bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of background on host‐plant selection and subsequent oviposition by the cabbage root fly (Delia radicum)
Authors: Kostal V. , Finch S. 
Published: April 2011

AbstractThe behaviour of female cabbage root flies during host plant selection was studied in the laboratory using brassica plants growing in backgrounds of bare soil, clover, grass, peas and four non‐living materials. Gravid females landed about twice as often on brassica plants growing in bare soil than on comparable plants growing amongst non‐host plants. Once a receptive female landed on a brassica plant, the female made, on average, four ‘spiral flights’ and two jumps on and off the plant before laying alongside the plant. Surrounding a brassica plant with a diverse background altered the behaviour of the flies, so that the spiral flights around the host plant were replaced by short hops between nearby vertical objects. The loss of contact and recontact with the host plant then prevented the females from accumulating sufficient contacts with the host plant to be stimulated to lay. Spiral flights around host plants appear to determine whether or not flies will lay alongside host plants. Flies in mixed plantings have a reduced rate of settling on the host plant, and a higher rate of locomotion, because they land frequently on non‐host plants. Hence, visual stimuli appeared to have greater effects than chemical or mechanical barriers in deterring flies from laying alongside brassica plants in diverse backgrounds. In ‘choice’ situations, backgrounds of real plants reduced oviposition alongside brassica plants by at least 50%. In ‘no‐choice’ situations, flies laid similar numbers of eggs alongside all brassica plants irrespective of plant background or plant size. If numbers of fly eggs are to be reduced on commercial brassica crops by undersowing the crops with clover, plants growing in bare soil may also have to be included to provide the flies with sites preferred for oviposition.
Flight manoeuvers used by a parasitic wasp to locate host‐infested plant
Authors: Kaiser L. , Willis M. A. , Cardé R. T. 
Published: April 2011

AbstractCotesia rubeculaMarshall (Hymenoptera: Braconidae) is a specialist larval parasitoid of the butterflyPieris rapaeL. which itself feeds almost exclusively upon cruciferous plants. Female wasps are attracted to the odour of host‐infested plant (plant‐host complex: PHC) and the probability of flights in a wind tunnel depends on females' prior oviposition experience with the PHC and on the concentration of the PHC odour. This study considers the effect of both factors on characteristics of oriented flight upwind towards the PHC. The flight track parameters that we measured and calculated were not significantly affected by these factors.C. rubeculafemales exhibited high average flight velocity and relatively straight flight tracks. There was a considerable variability between individuals, however, in their odour‐modulated upwind flight tracks. Some females generated a zigzagging upwind flight track similar to those commonly observed from male moths responding to female sex pheromone. Other females flew along a straight track directly upwind. The flight tracks of most female wasps were intermediate between these extremes. The full range of these flight performances was observed to all experimental treatments.
Variation in selected life‐history parameters of the parasitoid wasp, Aphidius ervi: influence of host developmental stage
Authors: Sequeira R. , Mackauer M. 
Published: April 2011

AbstractWe determined the age‐specific fecundity and survival of the solitary parasitoid wasp, Aphidius ervi Haliday (Hymenoptera: Aphidiidae), under constant laboratory conditions. Wasps were reared in each of the four nymphal instars of apterous pea aphids, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae): (age 24 h), L2 (48 h), L3 (72 h), and L4 (120 h). Age‐specific survival (lx) and fecundity (mx) differed between parasitoids developing in different aphid instars. The wasps' life‐time reproductive success, as indexed by the intrinsic rate of population increase (rm), varied non‐linearly with adult biomass and host size at parasitization. A close agreement between larval growth rates in different host instars and adult reproductive performance suggests that, in A. ervi, fitness correlates may be significantly influenced by larval ontogeny and trade‐offs in resource allocation.
Effect of temperature on development rate and intrinsic rate of increase of Aphis gossypii reared on greenhouse cucumbers
Authors: Kocourek F. , Havelka J. , Beránková J. , Jaroŝik V. 
Published: April 2011

