bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of protein hydrolysate baits on oviposition in the apple maggot, Rhagoletis pomonella
Authors: Mohammad A. B. , AliNiazee M. T.
Published: April 2011

Ovipositional responses of apple maggot (AM), Rhagoletis pomonella (Walsh), females were studied in the laboratory on apples (var: Golden Delicious) treated with different rates of four protein hydrolysate baits in choice and no‐choice tests. Protein hydrolysate baits at rates of 0.5 and 1% had no significant effect, but oviposition was greatly reduced at higher rates of 5 and 10%. Apple maggot females exposed to apples treated with protein hydrolysate baits at a rate of 10% made 41–71% fewer punctures and laid 41–73% fewer eggs than in untreated control. No oviposition activity was shown on apples treated with 25 and 100% Nulure®. In no‐choice tests the AM females laid 75–96% fewer eggs in apples treated with 10 and 25% Nulure compared to controls and no oviposition occurred in apples treated with 100%, Nulure. Apple maggot females arrived in similar numbers on apples treated with 10% Nulure and untreated apples, but only 5% of those arriving on Nulure‐treated apples showed ovipositor boring with no egg deposition while 60% of females arriving on untreated apples showed ovipositor boring activity and laid an average of 2.5 eggs per apple. In another experiment, individual AM females displayed similar behavioral responses to 10% Nulure‐treated apples; none of the 56 females tested on treated apples displayed ovipositor boring activity, but 59% of the females (N = 56) tested on untreated apples displayed ovipositor boring within 5 min of their arrival. Ninetyeight percent of AM females stayed and fed on fruit surfaces for 5 min on Nulure‐treated apples without ovipositor boring compared to only 2% on untreated apples. Of the females that arrived on untreated apples, 39% flew away within 5 min without ovipositor boring compared to only 2% of those that arrived on Nulure‐treated apples. Results of these two behavioral experiments suggest that upon arrival on a protein bait‐treated apple, an apparent change of behavior occurs in AM females and instead of attempting to oviposit, they attempt to feed on fruit surfaces resulting in reduced oviposition activity. These results indicate that the feeding and oviposition‐related activities of AM females are probably mutually exclusive and that the feeding behavior preempts oviposition activities on host fruits treated with higher rates of protein hydrolysate baits.
Prey selection by in vitro‐ and field‐reared Geocoris punctipes
Authors: Hagler J. R. , Cohen A. C.
Published: April 2011

The patterns of prey selection of Geocoris punctipes (Say) (Hemiptera: Lygaeidae), reared continously on artificial diet for six years, were almost identical with patterns shown by their field‐derived counterparts.

In paired choice experiments both the in vitro‐reared and the wild G. punctipes showed a significant preference for Lygus hesperus over Aphis nerii, Heliothis zea, H. virescens, and Spodoptera exigua. There were no significant differences in choices made by the in vitro‐reared and the wild G. punctipes. These similar feeding patterns suggest that in vitro rearing, even over extended periods, does not cause degradation in the prey selection characteristics of G. punctipes.
Sex pheromone components of female Cornutiplusia circumflexa
Authors: Mazor M. , Harel M. , Levsky S. , Dunkelblum E.
Published: April 2011

Capillary gas chromatography indicated the presence of (Z)‐7‐dodecenyl alcohol and (Z)‐7‐dodecenyl acetate in the abdominal tip extracts of female Cornutiplusia circumflexa (L.) (Lepidoptera: Noctuidae: Plusiinae) moths. Gas chromatography combined with mass spectrometry and dimethyl disulfide derivatization confirmed the structure of these two principal pheromone components. In a flight‐tunnel bioassay, a 5:1 blend of alcohol and acetate elicited the complete courtship sequence by males. The response was comparable to that evoked by a live virgin female, but males spent significantly longer time at calling females than at the synthetic source. The 5:1 blend was also attractive to male C. circumflexa in the field, as indicated by catches in traps baited with this mixture. (Z)‐7‐dodecenyl alcohol alone was slightly attractive whereas (Z)‐7‐dodecenyl acetate alone was completely inactive. C. circumflexa is the first reported Plusiinae species which utilizes (Z)‐7‐dodecenyl alcohol as the major pheromone component.
Binomial sequential sampling of adult Saccharicoccus sacchari on sugarcane
Authors: Allsopp P. G.
Published: April 2011

The between‐stalk dispersion characteristics of adults of the pink sugarcane mealybug Saccharicoccus sacchari (Cockerell) were determined in southern Queensland. Iwao's patchiness regression was inappropriate to describe the relationship between mean and variance. Taylor's power law indicated that adults were aggregated, especially at the beginning and end of the ratoon growth period. Binomial data were modelled by the Nachman model; the model of Grout and two models of Wilson & Room were inappropriate to describe the relationship between proportion of stalks infested and mean numbers of adults per stalk. Relationships to determine sample sizes for fixed levels of precision and binomial fixed‐precision‐level stop lines are developed for different sampling times using Taylor's power law and Nachman's equation.
Nocturnal behaviour of female Mythimna convecta
Authors: . Del Socorro A. P. , Gregg P. C.
Published: April 2011

