bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative efficacy of two controlled‐release gypsy moth mating disruption formulations
Authors: Thorpe K.W. , Mastro V.C. , Leonard D.S. , Leonhardt B.A. , McLane W. , Reardon R.C. , Talley S.E. 
Published: October 2003

AbstractThe effects of aerial applications of the gypsy moth sex pheromone, disparlure, on mating disruption and suppression of growth of populations of the gypsy moth, Lymantria dispar (L.), were investigated. Two formulations of disparlure, plastic laminate flakes applied in a single application and polymethacrylate beads applied in two applications, were compared in two separate tests conducted in 1993 and 1994. The beads were applied in two applications spaced 2 weeks apart because preliminary tests had indicated that they released pheromone too rapidly to maintain adequate emission rates throughout the period of male flight. In 1993, the flakes were applied at a rate of 50 g a.i./ha, and the beads were applied at a rate of 15 g a.i./ha for each application. In 1994, the flakes were applied at a rate of 75 g a.i./ha and the beads were applied at rates of 32.5 and 42.5 g a.i./ha for the two applications. Beads with larger average particle size were used in 1994 to prolong disparlure release. The treatments applied in 1993 resulted in >97% reduction in mating and >82% suppression of population growth in the following year. Because of a 1995 collapse of gypsy moth populations in the vicinity of the tests, reliable population growth data were not available for the treatments applied in 1994, but significant mating disruption did occur under both treatments. Based on measurements of residual disparlure after field aging, the flakes released 32 and 48% of their disparlure content during the 6 weeks of male moth flight in 1993 and 1994, respectively. The smaller beads used in 1993 released 75% of their disparlure content, and the larger beads used in 1994 released 52% of their disparlure content, during the 6 weeks of male flight. The biological efficacy data suggest that the bead and flake formulations, as applied in these tests, have similar effects on gypsy moth mating disruption and subsequent population growth. Based on the observed release rates from both 1993 and 1994, a single application of the beads would provide emission rates equal to or greater than those provided by the flakes when applied at an equal dose.
Effects of experimental stress factors on probing behaviour by aphids
Authors: Prado Ernesto , Tjallingii W. Freddy 
Published: October 2003

AbstractProbing behaviour of Aphis fabae Scopoli and Rhopalosiphum padi (L.) was tested in different stress situations normally occurring in aphid‐plant studies such as interruption of feeding or starvation, transfer to a new plant, and attachment to the electrode wire. The DC electrical penetration graph (EPG) technique and a ‘honeydew clock’ were used to collect data on behavioural effects of these stress conditions. As a general effect, an interruption of feeding behaviour acted as a ‘reset‘, i.e., the same sequence and time course of probing events were shown, irrespective the interruptions duration, from 1–100 min. Nevertheless, some minor differences were found, especially in A. fabae. Increased interruption times (deprivation from the host plant) stimulated the aphids to insert their stylets earlier. When A. fabae was put back on its host plant after a one min interruption phloem feeding started earlier than with longer interruption times, but only when it was put back to the same plant and feeding site on which it fed before. It is concluded that this effect is at least partly due to ‘memory’ of previous probing/feeding experience on the plant as it vanishes with longer interruption times. This explanation also holds for phloem salivation (E1) before starting sustained sap ingestion, which was reduced on the previous feeding site, but only after the one min interruption in A. fabae. The aphid‐plant specificity appeared high in these effects. Both aphids were somewhat affected by wiring, resulting in earlier probing, longer total pathway phase, and less and later phloem feeding (as reflected by honeydew excretion). Thus confirming, that the evaluation of EPG results can be improved with supplementary data from free aphids.
Isolation of insecticidal lectin‐enriched extracts from African yam bean (Sphenostylis stenocarpa) and other legume species
Authors: Omitogun O.G. , Jackai L.E.N. , Thottappilly G. 
Published: October 2003

