bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of plant spacing and interplanting with oilseed rape on colonisation of dwarf hops by the damson‐hop aphid, Phorodon humuli
Authors: Campbell Colin A.M. , Ridout Martin S. 
Published: October 2003

AbstractThe pattern of colonisation of dwarf hops (Humulus lupulus) by damson‐hop aphid (Phorodon humuli (Schrank)) migrating from Prunus spp. was investigated at six plant spacings and where some of the hops were replaced by oilseed rape (Brassica napus L.), a non‐host of the aphid. The number of migrant aphids that accumulated on hop stems (bines) increased with increasing bine size and density. The numbers of aphids that colonised hops interplanted with oilseed rape reflected the density of the hop plants only and not the overall plant density. As the physical size of the wind shadow within which flying aphids can manoeuvre and land was unimportant unless provided by a host plant, the finding supports the theory that flying aphids respond to olfactory stimuli associated with their hosts. Variation in bine height (as a measure of plant size) explained 29–93% of the variance in aphid counts during the 3 years' study and bine density 1–14%. Standardising the data as the numbers of aphids per metre of bine and taking a square‐root transformation of these standardised counts improved the precision of the analyses and, by stabilising variances, facilitated comparisons between years as growth became more vigorous as the plants matured. Each year, the rate of increase in numbers of aphids settling on plots of hops declined curvilinearly with increasing bine density. Maximum colonisation by P. humuli occurred at a bine density of five per metre row, a density similar to that used commercially by growers of dwarf hops.
Effect of orange peel substances on mating competitiveness of male Ceratitis capitata
Authors: Papadopoulos Nikos T. , Katsoyannos Byron I. , Kouloussis Nikos A. , Hendrichs Jorge 
Published: October 2003

AbstractThe response of wild Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) males to orange peel chemicals and their effect in mating competitiveness of males exposed to these chemicals was studied in the laboratory (25±2 °C, 65±5%, r.h.). Males were attracted, landed, and arrested on ripe oranges that were superficially wounded in the flavedo region of the peel, and fed on the wounds. Exposure to wounded oranges conferred to males a mating advantage over unexposed males. In flies of 1 to 10 days of age, this advantage was independent of the age of the flies during exposure and lasted at least 10 days following exposure. Twenty‐four hours of exposure ensured this effect. Exposure to intact oranges, or to wounded oranges covered with a wire‐screen, which allowed olfactory response and landing on the screen but not direct contact with the fruit, did not confer any mating advantage. Apparently, males required direct contact with wounded oranges in order to increase their mating competitiveness. It is suggested that the acquisition of certain substances of the flavedo, most probably through their ingestion, is responsible for the observed phenomenon. Our findings are discussed in relation to the sexual behaviour of this fly. Implications of these findings for the enhancement of the mating competitiveness of released sterile males and of the effectiveness of the Sterile Insect Technique programs are discussed as well.
Genetic variation in Myzus persicae populations associated with host‐plant and life cycle category
Authors: Zitoudi Kiriaki , Margaritopoulos John T. , Mamuris Zissis , Tsitsipis John A. 
Published: October 2003

AbstractRandom amplified polymorphic DNA (RAPD) analysis was applied on 96 clones of Myzus persicae (Sulzer) (Homoptera: Aphididae) representing seven populations collected from different host‐plants and regions of Greece. Ten decamer random primers were used to evaluate genetic variation among the examined samples. Despite the variability found between clones, no specific RAPD marker was detected to discriminate the different populations. A significant finding was that aphids from peach and pepper, which were collected far away from tobacco‐growing regions, especially those from peach, showed genetic divergence from the tobacco‐feeding clones. Moreover, data analysis revealed a significant genetic divergence between holocyclic and anholocyclic populations from tobacco. Lastly, holocyclic clones showed higher level of estimated heterozygosity than the nonholocyclic (anholocyclic, androcyclic and intermediate) ones.
Host specificity and comparative foraging behaviour of Aenasius vexans and Acerophagus coccois, two endo‐parasitoids of the cassava mealybug
Authors: Dorn Brigitte , Mattiacci Letizia , Bellotti Anthony C. , Dorn Silvia 
Published: October 2003

