bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of hosts, temperature and food sources on the longevity of Trichogramma platneri
Authors: McDougall S. J. , Mills N. J. 
Published: October 2003

AbstractFeeding experiments were conducted with Trichogramma platneri Nagarkatti (Hymenoptera: Trichogrammatidae) reared from the Angoumois grain moth, Sitotroga cerealella (Oliver) (Lepidoptera: Gelechiidae). T. platneri provisioned with host eggs do not live any longer than T. platneri without host eggs. Longevity of T. platneri is inversely related to temperature declining from 53 days at 10 °C to 3 days at 35 °C for honey‐fed parasitoids and from 9 days at 10 °C to 1 day at 35 °C for unfed parasitoids. Sugar sources are necessary to prolong longevity of T. platneri, but a source of amino acid did not promote longevity. Honey solutions greater than 10%, and 43% fructose and sucrose solutions increased longevity 10–13 fold to 15–20 days in comparison to water when fed daily to T. platneri. Parasitoids fed only at the onset of the trial had greater longevity than unfed parasitoids but had a shorter longevity than parasitoids fed daily, due to the evaporation of the sugar solutions and consumption of the honey. Aphid honeydew is a suitable field‐available sugar source supporting longevity up to 10 days, but is not as good as other sugar sources. Stabilizing additives did not reduce evaporation of a dilute sugar solution nor prolong longevity of T. platneri. Simulating a daily dew fall by misting vials, to redissolve the crystallized food residues left after providing food at the onset of the trial, failed to increase parasitoid longevity.
The influence of clutch size on survival and reproductive potential of Hessian fly
Authors: Withers T. M. , Madie C. , Harris M. O. 
Published: October 2003

AbstractThe clutch size laid by Hessian flies (Mayetiola destructor Say) (Diptera: Cecidomyiidae) was manipulated over a range of 1 to 30 eggs on single wheat plants (Triticum aestivum, L.). Pupae developing from egg clutches were removed from plants, counted and reared through to adult eclosion. Wing lengths of adult males and females were recorded and used as an indicator of body size. Survival to pupal and adult stages, as well as mean wing length of resulting males and females, decreased as clutch size increased. Wing length of females from clutches showed a positive linear relationship with potential fecundity. The benefits of small clutches for a female Hessian fly's offspring are discussed in the context of the foraging behaviour of the ovipositing female. We predict that under high probabilities of survival and availability of host plants, females will lay smaller‐sized clutches per plant. However when the probability of survival is low and host plants scare, the female will respond by laying larger‐sized clutches.
Effect of insectary rearing on host preference and oviposition behavior of the fruit fly parasitoid Diachasmimorpha longicaudata
Authors: Bautista Renato C. , Harris Ernest J. 
Published: October 2003

Abstract Diachasmimorpha longicaudata (Ashmead) has been produced in the laboratory for >160 generations on the larvae of oriental fruit fly, Bactrocera dorsalis (Hendel), the propagation hosts raised routinely on a semi‐synthetic wheat diet formulation. Choice tests using modified stinging units were conducted in the laboratory to investigate whether insectary rearing had altered the host seeking and oviposition behavior of female parasitoids. Results showed that fruit fly larvae that developed in papaya, Carica papaya L. var. ‘solo’, were less preferred for oviposition than fruit fly larvae that developed on wheat diet when both were exposed concurrently to naive D. longicaudata females (= females without prior oviposition experience). The substrates (pureed papaya or wheat diet) in which treatment larvae were exposed to parasitoids did not affect oviposition preference of gravid D. longicaudata for wheat diet‐reared fruit fly larvae. Our study demonstrated the possibility that rearing in an insectary system may have modified the parasitization behavior of female D. longicaudata.
Differential acquisition of chrysanthemum yellows phytoplasma by three leafhopper species
Authors: Bosco Domenico , Minucci Claudia , Boccardo Guido , Conti Maurizio 
Published: October 2003