Nocturnal behaviour of Mythimna convecta (Walker) (Lepidoptera: Noctuidae) virgin females was studied in the laboratory under 20 °C and 16:8 LD conditions. The periodicity of activity, feeding, calling, pre‐oviposition extrusion and oviposition varied with female age and hour of the scotophase. Females called for the first time between the 2nd and 11th scotophases with the peak in the 4th scotophase. Maximum calling occurred on the 7th hour of the scotophase. Young moths called more frequently with shorter bouts while old moths called less often but with longer bouts. In the presence of older females, moths spent significantly more time in pre‐oviposition extrusion and resting and less in activity and feeding than they did when only females of the same age or younger were present. There were no significant differences for calling suggesting that pheromones of older calling females did not affect calling of younger females.
Effects on German cockroach nymphs of contact exposure to IGRs, singly and in combination
Authors: Ross M. H. , Cochran D. G.
Published: April 2011

Late instar German cockroach male and female nymphs were exposed continuously for two weeks to surfaces treated with fenoxycarb, diflubenzuron, and pyriproxyfen, singly and in combination. Concentrations were determined that eliminated or nearly eliminated reproduction in matings with untreated mates, either through mortality, effects on reproduction, or a combination of mortality and ‘sterility’ (no hatch). The major effect of fenoxycarb, pyriproxyfen, and pyriproxyfen plus fenoxycarb was on reproduction. The major effect of diflubenzuron was mortality. No hatch occurred in matings of females that were exposed to low concentrations of pyriproxyfen and fenoxycarb (2 ng/cm2 and 6 ng/cm2, respectively); sterility was incomplete when females were exposed to 600 ng/cm2 of diflubenzuron. Mortality and sterility acted together to eliminate productive matings (matings that produced nymphs) when relatively high concentrations of diflubenzuron were combined with one or both of the other insect growth regulators (IGRs). In the triple combination, very small amounts of fenoxycarb and pyriproxyfen (total 1.1 ng/cm2) combined with 200 ng/cm2 of diflubenzuron eliminated productive matings of treated females, but similar results with treated males were found only at higher concentrations of each IGR.
Oviposition behavior of Edovum puttleri, reared on two hosts, Leptinotarsa decemlineata and L. texana
Authors: Corrigan J. E. , Lashomb J. H. , May M. L. , Schal C.
Published: April 2011

Female Edovum puttleri Grissell [Hymenoptera: Eulophidae], reared from eggs of Leptinotarsa decemlineata (Say) or Leptinotarsa texana Schaeffer [Coleoptera: Chrysomelidae], were videotaped as they attacked egg masses of L. decemlineata containing 20 host eggs. We identified 15 components of ovipositional behavior. Parasitoids reared on L. texana attacked and oviposited in significantly more host eggs than did females reared on L. decemlineata. Ethometric analyses of behavioral transitions and a clustering analysis of 34 behavioral parameters showed that females reared on L. texana attacked the host egg mass in a different manner than those reared from L. decemlineata. It was concluded that differences were associated with the host species upon which they were reared. Contrary to previous reports, mortality of unparasitized hosts was caused by an ovipositor probe of short duration, which was not related to host‐feeding.
Oviposition by the African migratory locust,Locusta migratoria migratorioides, in a crop environment in South Africa
Authors: Price R. E.
Published: April 2011

Oviposition by the African migratory locust,Locusta migratoria migratorioides(Orthoptera: Acrididae), was studied in maize and wheat crops on the Orange Free State Highveld. Maize was shown to be the most important oviposition habitat with peak laying taking place in autumn and early winter when highest pod densities were recorded. Laying was mainly concentrated along the middle of the crop interrows in maize and within clearings in the wheat crop. Despite the uniform layout of these crops, the distribution of egg pods was found to be aggregated. Non‐reproductive behaviour, such as locust aggregation, basking and feeding, as well as environmental factors appeared to influence the distribution of egg pods in these crops. Secondary selection for optimum soil moisture and compaction on the laying site enhanced the aggregation of pods.
The influence of nutritional and genetic factors on larval performance of the cinnabar moth, Tyria jacobaeae
Authors: Soldaat L. L. , Vrieling K.
Published: April 2011

In a laboratory experiment using full‐sibs, 60% of the variation in pupal weight of the monophage Tyria jacobaeae L. (Lepidoptera, Arctiidae) could be explained by variation in the nitrogen concentration of the food plant, Senecio jacobaea L. and only 4% by variation in sugar concentration. Larval weight and growth rates of young and old larvae were also positively correlated with nitrogen and sugar concentration. Developmental time was negatively correlated with nitrogen concentration. In a second experiment full‐sib families differed significantly in larval weight at day 7, mortality, growth rate and developmental time. Pupal weight did not differ significantly among families, but was positively correlated with nitrogen concentration of Senecio. Larval performance was not significantly influenced by concentrations of sugars or alkaloids. We conclude that larval performance of Tyria during most of the larval period is mainly determined by genetic factors, but pupal weights are primarily determined by nitrogen concentration of the food plant.
Discrimination of sunflower volatiles by the red sunflower seed weevil
Authors: Roseland C. R. , Bates M. B. , Carlson R. B. , Oseto C. Y.
Published: April 2011