AbstractThermal requirements for development and life table statistics of Aphis gossypii Glover (Homoptera, Aphididae) were determined over a range of constant temperatures from 10 to 30 °C. The lower development threshold and the sum of effective temperatures were 6.9 °C and 90.1 °C, respectively, for preimaginal development, and 5.8 °C and 113.6 °C from birth to the onset of reproduction. Mean total fecundity ranged from 36 larvae per female at 10 °C to 76 larvae at 30 °C. On a time scale of days, net reproductive rate (R o) increased with increasing temperature while generation time (T) decreased causing the intrinsic rate of increase (rm) to increase linearly from 0.115 to 0.465. On a day‐degree scale r m only varied from 0.019 to 0.028 because the growth of R o was compensated by an increase in T with increase in temperature. The nearly constant r m in terms of day‐degrees, over a wide range of temperatures, greatly simplifies the prediction of future population numbers of A. gossypii.
Field evaluation of insect resistance in a wild tomato and its effects on insect parasitoids
Authors: Kennedy G. G. , Farrar R. R. , Barbour J. D. , Kennedy G. G. 
Published: April 2011

AbstractPopulations of Helicoverpa (= Heliothis) zea (Boddie), Heliothis virescens (F.), Manduca sexta (L.) and M. quinquemaculata (Haw.) and their egg and larval parasitoids were sampled in field plots of the: insect‐resistant wild tomato, Lycopersicon hirsutum f. glabratum C. H. Mull, accession PI 134417; susceptible commercial tomato cultivar ‘Better Boy’ F1 hybrid; and selected, moderately resistant backcross genotype. Densities of H. zea and H. virescens eggs and small larvae were higher on resistant genotypes than on susceptible genotypes, but densities of large larvae were similar on all genotypes. Densities of Manduca spp. larvae were too low to permit similar analyses of the effects of plant genotype. Rates of egg parasitism by Trichogramma spp. and Telenomus sphingis (Ashmead) were reduced on insect‐resistant genotypes. Rates of parasitism by the larval parasitoids Campoletis sonorensis (Cameron) and Cotesia congregata (Say) were reduced on resistant genotypes. No consistent effects on parasitism rates by Cotesia marginiventris (Cresson) were observed and parasitism rates by Cardiochiles nigriceps Viereck were unaffected.
Sub‐lethal effects of deltamethrin residues on the within‐crop behaviour and distribution of Coccinella septempunctata
Authors: Wiles John A. , Jepson Paul C. 
Published: April 2011

AbstractThe behaviour and distribution of adult Coccinella septempunctata L. (Coleoptera: Coccinellidae) were recorded in two plots of winter wheat infested with the cereal aphids Sitobion avenae (F.) and Metopolophium dirhodum (Walk.) (Homoptera: Aphididae). One plot was sprayed with the pyrethroid insecticide deltamethrin at a rate of 6.25 g a.i./ha and the other was left unsprayed. Single ladybird beetles were released sequentially on the ground at the centre of the sprayed and unsprayed plots and their behaviour and position in the crop canopy were recorded at 30 second intervals for a total of 15 min per beetle. Assessments, with fresh beetles, continued for four days after spray application with a total of eighty ladybird beetles observed. The 15 min period was selected to avoid lethal effects and no ladybird beetles were killed or knocked down as a result of exposure to deltamethrin residues during this period. Significant differences were found between the overall behaviour patterns of C. septempunctata in the untreated and deltamethrin treated plots up to three days after the spray application. Ladybird beetles exposed to deltamethrin residues were observed to walk and groom significantly more frequently and to rest significantly less frequently than those in the unsprayed plot. Significant differences were also found between the observed distribution of ladybird beetles in the sprayed and unsprayed crop canopies, with higher numbers of observations towards the bottom of the crop canopy and on the ground in the deltamethrin treated plot than in the untreated plot during the first two days after deltamethrin application. Upon the foliage itself, ladybird beetles were observed significantly more frequently on the abaxial leaf surface in the deltamethrin treated crop compared with the untreated crop. The results are discussed in terms of possible evidence for the repellency of deltamethrin to C. septempunctata and also the implications for integrated pest management of changes in predator behaviour and crop distribution resulting from sub‐lethal uptake of insecticides.
Simultaneous effects of potassium, rutin and temperature on performance of Manduca sexta caterpillars
Authors: Stamp N. E. 
Published: April 2011

