bluuebunny/crossref_metadata_2025 huggingface dataset:
Response of the parasitoid Eupelmus vuilleti to the odours of the phytophagous host and its host plant in an olfactometer
Authors: Cortesero A. M. , Monge J. P. , Huignard J.
Published: April 2011

Eupelmus vuilleti (CRW) is a solitary ectoparasitoid which, under our experimental conditions, developed at the expense of the larvae and pupae of Bruchidius atrolineatus (Pic) (Coleoptera, Bruchidae). The larvae of this beetle are found inside the seeds of cowpea, Vigna unguiculata (Walp). Using a tubular olfactometer, we determined the olfactory stimuli involved in the orientation of females of the hymenopterous species E. vuilleti towards one of its hosts; B. atrolineatus. Several odours were tested including those from host plants of B. atrolineatus, from non‐host plants, from the host itself and from the waste products of the host. The odours of pods or dry seeds of V. unguiculata (host plant of the phytophagous insect) affected the locomotor behaviour of females of E. vuilleti. The odours from the plant in the vegetative stage had no effect. Kairomones from larvae, pupae or faeces of B. atrolineatus were attractive to the parasitoid females. Odours from adult male or female B. atrolineatus, as well as the sex pheromone emitted by females were not attractive to E. vuilleti females. This sex pheromone did however stimulate the locomotor activity of the parasitoid. The adaptive significance of these olfactory stimuli is discussed.

Réponse du parasitoïde Eupelmus vuilleti aux odeurs de son hôte phytophage et de la plante‐hôte dans un olfactomètre

Eupelmus vuilleti (CRW) est un ectoparasitoïde solitaire qui se développe dans nos conditions expérimentales aux dépens des larves et des nymphes de Bruchidius atrolineatus (Pic) (Coléoptère: Bruchidae). Les larves de ce Coléoptère se trouvent à l'intérieur des graines d'une Légumineuse Vigna unguiculata (Walp). Grâce à un olfactomètre tubulaire, nous avons déterminé les différents stimuli olfactifs intervenant dans l'orientation des femelles de cet hyménoptère, vers l'un de ses hôtes; Bruchidius atrolineatus. Plusieurs odeurs émanant soit de plantes‐hôtes ou non‐hôtes de B. atrolineatus, soit de l'hôte lui‐même ou résultant de son métabolisme ont été testées. Les odeurs de gousses ou de graines sèches de Vigna unguiculata Walp (plante‐hôte du phytophage) influencent le comportement locomoteur des femelles. Par contre, les odeurs de plantes au stade végétatif n'ont pas d'effet. Les kairomones émanant de larves, nymphes ou fèces de larves de B. atrolineatus exercent un effect attractif sur les femelles parasitoïdes. Les odeurs émanant d'adultes mâles ou femelles de B. atrolineatus ainsi que la phéromone sexuelle émise par les femelles ne sont pas attractives pour les femelles de E. vuilleti. Cette phéromone sexuelle, par contre, stimule l'activité locomotrice des parasitoïdes. La signification adaptative de ces différents stimuli olfactifs est discutée.
The effects of climate, host plant phenology and host fidelity on the genetics of apple and hawthorn infesting races of Rhagoletis pomonella
Authors: Feder Jeffrey L. , Hunt Timothy A. , Bush L.
Published: April 2011