AbstractChrysanthemum yellows (CY) phytoplasma has been transmitted with three leafhopper species: Euscelidius variegatus (Kirschbaum), Macrosteles quadripunctulatus (Kirschbaum) and Euscelis incisus (Kirschbaum): the first two species are reported as CY phytoplasma vectors for the first time. Leafhoppers were allowed to acquire the pathogen from the following source plants: Apium graveolens L., Catharanthus roseus L., Chrysanthemum carinatum Schousboe L. and C. frutescens L. DNA extracted from healthy or inoculative leafhoppers‐exposed plants were analyzed by dot‐blot and Southern hybridizations with a molecular probe constructed onto a fragment of European aster yellows phytoplasma DNA. The three leafhopper species were able to transmit CY phytoplasma after acquisition on chrysanthemum, but only M. quadripunctulatus and E. variegatus transmitted after feeding on periwinkle, and none acquired it from celery. All plant species tested were susceptible to CY, but while chrysanthemum and periwinkle were suitable for both inoculation and acquisition, celery did not seem to be a good source of phytoplasma for further inoculations. It is concluded that host plants influence leafhoppers' vectoring ability, possibly due to the different feeding behaviour of the insects on diverse plant species. Since CY, like several other phytoplasmas, can be transmitted by different insect species, it is likely that a close transmission specificity probably does not exist between phytoplasmas and their leafhopper vectors.
Monitoring of rice weevil, Sitophilus oryzae, feeding behavior in maize seeds and the occurence of supernumerary molts in low humidity conditions
Authors: Pittendrigh B. R. , Huesing J. E. , Shade R. E. , Murdock L. L. 
Published: October 2003

AbstractRice weevils, Sitophilus oryzae (L.), complete their development from egg to early adulthood inside grains of wheat, rice or maize, but little is known about their feeding behavior within the seeds. An ultrasonic insect feeding monitor was used to characterize the feeding patterns of individual rice weevils as they developed in maize grains. Weevils reared in grains held at ca. 40% r.h. took longer to develop from egg to pupation than those reared in grains kept at ca. 70% r.h. Feeding patterns revealed that larvae developing in grains held at ca. 70% r.h. had only four instars, whereas supernumerary molts (five instars) occurred in certain individuals reared in grain held at ca. 40% r.h. The supernumerary molts may represent a response of the insect to stresses associated with low moisture levels in the seeds.
Comparative susceptibility of two different hosts to genotypic variants of the Anticarsia gemmatalis nuclear polyhedrosis virus
Authors: Ribeiro H. C. T. , Pavan O. H. O. , Muotri A. R. 
Published: October 2003

AbstractThe susceptibility of third instar larvae of Anticarsia gemmatalis (Lepidoptera: Noctuidae) and Diatraea saccharalis (Lepidoptera: Pyralidae) to ten distinct plaque purified genotypic variants of a selected isolate of the Anticarsia gemmatalis multiple‐embedded nuclear polyhedrosis virus (AgMNPV), was compared. Despite the fact that this isolate, AgMNPV‐Ds20, represents a wild strain of the AgMNPV selected for higher virulence to D. saccharalis, an alternate host, most of the variants are much more virulent to the original host Anticarsia than to Diatraea. Bioassays have shown an over one hundred‐fold variation in LD50 values ranging from 1700 polyhedron inclusion bodies (PIBs) to more than 200 000 PIBs/larva. The PIB production in infected larvae increased with the pathogenicity of the variant to the host, showing an average ten‐fold reduction in Diatraea when compared to Anticarsia for the same variant. The virus particle yield ranged from 6×107 to more than 109 PIBs/g of infected larvae in Diatraea and from 8×108 to more than 1010 PIBs/g of infected Anticarsia larvae. The data show a clear difference of the pathogenicity of the genotypic variants of AgMNPV in vivo both between the original and alternate host and between the individual variants for the same host. These differences found in vivo indicate that monitoring of shifts in variant frequency of wild and laboratory‐propagated viral isolates in these highly heterogeneous populations would help ensure the efficacy of biological control programs.
Oviposition behavior of Anastrepha fraterculus in apple and diel pattern of activities in an apple orchard in Brazil
Authors: Sugayama Regina L. , Branco Elisabete S. , Malavasi Aldo , Kovaleski Adalecio , Nora Ildelbrando 
Published: October 2003