Five principle monoterpenoid and other constituent volatile chemicals of sunflower heads were combined to resemble two lines of sunflower (Helianthus annuus L.): one U.S.D.A. standard line and one French line which was ‘poorly visited by insects’ (Etievant et al., 1984). Field trials of attraction to red sunflower seed weevils (Smicronyx fulvus Le Conte, Coleoptera: Curculionidae) showed that one was clearly preferred over the other. The more attractive mixture contained α‐pinene, β‐pinene, limonene, camphene and bornyl acetate in a ratio resembling that of Flath et al. (1985) rather than that described by Etievant et al. (1984). One or two volatiles were deleted from the optimal blend but only mixtures of five volatiles showed the highest attraction. Substitution of sabinene, another volatile prominent in sunflower, for one of the five in the optimal blend also decreased attraction of seed weevils. When the monoterpenoid components and ‘green leaf volatiles’ in the traps resembled the ratios of most of the prominent volatiles of sunflower, attraction was significantly greater than controls.
Survival and behavior of Plutella xylostella larvae on cabbages with leaf waxes altered by treatment with S‐ethyl dipropylthiocarbamate
Authors: Eigenbrode S. D. , Shelton A. M.
Published: April 2011

Cabbages (Brassica oleracea L.) treated with S‐ethyl dipropylthiocarbamate (EPTC) herbicide had reduced amounts of leaf surface waxes (40.6% of controls) and reduced densities of leaf surface wax crystallites (20.8% of controls). Leaf waxes of EPTC‐treated plants chemically and morphologically resembled leaf waxes of genetically glossy cabbages resistant to the diamondback moth Plutella xylostella (L.) (Lepidoptera: Plutellidae). Survival of larvae was significantly reduced on EPTC‐treated cabbage plants in three out of four experiments (62.0–15.3% of survival on controls). P. xylostella neonates also moved more rapidly on EPTC‐treated plants than on untreated controls (1.84 ± 0.16 cm/min on controls vs. 3.94 ± 0.24 cm/min on treated plants; P = 0.0001). These results support the hypotheses that reduction in leaf waxes is the basis of resistance to P. xylostella in genetically glossy plants and that reduced acceptance by larvae is associated with this resistance. Modification of leaf surface waxes with EPTC or similar compounds may have potential as an economic control for P. xylostella in Brassica crops.
Time‐related rejection of parasitised hosts in the aphid parasitoid, Aphidius ervi
Authors: Micha S. G. , Wellings P. W. , Morton R.
Published: April 2011

Time‐related changes in the patterns of host discrimination may have a complex form depending on whether or not hosts are marked following first parasitisation, the persistence of chemicals in these marks, and changes in the host as a result of being parasitised. Here we present an experimental design capable of detecting temporal patterns in host discrimination of solitary parasitoids. This method is tested against experimental data from Aphidius ervi attacking the aphid, Acyrthosiphon kondoi. The results demonstrate that there are statistically significant changes in the patterns of egg distribution in aphid hosts held for intervals between 1 and 48 h between parasitisation. These changes appear to be attributable to increasing oviposition restraint by the superparasitising female as the time interval between attacks is increased. The form of this relationship is not significantly different to a sigmoid function and the rate of change of restraint was greatest between 6–8 h after the first oviposition.
In vitro bioassay for the effect of Ajuga reptans phytoecdysteroids on Trialeurodes vaporariorum larval development
Authors: Melé E. , Messeguer J. , Gabarra R. , Tomás J. , Coll J. , Camps F.
Published: April 2011

A rapid and reliable in vitro bioassay method to test the effects of synthetic and natural compounds on the development of greenhouse whitefly Trialeurodes vaporariorum Westwood (Homoptera Aleyrodidae) is described.

Leaf fragments of Nicotiana glauca Graham infested with eggs of whitefly were cultured under aseptic conditions on half‐strength Murashige‐Skoog medium. The development of the insect in vitro and in vivo were comparable except for a higher mortality rate in the first larval instar.

Ecdysteroids from Ajuga reptans L. were applied to leaf fragments by immersion in aqueous solution of the compounds or by addition to the culture medium. A high mortality rate of first larval instars was detected with 29‐norsengosterone and ajugalactone treatments. This effect was specially pronounced when the products were incorporated in the medium. A significant increase in mortality was also recorded in the pupal state with a 20‐hydroxyecdysone treatment. This effect was never observed before, because all whitefly larvae on A. reptans leaves die in the first larval instar.
Metabolism and elimination of ingested allelochemicals in a holometabolous and a hemimetabolous insect
Authors: Smirle M. J. , Isman M. B.
Published: April 2011

Experiments were conducted to test the hypothesis that hemimetabolous insects such as Orthoptera utilize physical barriers in the gut to provide protection from ingested toxins, whereas holometabolous Lepidoptera metabolize such toxins more efficiently. Migratory grasshoppers, Melanoplus sanguinipes Fab. (Acrididae), eliminated the thiophene α‐terthienyl in their feces more quickly and metabolized it to a lesser degree than did variegated cutworms, Peridroma saucia Hübner (Noctuidae). Xanthotoxin, a phototoxic linear furanocoumarin, and digitoxin, a cardiac glycoside, underwent similar metabolic modification in both species. Rates of fecal elimination of xanthotoxin were similar, whereas digitoxin was voided more rapidly by P. saucia. Overall, our results fail to provide convincing evidence in support of the test hypothesis because the two species investigated do not differ markedly in the manner in which they metabolize and eliminate the allelochemicals utilized in these studies.
The protective role of dietary unsaturated fatty acids against 2‐undecanone‐induced pupal mortality and deformity in Helicoverpa zea
Authors: Farrar R. R. , Kennedy G. G. , Roe R. M.
Published: April 2011

