bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel test system for detection of tick repellents
Authors: Dautel H. , Kahl O. , Siems K. , Oppenrieder M. , Müller‐Kuhrt L. , Hilker M. 
Published: October 2003

AbstractA bioassay was developed to examine the response of ticks towards potential repellents that may protect vertebrates against tick bites. Such tick repellents must be effective despite the unavoidable presence of various attractive host‐derived stimuli. Therefore, a moving‐object‐bioassay (MO‐bioassay) was developed that mimicks body warmth and movement of vertebrates by a rotating and heated drum. Compounds which were tested for their effects on ticks were applied onto a small elevated area of the drum. Ticks were allowed to approach the drum by walking on a glass rod which ended ≈1 mm away from the local elevation. Ticks could cling to this elevation that intermittently passed by, whereas the remaining drum surface was too far away from the tip of the rod to be contacted by the ticks.Without the presence of any repellents, 85.5% of 600 hungry, field‐collected Ixodes ricinus nymphs moved to the heated, rotating drum within 2 min. Further experiments with unfed I. ricinus nymphs were performed to test whether one established and two potential tick repellents elicit an avoidance reaction in the ticks despite the proven attractiveness of the drum. Freshly applied DEET (N,N‐diethyl‐m‐toluamide) at a concentration of 0.11 mg cm−2 proved active as a repellent in the MO‐bioassay over a distance of a few mm as well as by direct contact. A similar repellent effect was observed with (−)‐myrtenal at 1 mg cm−2, but not at 0.1 mg cm−2, indicating that this terpenaldehyde is a weaker repellent for I. ricinus nymphs than DEET. No repellent effect was observed with camphor (0.1 mg cm−2).The MO‐bioassay thus is a rapid, simple and low‐cost test method allowing the investigation of tick host‐contact behaviour as well as the screening of candidate repellents which are either perceived as volatiles or via contact chemoreception.
Reproductive status and flight activity of the overwintered Colorado potato beetle
Authors: Ferro David N. , Alyokhin Andrei V. , Tobin Daniella B. 
Published: October 2003

AbstractMating behavior of post‐diapause Colorado potato beetles, Leptinotarsa decemlineata (Say), was observed within an overwintering site, a rotated potato field, newly colonized potato plants, and under laboratory conditions. The influence of spring mating on beetle flight in the presence and in the absence of host plants was investigated using a computer‐linked flight mill system. Diapause was terminated simultaneously in male and female beetles, and the first matings were observed as early as within the first 24 h after the beetles emerged from the soil (60–90 DD accumulated). The beetles mated within the overwintering site, the potato field, and the fields rotated out of potatoes. Mating status did not affect flight behavior of overwintered beetles; however, unfed beetles displayed higher flight activity than fed beetles. Most flight activity took place soon after flight muscle regeneration, and then declined sharply by the 5th day after flight initiation. Mating in or near overwintering sites soon after diapause termination might be an important factor in providing gene flow between insecticide‐resistant and insecticide‐susceptible Colorado potato beetle populations, and should be considered in designing resistance management plans.
A new Y‐tube olfactometer for mosquitoes to measure the attractiveness of host odours
Authors: Geier Martin , Boeckh Jürgen 
Published: October 2003

AbstractIn a new bioassay a small Y‐shaped wind tunnel is used to quantitatively investigate the responses of mosquitoes to host odours. Female yellow fever mosquitoes, Aedes aegypti (L.) (Diptera: Culicidae) were tested to (1) a human hand, (2) an extract with human skin residues, (3) L‐(+)‐lactic acid, and (4) carbon dioxide. The responses to the skin extract followed a sigmoid dose response curve. The most effective dose attracted 80–90% of the mosquitoes within 30 s and was as effective as the human hand. L‐(+)‐lactic acid was identified in this extract and found attractive for mosquitoes also when presented alone. Carbon dioxide stimulated taking flight and was attractive, an effect which was synergistically enhanced in combination with L‐(+)‐lactic acid. The presented bioassay is especially suited to test the behavioural effects of synthetic odours as well as of natural odour sources. Due to the fast response of the mosquitoes, the sensitivity, and the simplicity of the testing procedure it is a potent tool in the search for new attractive components.
Interpopulation variation of hibernal‐aestival‐diapause in the egg parasitoid wasp Anagrus takeyanus: adaptation to seasonal host‐plant alternation of the tingid host, Stephanitis takeyai
Authors: Tsukada Morio 
Published: October 2003