AbstractThe oviposition behavior and diel pattern of activities of Anastrepha fraterculus (Wied.) (Diptera: Tephritidae) were observed in an apple orchard and fruit characteristics involved in oviposition preferences were investigated in field cage tests. Fruit size influenced fruit acceptability as an oviposition site by females which did not discriminate among the cultivars ‘Gala’, ‘Fuji’, and ‘Golden Delicious’ when same‐size fruits were presented simultaneously. Oviposition behavior in apples was basically the same as that described for primary hosts. Hourly census of fly activity indicated that adults did not overnight in the orchard and that they entered the orchard around 1100 h when temperature reached about 21 °C. Bird droppings were an important food item for adults. Behavioral differences between males and females might account for a significant biased sex ratio both in the orchard and at the edge of the native surrounding vegetation. Implications for fruit fly management in Brazilian apple orchards are discussed.
Dropping of pea aphids from feeding site: a consequence of parasitism by the wasp, Monoctonus paulensis
Authors: Chau Amanda , Mackauer Manfred 
Published: October 2003

AbstractWe examined the dropping behaviour of the pea aphid, Acyrthosiphon pisum (Harris), feeding on broad‐bean plants in the laboratory. Aphid responses to foraging and oviposition by females of Monoctonus paulensis (Ashmead) were instar‐specific and included kicking with the hind legs, walking away and dropping from the feeding site. Fourth nymphal instars were most likely to drop, followed by second, third, and first instars, in that order. Compared with first instars, the odds that a fourth‐instar aphid will drop were 6‐times higher independent of the stimulus, and 16‐times higher after parasitoid attack. Dropping from the feeding site increases an aphid's mortality risk. If parasitoid offspring are more likely to survive in small pea aphids, it may be adaptive for M. paulensis to choose smaller hosts, regardless of possible fitness gains due to increased body size from development in larger aphids.
Sublethal effects of Bacillus thuringiensis on the spruce budworm, Choristoneura fumiferana
Authors: Pedersen Anita , Dedes John , Gauthier Debbie , van Frankenhuyzen Kees 
Published: October 2003

AbstractExposing larvae of the spruce budworm, Choristoneura fumiferana (Clemens), to sublethal (≤ 50% lethal dose) levels of Bacillus thuringiensis subsp. kurstaki at various stages of their development significantly increased development time to the pupal stage and reduced pupal size and number of eggs laid per female, but did not affect the proportion of embryonated eggs. The changes in larval development time, pupal weight and fecundity depended on the larval stage that was treated. Exposure of fourth instars delayed larval development and reduced only male pupal weights with no effects on fecundity. Exposure of sixth instars delayed larval development to a lesser extent than exposure of fourth instars but had a pronounced effect on weight of both male and female pupae. The effect on pupal weight was sex dependent, as males tended to be more affected than females. The reduction in male pupal weight did not appear to influence fecundity, because the effect of exposure was explained by the change in female pupal weight. Effects on larval growth and pupal weight were proportional to the dose that was ingested during exposure, and were observed at doses as low as one‐tenth of the LD50. Ingestion of an LD50 caused a 29 or 45% delay in development of, respectively, female or male larvae when exposed as fourth instars and a 30% reduction in female pupal weight when larvae were exposed as sixth instars.
The effects of ingested ecdysteroid agonists (20‐hydroxyecdysone, RH5849 and RH5992) and an ecdysteroid antagonist (cucurbitacin B) on larval development of two polyphagous lepidopterans (Acherontia atropos and Lacanobia oleracea)
Authors: Blackford Michaela , Dinan Laurence 
Published: October 2003