AbstractInsecticidal lectins were isolated from 20 resistant Vigna and non‐Vigna legumes and tested againstn 3 pests of cowpea namely: Maruca vitrata, Callosobruchus maculatus and Clavigralla tomentosicollis. Crude lectins were separated from seeds using sodium chloride extraction, ammonium sulfate fractionation, and dialysis. SDS‐PAGE indicated the molecular size of ca. 30 kDa for the most intense (and presumably active) band. Haemagglutination assays using trypsin‐treated rabbit erythrocytes suggested that lectins were among the extracted proteins. Extracts from Lablab purpureus and Sphenostylis stenocarpa both non‐Vigna spp., caused greater agglutination than those from the wild Vigna species. Bioassays on all three insect species using the lectin extracts incorporated in either artificial cowpea seeds (5% w/w) or in modified Vanderzant legume pod borer diet (1% w/v) indicated that the non‐Vigna extracts were highly toxic to the insects. Mortality after 10 days was >80% in the most toxic extracts. The extract from one of the accessions of Sphenostylis stenocarpa, an edible legume, was singled out for lectin purification and future gene cloning with the view of using it for engineering resistance to cowpea pests.
Factors influencing dispersal of larval Coleomegilla maculata from the weed Acalypha ostryaefolia to sweet corn
Authors: Cottrell Ted E. , Yeargan Kenneth V. 
Published: October 2003

AbstractThe polyphagous predator, Coleomegilla maculata (DeGeer) (Coleoptera: Coccinellidae), commonly oviposits on the native weed, Acalypha ostryaefolia Riddell (Euphorbiaceae), in and around Kentucky sweet corn fields. Cannibalism of eggs by C. maculata adults and larvae is drastically lower on A. ostryaefolia than on nearby sweet corn plants. We examined ovipositional preference of C. maculata for A. ostryaefolia plants or sweet corn plants, dispersal of larvae from A. ostryaefolia plants, capability for dispersal of larvae across bare soil (e.g., to nearby plants), ability of larvae to climb from ground level up A. ostryaefolia plants or sweet corn plants, and effect of A. ostryaefolia borders adjacent to sweet corn plots on C. maculata population density in sweet corn. The ovipositional preference study revealed that C. maculata laid more eggs on A. ostryaefolia than on corn. First‐instar C. maculata that hatched from egg clusters on A. ostryaefolia dispersed predominantly by falling, rather than crawling, to the ground. Glandular trichomes on A. ostryaefolia petioles and stems apparently inhibited intraplant movement of first instars, resulting in those larvae falling directly from leaves to the ground. Some first instars were capable of moving at least 8 m across bare soil in 24 h. From the ground, significantly more first instars climbed sweet corn plants than climbed A. ostryaefolia plants. Significantly more larvae were present in sweet corn plots bordered by A. ostryaefolia plants than in sweet corn plots without an A. ostryaefolia border. These findings show that physical attributes of companion plants can significantly influence natural enemy populations on crop plants by affecting interplant dispersal of natural enemies.
Chemo‐discriminatory neurones in the sub‐oesophageal ganglion of Locusta migratoria
Authors: Rogers Stephen M. , Simpson Stephen J. 
Published: October 2003

AbstractThe sub‐oesophageal ganglion of Locusta migratoria was searched for neurones responsive to stimulation of the maxillary palps using intracellular recording techniques. Two plant stimuli were used: wheat, a host plant and cabbage, an unacceptable non‐host plant. The stimuli were presented to the palp as both intact leaf tissue and as droplets of aqueous solutions of plant extracts. All the sampled neurones that responded to stimulation of the palp also responded to simple mechanical stimulation. However, 25% of the neurones exhibited consistent differences in response to the two plants when presented as both leaf tissue and droplets, strongly suggesting that they also received a chemosensory input. These differential responses most commonly took the form of differences in the duration of cell activity and/or variation in the latency of the onset of response. The receptive fields of differentially responding neurones were confined to the maxillary palp, or at most to the maxillary and labial palps.
Specialist deterrent chemoreceptors enable Pieris caterpillars to discriminate between chemically different deterrents
Authors: van Loon Joop J.A. , Schoonhoven Louis M. 
Published: October 2003