As previously reported, the addition of 2‐undecanone to the diet of Helicoverpa (Heliothis) zea (Boddie) causes pupal mortality and deformity. These toxic effects are antagonised by the addition of the unsaturated fatty acid linolenic acid to diet, with pupal deformity eliminated and mortality reduced by as much as one‐half. Similar results were obtained with two other unsaturated fatty acids, linoleic and oleic acids, but not with saturated stearic acid. These unsaturated fatty acids also increased pupal weight and developmental time. However, measurement of food consumption indicated that the effect of unsaturated fatty acids on pupal mortality is not an artifact of dilution of the fatty acid dietary dosage by an increased body size or of evaporation of 2‐undecanone during prolonged larval development.
Interactions among three trophic levels: the influence of host plant on performance of Pieris brassicae and its parasitoid, Cotesia glomerata
Authors: Karowe D. N. , Schoonhoven L. M.
Published: April 2011

The relative suitability of four host plants was determined both for unparasitized Pieris brassicae L. caterpillars and for Cotesia glomerata (L.) developing in P. brassicae. For unparasitized P. brassicae, growth rate and pupal weight were highest on Brussels sprouts and Swedish turnip, intermediate on rape, and lowest on nasturtium. In contrast, C. glomerata larval developmental rate and adult longevity were greatest for wasps from P. brassicae reared on nasturtium.

On all four plants, the host‐parasitoid complex attained a lower final weight than unparasitized P. brassicae, and it is argued that this difference is due primarily to reduced consumption by parasitized P. brassicae. Among parasitized caterpillars, however, complex weight was positively correlated with clutch size, suggesting that C. glomerata larvae are able to partially counteract the effect of parasitization per se on host consumption.

The host plants of P. brassicae appear to face an evolutionary dilemma: in order to increase the total mass of parasitoids produced, they must suffer greater loss of foliage. This trade‐off, if common in nature, may represent a formidable constraint on coevolution between host plants and parasitoids.
Une phéromone d'agrégation chez Forficula auricularia
Authors: Sauphanor B.
Published: April 2011

Un comportement d'agrégation est fréquemment observé chez les larves et les adultes de Forficula auricularia L. L'hypothèse d'un controle phéromonal de ce comportement est confirmée expérimentalement par un test biologique qui, en condition de choix, met en évidence le regroupement des forficules dans des abris déjà visités par d'autres individus de l'espèce, préférentiellement aux abris témoins. Une interattractivité existe entre tous les stades de développement et la phéromone intervient

galement pendant la phase de soins maternels: les traces de larves du premier stade encore confinées dans le terrier maternel, ainsi que de femelles en période de soins, provoquent l'agrégation de larves âgées. La comparaison de l'attractivité de différents extraits par l'hexane (traces, fractions de corps, feces) indique la localisation de la sécrétion phéromonale au niveau des pattes, et désigne les glandes tibiales comme organes sécréteurs.

An aggregation pheromone in the European earwig, Forficula auricularia

Adults and nymphs of Forficula auricularia often present an aggregation behaviour. The hypothesis of a pheromonal control of this behaviour was demonstrated with a biological test, in which the earwigs aggregated in shelters already visited by insects of the same species. An interattractivity was observed between all developmental instars, and the pheromone also controls the parental behaviour: trails of first instar nymphs, still confined in maternal cell, or of females in nesting period, are also attractive for old nymphs. The anatomical source of the pheromone was determined with differential extracts in hexane: trails on filter papers, faeces, parts of the body. The secretions are localized in the legs, and originate from the tibial system already described in two species of Dermaptera.
Genetic structure of leaf‐beetles populations: microgeographic and sexual differentiation in Oreina cacaliae and O. speciosissima
Authors: Rowell‐Rahier M.
Published: April 2011

We used F‐statistics to quantify the population structure of two sympatric species of leaf beetles, Oreina cacaliae and O. speciosissima (Chrysomelinae, Coleoptera), which share the same microhabitat since they feed on the same herbaceous host plants. We measured genetic differentiation at six allozyme loci 1) among populations separated by relatively small distances (40 to 250 kilometers), 2) within each population, and 3) between sexes within populations. For both species, the populations studied are not panmictic. For each population, heterozygosities are relatively high, but the observed heterozygosities are generally lower than the expected values. Overall, within‐population differentiation is high and similar for both species (Fis = 0.326 for O. cacaliae and 0.332 for O. speciosissima). Additionally, populations of both species are highly differentiated (Fst = 0.234 versus 0.051 for O. speciosissima). For O. cacaliae, Fis and Fst are greater among females than among males, while for O. speciosissima, Fst is sustantially greater among the males while Fis is slightly greater among males. Differences in gene frequency among the sexes were statistically tested using a modified Fst with sex as the defining category, and the sexes differed significantly with the exception of one population in O. cacaliae. Possible explanations for this difference are discussed.
Size specific demography of three species of Anastrepha fruit flies
Authors: Liedo P. , Carey J. R. , Celedonio H. , Guillen J.
Published: April 2011

Individuals of three Anastrepha species: A. obliqua, A. ludens, and A. serpentina (Diptera: Tephritidae), were sorted according to pupal weight in cohorts of large and small flies. Demographic parameters and reproductive patterns and heterogeneity were determined for each cohort. Large flies of the three species presented greater expectation of life and gross fecundity rates.