AbstractLarvae of two polyphagous lepidopteran species, Lacanobia oleracea (Tomato moth) and Acherontia atropos (Death's head hawkmoth), have been treated with representatives of three classes of compounds which are known to interact with the ligand binding site of insect steroid hormone receptors: a steroidal ecdysteroid (20‐hydroxyecdysone; 20E; agonist), two non‐steroidal dibenzoylhydrazines (RH5849 and RH5992; agonists) and the triterpenoid cucurbitacin B (cucB; antagonist). Both species are unaffected by dietary 20E at concentrations up to 400 ppm. L. oleracea metabolises ingested [3H]20E to a mixture of C‐22 fatty acyl esters, while A. atropos excretes [3H]20E unmetabolised. Both species are susceptible to the dibenzoylhydrazines when these are incorporated into the diet, with RH5992 proving lethal at 1 ppm and RH5849 proving lethal at 10 ppm. Thus, the metabolic/excretion mechanisms which are so effective against ingested 20E do not recognise the non‐steroidal agonists. The two species showed varying degrees of tolerance to cucB; L. oleracea was unaffected by 400 ppm in the diet, while A. atropos showed effects at 400 ppm, but not at 40 ppm. Feeding cucB in conjunction with 20E or injecting cucB when the ecdysteroid titre was low or rising also had no effect in L. oleracea. It is suggested that tolerance to the two classes of natural products (ecdysteroids and cucurbitacins) is associated with the occurrence of these compounds in some of the host plants of these species; evidence is presented for the presence of phytoecdysteroids in the host plants.
Host selection and sex allocation in Leptomastidea abnormis, a parasitoid of the citrus mealybug Planococcus citri
Authors: Cadée Niels , van Alphen Jacques J.M. 
Published: October 2003

Abstract Leptomastidea abnormis (Girault) and Leptomastix dactylopii (Howard) [Hymenoptera: Encyrtidae] are the two parasitoid species frequently used for biological control of the citrus mealybug Planococcus citri (Risso) [Homoptera: Pseudococcidae]. As part of a programme to determine the best control practice, host size selection and sex allocation were studied in L. abnormis, and compared with those of L. dactylopii. L. abnormis showed a preference for the second size class, but also attacked third and fourth size class and adult mealybugs, while in previous studies L. dactylopii was found to prefer the third and fourth size class and adults, and never attacked second size class mealybugs. Female L. abnormis reared from parasitized mealybugs had a higher mean body mass than males, as is predicted by Charnov's theory on sex allocation. However, sex ratios of emerging L. abnormis did not differ between mealybug size classes. These results imply possibile coexistence of the two parasitoids. As field evidence suggests a more complex interaction between the two species, studying direct competition would be a useful next step.
Willow hybridization differentially affects preference and performance of herbivorous beetles
Authors: Orians Colin M. , Huang Cynthia H. , Wild Alexander , Dorfman Katherine A. , Zee Pamela , Dao Minh Tam T. , Fritz Robert S. 
Published: October 2003

AbstractWe examined the preferences and performances of five beetle species (four chrysomelids and one scarab) on two species of willows (Salix sericea and S. eriocephala) and their interspecific hybrids. Beetle species differed markedly in their responses. In preference assays, two chrysomelid beetle species (Calligrapha multipunctata bigsbyana and Plagiodera versicolora) preferred hybrids, two chrysomelids (Chrysomela scripta and Ch. Knabi) preferred hybrids and S. sericea, and the scarab beetle (Popillia japonica) preferred S. eriocephala. Experiments with purified salicortin indicated that salicortin concentration may contribute to these preferences.The relative performance (growth rate, pupal/adult weight and survivorship) of these beetles on the three willow taxa did not correspond with their feeding preferences. Three species exhibited intermediate performance on hybrid willows (the two Chrysomela spp. and P. japonica); the Chrysomela spp. performed best on S. sericea, while P. japonica performed best on S. eriocephala. One species performed equally well on all three taxa (C. multipunctata bigsbyana). The performance of Pl. versicolora was not tested.Our results support the general pattern that willow taxa with phenolic glycosides are more acceptable to specialist willow herbivores while those taxa without phenolic glycosides are more acceptable to generalist herbivores. We also show that to predict the relative susceptibility of hybrid and parental plants to herbivores, consideration must be given to the inheritance of traits affecting both preference and performance.
Effect of chronic ingestion of the cysteine proteinase inhibitor, E‐64, on Colorado potato beetle gut proteinases
Authors: Bolter Caroline J. , Latoszek‐Green Marysia 
Published: October 2003