AbstractTwo encyrtid parasitoids, Aenasius vexans Kerrich (Hymenoptera: Encyrtidae) and Acerophagus coccois Smith (Hymenoptera: Encyrtidae), were compared for their degree of dietary specialisation and the impact this has on their foraging strategies. Both parasitoid species are significant for biological control of the cassava mealybug, Phenacoccus herreni, Cox & Williams (Homoptera: Sternorrhyncha) a major Latin American pest of cassava, Manihot esculenta Crantz, an important root crop. Host acceptance and parasitism were analysed in seven mealybug species (with different levels of polyphagy) occurring in and around cassava fields. Results demonstrate that, in this ecosystem, An. vexans is a specialist for P. herreni while Ac. coccois is a generalist on the first and second trophic level. Of the seven mealybug species, P. herreni and P. madeirensis Green were the most acceptable hosts for Ac. coccois, followed by Ferrisia virgata Cockerell. Ac. coccois did not accept the other four mealybug species.The foraging and oviposition behaviour of individual parasitoids was observed in bioassays with cassava leaves infested by P. herreni. The two species used different strategies to locate their host. Aenasius vexans spent significantly more time walking and standing on an infested leaf and examined a host longer than did Ac. coccois. Acerophagus coccois, in contrast, spent more time for oviposition. As a consequence An. vexans parasitised more hosts in a given time than did Ac. coccois. Because the rate of offspring production of the two species did not differ, we conclude that the gregarious Ac. coccois's strategy to deposit several eggs at once might compensate for its relatively low number of ovipostitions, compared with the solitary An. vexans. These findings suggest that, given the advantages and limitations of each species, a multi‐species approach to biological control of P. herreni may yield best results.
Learning of host‐infested plant volatiles in the larval parasitoid Cotesia kariyai
Authors: Fukushima Junji , Kainoh Yooichi , Honda Hiroshi , Takabayashi Junji 
Published: October 2003

AbstractThe ability to learn plant volatiles in Cotesia kariyai females was examined by wind tunnel bioassays. Searching experience on a host‐infested corn plant increased subsequent flight responses of females to the infested plant. Females experiencing host by‐products together with the volatiles extracted from infested leaves one time showed an increased response. However, such behavioral changes were not observed in females which experienced only the host by‐products or the volatiles. Thus, the increased response is considered to be preference learning. Multiple experiences of C. kariyai with host by‐products together with the volatiles did not increase their flight response to the volatiles. Furthermore, this learned response gradually decreased within 2 days. These behavioral modifications based on experience would be advantageous for C. kariyai to locate their polyphagous hosts efficiently.
Effects of metal contamination on the activity and diversity of carabid beetles in an ancient Pb‐Zn mining area at Plombières (Belgium)
Authors: Lock Koen , Desender Konjev , Janssen Colin R. 
Published: October 2003

AbstractCarabid beetles were monthly sampled with pitfall traps in the ancient Pb‐Zn mining area of Plombières during one year. Based on the total soil concentrations of lead, zinc, cadmium and copper, it was expected that zinc would probably have the most adverse effects on the populations. Activity and species richness of carabid beetles were, however, not significantly correlated with total zinc concentration nor with the water soluble and the calciumchloride extractable concentration. In fact, despite the high soil concentrations, carabid beetles did not seem to be affected in the study area. The apparent lack of effects at the high observed zinc concentrations is probably caused by the low bioavailability of zinc to the beetles in the litter of the study sites which was also reflected in the low observed water soluble zinc concentrations.
Development of European corn borer larvae on Event 176 Bt corn: influence on survival and fitness
Authors: Siegfried Blair D. , Zoerb Amelia C. , Spencer Terrrence 
Published: October 2003

