bluuebunny/crossref_metadata_2025 huggingface dataset:
Induction of sexual forms in the rose aphid Macrosiphum rosae
Authors: Wöhrmann K. , Hales D. F. , Tomiuk J. , Schmiedt E. M. , Rettenmeier G.
Published: April 2011

The rose aphid, Macrosiphum rosae (L.), was tested for its ability to produce sexual forms on rose leaves, after induction by environmental conditions in the field and in the laboratory. Clones were collected in Tübingen, Federal Republic of Germany, and in south‐eastern New South Wales, Australia. The German clones all produced sexual forms, while the response of the Australian clones was weak. There appeared to be a bias in the sex ratio towards females: This is discussed in developmental terms. The environmental and genetic factors influencing the response are considered.
Role of bilateral chemosensory input in food discrimination by Manduca sexta larvae
Authors: de Boer G.
Published: April 2011

The function of bilateral chemosensory input in food discrimination was examined using larvae of the tobacco hornworm, Manduca sexta (Johan.) (Lepidoptera: Sphingidae), in 2‐choice preference tests. Larvae having three different complements of chemosensory organs remaining after microsurgery were tested: unoperated, unilaterally‐ablated, and bilaterally‐ablated. Discrimination between Solanum pseudocapsicum (L.) and Pelargonium hortorum (Bailey) was reduced after unilateral removal of chemosensory organs. A similar effect was found in tests offering larvae a choice between one plant species or an ethanolic extract of S. pseudocapsicum and wetted filter paper, indicating an impaired food detection. These results demonstrate that both sets of chemosensory organs are required for normal feeding decisions about these plants.

Six additional plant species were each tested against wetted filter paper. The function of bilateral chemosensory input in food discrimination varies with the plant species tested. Bilateral chemosensory input is required for discrimination of Vigna sinensis (Savi) and Raphanus sativus (L.), but not for that of Lycopersicon esculentum (Mill.), Datura innoxia (L.), Brassica napus (L.), and Canna generalis (Bailey). Discrimination of V. sinensis, S. pseudocapsicum, and P. hortorum by unoperated larvae is twice as strong as that by unilaterally‐ablated larvae, suggesting algebraic addition of unilateral sensory inputs. For R. sativus unilateral input does not mediate discrimination, but bilateral input does, indicating sensory processing which may be more than additive. These results show that information mediated by bilateral chemosensory organs of M. sexta is not redundant in mediating feeding decisions, but provide the necessary sensory input for normal discrimination. This suggests that, for some plant species, feeding decisions are based on both qualitative and quantitative aspects of chemosensory input.

No difference in preferences between left‐sided and right‐sided operated larvae were observed which suggests functional duplication of each set of unilateral chemosensory organs. Possible neural mechanisms underlying feeding decisions mediated by bilateral versus unilateral chemosensory inputs are discussed.
Behavioral and physiological responses of susceptible and resistant diamondback moth larvae to Bacillus thuringiensis
Authors: Schwartz J. M. , Tabashnik B. E. , Johnson M. W.
Published: April 2011

To determine whether field‐selected resistance of diamondback moth (Plutella xylostella L.) (Lepidoptera: Plutellidae) to Bacillus thuringiensis is based on behavioral or physiological adaptation, we measured mortality, consumption, and movement of larvae from a susceptible and a resistant colony when placed on untreated and B. thuringiensis treated cabbage. Colonies did not differ in mortality, consumption, or movement on untreated cabbage. However, for a given amount of consumption of treated cabbage, resistant larvae had lower mortality than susceptible larvae, demonstrating that resistance had a physiological basis. The movement patterns could not account for the differences between colonies in survival. Resistant larvae did not avoid B. thuringiensis more than did susceptible larvae. Thus, we found no evidence for behavioral resistance.
Flight behaviour of the cabbage seedpod weevil
Authors: Kjær‐Pedersen C.
Published: April 2011

The influence of host odour, windspeed, position of the sun, and temperature on flight behaviour of the cabbage seedpod weevil (Ceutorhynchus assimilis Paykull) were studied. This weevil showed a positive anemotaxis (upwind flight) inside the odour plume of a host crop (Brassica napus L.). Outside the odour plume the weevil showed a pronounced phototaxis at windspeeds below 1.5 m/s. At higher windspeeds, the seedpod weevils flew downwind. The cabbage seedpod weevil flies most readily at low windspeeds (less than 0.5 m/s) and at temperatures above 22 °C.
Beyond origami: using behavioural observations as a strategy to improve trap design
Authors: Phillips A. D. G. , Wyatt T. D.
Published: April 2011

In contrast to ad hoc methods of developing traps for pest monitoring systems, a systematic approach using direct observation of animals allowed a greater understanding of the reasons why trap catch was significantly different in traps of basically similar design. The information gained using this approach could then be used to guide the further development of the trap. The same feature on two related designs of cockroach trap was varied: the slope of the ramp leading into the trap was either 60°, 30°, or 0°. The 30° ramp version of both traps caught significantly more Blattella germanica (L.) (Dictyoptera: Blattellidae). The 60° and 0° ramp versions both caught equal, lower, numbers but observation showed that these net catches were achieved by quite different means; few insects entered over the 60° ramps but none escaped, whereas all entered over the 0° ramps but half escaped. Similar approaches could be applied to other insect‐trap systems.
Variability in the efficacy of delayed inducible resistance in mountain birch
Authors: Ruohomäki K. , Hanhimäki S. , Haukioja E. , Iso‐Iivari L. , Neuvonen S. , Niemelä P. , Suomela J.
Published: April 2011