AbstractThe egg parasitoid wasp, Anagrus takeyanus Gordh & Dunbar (Hymenoptera: Mymaridae), is one of the few natural enemies of the andromeda lace bug, Stephanitis takeyai Drake & Maa (Heteroptera: Tingidae). Studying this wasp in two habitats, I found that at Kyoto, where the bug alternates its host plants seasonally, most wasp individuals in the overwintering eggs of the bug entered summer diapause immediately after winter diapause. However, at Nara, where the bug does not alternate its host plant, the wasp proved to have no summer diapause. Changes in the parasitization rate between generations differed at the two study sites. In Kyoto, the overwintered generation suffered the highest parasitism among the three generations of the year. In contrast, the first and second generations suffered higher parasitization rates in Nara. This difference in level of parasitization between the two study sites corresponded to the different diapause regime of the wasp and the seasonal population trends of the lace bug. Laboratory experiments showed that short photoperiod in combination with low temperature could terminate the long diapause at the time the non‐aestivating individuals terminate winter diapause. As a life cycle without host plant alternation is likely to be an ancestral character of the bug, the aestivation of the wasp is thought to have been appended to overwintering as an adaptation to the evolution of seasonal host plant alternation in the lace bug.
Absence of odour‐mediated avoidance of heterospecific competitors by the predatory mite Phytoseiulus persimilis
Authors: Janssen Arne , Pallini Angelo , Venzon Madelaine , Sabelis Maurice W. 
Published: October 2003

AbstractArthropods use odours associated with the presence of their food, enemies and competitors when searching for patches. Responses to these odours therefore determine the spatial distribution of animals, and are decisive for the occurrence and strength of interactions among species. Therefore, a logical first step in studying food web interactions is the analysis of behaviour of individuals that are searching for patches of food. We followed this approach when studying interactions in an artificial food web occurring on greenhouse cucumber in the Netherlands. In an earlier paper we found that one of the predators of the food web, the predatory mite Phytoseiulus persimilis Athias‐Henriot, used to control spider mites, discriminates between odours from plants with spider mites, Tetranychus urticae Koch, and plants with spider mites plus conspecific predators. The odours used for discrimination are produced by adult prey in response to the presence of predators, and probably serve as an alarm pheromone to warn related spider mites. Other predator species may also trigger production of this alarm pheromone, which P. persimilis could use in turn to avoid plants with heterospecific predators. We therefore studied the response of the latter to odours from plants with spider mites and 3 other predator species, i.e. the generalist predatory bug Orius laevigatus (Fieber), the polyphagous thrips Frankliniella occidentalis and the spider‐mite predator Neoseiulus californicus (McGregor). Both olfactometer and greenhouse release experiments yielded no evidence that P. persimilis avoids plants with any of the 3 heterospecific predators. This suggests that these predators do not elicit production of alarm pheromones in spider mites, and we argue that this is caused by a lack of coevolutionary history. The consequences of the lack of avoidance of heterospecific predators for interactions in food webs and biological control are discussed.
Odour‐mediated host preference of Culex quinquefasciatus in Tanzania
Authors: Mboera L.E.G. , Takken W. 
Published: October 2003