True fruit flies belonging to the Rhagoletis pomonella (Walsh) sibling species complex have been proposed to speciate sympatrically by shifting and adapting to new host plants. Here, we report the results from a series of ecological and genetic experiments conducted at a study site near Grant, Michigan, U.S.A., aimed at clarifying the relationship between host specialization and reproductive isolation for these flies. Our findings indicate that apple (Malus pumila) and hawthorn (Crataegus mollis) infesting populations of R. pomonella are partially allochronically isolated. Differences in the timing of adult eclosion account for part of the allochronic divergence, as apple adults emerge approximately ten days earlier than hawthorn flies in the field. Genetic analyses across different life history stages of the fly show that adults do not randomly move between apple and hawthorn trees, but trend to attack the same species of plant that they infested as larvae. Estimates of interhost migration from the allozyme data suggest that from 2.8 to 10% of the apple population is of hawthorn origin and that over 20% of the hawthorn population is of apple origin. The length and quality of the growing season appear to affect the genetic composition of the host races, as allele frequencies in the hawthorn population are correlated with ambient temperature and rainfall during the spring of the preceding year. Finally, allele frequencies for six allozyme loci displaying host associated differentiation also show significant linear regressions with the timing of adult eclosion within both races. These regressions establish a link between allozyme loci displaying inter‐host differentiation and a developmental trait (adult eclosion) responsible for partially isolating the races. The slopes of the regressions are paradoxical, however, as they suggest that apple adults should eclose later, not earlier, than hawthorn flies. We conclude by discussing potential resolutions to the eclosion time paradox.
Xylem transport interruption by Anasa tristis feeding causes Cucurbita pepo to wilt
Authors: Neal J. J.
Published: April 2011

The plant tissues ingested by Anasa tristis (DeGeer) (Heteroptera: Coreidae) and the wilting of Cucurbita pepo L. (Cucurbitaceae) caused by A. tristis were investigated by feeding and light microscopy studies. Anasa tristis ingests both cell contents and xylem. Wilting of leaves and young plants by A. tristis is due to the interruption of all xylem transport to the plant apical to the feeding site. Xylem transport is interrupted by blockage of xylem vessels with salivary secretions or severing of xylem vessels by A. tristis stylets. Restricting feeding sites by caging demonstrates that squash bug does not produce a toxin that is responsible for wilting.
Factors influencing the acaricidal activity of flucycloxuron
Authors: Grosscurt A. C.
Published: April 2011

Contact activities of flucycloxuron on immature stages of the two‐spotted spider mite (Tetranychus urticae (Koch)) and the European red mite (Panonychus ulmi (Koch)) gradually decrease in the successive developmental stages. The levels of contact activity of flucycloxuron on larvae and protonymphs of T. urticae and P. ulmi are of the same order. Deutonymphs of T. urticae are less susceptible to contact activity than the similar stage of P. ulmi. In adult T. urticae, the transovarial ovicidal activity was used as an indicator for cuticular penetration. More than 90% of the maximal penetration into adult mites occurs within 8 h. Reversibility of the transovarial activity was not observed after 24 h, but did occur after a subsequent 48 h stay on untreated leaves.

The ovo‐larvicidal activity of flucycloxuron on P. ulmi after treatment of apple leaves is strongly negatively influenced by leaf age, partly by lower retention of the spray liquid on the leaves. Leaf penetration was measured by application of flucycloxuron on leaf uppersides and assessment of the transovarial activity in mites (P. ulmi or T. urticae) infested on the undersides, one day after treatment. In this test system, leaf penetration was found to be strongly species dependent. Penetration was high in cucumber, moderate in French beans, cotton, roses and strawberry, but low in apple and pepper. Leaf penetration in French bean plants is drastically reduced at increasing leaf age. The overall positive effect of increase in relative air humidity on leaf penetration, is statistically highly significant (P = 0.001) for French beans and almost significant (P = 0.08) for cucumbers. With T. urticae on French bean it was found that in this test flucycloxuron needs more than one day for maximal leaf penetration.

