south-western Japan

ENTOMOLOGICAL SCIENCE, Issue 2 2004
Shinji SUGIURA
Abstract Herbivory in the syconia of six Ficus (Moraceae) species (F. superba, F. varieagata, F. virgata, F. irisana, F. bengutensis and F. septica) was examined in March 2002 on Iriomote Island, south-western Japan. Larvae of two lepidopteran species, Pachybotys spissalis (Guenée) (Pyralidae: Pyraustinae) and Stathmopoda sp. (Stathmopodidae) were observed to bore into the Ficus syconia. The attack rate by the moths varied from 0 to 38.5% across Ficus trees. The interiors of the syconia were heavily grazed by the moth larvae. Because figs (syconia) can be regarded as galls and seeds, according to sex and developmental stage, the moth larvae could be considered as gall or seed herbivores, and predators of fig wasps. Moth attack in the Ficus syconia could cause the destruction of fig wasp populations, as fig wasps develop in the syconia. [source]

Dual enantioselective effect of the insecticide bifenthrin on locomotor behavior and development in embryonic,larval zebrafish

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2010
Meiqing Jin
Abstract Bifenthrin (BF) is a synthetic pyrethroid that targets the nervous system of insects and may have adverse effects on the behavior and development of nontarget organisms. However, no reports have been issued on the effects of different enantiomers on locomotor behavior for synthetic pyrethroids (SPs) in zebrafish, and whether locomotor activity is associated with the developmental toxicities remains unclear. In this study, enantioselectivity of BF (1S and 1R) on the acute locomotor activity and developmental toxicities of embryonic,larval zebrafish were first evaluated. The results indicated that 1R -BF was more toxic, causing morphological impairments, with a 96-h median effective concentration (EC50) of 226,µg/L for pericardial edema and 145,µg/L for curved body axis. Administration of 20,µg/L of one enantiomer of BF had differential effects on the locomotor activity of zebrafish larvae at 4 d postfertilization (dpf) under alternating light and dark conditions. Larvae treated with 1R -BF were not sensitive to the alteration of light to dark, and the locomotor activities were reduced to a level similar to that observed in light, which otherwise increased rapidly and markedly. However, 1S -BF did not alter the general pattern of zebrafish response to the light or dark compared with the control. The results demonstrated that the differential effects on development might have contributed to the enantioselectivity in the locomotor activity. The consistency of enantioselectivity with insecticidal activity may also indicate a common mode of action. Furthermore, 1R -BF accelerated the spontaneous movement and hatching process, whereas 1S -BF seemed to be inhibitory. The results suggest the need to link behavioral changes to developmental toxicities in order to achieve more comprehensive health risk assessments of chiral pesticides. Environ. Toxicol. Chem. 2010;29:1561,1567. © 2010 SETAC [source]

Development of Issoria lathonia (Lepidoptera: Nymphalidae) on zinc-accumulating and nonaccumulating Viola species (Violaceae)

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2007
Nausicaa Noret
Abstract The larvae of Issoria lathonia L. feed in natural conditions on several Viola spp., among which are the zinc-accumulating Viola calaminaria (Gingins) Lej. and the nonmetal-accumulating Viola tricolor L. To examine how I. lathonia caterpillars cope with the naturally high foliar zinc concentration of V. calaminaria, we compared the growth of caterpillars reared on leaves varying in zinc concentration. Larvae were fed in controlled conditions with V. calaminaria and V. tricolor grown on noncontaminated soil (i.e., two low-Zn diets) and with V. calaminaria grown on zinc-enriched soil (i.e., one high-Zn diet). Larvae had a higher growth rate when fed with noncontaminated V. calaminaria compared to zinc-enriched V. calaminaria, suggesting that zinc slows down larval growth. However, larvae consumed more leaves of zinc-enriched V. calaminaria (+45%; estimated from fecal mass) compared with noncontaminated V. calaminaria, suggesting that zinc accumulation would not be advantageous to plants. Caterpillars reared on high-zinc leaves regulate their internal zinc concentration through excretion of highly metal-concentrated feces. When kinetics of growth on both low-zinc diets were compared, it appeared that larval development was faster on noncontaminated V. calaminaria than on V. tricolor. This suggests that more nutrients or less feeding inhibitors in V. calaminaria account for fastest growth. Developmental rates on V. tricolor and on zinc-enriched V. calaminaria were similar, despite the high leaf zinc concentration of the latter species. Together with the abundance of V. calaminaria on calamine soils, this may explain why the largest populations of I. lathonia develop on V. calaminaria in Belgium. [source]

Effects of atrazine and iridovirus infection on survival and life-history traits of the long-toed salamander (Ambystoma macrodactylum)