Abstract Pieris butterflies (Lepidoptera: Pieridae) are specialist herbivores of cruciferous plants. They exploit glucosinolates, secondary plant metabolites chemotaxonomically characteristic for this plant family, as token stimuli. In addition to particular glucosinolates, some genera of the Cruciferae contain cardenolides, steroidal allelochemicals that act as potent feeding and oviposition deterrents to several Pieris species. We investigated the sensory mechanisms by which these compounds are perceived in larvae. Pieris caterpillars and many other lepidopterous species are endowed with so‐called generalist deterrent receptors, that respond to a broad spectrum of secondary plant substances. In Pieris caterpillars we found a second type of deterrent chemoreceptor in maxillary styloconic taste sensilla. This neuron is very sensitive to cardenolides (threshold 0.1–0.3 μM). The generalist deterrent receptor also responds to these substances but its threshold lies at 50–100× higher concentrations. In behavioural preference experiments Pieris brassicae L. caterpillars preferred cardenolide‐treated cabbage leaf discs when confronted with a choice between them and a deterrent substance that does not occur in the Brassicaceae. The cardenolides acted as potent deterrents when offered against untreated cabbage leaf discs. This demonstrates that the balance of activity elicited in the two types of deterrent chemoreceptors determines the behavioural decision.
Integrating nutrition: a geometrical approach
Authors: Raubenheimer D. , Simpson S.J. 
Published: October 2003

AbstractWe present and illustrate using data from insects an integrative approach to modelling animal nutrition. This framework enables the unification within simple geometrical models of several nutritionally relevant measures. These include: the optimal balance and amounts of nutrients required to be ingested and allocated to growth by an animal over a given time period (the intake and growth targets, respectively); the animal's current state in relation to these requirements; available foods and the consequences for the animal's state of ingesting them; the amounts of ingested nutrients that are retained and eliminated; and animal performance. Data are presented on intake targets in insects, illustrating how they change over various time‐scales (physiological, developmental, and evolutionary). Most importantly, the geometrical approach enables a clear description to be made of the trade‐offs reached by animals in regulating their nutritional balance. Animals given a nutritionally balanced food, or two or more imbalanced but complementary foods, can satisfy their nutrient requirements. However, those eating non‐complementary imbalanced foods must reach a suitable compromise between over‐ingesting some nutrients and under‐ingesting others. Data are presented comparing the rules of compromise for protein and carbohydrate ingestion in grass‐feeding (Locusta migratoria) and polyphagous (Schistocerca gregaria) locusts.
Absence of food‐aversion learning by a polyphagous scarab, Popillia japonica, following intoxication by geranium, Pelargonium × hortorum
Authors: Potter Daniel A. , Held David W. 
Published: October 2003

AbstractIt is commonly held that food‐aversion learning should be more prevalent in polyphagous herbivores than in specialists. We tested the ability of Popillia japonica, a polyphagous scarab, to learn avoidance of a palatable but illness‐inducing plant. Beetles that feed on flowers of geranium, Pelargonium × hortorum, became paralyzed, although most recovered within 24 h. In choice tests, naive beetles strongly preferred geranium petals over leaves of linden, Tilia cordata, a highly suitable host. Experienced beetles maintained this preference although it resulted in repeated bouts of paralysis. Fecundity was >10 times higher for beetles fed linden foliage for 2 wk than for those fed only geranium. Nevertheless, when a surplus of both foods was provided, the beetles fed mainly on geranium, resulting in greatly reduced fecundity. These results contradict the view that generalists should show propensity for food‐aversion learning. Indeed, in this case, P. japonica continued to prefer the toxic plant, compromising its fitness.
Examining the hierarchy threshold model in a no‐choice feeding assay
Authors: Withers Toni M. 
Published: October 2003