This paper summarizes the results from experiments during 12 years on effects of delayed inducible resistance of mountain birches (Betula pubescens Ehrh. ssp. tortuosa (Ledeb.) Nyman) on performance of a geometrid, Epirrita autumnata (Bkh.). Manual defoliation usually reduced significantly pupal mass of E. autumnata the next summer. The years interacted significantly with the defoliation treatment indicating variation among years in the responses of trees or larvae, or that the methodological differences between different experiments may have affected the results. Potential methodological sources for the annual variability were discussed and found unlikely. In addition, the efficacy of defoliation treatment in reducing the pupal mass was greatest when foliage quality in control trees was best, suggesting a contribution of biological causes to the annual variability.
Self‐selection and utilization efficiency of Heliothis zea larvae feeding on seeds and the walls of snap bean pods
Authors: Naeem M. , Waldbauer G. P. , Friedman S.
Published: April 2011

First instar Heliothis zea larvae tended to feed on the leaves of snap beans, but later instars preferred to burrow in the pods. Fifth instars offered only leaves grew poorly because they ate them in small quantities, presumably because of deterrency. The utilization efficiency and growth of fifth instars fed pulp was slightly but significantly inferior to that of seed‐fed larvae but was greatly superior to that of leaf‐fed larvae. Since the dry matter content of pulp is less than one‐third that of seeds, larvae allowed to eat only pulp had abnormally large fresh weight intakes and devoted about three times as much time to feeding as did seed‐fed larvae. Larvae offered a mix of seeds and pulp ate both and had a total fresh weight food intake somewhat greater than that of seed‐fed larvae but much less than that of pulp‐fed larvae. Eating both seeds and pulp offers no obvious nutritional advantage but presumably offers a significant ecological advantage. It is argued that the number of foraging trips a larva must make to discover pods is minimized by feeding on a mix, thus reducing exposure to mortality factors such as predation.
Electroantennogram responses to plant volatiles in two species of Pieris butterflies
Authors: van Loon J. J. A. , Frentz W. H. , van Eeuwijk F. A.
Published: April 2011

Electroantennogram (EAG) responses were recorded from females of two related butterfly species, Pieris brassicae L. and P. rapae L. (Lepidoptera: Pieridae) to 23 volatiles of plant origin, 19 of which have been reported to occur in the headspace of their preferred host plants, Brassica and Sinapis species (Cruciferae), In both species, selective responses were observed and the most effective compounds were the 6‐carbon fatty acid derivatives trans‐hex‐2‐enal, hexan‐1‐ol and hexanal, which are common green leaf volatiles. Of the 6 isoprenoids tested, myrcene and geraniol were most effective. Of the 4 crucifer‐specific compounds tested, phenylacetonitrile was a distinctly stronger stimulant than the three isothiocyanates in both species. The rank order of mean stimulating effectiveness of all compounds tested was strongly correlated between the two species. Statistical analysis of dose‐response relationships for 6 compounds revealed significant differences between compounds. The rank order of effectiveness changed with dose. Exclusive exposure to Sinapis arvensis during larval life and young adulthood resulted in quantitative changes in EAG responses to several compounds in both species, although the overall rank order of effectiveness was strongly correlated between the groups reared on the two host plants.
Effects of dietary nicotine and partial starvation of tobacco hornworm, Manduca sexta, on the survival and development of the parasitoid Cotesia congregata
Authors: Bentz J.‐A. , Barbosa P.
Published: April 2011

A factorial experiment tested the effects of dietary nicotine and of partial starvation of fifth instar tobacco hornworm, Manduca sexta (L.) (Lepidoptera: Sphingidae), on the survival and development of the parasitoid Cotesia congregata (Say) (Hymenoptera: Braconidae) in the laboratory. More parasitoids failed to emerge from partially starved hosts when reared on 0.1% nicotine diet, than from partially starved hosts fed control diet. Parasitoids reared from hornworms starved by 75% on nicotine diet had the longest development. The number of wasps was reduced when reared from hosts that were fed less than 50% of their daily consumption on nicotine diet. Pupal mortality was increased by dietary nicotine.