AbstractField experiments to determine the host preference of Culex quinquefasciatus Say (Diptera: Culicidae) between man, calf and goat, were conducted in Muheza, north‐east Tanzania. The responses of the mosquito to the three hosts were also compared to their responses to carbon dioxide. A total of 2565 unfed female mosquitoes were collected, of which Cx quinquefasciatus accounted for 96.6% of the catch. A human‐baited tent caught a larger number of host‐seeking Cx quinquefasciatus than a calf‐baited or goat‐baited tent (P<0.05). The man:calf ratio was 7.8:1 while the man:goat ratio was 10:1. The difference in response to either a calf‐ or goat‐baited tent was not statistically significant (P>0.05). The number of mosquitoes attracted to a human‐baited tent was significantly larger than that attracted to carbon dioxide released at 300 ml min−1. Only 25.3% of the human host attractancy was attributed to carbon dioxide. The number of Cx quinquefasciatus responding to a tent baited with a calf or goat was not significantly different from the number responding to a tent baited with carbon dioxide. It can be concluded that with equal availability of the three vertebrate hosts, Cx quinquefasciatus would respond more to volatile cues from a human host than from either a calf or goat, thereby supporting earlier data about its high degree of anthropophily. The major olfactory cue from a goat or a calf to which this mosquito responds is probably carbon dioxide.
Evaluation of damage to physic nut (Jatropha curcas) by true bugs
Authors: Grimm C. 
Published: October 2003

AbstractThe type of injury and amount of damage to the fruits and seeds of physic nut (Jatropha curcas L., Euphorbiaceae) caused by two species of fruit feeding true bugs, Pachycoris klugii Burmeister (Heteroptera: Scutelleridae) and Leptoglossus zonatus (Dallas) (Heteroptera: Coreidae), and the flower feeding true bug, Hypselonotus intermedius Distant (Heteroptera: Coreidae), were assessed using field cages. The parameters analysed were infructescence, fruit, seed and seed kernel weight, seed length, fruit and seed abortion, seed malformation and oil and protein content of the seed kernels. All three species reduced overall yield. The two members of the fruit feeding guild led to premature fruit abortion and malformed seeds. Reduction of fruit, seed and seed kernel weight as well as seed length could be expressed as linear regressions of adult population densities. The oil content of the seeds was slightly reduced by the bugs, but protein content remained unchanged. Damage increased with the developmental stage of the larvae. Whereas adult L. zonatus of both sexes produced more damage than the nymphs, female P. klugii caused less damage than nymphs, and male P. klugii no significant damage at all. H. intermedius is a pollinator of this entomogamous plant. At high densities, however, it reduced the number of fruits maturing.
Reidentification of the female sex pheromone of the Indian meal moth, Plodia interpunctella: evidence for a four‐component pheromone blend
Authors: Zhu Junwei , Ryne Camilla , Unelius C. Rikard , Valeur Peter G. , Löfstedt Christer 
Published: October 2003

AbstractPheromone gland extracts from calling female Plodia interpunctella contained at least seven compounds that consistently elicited electroantennographic responses from male antennae upon gas chromatographic analysis. Three of these compounds were found to be the previously identified gland constituents, i.e., (Z,E)‐9,12‐tetradecadienyl acetate (Z9,E12‐14:OAc), (Z,E)‐9,12‐tetradecadienal (Z9,E12‐14:Ald) and (Z,E)‐9,12‐tetradecadienol (Z9,E12‐14:OH). A fourth EAD‐active compound was identified as (Z)‐9‐tetradecenyl acetate (Z9‐14:OAc). The homologue (Z)‐11‐hexadecenyl acetate (Z11‐16:OAc) was also identified in the extracts, but showed no EAD activity. The identity of all five compounds was confirmed by comparison of GC retention times and mass spectra with those of synthetic standards. In flight tunnel tests there were no significant differences in response of male P. interpunctella to the bait containing all four EAD‐active compounds and the responses to female gland extacts. A behavioural assay of different two‐compound blends in the flight tunnel showed that only addition of the corresponding aldehyde to the major pheromone component Z9,E12‐14:OAc raised the male response. A subtractive assay, however, revealed that the exclusion of any of the compounds from the complete four‐compound blend reduced its activity significantly. We thus conclude that the female‐produced sex pheromone of P. interpunctella consists of at least four components, i.e., Z9,E12‐14:OAc, Z9,E12‐14:Ald, Z9,E12‐14:OH and Z9‐14:OAc.In a field trapping test performed in a storage facility, the four‐component blend attracted significantly more males of P. interpunctella than traps baited with Z9,E12‐14:OAc alone. In contrast, the highest number of Ephestia kuehniella males was found in the traps baited with this major component, suggesting that the secondary pheromone components contribute to the species specificity of the blend.
Comparison of Diuraphis noxia resistance in wheat isolines and plant introduction lines
Authors: Budak Sibel , Quisenberry S.S. , Ni X. 
Published: October 2003