A. ludens was the species with the longest life span (expectation of life of large adults was 110 days) and the greatest gross fecundity rates (1597 eggs/female for the large flies). While, A. obliqua had the shortest mean age of reproduction (33 days), and the greatest daily egg production (14 eggs/female/day). Net fecundity was similar in these two. A. serpentina had lower fecundity rates.

Reproductive information for each size and each species include: age‐by‐parity relations, fraction of sexually mature life in which females lay eggs, and frequency distribution of individual egg production. Results demonstrate that even under constant laboratory conditions and using standard artificial hosts, there is a great deal of life history variation among these Anastrepha species and among other tephritid fruit flies.
Photoperiodic responses during larval development and diapause of two geographic ecotypes of the rice stem maggot, Chlorops oryzae
Authors: Takeda M. , Nagata T.
Published: April 2011

Chlorops oryzae is bivoltine in northern Japan but trivoltine in the southern part of the country. In the bivoltine strain, both the egg and larval stages were found to be sensitive to photoperiod. When the egg stage was exposed to a long‐day photoperiod (16L:8D), larval development showed a short‐day type response, and mature third‐instar larvae entered a summer diapause under a long‐day photoperiod (15L:9D). When eggs experienced short days, the first‐instar larvae entered a winter diapause under short‐day conditions, and the critical photoperiod in the larval stage ranged from about 14L:10D to about 12L:12D as the photoperiod experienced by the eggs increased from 12L:12D to 14L:10D. However, the development of the larvae after overwintering was not influenced by the photoperiod. In the trivoltine strain, larval development was retarded under a 14L:10D photoperiod but not under either shorter or longer photoperiods, when larvae had spent the egg stage under a 16L:8D photoperiod. The critical photoperiod of the larval stage for the induction of a winter diapause in the first instar was about 12L:12D, though it varied to some extent with the photoperiod during the egg stage. Thus, Chlorops oryzae was able to adapt itself to the local climatic conditions by the development of variable and complicated photoperiodic responses.
Orientation of males of sorghum midge, Contarinia sorghicola to sex pheromones from virgin females in the field
Authors: Sharma H. C. , Vidyasagar P.
Published: April 2011

The orientation of males of the sorghum midge, Contarinia sorghicola Coq. (Diptera: Cecidomyiidae) towards virgin female baited sticky traps was studied in the field. Male response increased linearly with an increase in the number of virgin females in the sticky traps. Five females per vial were optimum for monitoring midge populations in the field. Numbers of males trapped were significantly greater in traps placed at 0.5 and 1.5 m above ground level compared with those placed at 2.5 m. Peak trap catches occurred at 0900 h. The number of males trapped decreased significantly after 1400 h; male catches continued till sunset. Trap catches followed the same pattern as the number of ovipositing females on sorghum panicles at the half‐anthesis stage. Midge activity decreased with an increase in temperature and a decrease in relative humidity. Peak midge density was observed during the second fortnight of October in the rainy season and during February‐March in the post‐rainy season. Sex pheromones can be used to monitor midge population dynamics for integrated pest management and to screen for host plant resistance to this insect.
Intraspecific variation of Drosophila buzzatii larval breeding success on Opuntia: A yeast‐plant‐insect relationship
Authors: Moreteau B. , Carton Y. , Pignal M. C. , David J. R.
Published: April 2011

The cactophilic species, Drosophila buzzatii, normally breeds in decaying pockets of Opuntia cladodes, in which there is a complex interaction with the microbial flora, especially yeast species. Isofemale lines were used to estimate genetic variation among larvae reared on their natural feeding substrate. Four naturally occurring cactophilic yeast species isolated from the same Tunisian oasis as the Drosophila population were used. Two fitness components were studied for each line, viability and developmental time. Genetic variations among D. buzzatii lines were observed for both traits. A significant yeast species × isofemale line interaction for viability was also evidenced, suggesting the occurrence of specialized genotypes for the utilization of breeding substrates. This genetic heterogeneity in the natural population may favor a better adaptation to the patchily distribution of yeasts.
Geographical variation in pheromone response of the European corn borer, Ostrinia nubilalis, in North Carolina
Authors: Sorenson C. E. , Kennedy G. G. , van Duyn W. , Bradley J. R. , Walgenbach J. F.
Published: April 2011

The response of male European corn borer, Ostrinia nubilalis (Hübner) to synthetic pheromone lures containing various isomeric blends of the sex pheromone 11‐tetradecenyl acetate was measured in 13 counties in North Carolina. The blends consisted of either 3% Z (‘E strain’), 97% Z (‘Z strain’), or 35% Z (‘hybrid’) 11‐tetradecenyl acetate. Response to E strain lures predominated in those counties located in the Coastal Plain (east) of the state, while response to the Z strain pheromone was dominant in the west. A zone of overlap of these broad strain distributions appears to occur in the eastern Piedmont. Within this zone there was substantial response to both E and Z blends. The proportion of these responses changed considerably between generations within years as well as between years. Significantly higher capture rates in hybrid baited traps in parts of the overlap zone may be indicative of increased rates of hybridization between the E and Z strains.
Relation entre aphides et fourmis dans la production et la récolte du miellat sur oranger
Authors: Dartigues D.
Published: April 2011