Nicotine, within the host tissues, may be directly toxic to the parasitoids before their emergence from hornworms. Our data suggest that nicotine may act by mediating the availability of nutrients or reduce assimilation of nutrients by developing parasitoids.
Oriented flight responses of female Mediterranean fruit flies to calling males, odor of calling males, and a synthetic pheromone blend
Authors: Landolt P. J. , Heath R. R. , Chambers D. L.
Published: April 2011

Male Mediterranean fruit flies, Ceratitis capitata (Wiedemann), produce volatile chemicals thought to be attractive sex pheromones. We demonstrated for the first time that male odor elicits upwind flight and zigzagging upwind flight patterns in mature unmated females. Such flight patterns indicate the mechanisms involved in female location of the pheromone source and arrival at that source. Similar female oriented upwind flight responses occurred with a three component blend comprised of ethyl‐(E)‐octenoate, geranyl acetate, and E,E‐alpha farnesene. These findings clarify the role of male sex pheromone in mate‐location strategies in this species and provide new bioassay criteria for evaluating attraction responses to male pheromone and synthetic blends.
Effects of protein type and concentration on development and reproduction of the German cockroach, Blattella germanica
Authors: Cooper R. A. , Schal C.
Published: April 2011

Nymphal development and adult female reproduction were examined in the German cockroach, Blattella germanica, using a defined artificial diet in which the type of protein was varied. Milk proteins, including casein, supported development poorly compared to meat and plant proteins. Soybean protein supported development better than all other highly purified proteins including vitamin‐free casein which is commonly used in artificial diets. Last instar females fed the soybean‐based diet eclosed earlier at higher eclosion weights, developed their oocytes at a faster rate and experienced higher fecundity than females fed a vitamin‐free casein‐based diet. Last instar females exhibited different dose‐response patterns on diets containing soybean isolate or vitamin‐free casein. However, at all concentrations soybean protein was superior to casein in supporting development. The results of a food utilization study during the last instar revealed that consumption rates varied between females fed the soybean and casein based diets. However, approximate digestibility, efficiency of conversion of digested food and the efficiency of conversion of ingested food did not vary significantly between the two dietary treatments. Differential development of females fed the two diets was attributed to differences in stage‐specific consumption rates and the poorer quality of casein as a source of protein for development in this species.
Mode of inheritance of azinphosmethyl resistance in a laboratory‐selected strain of Trioxys pallidus
Authors: Brown E. J. , Cave F. E. , Hoy M. A.
Published: April 2011

Homogeneity in azinphosmethyl resistance was assessed in males of a laboratory‐selected (Select‐17) and susceptible (Yolo) colony of Trioxys pallidus Haliday (Hymenoptera: Aphidiidae) using a time response assay. No evidence of heterogeneity within the two colonies was found. Reciprocal crosses between the Yolo and the Select‐19 (the Select‐17 colony following two additional selections) colonies resulted in F1 females that exhibited a semidominant response to azinphosmethyl with a dominance value (D) of 0.32, as well as no evidence of maternal effects or sex linkage. Responses of F2 progeny to azinphosmethyl suggest that more than one gene may be involved because no inflection was observed in the time response lines of F2 males. Additional research is required to fully elucidate the mode of inheritance.
Irrigation effects on European corn borer ‐ maize water relations
Authors: Ellsworth P. C. , Bradley J. R. , Kennedy G. G. , Patterson R. P. , Stinner R. E.
Published: April 2011

This study examined the impact of irrigation water on certain aspects of an insect‐plant relationship in the field including the assessment of plant‐mediated water effects on an herbivore's development, survival, and behavior, and plant damage parameters and host tissue water status. Maize (Zea mays L.) plants were arranged in a randomized complete block design in the field over two years in North Carolina (NC). Four blocks were subjected to three different irrigation treatments initiated ca. one week before anthesis: optimal, intermediate, deficit water supply. Each plant was infested with one (1986) or two (1987) black head stage, E‐race European corn borer [Ostrinia nubilalis (Hübn.)] (ECB) egg masses at tasselling. ECB development, tunnelling site, and survival as well as plant tissue water status (tissue % water contents [θ] & leaf water potentials [Ψ]) were recorded through July. The irrigation effect on ECB parameters was slight and variable. Internal stalk temperatures of optimal plants were consistently cooler than their deficit counterparts (1 day‐degree/day). With degree‐days included as an explanatory variable in the analyses, there were no significant irrigation effects on the ECB parameters, except for total proportion of ECB's bored into maize plant parts. More ECB's bored into drier plants than in optimal plants; however, this trend was not significant in 1987.

Plant water indices showed that though responded to irrigation, there were only minor changes in tissue θ, particularly in view of the larger diurnal tissue changes observed and the relatively high, sustained stalk θ levels seen over all treatments. Examination of ECB pupal θ confirmed that dietary water changes were minor or non‐limiting to the insects' developmental physiology, because pupal θ was not sensitive to the irrigation treatments.

Though water supply changes have drastic developmental and agronomic consequences for the maize plant, little or no changes were seen in the ECB feeding environment. Furthermore, a plant damage model was developed whereby the total % of ECB's tunnelled into maize was related to the mean larval age. The implications of this model on the understanding of ECB tunnelling behavior, damage potential, and pest management is noted.
Observers' bias in the assessment of pest and disease symptoms in leek
Authors: Theunissen J. , Legutowska H.
Published: April 2011

In the vegetable crop leek, Allium porrum L., the performance of observers was compared to the ‘real situation’ of pest and disease infestation. In two experiments the infestation of plants in a number of rows was meticulously investigated thus reflecting the ‘real situation’ as contrasted with the results of one or more observers. Included were the symptoms of leek moth (Acrolepiopsis assectella Zeller) feeding, both fresh and old, of onion thrips (Thrips tabaci Lindeman) feeding and of infestation with rust (Puccinia allii Rud.). The method of scouting was similar to growers' practice in commercial leek growing. The results show that even trained scouts vary considerably in accuracy when assessing infestation in rows at the same field. A group of observers show individual patterns of estimation, a wide variation in ability to make a correct assessment and a strong density dependency of deviations of the ‘real situation’ with the perceived density of the symptoms in the crop.
Diet‐switching by gypsy moth: effects of diet nitrogen history vs. switching on growth, consumption, and food utilization
Authors: Stockhoff B. A.
Published: April 2011