AbstractThe hierarchy threshold model of individual insect diet predicts the acceptance or rejection of individual hosts when encountered by insects. One assumption of the hierarchy threshold model is that ‘post‐discrimination phase’ insects which accept lower ranked hosts will also accept hosts that are ranked higher. This assumption does not however suggest whether or not such insects behave differently when encountering these two hosts. This question is explored using Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae). Adult beetles that had just fed, or were one inter‐meal interval after feeding, or were deprived for three or six days after feeding, were individually observed on a plant that either ranked high, Parthenium hysterophorus L., or low Xanthium occidentale Bertol. (Heliantheae: Ambrosiinae) in choice tests. Just‐fed beetles were generally unresponsive to either host plant and did not feed. Beetles held for one inter‐meal interval showed more feeding responses (shorter lag time between sampling and feeding, higher proportions of individuals feeding, and more time feeding) towards the higher ranked plant. As the beetles approached six days deprivation, behaviours of sampling, feeding and locomotion differed less between the two plants, but were still apparent. I conclude that food deprived Z. bicolorata beetles do still discriminate between the two plants. This result partially supports the hierarchy threshold model.
Anomalous stylet punctures of phloem sieve elements by aphids
Authors: Tjallingii W. Fred , Gabryś Beata 
Published: October 2003

AbstractA deviating type of potential drop (pd), i.e. the electrically recorded intracellular punctures during the pathway phase of plant penetration by aphids, is described and discussed. This so‐called repetitive pd (R‐pd) has been observed in 4 aphid species, two on herbs and two on sycamore. Apart from a regular repetition with short intervals, the most characteristic feature of the R‐pd is the middle intracellular part, i.e. sub‐phase 2, which is extended, making the individual R‐pd 2–3 times longer than the normal pd. Differences between the normal and R‐pd are described, as well as differences within each pd type between species. The R‐pd's seem to reflect repeated punctures of phloem sieve elements. Their biological significance is unknown.
Acceptability of different species of Brassicaceae as hosts for the cabbage aphid
Authors: Gabryś Beata , Pawluk Magdalena 
Published: October 2003

AbstractThe probing and feeding behaviour of the cabbage aphid, Brevicoryne brassicae (L.), (Homoptera, Aphididae) was studied on several plant species that represented various levels of acceptability: Sinapis alba L. (a permanent host plant), Capsella bursa‐pastoris (L.) Med., Thlaspi arvense L., Lunaria annua L., Erysimum cheiranthoides L. (accidental host plants), Vicia faba L. (a non‐host plant), using the electrical penetration graph technique (EPG). B. brassicae on V. faba did not show any patterns related to penetration of phloem vessels. Stylet penetration was deterred on L. annua and E. cheiranthoides where non‐penetration prevailed, the periods of sap ingestion were short or did not occur, the percentage of time spent in the phloem was consistently low (5–6%) and E1 salivation predominated. The pathway activities were not suppressed on C. bursa‐pastoris and T. arvense and the aphids spent an average of 3 h in the phloem during the 8‐h experiment. However, a considerable delay between finding and accepting the phloem and a substantial proportion of E1 salivation (20–30% of all phloem activities) indicated a deterrent factor in the sieve elements of these plants. Aphid probing and sap ingestion were rarely interrupted on S. alba. The results of this study suggest that the deterrent agents vary in activity and may hinder stylet penetration at different levels (epidermis, parenchymatous tissues and/or phloem elements), depending on the plant species.
Active defence of herbivorous hosts against parasitism: Adult parasitoid mortality risk involved in attacking a concealed stemboring host
Authors: Potting R.P.J. , Vermeulen N.E. , Conlong D.E. 
Published: October 2003

AbstractPhytophagous insects have several defence strategies to defend themselves against attack by parasitic wasps. Larval lepidopteran hosts can defend themselves actively to prevent oviposition by the parasitoid. Among the aggressive kinds of behaviour exhibited by hosts against parasitoids are violent wriggling, biting and spitting. The behaviour of the braconid parasitoid Cotesia sesamiae attacking stemboring larvae inside their feeding tunnel in the plant stem was investigated in maize and sugarcane stem pieces and transparent artificial tunnels. Attacking a defending stemborer host inside the confined space of a tunnel was shown to be risky for the female parasitoid. A considerable proportion (25%) of female wasps were killed in their attempt to attack the spitting and biting host. No difference was found in the behaviour of C. sesamiae attacking the suitable host Sesamia calamistis or the unsuitable host Eldana saccharina. The consequences of this high mortality risk involved in each host attack is discussed in relation to the ecology of the parasitoid.
Flowers in tri‐trophic systems: mechanisms allowing selective exploitation by insect natural enemies for conservation biological control
Authors: Baggen L.R. , Gurr G.M. , Meats A. 
Published: October 2003