AbstractThe simultaneous effects on an insect herbivore (third instar tobacco hornworm Manduca sexta (L.): Sphingidae) of temperature (daytime temperatures of 20 °C, 25 °C and 30 °C), a mineral that may play a role in plant defense (potassium) and a common allelochemical (rutin) were examined in a factorial experiment. To manipulate potassium levels, a modified diet with limited plant material was used as the base and KCl and rutin added. Temperature affected efficiency of conversion of ingested food (ECI), efficiency of conversion of digested food (ECD), time to head‐capsule slippage, stadium duration, relative consumption rate (RCR) and relative growth rate (RGR) but not food consumed, biomass gained and approximate digestibility (AD). Potassium concentration influenced all of the variables except AD, time to head‐capsule slippage (HCS), duration of the stadium and percent of stadium time to HCS. Rutin impacted negatively on all of the variables except food consumed. Compared to larvae on the non‐rutin diets, fewer larvae fed rutin survived through molt initiation to ecdysis and fewer successfully completed ecdysis. Temperature and rutin had interactive effects for AD, ECD, RCR, RGR, time to HCS, and percent of stadium required to reach HCS. Rutin and potassium had interactive effects for biomass gained, RCR, ECI, time to HCS, duration of stadium, and percent of stadium required to reach HCS. Comparison of larval responses on an average potassium concentration (3.1%) versus high concentration (6.1%) showed that at the low daytime temperature increasing potassium concentration depressed biomass gained, but at the warmer temperatures potassium concentration had little effect unless rutin was present. In addition, potassium concentration had little impact on ECI unless rutin was present. These results indicate that significant interactive effects occur among temperature, potassium and rutin, and thus suggest that such interactive effects on larval performance may be common under field conditions, which are characterized by varying temperature and different concentrations of minerals and allelochemicals in hostplants.
Comparative headspace analysis of cabbage plants damaged by two species of Pieris caterpillars: consequences for in‐flight host location by Cotesia parasitoids
Authors: Blaakmeer A. , Geervliet J. B. F. , van Loon J. J. A. , Posthumus M. A. , van Beek T. A. , de Groot Ae. 
Published: April 2011

AbstractHeadspace composition, collected from intact cabbage plants and cabbage plants infested with either Pieris brassicae L. or P. rapae L. (Lepidoptera: Pieridae) first instar larvae, was determined by GC‐MS. Twenty‐one volatiles were identified in the headspace of intact plants. Twenty‐two volatiles were identified in the headspace of plants infested by P. brassicae larvae, 2 of which, Z‐3‐hexenyl butyrate and Z‐3‐hexenyl isovalerate, were not detected in the headspace of either intact or P. rapae damaged plants. In the headspace of the latter, 21 compounds were identified, all of which were also produced by intact plants. No significant quantitative differences were found between headspace composition of the plants damaged by one or the other caterpillar species. Major differences between intact and caterpillar‐damaged plants in contribution to the headspace profile were revealed for hexyl acetate, Z‐3‐hexenyl acetate, myrcene, sabinene and 1, 8‐cineole. The larval endoparasitoid Cotesia glomerata L. was attracted by the volatiles emanating from B. oleracea damaged by P. brassicae first instar larvae. C. rubecula L., a specialized larval endoparasitoids of P. rapae, was attracted by the volatiles released from the B. oleracea ‐ P. rapae plant‐host complex. This shows that cabbage plants kept under the conditions of headspace collection produce attractive volatiles for both parasitoids.
Adult response of the almond seed wasp, Eurytoma amygdali, to chemicals from its host and certain nonhosts
Authors: Kouloussis N. A. , Katsoyannos B. I. 
Published: April 2011