Gypsy moth (Lymantria dispar (L.) (Lepidoptera: Lymantriidae)) larvae were reared from hatch on 1.25% N or 3.5% N artificial diet (previous diet) and switched reciprocally to the other diet (current diet) after molting into the second, third, fourth, or fifth instar. The nitrogen concentration of food consumed during previous instars had a strong residual effect on the growth rate in subsequent instars when a diet switch was made during instars two through four, but did not affect growth rate of fifth‐instar larvae despite effects on food consumption and utilization. In early instars, larvae reared on 1.25% N artificial diet and then switched to 3.75% N diet had lower mass‐adjusted growth rates than larvae continuously reared on 3.75% N diet. Conversely, larvae reared on 3.75% N diet and switched to 1.25% N had higher mass‐adjusted growth rates than larvae reared continuously on 1.25% N diet. Relative to larvae previously reared on 1.25% N diet, fifth‐instar male larvae previously reared on 3.75% N diet had slightly lower consumption rates, higher net growth efficiency (ECD), and higher gross growth efficiency (ECI). Larvae previously reared on 3.75% N diet tended to have lower food assimilation efficiency (AD) and lower nitrogen assimilation efficiency (AD(N)). Although both previous and current diet nitrogen concentration strongly affected larval growth and food utilization, the interaction term between these was not significant for any response variables except ECD and ECI. Because the interaction term reflects the effect of switching per se, the results indicate that there was a metabolic cost associated with switching, but no inherent net cost or benefit of diet‐switching to growth.
Relationship between deterrence and toxicity of plant secondary compounds for the alfalfa weevil Hypera brunneipennis
Authors: Bernays E. A. , Cornelius M.
Published: April 2011

A variety of plant secondary compounds, several of which are quite widespread in nature were tested for their deterrence to the specialist coleopteran Hypera brunneipennis (Boheman) in short‐term behavioral assays. The compounds were nicotine, quinine, sparteine, hordenine, linamarin, amygdalin, sinigrin, morin, juglone, chlorogenic acid, digitonin, mimosine, diosgenin, rutin and ursolic acid. Nine of these were then tested for their post‐ingestional effects over one to two weeks of adult life, using fecundity as a measure of the effects. In only one case was there any indication of a detrimental effect or any trend suggesting one. The evolutionary implications of these findings are discussed.
Host plant exploitation within a population of a generalist herbivore, Choristoneura rosaceana
Authors: Carrière Y.
Published: April 2011

Feeding performance of larvae of the obliquebanded leafroller, Choristoneura rosaceana (Harris), was estimated on apple and three alternative hosts in the Okanagan Valley. The obliquebanded leafroller is native to the study area and apple was introduced in the valley at the beginning of the century. Components of insect fitness were measured to help formulate predictions about the evolution of host preference in this generalist herbivore. In the summer, females attained a higher pupal weight on apple than on trembling aspen, wild rose and snowberry. Males performed best on apple and trembling aspen. In the field, females arising from caterpillars fed on apple leaves had a 26% greater mean fecundity than if fed on alternative hosts. The diet also affected development time; females initiated pupation later on trembling aspen than on the other hosts. Finally, no differences were found in larval survival nor in the proportion of larvae diapausing when fed on different hosts. These components of fitness indicate apple as the most suitable host in the summer.

In the fall, diet influenced larval propensity to initiate diapause in the second or third instar, the time elapsed from hatching to diapause initiation and the weight of the instars initiating diapause. However, no difference in overwintering survival among larvae fed on different hosts was detected. The rank order of water and nitrogen contents of leaves of the host plants did not match the rank order of larval feeding performance in either season. A high suitability of apple and its abundance in the Okanagan valley are factors that would favor the evolution of an increased utilization of this host by the obliquebanded leafroller.
Toxicity and anticholinesterase activity of the fungal metabolites territrems to the corn earworm, Helicoverpa zea
Authors: Dowd P. F. , Peng F. C. , Chen J. W. , Ling K. H.
Published: April 2011

The toxicity and anticholinesterase activity of tremorgenic fungal metabolites, territrems, to the corn earworm, Helioverpa zea (Boddie) (Lepidoptera, Noctuidae) were examined. In oral toxicity studies, territrem A significantly inhibited growth by 40% at 25 ppm and by 89% at 250 ppm. Territrem B and an epoxy‐derivative significantly inhibited growth by ca. 45% at 250 ppm. Piperonyl butoxide administered orally synergized the toxicity of the territrems tested. In topical toxicity studies, the epoxy‐derivative caused 26% mortality and 25% growth retardation at 10 mg/gm insects. Territrem A and B were not significantly lethal, but did reduce growth by 15–20% at 10 mg/gm insect. Paraoxon tested in the same way caused 100% mortality at 25 ppm orally and 10 mg/gm topically. However, all territrems tested in vitro as inhibitors of H. zea head acetylcholinesterase were at least comparable to or were more active than paraoxon. Topically administered epoxy‐territrem B also inhibited H. zea head acetylcholinest‐erase. The potential for development of new insecticides from a territrem lead structure is discussed.
Trichome‐borne and artificially applied acylsugars of wild tomato deter feeding and oviposition of the leafminer Liriomyza trifolii
Authors: Hawthorne D. J. , Shapiro J. A. , Tingey W. M. , Mutschler M. A.
Published: April 2011