La fréquence des gouttelettes de miellat excrétées par Toxoptera aurantii (Boyer de F.) augmente en la présence de Tapinoma simrothi Krausse., mais le phénomène est seulement important quand les aphides sont familiarisés avec la visite des fourmis. En présence d'ouvrières pourvoyeuses âgées, le nombre de gouttelettes de miellat excrétées par une colonie d'aphides est multiplié par 4, 9. Les meilleures performances sont obtenues avec les larves, qui défèquent plus vite que les adultes. Les jeunes ouvrières âgées de moins de deux semaines et isolées juste avant la naissance, sont capables d'augmenter la production de gouttelettes, et ceci sans apprentissage. Mais l'effet est plutôt faible. Dans tous les cas, le nombre de sollicitations pour la nourriture est plus élevé que le nombre des gouttelettes excrétées. Habituellement, les fourmis collectent le miellat directement sur les aphides. Néanmoins, le miellat restant sur les feuilles peut ětre ramassé, mais cette récolte n'est pas très importante.
Modification de la fertilité du carpocapse Cydia pomonella à la suite du contact des adultes avec un régulateur ou un inhibiteur de croissance d'insectes
Authors: Charmillot P.‐J. , Pasquier D.
Published: April 2011

Des papillons de carpocapse Cydia pomonella L., mâles et femelles séparés, sont soumis au contact des résidus secs du CGA 184′699, un inhibiteur de croissance d'insectes (ICI) et du fenoxycarb, un régulateur de croissance d'insectes (RCI). Ils sont ensuite regroupés dans des boîtes non traitées pour l'accouplement et la ponte. La fécondité du carpocapse n'est pratiquement pas affectée par ce conditionnement mais sa fertilité diminue avec l'augmentation de la concentration des produits et avec la durée d'exposition. Avec le CGA 184′699, l'efficacité ovicide induite atteint environ 50% suite à un contact de trois jours avec les résidus d'un traitement à 100 mg/l, alors qu'avec le fenoxycarb elle s'élève à 87% dans les mêmes conditions. Avec le CGA 184′699, seul le contact des femelles avec les résidus provoque cette réduction de fertilité, alors que le fenoxycarb agit sur les deux sexes.
Spring dispersal of Sitona lineatus: the use of aggregation pheromone traps for monitoring
Authors: Nielsen B.S. , Jensen T.S.
Published: April 2011

The spring dispersal of Sitona lineatus L. (Coleoptera; Curculionidae) was investigated on a Danish farm. S. lineatus dispersed by flight in the early spring on sunny, calm days with temperatures above ca. 15 °C.

Two thirds of the population of S. lineatus dispersed from perennial leguminous crops (clover and lucerne) in the first period of flight activity. The next dispersal did not occur until one month later despite several intermediate flight activity periods. The first period of dispersal occurred before the germination of the spring sown summer host crop, Vicia faba L. The field bean crop was infested in three later invasions during a period of more than three weeks.

The aggregation pheromone, 4‐methyl‐3,5‐heptanedione, had a significant effect on captures of both males and females in cone traps placed on the ground. There was no effect of the pheromone on captures in yellow sticky traps placed 1.5 m above ground. The pheromone effect is discussed in relation to behavioural observations.

Both types of traps may be used in a survey system for monitoring spring dispersal of S. lineatus and optimal timing of insecticide spraying. However, the pheromone cone traps were highly specific whereas all kinds of flying insects were caught in the yellow sticky traps, thus making the latter traps less suitable for monitoring.
An improved leaf‐disk antifeedant bioassay and its application for the screening of Hokkaido plants
Authors: Escoubas P. , Lajide L. , Mitzutani J.
Published: April 2011

In the course of our search for new insect antifeedant substances from plants, we have devised an improved antifeedant leaf‐disk bioassay. Our system allows an accurate measurement of consumed disk surfaces, using a video camera interfaced with a computer. The scanned image of the leaf disks is stored, and the eaten areas are measured with the help of a video‐image analysis software. This new method allows for precise quantification of insect antifeedant activity tested on leaf material.

This method was applied to the screening of Hokkaido plants for antifeedant activity. Out of 206 samples, seven demonstrated significant activity against larvae of the tobacco cutworm, Spodoptera litura.
Interactions between a specialist herbivore, Crocidosema plebejana, and its host plants Malva parviflora and cotton, Gossypium hirsutum: Larval performance
Authors: Hamilton J. G. , Zalucki M. P.
Published: April 2011

Previous studies have shown populations of tipworm, Crocidosema plebejana Zeller (Lepidoptera: Tortricidae), on Malva parviflora L. persist throughout the development of the plant while those on cotton are greatly reduced after plant flowering. We investigated larval performance of tipworm on plants of both species at various stages of development. Tipworm reared on M. parviflora developed faster, survived better and tended to be heavier than those reared on cotton. On M. parviflora all parts of the plant were eaten while on cotton large squares, flowers and small to medium bolls were never eaten. Cotton quality for tipworm development decreased markedly at flowering and remained low thereafter, as shown by low survival of neonate larvae and extended development time of late instar larvae. The poor performance of tipworm on flowering cotton is strongly correlated with major changes in plant chemistry at that stage of plant development.
Patterns of change in secondary and tertiary sex ratios of the Terebrantian thrips, Frankliniella occidentalis
Authors: Terry L. I. , Kelly C. K.
Published: April 2011