AbstractEuropean corn borer larvae, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae) that have completed development on Event 176 Bt corn hybrids have survived exposure to sublethal doses of the Cry1Ab Bt toxin or are exploiting plant tissues that do not express the toxin. To evaluate the impact of such exposure, diapausing larvae were collected from Event 176 and conventional hybrids and compared for rates of pupation, parasitism, fitness (pupal weight, longevity, and fecundity) and susceptibility to the Cry1Ab toxin. Larvae completing development on Event 176 corn exhibited approximately 10% higher survival rates and correspondingly lower parasitism rates than larvae completing development on conventional hybrids. No significant differences were detected in pupal weight, fecundity, longevity or susceptibility to the Cry1Ab Bt toxin. These results indicate that survival on Event 176 corn are not adversely affect fitness and does not cause increased tolerance to the Cry1Ab toxin in subsequent generations.
Visual and olfactory disruption of orientation by the western pine beetle to attractant‐baited traps
Authors: Strom B.L. , Goyer R.A. , Shea P.J. 
Published: October 2003

AbstractOlfactory deterrents have been proposed as tree protectants against attack by bark beetles, but their development has been hindered by a lack of knowledge of host selection behavior. Among the primary tree‐killing (aggressive) Dendroctonus, vision appears to be an integral part of the host selection process. We evaluated the importance of vision in host finding by D. brevicomis LeConte, and our ability to affect it by modifying the visual stimulus provided by attractant‐baited multiple‐funnel traps. White‐painted traps caught ∼42% fewer D. brevicomis than black traps in California, USA (P < 0.05). Visual treatments were less effective (P < 0.0001) than olfactory disruptants (verbenone with ipsdienol), which reduced catch by about 78%. When combined, olfactory and visual disruptants resulted in ∼89% fewer D. brevicomis being caught, but this combination was not more effective than olfactory disruptants alone (P > 0.05). Our results demonstrate that the visual component of D. brevicomis host finding behavior can be manipulated, but that D. brevicomis may be more affected by olfactory than visual disruptants. In contrast, visual disruption is more pronounced in the southern pine beetle, Dendroctonus frontalis Zimmermann, suggesting that non‐insecticidal tree protection strategies for these related species should differ.
Intraguild predation by aphidophagous predators on parasitised aphids: the use of multiple video cameras
Authors: Meyhöfer R. 
Published: October 2003

AbstractA video technique that allows simultaneous behavioural observations of several experimental replicates under field and laboratory conditions is described. The technique was used to analyse predation risk of parasitised aphids in a sugar beet field. The images of 16 black and white video cameras were recorded by a video multiplexer in combination with a time‐lapse video recorder. Each camera was weather protected and equipped with a single infrared diode to allow observations during night times. Single leaves carrying aphid mummies only or mummies and unparasitised aphids were monitored. All colonies were exposed to predation and parasitation by the community of natural enemies in the field. Colonies with mummies and unparasitised aphids were visited significantly more often by predators than those without additional aphids. Predators also stayed significantly longer in patches with unparasitised aphids. Although an equal proportion of aphid mummies were destroyed in both treatments, the video analysis showed differences in predator species spectrum between treatments. In patches with aphids, coccinellid and hemipteran predators preyed on mummies, while in patches with only mummies, chrysopids accounted for most of the damage. The decrease in parasitoid survival could be attributed to the increasing number of predator visits in aphid patches and to a lesser extent to the decreasing number of unparasitised aphids (alternative prey). Parasitoid survival in colonies without alternative prey was correlated with the number of predator visits and the time predators spent on a leaf.Continuous video observations gave additional behavioural information for the interpretation of field data. Other prospective research fields for the use of the multi video camera technique are outlined and general advantages and disadvantages are discussed.
Identification of novel sex pheromone components from a tussock moth, Euproctis pulverea
Authors: Wakamura Sadao , Arakaki Norio , Ono Hiroshi , Yasui Hiroe 
Published: October 2003