Oviposition and adult feeding of the leafminer Liriomyza trifollii (Burgess) (Diptera, Agromyzidae) on Lycopersicon pennellii (Corr.) D'Arcy and its F1 hybrid with Lycopersicon esculentum (Mill.) was significantly less than that on the cultivated tomato, L. esculentum. The resistance of L. pennellii and the F1 was reduced following rinsing of foliage with ethanol. Resistant attributes of L. pennellii were transferred to L. esculentum through appression of L. pennellii foliage to L. esculentum leaflets. Application of purified 2, 3, 4‐tri‐O‐acylglucoses (the principal component of type IV glandular trichome exudate of L. pennellii) to L. esculentum significantly decreased feeding and oviposition on L. esculentum leaflets by 61–99%. Therefore the principal mechanism of resistance to this leafminer by L. pennellii is the secretion of these acylglucoses. Dose response analysis of acylglucoses applied to L. esculentum shows that dosages as low as 10% those found on L. pennellii provide large reductions (91%) in leaf punctures and mines.
Host marking pheromone of Rhagoletis cerasi: field deployment of synthetic pheromone as a novel cherry fruit fly management strategy
Authors: Aluja M. , Boller E. F.
Published: April 2011

We tested the efficacy of synthetic host marking pheromone (HMP) of the European cherry fruit fly (R. cerasi) as a fruit‐infestation‐reducing‐agent in an experimental cherry orchard. Two different pheromone deployment strategies were compared: covering entire tree canopies with synthetic HMP or treating only one half (top to bottom or lower half) of the tree canopy. Pheromone application caused a tenfold reduction in fruit infestation if the entire tree canopy was covered (0.226 vs 0.021 pupae/fruit in untreated and treated trees, respectively). Results show, nevertheless, that a significant reduction in fruit infestation can be achieved by treating only one half of tree canopies (top to bottom) (0.021 vs 0.048 pupae/fruit when comparing totally vs partially treated trees). We conclude that synthetic cherry fruit fly HMP has potential as a fruit fly management tool, especially in cases where ‘organically’ grown fruit reaches high market values.
Diel flight periodicity of Chilo partellus
Authors: Päts P. , Wiktelius S.
Published: April 2011

The diel flight periodicity of the nocturnal moth Chilo partellus (Swinhoe) (Lepidoptera; Pyralidae) was measured in the laboratory using an actograph and in the field with suction traps. Females showed almost no flight activity on the night of eclosion. Flight activity of mated females peaked before midnight, the period of peak oviposition activity. Male peak activity occurred after midnight coinciding with female eclosion. Presence or absence of females did not affect when or how long males were active. Data on flight activity and reproductive behaviour are discussed in relation to the use of pheromones to protect maize.
The thelytokous Trichogramma chilonis in Taiwan
Authors: Chen Bing‐huei , Kfir R. , Chen C. N.
Published: April 2011

Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) with a mode of reproduction different from arrhenotoky was discovered and maintained in the laboratory. With or without mating, individuals of this form were able to produce males, females, and mosaics which varied in morphological characters. Reciprocal and backcrosses between males and females from this form and the arrhenotokous population revealed that they were compatible in mating. Progeny obtained from F1 and F2 proved the existence of gene flow between these two forms which are morphologically indistinguishable. More males were produced as temperature rose to above 25 °C, or when females fed on a mixture of tetracycline‐hydrochloride and honey (1 mg/1 ml). The impact of parasitoids with such mode of reproduction on biological control is discussed.
Diet‐induced food preference by Manduca sexta larvae: acceptable non‐host plants elicit a stronger induction than host plants
Authors: de Boer G.
Published: April 2011

Diet‐induced changes in food preference by fifth instar larvae of the tobacco hornworm, Manduca sexta (Johan.) (Lepidoptera, Sphingidae), were examined. Two groups of larvae with different diet experience were used: larvae reared on a host or on an acceptable non‐host plant species. Each group of larvae was offered a choice between leaf discs from each rearing plant species (2‐plant choice test) and food preference was measured as the consumption of one plant species relative to that of the other plant species. Diet‐induced changes in preferences were larger with the host versus acceptable non‐host plant pairs Solanum pseudocapsicum (L.) versus Raphanus sativus (L.), Lycopersicon esculentum (Mill.) versus Vigna sinensis (Savi), and Datura innoxia (L.) versus V. sinensis than with the host versus host plant pairs L. esculentum versus Capsicum annuum (L.) and L. esculentum versus D. innoxia. To examine how much the food preference had been altered for each test plant species alone, two other groups of larvae were offered a choice between leaf discs from a single plant species and filter paper discs laced with distilled water (l‐plant choice test). Larvae preferred the dietary plant species more strongly than the non‐dietary plant species in tests using the following plant species: for C. annuum with C. annuum and L. esculentum as diets, for V. sinensis with V. sinensis and L. esculentum or D. innoxia as diets, and for R. sativus with R. sativus and S. pseudocapsicum as diets. The preference for the hosts L. esculentum and D. innoxia did not change significantly after rearing larvae on different hosts or on an acceptable non‐host. Thus, diet‐induction by M. sexta larvae results in an enhancement of preference for the dietary plant species which is much stronger with acceptable non‐hosts than with hosts.
Responses of the African Armyworm and three species of borers to carbohydrates and phenolic substances: an electro‐ and behavioural physiological study
Authors: Den Otter C.J.
Published: April 2011