Adult sex ratios (tertiary sex ratios) of the haplo‐diploid Terebrantian thrips species, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) were examined from several native and introduced hosts in an apple (Malus spp.) ecosystem. The ratios were variable and most were female‐biased, ranging from 0 to 61% males. Populations in apple bud clusters during early bloom were female‐biased (0–10% males). At later bloom states, populations were less female‐biased in open blossom clusters (up to 33% males) compared with those in either unopened buds or older petalless blossoms (<11% males). Changes in tertiary sex ratio in all hosts were associated with changes in resource quality, suggesting a possible effect of host quality on sex allocation. In contrast, larval (secondary) sex ratios within apples were slightly male‐biased (57%) with little change across apple bud reproductive stages or over time, indicating little to no differential sex allocation. Sex ratios of populations in flight were less female‐biased than those found on plants in 62 of 65 comparisons, which suggests that males are more likely to be in flight relative to females. The evidence supports that differential dispersal and distribution of sexes toward various host qualities together with a shorter longevity of adult males determines the pattern of adult sex ratios rather than any significant differential sex allocation.
Effects of host instar and size on parasitization efficiency and life history parameters of Opius dissitus
Authors: Petitt F.L. , Wietlisbach D.O.
Published: April 2011

The braconid parasitoid Opius dissitus Muesebeck (Hymenoptera, Braconidae) produced 1.7 to 3 times more offspring when provided second and third instar leafminers (Liriomyza sativae Blanchard) as compared to first instars. Females arising from parasitization of different instars did not differ significantly in numbers of chorionated eggs in their ovaries at adult eclosion. Development time was prolonged by about two days when parasitoid oviposition occurred in first, as compared to third instar hosts. Parasitoid length was positively correlated with host weight (r2 = 0.75). Because only 7% of variation in host weight could be explained by host density, parasitoid length varied considerably among hosts reared at the same density. Longevity and lifetime fecundity of parasitoids were inversely related to the weight of their hosts.
A comparison of food‐related behaviour between geographic populations of the Colorado potato beetle (Coleoptera, Chrysomelidae), on six solanaceous plant species
Authors: Szentesi A. , Jermy T.
Published: April 2011

Some components of the food‐related behaviour (biting, feeding, walking on the plant or walking elsewhere, and resting) of two North American and three European Colorado potato beetle (CPB) populations, on six solanaceous plant species were monitored with the help of a microcomputer‐based program, testing the hypothesis whether populations showed differences at the behavioural level to alternative host plants (S. melongena, S. dulcamara, and Lycopersicon esculentum), as well as to non‐host plants occasionally encountered (S. luteum, S. nigrum). The few significant differences found were among populations of the same continent in 1) the number of activities monitored, 2) the duration of feeding periods, 3) the number of bites taken to the onset of feeding, 4) the ‘amount of behavioural plasticity’, and 5) the ‘behavioural diversity’. On the basis of two‐way ANOVA analyses, no plant‐by‐population interactions were detected indicating that the CPB populations studied did not have specific relationships with any of the plant species tested. The lack of substantial differences in food‐related behaviour was unexpected since considerable isolation in space and time exists between the populations occurring on the two continents.
A relationship between dry matter and damage by larvae of the turnip root fly Delia floralis in cultivars of the swedish turnip Brassica napus
Authors: Shaw M. W. , Allan R. M. , Hunter E. A. , Munro I. K.
Published: April 2011

A series of trials from 1981–85 investigating the amount of damage caused by larvae of the turnip root fly Delia floralis (Fallen) to cultivars of Swedish turnip Brassica Napus (L.) of varying percentages of dry matter indicated that those of high dry matter were damaged less than low dry matter cultivars. Pupal numbers of turnip root fly gave good correlations with damage but there was no relationship between damage and cabbage root fly pupae.
Protein toxicity to aphids: an in vitro test on Acyrthosiphon pisum
Authors: Rahbé Y. , Febvay G.
Published: April 2011

Recent progress in plant transformation for insect resistance has increased the interest in the potential toxicity of proteins towards insect pests. While studies have been targeted to a large array of insect species, phloem‐feeding Homoptera have not been investigated yet. The paper describes a routine test for screening toxicity and growth inhibition of purified proteins in artificial diets on Acyrthosiphon pisum (Harris). Twenty‐five commercially available proteins of different classes were tested and compared to some non‐protein chemicals (an insecticide, an antibiotic …). A. pisum proved to be very sensitive to all proteases tested and to some venoms with general cytolytic properties. A plant lectin, concanavalin A, displayed significant toxicity and growth inhibition, while various proteins such as a soybean proteinase inhibitor, a chitinase, and bovine serum albumin showed measurable impairments of growth only at higher dose (≥250 μg.ml−1). Some proteins were without short‐term effect on A. pisum physiology. The influence of these results on aphid‐plant interactions are discussed.