AbstractFemales of the almond seed wasp, Eurytoma amygdali Enderlein (Hymenoptera, Eurytomidae), responded in an olfactometer positively to odours from almond flowers and unripe fruits, but not to almond leaf odours and odours from flowers and unripe fruits of certain other nonhost Prunus species. Males responded to none of these odours. Extracts of undamaged unripe almond fruits (using ethanol, methanol, acetone, hexane, dichloromethane, or petroleum ether) stimulated female aggregation on glass surfaces treated with these extracts; in addition, certain fruit extracts (ethanol, methanol, or acetone) stimulated oviposition. Extracts of undamaged almond leaves (ethanol, methanol, or acetone) and flowers (ethanol or methanol) also stimulated female aggregation and oviposition. Aggregation and oviposition in response to an ethanol extract of almond fruits was intense in females aged 5 to 14 days and from 12:00 to 18:00 h (photophase between 06:00 and 20:00). Certain almond fruit (ethanol, methanol, acetone or hexane) and flower extracts (ethanol or methanol) also provoked female response in the olfactometer. The results strongly suggest that certain chemical stimuli emanating from parts of the almond tree play a major role in host selection and oviposition. Some of the extracts tested may be a good source for the isolation, identification and synthesis of compounds stimulating attraction, aggregation and oviposition in nature.
Volatiles from damaged plants as major cues in long‐range host‐searching by the specialist parasitoid Cotesia rubecula
Authors: Geervliet Jacqueline B. F. , Vet Louise E. M. , Dicke Marcel 
Published: April 2011

AbstractThe role of volatile stimuli in the long‐range host‐searching behaviour of the specialist parasitoid Cotesia rubecula Marshall (Hymenoptera: Braconidae) was studied. Components from the plant‐host‐complex Brussels sprouts (Brassica oleracea L. var. gemmifera (DC.) Schulz. cv. ‘Titurel’)‐Pieris rapae L. (Lepidoptera: Pieridae) were compared for their attractiveness in dual choice tests in a windtunnel. Stimuli from cabbage plants that were mechanically damaged or damaged by P. rapae caterpillars were more attractive to this parasitoid species than stimuli emitted by the host larvae or their faeces. Parasitoids preferred leaves from the plant‐host‐complex over artificially damaged leaves. Undamaged cabbage plants were the least attractive to the foraging females. These results indicate that in‐flight searching behaviour of C. rubecula is guided by plant‐derived information and that for this specialist species more reliable and specific host‐derived cues play a minor role at longer distances.
Trapping and sex pheromone‐mediated flight and landing behaviour of male Ctenopseustis obliquana
Authors: Foster S. P. , Ayers R. H. , Muggleston S. J. 
Published: April 2011

AbstractA sex pheromone‐baited delta trap was found to be inefficient at eliciting landing and entering of the trap by male Ctenopseustis obliquana. The inefficiency of the delta trap related to turbulence altering the pheromone plume and the concomitant effect on the flight manoeuvres of male moths. In the wind tunnel, high proportions of males flew upwind and landed on the sides, outside, of the trap, but only a relatively small proportion of these males entered the trap and contacted the sticky surface. When males approached the delta trap, they tended to fly in wide zigzags (i.e., large inter‐track reversal distances) and at an altitude near the top of the trap, where the trap was relatively narrow in width (compared to the bottom). Thus, these flight manoeuvres largely precluded males from entering the trap. Greater numbers of male moths entered the trap when: (i) the front barriers of the delta trap were removed, (ii) pheromone dosage was increased to 300μg, and (iii) the trap design was changed to a rectangular one. The first two changes appeared to influence the flight manoeuvres of males (who appeared to fly with narrower inter‐track reversal distances), while the third change apparently did not affect the flight manoeuvres of males, but rather allowed more males to enter the trap because of the greater area of the entrance. The low trap catches of male C. obliquana in the field are also a consequence of the glue which is currently used. After contact with this glue most males are able to escape, flying off the sticky surface and losing contact with the pheromone. A field trial found that delta traps with another glue caught more than three times the number of males of the related tortricid moth, Epiphyas postvittana, than delta traps with the currently used glue.
Variation in diapause and sex ratio in the parasitoid Asobara tabida
Authors: Kraaijeveld Alex R. , van Alphen Jacques J. M. 
Published: April 2011