Electrophysiological recordings were made from the maxillary sensilla styloconica of fifth instars of the African Armyworm, Spodoptera exempta (Wlk.) (Lep.: Noctuidae), and the borers (Lep.: Pyralidae) Eldana saccharina Wlk. and Maruca testulalis (Geyer), and fifth and sixth instars of the borer Chilo partellus (Swinhoe). Stimuli were different concentrations of 13 carbohydrates and 11 phenolic substances. It appeared that a sucrose sensitive cell is present in the lateral styloconic sensilla of Spodoptera, Maruca and Chilo, and in both the lateral and medial sensilla of Eldana. The sucrose cell of fifth‐instar Chilo is more sensitive than that of sixth instars. The additional responses of the medial cells to the phagostimulant sucrose are supposed to have contributed to the widespread infestation of sugarcane by Eldana. The medial sensilla of the Armyworm contain a cell type responding to both meso‐inositol and D‐ribose. Chilo appeared to be the only one of the three borer species able to perceive phenolic substances. It has a cell responsive to chlorogenic acid in its medial sensilla, which is a bit more sensitive in fifth‐ than in sixth‐instar larvae. The presence of this cell may account for the positive correlation between total phenols content and resistance of sorghum cultivars to this borer. Spodoptera can perceive four phenolic acids. Its lateral sensilla contain a cell responsive to chlorogenic acid and its medial sensilla a cell responsive to 4‐hydroxybenzoic acid, gallic acid as well as vanillic acid. Feeding experiments showed that the latter substances inhibit feeding in the Armyworm.

So far, in the borers adequate stimuli could be determined for only two or three of the four taste cells present in each sensillum styloconicum. This indicates that we are still unaware of chemicals that may be important to these caterpillars. On the other hand, for the sensilla styloconica of Spodoptera, electrophysiology suggests the presence of five or six taste cell types, whereas only four taste cells are known from morphological studies.
Egg distribution patterns in the almond seed wasp, Eurytoma amygdali
Authors: Kouloussis N. A. , Katsoyannos B. I.
Published: April 2011

The egg distribution patterns of Eurytoma amygdali Enderlein (Hymenoptera, Eurytomidae), which oviposits singly in green, developing almonds, were studied in the laboratory and in the field. In the laboratory, individual females were caged with a number of almonds and the eggs deposited in each fruit were counted. In the field, eggs were censused in almonds of different varieties at regular intervals, over four seasons (1988–91). In the susceptible ‘Retsou’ variety, eggs were uniformly distributed among fruits, both in the laboratory and in the field, as long as the mean number of eggs per almond was ≤2.5. When the mean number of eggs per almond was higher the egg distributions were random. This suggests that, up to a certain level of infestation, females were able to assess egg load of fruits and oviposit in the less infested ones. The main factor enabling the females to discriminate and select the less infested almonds for oviposition is probably a host‐marking pheromone. In 1990, the same patterns of egg distribution were observed in samples taken from 5 other almond varieties that are not as susceptible as Retsou and have thicker pericarp and harder endocarp. In 1991 however, when fruits developed more rapidly than in 1990, egg distributions in 3 of these 5 varieties (Truoito, Ai, and Marcona) were not uniform. Although the mean number of eggs per fruit was low (1.2–2.0), many fruits of these varieties contained no eggs. This suggests that, in some less susceptible varieties, egg distribution might also be affected by certain fruit parameters, unfavourable for oviposition, related to the pericarp thickness and endocarp hardness.
Ultrastructural and biochemical aspects of digestion in the imagoes of the fly Rhynchosciara americana
Authors: Ferreira C. , Ribeiro A.F. , Terra W.R.
Published: April 2011

The midgut of adult Rhynchosciara americana Wiedemann (Diptera: Sciaridae) displays, in contrast to the midguts of other adult Diptera, two caeca connected to a ventriculus. All midgut cells exhibit long apical microvilli, and narrow and ramified basal channels with openings to the underlying space. These morphological features are thought to be involved in the absorption of nutrients from food. Enzymatic assays in R. americana adults revealed that amylase occurs in salivary glands and midgut, whereas aminopeptidase, α‐glucosidases and trypsin occur only in the midgut, mainly in the ventriculus. There is a soluble (Mr 105000) and a membrane‐bound aminopeptidase (solubilized form, Mr 110000). Soluble α‐glucosidase inactivates easily and could not be characterized, whereas membrane‐bound α‐glucosidases were resolved after solubilization into three molecular species (Mr 186000, 105000 and 84000) with different substrate specificities. The activities of trypsin (pH optimum 9.0), which was inhibited completely by soybean trypsin inhibitor, and of amylase (pH optimum 5.5), were not sufficiently high to be further characterized. The data support the assertion that R. americana adults are able, to a limited extent, to digest and absorb starch and proteins, in addition to nectar sugars. The results, supported by published data, suggest that there is an inverse correlation between the digestive enzyme activities and midgut absorptive surface in insects which has nectar as a major food.
The size of the female and quality assessment of mass‐reared Trichogramma spp
Authors: Pavlík J.
Published: April 2011