AbstractThe Russian wheat aphid, Diuraphis noxia (Mordvilko), is one of the most important aphid pests of wheat, Triticum aestivum L., worldwide. Among the various pest management options, plant resistance is an economical management tactic to control D. noxia in cereal crops such as wheat. Researchers have identified D. noxia resistant germplasm and it has been incorporated into wheat. This study compared D. noxia resistance between the ’Betta‘ wheat isolines Betta‐Dn1, Betta‐Dn2, and Betta‐Dn5 and their corresponding donor gene plant introduction (PI) lines PI 137739 (Dn1), PI 262660 (Dn2), and PI 294994 (Dn5). Although the Betta isolines and PI lines showed D. noxia resistance when compared with Betta wheat, the degree of resistance in the isolines to D. noxia was different from their corresponding PI donors. Aphid number, aphid fecundity, and biomass per aphid were not different between Betta‐Dn1 and PI 137739 or Betta‐Dn2 and PI 262660; however, the same parameters were significantly lower on PI 294994 compared with Betta‐Dn5. This indicated that aphid resistance in PI 137739 and PI 262660 was probably governed by a single dominant gene, while the resistance in PI 294994 was controlled by more than one gene. Additionally, plant biomass reduction was aphid density dependent, which suggested that use of appropriate aphid infestation level is important when using plant biomass reduction as an indicator of resistance. Plant resistance categorization showed that there was no detectable difference in antixenosis among the seven lines evaluated. However, the higher aphid fecundity observed on PI 262660 compared with PI 137739 and PI 294994, in addition to no significant differences among the three PIs in plant biomass reduction, suggested PI 262660 was a tolerant line, while PI 137739 and PI 294994 were antibiotic lines. Plant tolerance could not be elucidated among the three Betta isolines using aphid fecundity and plant biomass reduction as indicators.
Host influences on sex ratio, longevity, and egg load of two Metaphycus species parasitic on soft scales: implications for insectary rearing
Authors: Bernal Julio S. , Luck Robert F. , Morse Joseph G. 
Published: October 2003

Abstract Metaphycus flavus (Howard) and M. stanleyi Compere (Hymenoptera: Encyrtidae) are currently being screened for use as augmentative biological control agents of citrus‐infesting soft scales (Homoptera: Coccidae). Two factors were investigated, host quality‐dependent sex allocation and local mate competition, which likely influence these parasitoid's sex allocation strategies and are therefore of interest for their mass‐rearing. The results of these studies suggested that, under the mass‐rearing protocol that is envisioned for these parasitoids, offspring sex ratios in both M. flavus and M. stanleyi are dominated by host quality (= size) influences, but not by interactions with other females. These results indicated that host size strongly influences offspring sex ratios and brood sizes; larger hosts led to more female offspring and larger broods. In contrast, increasing the number of parental females did not lead to fewer female offspring as expected under local mate competition. Additionally, within‐brood sex ratios did not vary with brood size; this result is inconsistent with expected sex ratios due to local mate competition. Other results also indicated that host quality was a dominant influence on M. flavus‘ and M. stanleyi's sex ratios. Larger hosts led to a larger size in the emerging wasps, and larger wasps had greater egg loads and lived longer than smaller wasps. However, wasp longevity, and the influence of wasp size on longevity were mediated by a wasp's diet. Metaphycus flavus females lived the longest when they had access to hosts, honey, and water, followed by honey and water, and shortest when they had access to water alone; M. stanleyi females lived longest with honey and water, followed by hosts, honey, and water, and shortest with water alone. Greater wasp size led to greater longevity in females only when they had access to food (honey, or hosts and honey). Finally, other results suggested that both M. flavus and M. stanleyi are facultatively gregarious. Wasp size did not decrease with brood size as expected under superparasitism. Overall, the results of these studies suggested that holding newly emerged females of both M. flavus and M. stanleyi for several days in the presence of an appropriate food source before field release could enhance a female's performance as an augmentative biological control agent. It increases their initial life expectancy following release, and maximizes the females‘ egg load (both Metaphycus species) and resources for replacing oviposited eggs (M. flavus only).
Molecular markers to differentiate two morphologically‐close species of the genus Sitobion
Authors: Figueroa Christian C. , Simon Jean‐Christophe , Le Gallic Jean‐Francois , Niemeyer Hermann M. 
Published: October 2003