AbstractChronic ingestion of the highly active, specific cysteine proteinase inhibitor, E‐64, has a profound effect on Colorado potato beetle (CPB) larval growth, development and survival, as well as on adult fecundity. However, the number of insects surviving to the adult stage did not decrease below 26% with increasing E‐64 concentration above 1.5 μg E‐64 cm−2 leaf surface. The development time to the pupal stage was increased from 13 days, when larvae were reared on control leaves, to 21 days at a concentration of 1.5 μg E‐64 cm−2. The most significant effect of dietary E‐64 was on adult fecundity, with mated females reared on untreated leaves laying an average 62 ± 5.7 eggs daily in the first 10 days, and those maintained on 0.5 μg E‐64 cm−2, laying only 16 ± 2.4 eggs day−1. Females given 1 μg E‐64 cm−2 laid few if any eggs, but started producing egg masses as large as control insects about 5 days after being switched to control leaves. These effects on the insect life cycle were directly related to the degree of inhibition of cysteine proteinase activity in gut extracts. The general proteinase activity in control extracts was 6.5 ± 0.16 units min−1 mg gut−1, which decreased to 1.9 ± 0.16 in guts of insects reared on 1 μg E‐64 cm−2. The proportion of proteinase activity inhibitable by E‐64 decreased from 66% in control guts to 10‐15% in guts from larvae reared on 1 μg E‐64 cm−2. The aspartate proteinase inhibitor, pepstatin, decreased proteinase activity by 35% in control guts. There was no induction of pepstatin‐inhibitable proteinases in response to inhibition by E‐64, and no inhibition of gut enzyme activity by soybean trypsin inhibitor from larvae fed any of the E‐64 concentrations. This study demonstrates that proteinase levels must be significantly reduced to have a pronounced effect on larval growth and survival, while fecundity of mated females is affected by lower concentrations of inhibitor. It also suggests that the CPB may be a difficult pest to control using a more specific, plant‐derived cysteine proteinase inhibitor, such as oryzacystatin.
Adult feeding and lifetime reproductive success in the parasitoid Aphytis melinus
Authors: Heimpel George E. , Rosenheim Jay A. , Kattari David 
Published: October 2003

AbstractThe diet of adult females of the parasitoid Aphytis melinus DeBach (Hymenoptera: Aphelinidae) includes host insects and sugar‐rich foods such as nectar and honeydew. We compared the contributions of host feeding to longevity and fecundity in A. melinus females in the presence and in the absence of honey meals. First, we assessed the longevity of females that were not allowed to oviposit. While the longevity of females fed honey was significantly increased by host feeding (median ages were 30.5 days for host‐fed females and 17 days for females not allowed to host feed), the lifespan of parasitoids not fed honey did not exceed 3 days for any individual and there was no effect of host feeding on longevity in this group. In the second set of experiments, we assessed the fecundity and longevity of females allowed to oviposit. We conducted two experiments, one in which honey was continuously available, and one in which honey was not available. In both experiments, daily observations were made of females that were either allowed to host feed or manually prevented from host feeding. In the presence of honey, host feeding significantly increased both fecundity and longevity, and in the absence of honey, parasitoids died within 2 days and host feeding had no significant effect on either fecundity or longevity. The lifetime fecundity of females fed honey but not hosts exceeded the initial egg complement by 60% on average. Approximately one host per day was used for host feeding whether honey was supplied or not, and each host‐feeding meal contributed approximately 3.9 eggs to the lifetime fecundity of honey‐fed females. In the last experiment, we compared the rate of egg resorption over a 36‐h period in A. melinus females that were deprived of hosts and either fed honey or starved. While no egg resorption was detected in honey‐fed females over this time period, starved females resorbed approximately 9 eggs. Thus, the availability of a sugar‐rich food interacts strongly with host feeding in influencing longevity and fecundity and has a strong direct effect on egg resorption.
Comparison of the performance of Cicadulina leafhoppers on flight mills with that to be expected in free flight
Authors: Riley J. R. , Downham M. C. A. , Cooter R. J. 
Published: October 2003

AbstractFlight mills are commonly used to assess the relative flight performance of migratory insects, but uncertainties about the rate of energy expenditure on the mill mean that absolute estimates of flight endurance are not usually attempted. In this paper we describe how we measured the power delivered to a lightweight flight mill by tethered Cicadulina storeyi China leafhoppers (Homoptera: Cicadellidae), and compared this to estimates of the power they use to maintain free flight. Our results showed that the leafhoppers were generating more than 0.90 μW of mechanical power when on the mill, and that they probably have 3–4 μW available for free flight. We conclude that whilst flying on the mill, the insects were generating at least 20–30% of the mechanical power needed for free flight, and that this percentage may have been significantly higher.