AbstractTwo EAG‐active compounds were found in the solvent extract of abdominal tips of virgin females of the tussock moth Euproctis pulverea (Leech) (Lepidoptera: Lymantriidae), and identified as (Z,Z,Z)‐11,14,17‐icosatrienyl isobutyrate and (Z,Z,Z)‐11,14,17‐icosatrienyl 4‐methylvalerate at 190 and 80 ng female−1, respectively, by means of GC‐MS analyses and chemical derivatization. Esters of n‐butyric acid, n‐valeric acid, n‐hexanoic acid and a methylheptanoic acid were also found at 3, 2, 0.4 and 9 ng female−1 as minor EAG‐inactive compounds. Two active compounds were also detected in the hexane extract of female anal tufts at 17 and 6 ng female−1, respectively. In Okinawa, the binary blend of the synthetic compounds attracted male moths to the sticky traps, but single compounds did not. The significance of these findings in relation to parasitism by Telenomus euproctidis (Hymenoptera: Scelionidae) is discussed.
Performance of adult psyllids in no‐choice experiments on juvenile and adult leaves of Eucalyptus globulus
Authors: Brennan Eric B. , Weinbaum Steven A. 
Published: October 2003

AbstractThe presence of glaucous juvenile leaves and glossy adult leaves in the canopy of the heteroblastic plant Eucalyptus globulus Labill., is a source of within‐tree variation that affects herbivory by three psyllid species (Ctenarytaina eucalypti Maskell, C. spatulata Taylor and Glycaspis brimblecombei Moore) (Homoptera, Psyllidae). In no‐choice field experiments with adult female psyllids in clip‐on cages, we compared (1) leaf‐settling, honeydew production, and survival of the Ctenarytaina species on juvenile and adult leaves of E. globulus, (2) leaf‐settling and survival of G. brimblecombei on juvenile and adult leaves, (3) leaf‐settling and survival of the three species on waxy (untreated) juvenile leaves and de‐waxed (rubbed) juvenile leaves, and (4) leaf‐settling and survival of C. spatulata on juvenile leaves from which wax was repeatedly removed. Leaf‐settling by C. eucalypti was significantly greater on juvenile than adult leaves, however, honeydew production and survival were equal on both leaf types. In contrast, leaf‐settling, honeydew production, and survival by C. spatulata were significantly greater on adult than juvenile leaves. Similarly, leaf‐settling and survival by G. brimblecombei were significantly greater on adult than juvenile leaves. Wax removal from juvenile leaves significantly increased leaf‐settling and survival of C. spatulata and G. brimblecombei. Although wax removal decreased leaf‐settling by C. eucalypti, it did not affect survival. Repeated removal of regenerating wax from juvenile leaves did not affect leaf‐settling or survival of C. spatulata. These results suggest that the epicuticular wax of juvenile leaves plays a role in resistance to C. spatulata and G. brimblecombei, however other unknown factors are probably also involved.
Mating disruption of the Japanese giant looper in tea gardens permeated with synthetic pheromone and related compounds
Authors: Ohtani Kazuya , Witjaksono  , Fukumoto Takehiko , Mochizuki Fumiaki , Yamamoto Masanobu , Ando Tetsu 
Published: October 2003

AbstractThe Japanese giant looper, Ascotis selenaria cretacea, is a serious defoliator of tea gardens in Japan. The females produce racemic (Z,Z)‐6,9‐cis‐3,4‐epoxynonadecadiene (epo3,Z6,Z9‐19:H, main component) and (Z,Z,Z)‐3,6,9‐nonadecatriene (Z3,Z6,Z9‐19:H, minor component). The orientation of the males to the synthetic pheromone placed in a trap was strongly disrupted by Z3,Z6,Z9‐19:H or a mixture of its monoepoxy derivatives (epoxydiene mixture, EDM) impregnated in septa and placed around the trap. Based on this result, polyethylene tubes containing Z3,Z6,Z9‐19:H or EDM were prepared and effect of these dispensers was examined in a field. Disruption of male orientation to synthetic pheromone traps was achieved in orchards permeated with Z3,Z6,Z9‐19:H at dispenser density of 3000 and 5000 tubes ha−1 (release rate: 0.55–0.61 mg day−1 tube−1) and with EDM at every tested dose, 250–5000 tubes ha−1 (release rate: 0.25–0.39 mg day−1 tube−1). Furthermore, disruption of mating in tethered females was observed in these orchards; particularly, the mating was perfectly inhibited in the areas treated with EDM at 3000 and 5000 tubes ha−1. This is the first formulation for the mating disruption of a geometrid pest.
Experimental simulation of some visual and physical components of a hedge and the effects on butterfly behaviour in an agricultural landscape
Authors: Dover J.W. , Fry G.L.A. 
Published: October 2003