The relationship between the index of female's size, hind tibia length (HTL), and selected fitness parameters used in quality assessment of mass‐reared Trichogramma spp. (Hymenoptera, Trichogrammatidae) was investigated. The studied fitness parameters were: the number of mature eggs present in the ovaries of females 0–2 hours, as well as 1, 2 and 3 days old, lifetime fecundity, fecundity during a 24 h period, longevity in the presence and absence of the factitious host (Ephestia kuehniella Zeller) and locomotor activity. The relationship between HTL and fitness parameters was analysed in 7 strains of Trichogramma spp. (Trichogramma dendrolimi Matsumura, T. evanescens Westwood, T. maidis Pinturea et Voegelé and T. ostriniae Pang et Chen) using linear correlation. No significant relationship was found between HTL and egg complement, fecundity, longevity and locomotor activity.

The results indicate that HTL used as an index of female's size is not suitable for quality assessment of Trichogramma reared on E. kuehnieIla.
Use of synthetic pheromone traps to time control of the lucerne leafroller, Merophyas divulsana
Authors: Bishop A. L. , McKenzie H. J. , Whittle C. P.
Published: April 2011

Catches of male Merophyas divulsana (Walker) (Lepidoptera:Tortricidae) in pheromone traps showed seven peaks per year in lucerne (Medicago sativa L.) between September and April at approximately five week intervals. The trap catches can be used to predict the occurrence of specific stages of the life cycle and periods of damage. By using trap catches to time both harvesting and the application of insecticide, damage to a lucerne crop was reduced. Harvesting was considered to be the more acceptable control strategy.
Gravimetric vs. respirometric determination of metabolic efficiency in caterpillars of Pieris brassicae
Authors: van Loon J. J. A.
Published: April 2011

Conventional gravimetry and a combination of gravimetry and respirometry were compared for their precision in measuring respiration and metabolic efficiency of growth of final stadium Pieris brassicae L. (Pieridae, Lepidoptera) caterpillars. This was done both for caterpillars feeding on an artificial diet and for caterpillars feeding on excised leaf material of a host plant, Brassica oleracea L. Gravimetry produced significantly greater variation in the total amount of matter respired and the metabolic efficiency than indirect calorimetry for caterpillars feeding on plant material, while the two methods gave similar results for the caterpillars reared on a meridic artificial diet. Respirometry (indirect calorimetry) revealed that caterpillars feeding on the artificial diet were growing with a higher metabolic efficiency than caterpillars feeding on the host plant. This difference was not revealed by conventional gravimetry. It is argued that metabolic efficiencies as derived from gravimetric budget calculations are subject to a number of random errors that distort precise determination of metabolic efficiencies in studies involving plant food.
Silicon: an indigestible marker for measuring food consumption and utilization by insects
Authors: Barbehenn R. V.
Published: April 2011

Silicon (Si) is a useful indigestible marker in plants for measuring food consumption and nutritional indices. Si concentrations in HF:HCl extracts of small (5–20 mg) samples may be measured easily using atomic emission spectroscopy. The Si marker and gravimetric methods were compared using Lymantria dispar (L.) larvae fed artificial diet with 2.5% silica (SiO2). Both methods produced equivalent measures of consumption and nutritional indices. The Si marker method was also used to measure the consumption of six grass species by larvae of Paratrytone melane Edwards. The results were similar overall when compared with estimates of consumption based on total fecal weight, but varied significantly for some grass species. The Si marker method may be a useful alternative to the gravimetric method, especially in field situations.
Survival, growth, and reproduction of two aphid species on sucrose solutions containing host or non‐host honeydews
Authors: Dorschner K. W.
Published: April 2011

Aphids, like most phloem‐feeding insects, commonly exhibit a high degree of host specificity. Plant‐specific chemical compounds are likely to serve as important host selection cues for monophagous aphids and such substances could be present in aphid honeydew. Apterous virginoparae of Myzus persicae (Sulzer) and Phorodon humuli (Schrank) were reared on a buffered sucrose solution containing various aphid honeydews or a mixture of amino acids. In two separate experiments, the host‐specific P. humuli (hop aphid) could grow and reproduce only on diets containing honeydew collected from hop (Humulus lupulus L.). M. persicae (the green peach aphid, GPA) did not perform well on diets containing hop honeydew, perhaps because hop is a poor GPA host. Honeydew collected from preferred GPA host plants rape, Brassica napus L., and jimsonweed, Datura stramonium L., allowed GPA growth and reproduction. Hop aphids, however, performed poorly on rape and jimsonweed honeydew diets. Bell pepper, Capsicum annuum L., honeydew supported neither the hop aphid nor GPA. The study of aphid honeydew components may contribute towards a more complete understanding of host preference and selection phenomena in aphids.
Superparasitism and sex ratio in the solitary parasitoid Epidinocarsis lopezi
Authors: van Dijken Marianne J. , van Stratum Pam , van Alphen Jacques J. M.
Published: April 2011