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2006
Diane Forson
Abstract Environmental contaminants and emerging infectious diseases are implicated as factors contributing to global amphibian declines. However, few studies have tested the interaction of these factors. We exposed six-week-old, larval long-toed salamanders (Ambystoma macrodactylum) to Ambystoma tigrinum virus (ATV; 0 or 103.5 plaque-forming units/ml) and sublethal concentrations of atrazine (0, 1.84, 18.4, and 184 ,g/L) in a 4 × 2 factorial design for 30 d. We tested the effects of atrazine and virus on mass and snout-vent length (SVL) at metamorphosis and larval period as well as on rates of mortality and viral infectivity. We confirmed ATV transmission to A. macrodactylum via polymerase chain reaction, but infection rates were lower than expected, consistent with the theory predicting lower pathogen transmission to nonnative hosts. Larvae exposed to both atrazine and ATV had lower levels of mortality and ATV infectivity compared to larvae exposed to virus alone, suggesting atrazine may compromise virus efficacy. The highest atrazine level (184 ,g/L) accelerated metamorphosis and reduced mass and SVL at metamorphosis significantly relative to controls. Exposure to ATV also significantly reduced SVL at metamorphosis. The present study suggests moderate concentrations of atrazine may ameliorate effects of ATV on long-toed salamanders, whereas higher concentrations initiate metamorphosis at a smaller size, with potential negative consequences to fitness. [source]

Susceptibility of the leaf-eating beetle, Galerucella calmariensis, a biological control agent for purple loosestrife (Lythrum salcaria), to three mosquito control larvicides

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2004
T. Peter Lowe
Abstract We evaluated the susceptibility of Galerucella calmariensis, a species used to control purple loosestrife (Lythrum salicaria), to three mosquito control larvicides. Larvae and adults were fed loosestrife cuttings dipped in Abate® (,375 g · L,1), Altosid® (,250 g · L,1), and Bacillus thuringiensis var israeliensis (Bti) (<110 g · L,1). Eggs on cuttings were dipped in the same concentrations. Pupae were immersed in Abate and Altosid solutions (,474.4 ,g · L,1 and ,1,169.2 ,g · L,1, respectively). Hatching success of eggs dipped in Abate (,3.75 g · L,1) was reduced significantly and survival was significantly lower among larvae and adults eating cuttings dipped in Abate (,0.17 g · L,1 and ,2.27 g · L,1, respectively). Hatching success of eggs dipped in Altosid (,2.52 g · L,1) was reduced significantly. With exposure to Altosid, larval survival to pupation and adult emergence was reduced significantly at concentrations of ,2.92 g · L,1 and ,0.63 g · L,1, respectively. Altosid (,0.23 g · L,1) also delayed the onset of pupation and adult emergence among larvae that survived to pupate. Larvae that survived with exposure to Altosid (,1.72 g · L,1) grew to 70% larger than those exposed to lower concentrations. Pupal survival was unaffected with exposure to Abate and Altosid and adult survival was unaffected with exposure to Altosid. Bacillus thuringiensis var israeliensis did not adversely affect any life stage of G. calmariensis. The mean Abate concentration on cuttings exposed to operational spraying was in the range that reduced egg hatchability and adult survival but was higher than concentrations that caused complete mortality of larvae. The mean Altosid concentration on cuttings exposed to operational spraying was in the range that reduced hatching success in eggs and delayed pupation and adult emergence of larvae. [source]

Comparative effects of pH and Vision® herbicide on two life stages of four anuran amphibian species,

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2004
Andrea N. Edginton
Abstract Vision®, a glyphosate-based herbicide containing a 15% (weight:weight) polyethoxylated tallow amine surfactant blend, and the concurrent factor of pH were tested to determine their interactive effects on early life-stage anurans. Ninety-six-hour laboratory static renewal studies, using the embryonic and larval life stages (Gosner 25) of Rana clamitans, R. pipiens, Bufo americanus, and Xenopus laevis, were performed under a central composite rotatable design. Mortality and the prevalence of malformations were modeled using generalized linear models with a profile deviance approach for obtaining confidence intervals. There was a significant (p < 0.05) interaction of pH with Vision concentration in all eight models, such that the toxicity of Vision was amplified by elevated pH. The surfactant is the major toxic component of Vision and is hypothesized, in this study, to be the source of the pH interaction. Larvae of B. americanus and R. clamitans were 1.5 to 3.8 times more sensitive than their corresponding embryos, whereas X. laevis and R. pipiens larvae were 6.8 to 8.9 times more sensitive. At pH values above 7.5, the Vision concentrations expected to kill 50% of the test larvae in 96-h (96-h lethal concentration [LC50]) were predicted to be below the expected environmental concentration (EEC) as calculated by Canadian regulatory authorities. The EEC value represents a worst-case scenario for aerial Vision application and is calculated assuming an application of the maximum label rate (2.1 kg acid equivalents [a.e.]/ha) into a pond 15 cm in depth. The EEC of 1.4 mg a.e./L (4.5 mg/L Vision) was not exceeded by 96-h LC50 values for the embryo test. The larvae of the four species were comparable in sensitivity. Field studies should be completed using the more sensitive larval life stage to test for Vision toxicity at actual environmental concentrations. [source]