AbstractExperiments on the corridor function of linear features in real landscapes are difficult and expensive to carry out using the classic replicated and controlled experimental regimes usually required as formal proof of a concept. We describe two experiments using model structures to simulate different attributes of hedges for their potential role in initiating corridor movement.We examined: (i) the visual signal or link provided by flowering plants associated with hedges (represented by a narrow red‐and‐white builder's warning tape) and (ii) the physical presence of the body of the hedge itself (represented by green horticultural windbreak). Removable, 100 m long, links were created between two habitat patches (Åkerholmer) in an arable field in Vestby, Norway. We recorded the effect of the links on the behaviour of three ‘species’ of the free‐flying butterfly community of the study area: the scarce copper (Heodes virgaureae), the heath fritillary (Mellicta athalia) and, as a complex, the high brown (Fabriciana adippe) and niobe fritillaries (F. niobe).The visual link did not elicit a uniform response by the different ‘species’. Significantly more high brown/niobe fritillaries flew along the visual link than along the control (no link) and mean distances traveled along the tape were significantly longer than for the control. The heath fritillary and scarce copper did not react in this way. The tape had a slight, but statistically significant, barrier effect on the scarce copper but did not act as a barrier to the other species.All three ‘species’ were strongly affected by the presence of the physical link. A significant barrier effect was detected for all three ‘species’ as was a corridor effect with an increased proportion of butterflies moving along the windbreak compared with the control. Mean distances traveled along the windbreak were significantly longer compared with the control, the response being strongest for the scarce copper.The results demonstrated that simple structures could modify the behaviour of species moving through the landscape and that individual species reacted in different ways to the same structure. The experimental approach of using model structures may have promise for modeling aspects of landscape elements in natural situations for a range of species. The results are discussed in relation to butterfly population structure, mate finding, dispersal and corridor design.
Life history study of Thrips setosus
Authors: Murai Tamotsu 
Published: October 2003

AbstractDevelopment, reproduction and population growth of Thrips setosus Moulton (Thysanoptera, Thripidae), reared on a leaf of kidney bean, was studied under six different constant temperatures, and the effect on reproduction of short photoperiod during immature stages was examined. Survival rates from hatch to adult were more than 67.5% at temperatures between 17.5 and 27.5 °C, but less than 55% at 30 °C. Developmental rates increased linearly as rearing temperature increased. A total of 181.1 degree‐days, above a developmental zero of 12.5 °C, were required to complete development from egg to adult oviposition. These data were related to records of field temperatures in Kurashiki in western Japan, and an estimate produced that, under outdoor conditions, a maximum of between seven and 12 generations could have developed annually between 1990 and 1999. There were no significant differences in mean adult longevity and mean fecundity among three temperatures (20, 22.5 and 25 °C). The intrinsic rate of natural increase (rm) was 0.1997 at 25 °C. Reproductive diapause was induced by a photoperiod less than 12 h at 20 °C.
Attraction of the fungus gnat Bradysia optata to cantharidin
Authors: Frank Jürgen , Dettner Konrad 
Published: October 2003

AbstractThe toxic terpenoid cantharidin has been reported to attract some specimens of undetermined fungus gnats. In order to investigate this phenomenon, the fungus gnat Bradysia optata Rudzinski, 1994 (Diptera: Sciaridae) was reared and its attraction to cantharidin was registered. Significant attractivity of the substance to males could be confirmed with both sticky baits in a greenhouse and an olfactometer under laboratory conditions. Ingestion of the toxic compound for chemical defence, which has been shown for some so‐called canthariphilous insects, was not observed. However, a high toxicity of cantharidin for the attracted species B. optata could be demonstrated. These unusual findings could be the result of the mycetophagous sciarids mistaking the terpenoid for certain structurally related fungal metabolites. These secondary metabolites might indicate a convenient meeting‐place for mating and oviposition.