Although in apple leaves penetration from uppersides was low, penetration from undersides was much higher. The surfactants Arkopal N130, Silwet L‐77 and X2‐5309 enhance penetration from leaf undersides.
Biotype‐specific expression of dsRNA in the sweetpotato whitefly
Authors: Jimenez Desmond R. , Shapiro Jeffrey P. , Yokomi Raymond K.
Published: April 2011

This study was conducted to evaluate the effect of two different biotypes of the sweetpotato whitefly, Bemisia tabaci (Gennadius), on the induction of squash silverleaf (SSL), and to determine if double‐stranded RNA (dsRNA) occurs in geographically remote populations of the two biotypes. Recently collected B‐biotype whiteflies from Florida, Arizona, Mississippi, and Texas (SPW‐B) all contained a 7.0 kb dsRNA molecule. Kb dsRNA molecule. Laboratory colonies of A‐biotype whiteflies that were originally collected in 1981 from cotton in Arizona and California did not contain the 7.0 Kb dsRNA. When the two biotypes were compared only the SPW‐B induced rapid onset, grade 5, SSL. DsRNA similar to that found in adult SPW‐B was concentrated in whitefly nymphs, but host plant leaf tissue did not contain any consistent dsRNA molecules. SPW‐A only induced low‐grade SSL and progeny of SPW‐A that were fed on pumpkin plants displaying SSL did not acquire the ability to express dsRNA or induce SSL. Our data suggest that dsRNA is not directly involved in the induction of SSL and that SSL is a host‐specific response to a feeding injury induced by B‐biotype whiteflies. The origin and source of the 7.0 Kb dsRNA molecule remains enigmatic but its expression is constant in the whitefly biotype that is responsible for the induction of SSL and several other plant disorders in the U.S.
The use of visual cues in host evaluation by aphidiid wasps: I. Comparison between three Aphidius parasitoids of the pea aphid
Authors: Michaud J. P. , Mackauer M.
Published: April 2011

Host evaluation behaviour was examined in three species of aphid parasitoids, Aphidius ervi Haliday, A. pisivorus Smith, and A. smithi Sharma & Subba Rao (Hymenoptera: Aphidiidae). Parasitoids were provided under laboratory conditions with three kinds of hosts representing two aphid species: (green) pea aphid, Acyrthosiphon pisum (Harris), and green and pink colour morphs of the alfalfa aphid, Macrosiphum creelii Davis. Females of all three Aphidius species distinguished between aphids on the basis of colour, movement, and host species. Patterns of host acceptance by parasitoids were species‐specific. In A. ervi, host preference was the same in light and dark conditions: pea aphid > green alfalfa aphid „ pink alfalfa aphid. In contrast, A. pisivorus attacked and accepted pea aphid and green alfalfa aphid equally in the light and preferred both of these over pink alfalfa aphid; however, it made no distinction between pea aphid and pink alfalfa aphid in the dark. Females of A. smithi attacked all three kinds of hosts (pea aphid > green alfalfa aphid „ pink alfalfa aphid) but apparently laid eggs only in pea aphid. The frequencies of attack and oviposition by all wasps were higher on ‘normal’ pea aphids than on those anaesthetized with CO2. Host recognition is confirmed by chemical cues in the aphid cuticle that are detected during antennation, and host acceptance is dependent on an assessment of host quality during ovipositor probing.
Selection of insect parasitic nematodes for biological control of the garden chafer, Phyllopertha horticola
Authors: Smits P. H. , Wiegers G. L. , Vlug H. J.
Published: April 2011

Larvae of Phyllopertha horticola L. (Coleoptera: Scarabaeidae) cause increasing problems on sports fields and lawns in NW‐Europe. A biological control programme using insect parasitic nematodes is being developed. This paper contains the results of bioassays with various species and isolates of the nematode genera Heterorhabditis and Steinernema. In bioassays in small pots with moist sand, most of the nematode isolates gave 30–60% mortality against each of the three larval stages. The susceptibility of the grubs for nematode infection generally increased with larval development. H. bacteriophora, H. heliothidis, H. megidis, a Dutch Heterorhabditis isolate NLH‐E87.3 and S. glaseri 326 showed the highest mortality rates, with nearly 100% mortality of third instar grubs. The Dutch Heterorhabditis isolate NLH‐E87.3 and S. glaseri 326 were selected as candidates for further studies on their potential as biological control agents for P. horticola grubs in the field.
Reproductive behaviour of mated and virgin females of a solitary sawfly Dineura virididorsata
Authors: Walter G. H. , Ruohomäki K. , Haukioja E. , Vainio E.
Published: April 2011