Highly variable sex ratios are found in the solitary parasitoid Epidinocarsis lopezi, both in the field and in a mass‐rearing situation. Superparasitism is one of a number of factors which can influence sex ratios in parasitoid Hymenoptera. We show that superparasitism in E. lopezi is common in the field. Sex allocation decisions when parasitizing unparasitized hosts are not different from those with parasitized hosts; neither does differential mortality occur between the sexes in superparasitized hosts. Therefore superparasitism does not contribute to the variable sex ratio of E. lopezi. Both the occurrence of superparasitism and the sex produced when ovipositing are shown to be functional for E. lopezi.
Development of a monoclonal antibody to detect predation of the sweetpotato whitefly, Bemisia tabaci
Authors: Hagler James R. , Brower Albert G. , Tu Zhijian , Byrne David N. , Bradley‐Dunlop Debbie , Enriquez F. Javier
Published: April 2011

We have developed an enzyme‐linked immunosorbent assay (ELISA) for detection of whitefly antigen in the guts of predaceous arthropods based on a monoclonal antibody (MAb) produced in response to Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) egg antigen. We observed positive antigen‐antibody reactions with the egg and the adult female stages of certain whitefly species and not with others. This MAb did not cross‐react with any of the whitefly nymphs or adult males we tested. Moreover, this MAb did not cross‐react with the various life stages of other insect species we examined. This immunologically‐based technique to identify whitefly egg facilitates examinations of predator gut contents in the field. Such a specific and sensitive whitefly egg immunoassay will expedite the characterization of the B. tabaci predator complex in the southwestern United States.
Colonization of potato fields in eastern North Carolina by Colorado potato beetle
Authors: French N. M. , Follett P. , Nault B. A. , Kennedy G. G.
Published: April 2011

Rotated and non‐rotated commercial potato fields were sampled intensively to follow Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), colonization and subsequent oviposition patterns in the spring of 1990 and 1991. Maximum densities of colonizing adults ranged from 0 to 14,891/ha and maximum egg mass densities ranged from 0 to 48,451/ha. Crop rotation generally resulted in lower potato beetle populations. Regardless of crop rotation management practices, colonization of fields planted in potatoes began at field edges and progressed inward in all fields for both years. Management of potato beetles is discussed in light of these findings.
Rates of growth and increase of Myzus persicae on virus‐infected potatoes according to type of virus‐vector relationship
Authors: Castle S. J. , Berger P. H.
Published: April 2011

Growth, reproduction and survival (= performance) of the aphid Myzus persicae Sulzer was measured on virus‐free and virus‐infected potato plants. The principle objective was to evaluate if various viral infections affected aphid performance differently, and if so, whether any order in the performance response of the aphid was discernible according to the type of virus‐vector relationship. Three viruses varying in their dependency on M. persicae as a vector were used. Plants infected with potato leafroll virus (PLRV), a circulative virus highly dependent upon M. persicae for dispersal and transmission, were superior hosts as determined by the significantly greater mean relative growth rate (MRGR) and intrinsic rate of increase (rm) of M. persicae compared with those of aphids reared on other plants. Plants infected with potato virus Y, a noncirculative virus less dependent upon M. persicae for dispersal than PLRV, were intermediate in their quality based upon intermediate MRGR and rm values. Plants infected with potato virus X, a nonvectored virus independent of M. persicae, were least suitable hosts along with the group of virus‐free plants according to the lower MRGR and rm values.
Avidin and streptavidin as insecticidal and growth inhibiting dietary proteins*
Authors: Morgan T. D. , Oppert B. , Czapla T. H. , Kramer K. J.
Published: April 2011

Avidin was found to be an insecticidal and growth inhibiting dietary protein for five species of Coleoptera (red flour beetle, Tribolium castaneum, confused flour beetle, T. confusum, sawtoothed grain beetle, Oryzaphilus surinamensis, rice weevil, Sitophilus oryzae, and lesser grain borer, Rhyzopertha dominica) and two species of Lepidoptera (European corn borer, Ostrinia nubilalis, and Indianmeal moth, Plodia interpunctella). At levels ranging from 10 to 1000 ppm in the diet depending on the species, avidin retarded the growth and caused mortality of all seven species. Addition of biotin to the avidin‐treated diets for T. castaneum, T. confusum, R. dominica, and O. nubilalis prevented the growth inhibition and mortality caused by avidin. Streptavidin exhibited similar insecticidal and growth inhibiting activity towards T. castaneum and O. nubilalis. The results support the hypothesis that feeding avidin or streptavidin to insects causes a biotin deficiency which in turn leads to stunted growth and mortality. Avidin and streptavidin are insect growth inhibiting proteins whose genes potentially could be manipulated into plants and provide host plant resistance to insect pests.