AbstractAsobara tabida Nees (Hymenoptera: Braconidae) is a widespread parasitoid, attacking larvae of Drosophila (Diptera: Drosophilidae) species in fermenting substrates. In this species, geographic variation is found in the percentage of parasitoids entering diapause and in the sex ratio of emerging parasitoids. Percentage diapause appears to be influenced by host species (more parasitoids enter diapause in D. melanogaster Meigen than in D. subobscura Collin) and temperature. It is not correlated with any of the abiotic factors investigated, but is correlated with survival probability in D. melanogaster larvae and with the time of year in which the experiment was conducted (even though none of the parasitoids experienced natural day light). Sex ratio was only found to correlate with percentage diapause, suggesting that males enter diapause more frequently than females. It is concluded that A. tabida uses diapause to survive both unfavourable abiotic and biotic circumstances.
Non‐freeze survival of spruce budworm larvae, Choristoneura fumiferana, at sub‐zero temperatures during diapause
Authors: Han Er‐Ning , Bauce Eric 
Published: April 2011

AbstractSpruce budworm larvae, Choristoneura fumiferana (Clem.) (Lepidoptera: Tortricidae), in early‐, mid‐ and late‐diapause (maintained at 2 °C), were exposed to various sub‐zero temperatures, above the supercooling point, for different periods to determine the insect's cold‐hardiness in terms of non‐freeze survival. Larvae which were in the middle of diapause showed the highest survival (percentage of larvae emerging from hibernacula after diapause), followed by larvae in late‐ and early‐diapause respectively. When exposed to −23 °C, larvae which were acclimatized to outside air temperatures had a much higher survival than the larvae maintained at 2 °C. This survival was correlated with a glycerol content that was ten times higher and a depressed supercooling point in acclimatized larvae compared to lab‐maintained larvae. Experiments also demonstrated that mortality of the larvae maintained in an extended supercooled state at −23 °C was due to cold injury rather than freezing. The present study supports the hypothesis that glycerol may have a cryoprotective role other than depressing the supercooling point in freeze‐intolerant insects and highlights the importance of investigating non‐freeze mortality during insect diapause.RésuméDes larves de tordeuse des bourgeons de l'épinette, Choristoneura fumiferana (Clem.), en début, milieu et fin de diapause (maintenue à 2 °C) furent soumises à divers régimes de températures supérieures au point de congélation cellulaire, de façon à déterminer la capacité de l'insecte à survivre à ces températures. Les larves en milieu de diapause furent celles ayant le mieux survécu (proportion des larves émergeant de leur hibernacula après la diapause). Elles furent suivies respectivement par celles en fin et en début de diapause. La suivie larvaire, suite à une exposition à −23 °C, fut plus élevée dans le cas des larves préalablement acclimatées aux températures de terrain que dans le cas des larves maintenues à 2 °C. Comparativement aux larves non acclimatées sur le terrain, le point de congélation cellulaire des larves acclimatées était inférieur et leur contenu en glycérol était dix fois plus élevé. Cette étude a aussi montré que la mortalité des larves maintenues durant une longue période à −23 °C ne fut pas causée par un phénomène de congélation cellulaire mais plutôt par d'autres effets létaux du froid. Les résultats de cette étude sont en accord avec l'hypothèse selon laquelle le glycérol jouerait, en tant que cryoprotectant, un rôle autre que celui d'abaisser les points de congélation cellulaire des insectes du type intolérant au gel. De plus, ces résultats montrent l'importance détudier la mortalité induite par les températures situées au‐dessus du point de congélation cellulaire durant la diapause de l'insecte.