AbstractA set of molecular markers to differentiate the aphid (Hemiptera: Aphidoidea) species Sitobion avenae (Fabricius) from Sitobion fragariae (Walker), is presented. These markers correspond to (1) a region of the mitochondrial DNA, (2) five species‐specific RAPD banding patterns and (3) four microsatellite loci. Each of the markers was able to clearly distinguish between the species. The utility of each molecular marker is discussed. Mitochondrial DNA is best applicable to species determination and relative abundance, RAPDs to the evaluation of genetic diversity, and microsatellites to the assessment of the population genetic structure; the combined use of mtDNA with the other techniques can be of importance when the presence of hybrids is suspected, and RAPDs with microsatellites are best used together in population genetics and host preference studies.
Predatory behavior of Delphastus pusillus in relation to the phenotypic plasticity of Bemisia tabaci nymphs
Authors: Guershon Moshe , Gerling Dan 
Published: October 2003

AbstractPhenotypic plasticity in Bemisia tabaci is expressed, among others, through the degree of nymphal setosity. We tested the hypothesis that the setose phenotype of nymphs can act as a defense mechanism against the predatory coccinellid Delphastus pusillus. Since it has been shown that the relative number of each phenotype is directly correlated with the tomentosity level of the host leaf, our study included characterization of D. pusillus predatory activity when exposed to the different nymphs upon two different leaf types: glabrous and tomentose. Leaf trichomes were found responsible for differences in durations of observed events, their frequency and transitions between events, leading to a break in the predatory sequence regularly found on glabrous leaves. However, despite this break, observational data and functional response tests showed no differences in prey consumption when the predator was exposed to each prey type separately. This is explained by a particular foraging behavior displayed by D. pusillus on tomentose leaves that included walking upon leaf trichomes while performing a vertical introduction of the head between the trichomes, thus reaching the leaf surface. Differences in handling times between the nymph phenotypes were recorded during direct observations of patch time allocation, but these did not result in significant differences in the number of prey eaten. Moreover, our estimates of handling time, calculated with a type II functional response equation, also failed to show these differences. However, foraging predators were more prone to discover smooth nymphs than setose nymphs when the former were offered on tomentose leaves. The significance of these findings in the context of predator‐prey‐plant interactions is discussed.
The toxicity of Jack bean (Canavalia ensiformis) cotyledon and seed coat proteins to the cowpea weevil (Callosobruchus maculatus)
Authors: Oliveira Antônia Elenir A. , Sales Maurício P. , Machado Olga Lima T. , Fernandes Kátia Valevski S. , Xavier‐Filho José 
Published: October 2003

AbstractThe seeds of the Jack bean, Canavalia ensiformis (L) DC are known to contain several toxic substances that prevent their utilisation as food for humans and animals. The lectin concanavalin A and the enzyme urease are the best known of these proteins. We have found that many proteins present in the seeds of the Jack bean, like trypsin inhibitors and canatoxin, are detrimental to the development of the bruchid insect Callosobruchus maculatus (F) (Coleoptera: Bruchidae). Among these proteins, canavalin (vicilin, 7S globulin) was found to be expressed in the seed coat. We suggest that seed coat canavalin, in addition to other detrimental proteins expressed in this tissue, may have been of importance in the evolutionary discrimination of the seeds of this legume by non‐pest bruchids.