AbstractMany insects have coevolved with certain angiosperm taxa to act as pollinators. However, the nectar and pollen from such flowers is also widely fed upon by other insects, including entomophagous species. Conservation biological control seeks to maximise the impact of these natural enemies on crop pests by enhancing availability of nectar and pollen‐rich plants in agroecosystems. A risk with this approach is that pests may also benefit from the food resource. We show that the flowers of some plants (viz., buckwheat, Fagopyron esculentum Moench and dill, Anethum graveolens L.), and the extrafloral nectaries of faba bean (Vicia faba L.) benefit both Copidosoma koehleri Blanchard (Hymenoptera: Encyrtidae) and its host, the potato pest, Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae). In contrast, phacelia (Phacelia tanacetifolia Benth) and nasturtium (Tropaeoleum majus L.) benefited only the parasitoid. When adult moths of P. operculella were caged with flowers of phacelia or nasturtium, longevity of males and females, egg laying life, fecundity, average oviposition rate, and number of eggs in ovaries at death were no greater than in the control treatment with access to shoots without flowers plus water. All the foregoing measures were increased compared to the control when the moths were allowed access to dill, buckwheat or faba bean extrafloral nectaries. Such ‘selectivity’ has the potential to make the use of floral resources in conservation biological control more strategic. We present morphometric and observational evidence to illustrate how such mechanisms may operate.
Vive la variance: a functional oviposition theory for insect herbivores
Authors: Roitberg Bernard D. , Robertson Ian C. , Tyerman Jabus G.A. 
Published: October 2003

AbstractWe developed state‐dependent life‐history theory to explain the variance in clutch size decisions made by insect herbivores under a variety of ecological scenarios. An important aspect of our theory is explicit representation of the distribution of host quality and frequency of occurrence. Examination of the theory suggests that clutch size decisions can be highly non‐linear with respect to host quality and variability. We then use our theory to explore the potential for bet‐hedging strategies to evolve as a function of unpredictable catastrophic events that decimate entire clutches. Our analysis suggests that the benefits to employing such a strategy will frequently be outweighed by costs brought on by delayed oviposition.
The assimilation and allocation of nutrients by symbiotic and aposymbiotic pea aphids, Acyrthosiphon pisum
Authors: Wilkinson T.L. , Ishikawa H. 
Published: October 2003

AbstractThe failure of a nutritionally balanced diet to ameliorate the impact of symbiont disruption in the pea aphid Acyrthosiphon pisum (Harris) was investigated using two approaches. The assimilation of dietary nutrients by aphids was investigated using chemically‐defined diets containing 3H‐labelled inulin and 14C‐labelled sucrose or amino acids. Symbiotic aphids (i.e., aphids containing their bacteria) had a high sucrose demand and assimilated 72% of sucrose ingested in the diet, whereas the assimilation of sucrose by aposymbiotic aphids (in which the bacteria had been disrupted), was significantly reduced to 47%. The assimilation of individual dietary amino acids by symbiotic aphids varied between 61 and 92%, and there was no impact on the feeding or assimilation rate when the aphids were fed a ‘phloem sap‐like’ diet containing a reduced amount of essential amino acids. Consequently, the absolute amount of each essential amino acid assimilated by symbiotic aphids feeding on a ‘phloem sap‐like’ diet was reduced by 36–59%. Aposymbiotic aphids consistently assimilated a lower proportion of ingested amino acids, and lysine in particular was poorly assimilated from the diet. In a second experiment, the allocation of free amino acids in the haemocoel to aphid embryos was investigated following microinjection of 14C‐labelled amino acids. After 2 h, radiolabel could be detected at varying levels from the embryo complement of both symbiotic and aposymbiotic aphids, indicating rapid but selective uptake by the embryos. The essential amino acids phenylalanine and lysine were incorporated into the protein fraction of embryo tissues, but the rate of incorporation per unit biomass was approximately 4‐fold higher in the embryos of aposymbiotic aphids, possibly reflecting increased demand due to the lack of amino acid provisioning from the symbiotic bacteria.