Toxicités des protéines pour les pucerons: un test in vitro sur Acyrthosiphon pisum

L'effet de protéines alimentaires sur les insectes phloémophages, dont les pucerons, n'a jamais été étudié. Nous proposons ici un test biologique standardisé sur milieu artificiel permettant d'analyser les effets de différentes classes de protéines sur la physiologie d'A. pisum. La validité de ce test est éprouvée (protocole, reproductibilité) et les différentes données récoltées (mortalité et inhibition de croissance) permettent de définir des paramètres toxicologiques tels que concentration létale 50 ou concentration inhibitrice 50. Cette caractérisation toxicologique a été réalisée sur 25 protéines appartenant à des classes différentes, ainsi que plusieurs substances non protéiques utilisées comme témoin de toxicité (insecticide, antibiotique, inhibiteur de synthèse protéique et glucoside phénolique). Les regroupements de protéines par proximités de profils toxicologiques ont été corrélés aux activités biochimiques des différentes protéines. Les implications de ces résultats sur les interactions plante‐puceron sont discutées, ainsi que le potentiel d'une stratégie de création de variétés transgéniques résistantes aux pucerons.
Soybean leaf responses to threecornered alfalfa hopper petiole girdling
Authors: Spurgeon D. W. , Mueller A. J.
Published: April 2011

Specific leaf weight, percent moisture, and free sugar, starch, and amino nitrogen content of soybean (Glycine max (L.) Merrill) leaves were measured at 1, 3, 7, and 10 day(s) after petiole girdling by threecornered alfalfa hopper, Spissistilus festinus (Say) (Homoptera: Membracidae) nymphs. Leaf starch was increased at 1, 3, and 7 day(s) after girdling and largely accounted for corresponding increases in specific leaf weight and decreases in percent moisture, free sugars, and amino nitrogen. Specific leaf weight was increased at 10 days after girdling despite no increase in starch. Amino nitrogen content was decreased 10 days after girdling. When leaf dry weights were corrected for starch, free sugar content was not affected by girdling, and amino nitrogen content was reduced only at 3 and 10 days. The amino nitrogen: free sugar ratio was reduced only at 10 days after girdling. Changes in leaf starch indicated a rapid but reversible effect of girdling on leaf carbohydrate metabolism.
Determination of prey antigen half‐life in Polistes metricus using a monoclonal antibody‐based immunodot assay
Authors: Greenstone M. H. , Hunt J. H.
Published: April 2011

In order to derive quantitative estimates of predation rate from serological gut analysis data, one must have an estimate of the interval during which a meal can be detected after feeding. In practice this has turned out to be ‘Dmax,’ defined as ‘…the time from finishing a meal until that meal could just no longer be detected in any individuals.’ However Dmax substitutes an absolute limit for what is really a continuous variable with significant variation. We examined this problem in a study of the detectability of Helicoverpa zea Boddie (Lepidoptera: Noctuidae) fifth instar remains in the guts of Polistes metricus Say (Hymenoptera: Vespidae). Wasps were maintained on Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) fifth instars before being fed a single H. zea fifth instar. They were killed and frozen at 0, 24, 48 and 96 h intervals, with those held for more than 24 h fed a single T. ni fifth instar at 24 h intervals in order to simulate continued feeding. Wasp abdomens were assayed by immunodot, using a monoclonal antibody to H. zea arylphorin. There was a logarithmic decay in the proportion of P. metricus positive over time, a single H. zea fifth instar meal having a detectability half‐life of 19.4 h at field temperatures. If prey antigen detectability decays exponentially, then a detectability half‐life is a more appropriate unit of detectability than an absolute detectability period.
Differential selection of host plants by two Pieris species: the role of oviposition stimulants and deterrents
Authors: Huang Xinpei , Renwick J. A. A.
Published: April 2011

Oviposition responses of Pieris rapae L. and P. napi oleracea Harris to nine crucifers, one Capparidaceae and one Tropaeolaceae were directly compared under controlled conditions. Chemical fractions from these plants were also tested on both insects for the presence of oviposition stimulants or deterrents. The results showed that plant chemistry is a key factor in differential selection of potential hosts by these Pieris species. Some plant species were equally acceptable to both Pieris species. However, P. rapae preferred cabbage over most test plants whereas P. napi oleracea strongly preferred plant species that were avoided by P. rapae. The observed preferences were explained in most cases by the presence of stimulants and deterrents in extracts of the plants. The two Pieris species have apparently evolved differential sensitivities to the chemical stimuli that trigger or deter oviposition. The balance of positively and negatively interpreted sensory signals evoked by plant chemicals obviously plays an important role in acceptance or rejection of a plant by both species. The role of specific glucosinolates and differing structure‐activity relationships is suggested.
Effects of mite age, mite density, and host quality on aerial dispersal behavior in the twospotted spider mite
Authors: Li Jianbo , Margolies David C.
Published: April 2011

Mite age, population density, and host leaf quality affect various life history traits in spider mites. We investigated the effects of these factors on the aerial dispersal behavior of adult female twospotted spider mites, Tetranychus urticae Koch (Acari: Tetranychidae). The proportion of adult females exhibiting the dispersal behavior dropped significantly with age following adult emergence, particularly in the first 3 days. Sixty to eighty percent of female mites 2‐days old or younger displayed the behavior under test conditions, whereas less than 20% of female mites older than 3‐days‐old showed the behavior. Younger adult females also exhibited shorter latency for the behavior, although this trend was not as clear. Leaf quality experienced during deutonymph development had no effect on the behavior adults subsequently displayed. On the other hand, adult females that fed on poor quality leaves after emergence were twice as likely to display the behavior (90% vs. 45%), and with shorter latency (37 vs. 77 min), than those that fed on high quality leaves. When newly emerged adult females encountered high mite density and dry leaves, the incidence of the behavior increased (69% vs. 47%) and latency decreased (69 vs. 93 min) compared to mites that encountered low density on well watered leaves. Our results suggest that both starvation and desiccation of adult females may enhance their dispersal behavior.