Sex ratios of the arrhenotokous sawfly Dineura virididorsata Retz. (Hymenoptera: Tenthredinidae) are variable among populations in the field, but are biased in favour of females. We have concluded elsewhere that the sex ratios of this species cannot be satisfactorily explained by any general sex ratio model that is available. Here we present data on the different behavioural traits that are relevant to interpretation of the evolution of female‐biased sex ratios under local mate competition. We report on oviposition behaviour, mating behaviour and the patterns of movement of ovipositing virgin and mated females. Our results show that adult emergence is synchronous and females will mate daily with different males (in the laboratory, at least). This would decrease the relatedness of offspring should it also take place in the field. In addition, ovipositing females (mated and virgin) leave their site of release in a relatively short time and deposit few eggs relative to their capabilities, so siblings are unlikely to be clumped. The time that virgins spend in deposition of an egg is not different from that spent by mated females, so there is no differential ‘investment’ in this regard. These behavioural observations agree with our previous conclusion that the preconditions of current sex ratio theories are not met by D. virididorsata.
Behavioural and chemosensory responses of the turnip root fly (Delia floralis) to glucosinolates
Authors: Simmonds M. S. J. , Blaney W. M. , Mithen R. , Birch A. N. E. , Lewis J.
Published: April 2011

This study investigates the behavioural and neural mechanisms involved in the oviposition behaviour of the turnip root fly, Delia floralis (Fallen). Behavioural studies showed that glucosinolates modulated the oviposition behaviour of the flies on artificial leaves as well as the number of eggs laid in the soil at the base of these leaves. Electrophysiological responses to glucosinolates were obtained from type A and type D sensilla on the prothoracic and mesothoracic tarsi, as well as from the long contact sensilla on the labellum. The neural responses from these sensilla were positively correlated with the oviposition behaviour of the flies and with the number of eggs laid. Of the eleven glucosinolates tested in the behavioural and electrophysiological tests, the flies were most responsive to glucobrassicanapin, gluconapin and glucobrassicin. The type D tarsal sensilla were more responsive to the glucosinolates than either the type A tarsal sensilla or the labellar sensilla. The structure‐activity investigations showed that slight modifications to the chemical composition of the glucosinolates resulted in changes in neural activity.
Effects of fluvalinate on two‐spotted spider mite dispersal, fecundity and feeding
Authors: Holland J.M. , Chapman R.B. , Penman D.R.
Published: April 2011

Residual deposits of fluvalinate caused two‐spotted spider mite, Tetranychus urticae Koch, dispersal by running off (run‐off) and spinning down (spin‐down) from treated leaves. Run‐off occured at concentrations from 0.0005 g a.i. 1−1 and reached a peak at 0.01 g a.i. 1−1. Spin‐down was more predominant at concentrations above 0.01 g a. i. 1−1. Spin‐down and run‐off proportions varied with fluvalinate formulation. Oviposition was temporarily suppressed on fluvalinate‐treated leaves, presumably because of an irritant effect which reduced feeding. An emulsifiable concentrate formulation caused the largest reductions in oviposition. Oviposition returned to the level exhibited by untreated mites two days after removal from treated surfaces. Oviposition and feeding were positively correlated and both declined reciprocally with increasing fluvalinate concentration.
Abiotic mortality factors of the coffee berry borer (Hypothenemus hampei)
Authors: Baker P. S. , Rivas A. , Balbuena R. , Ley C. , Barrera J. F.
Published: April 2011

Mortality of the coffee berry borer was studied under controlled laboratory conditions in Tapachula, Mexico. For adult female borers subjected to a range of relative humidities (RH) without food at 25°C, the longest mean survival time (20 days) was obtained at 93.5% RH. Adult borer survival was also studied at a range of temperatures for a fixed relative humidity (93.5% RH); at 20°C mean survival time was 28 days. Fecundity and mortality of borer stages in berries was studied for a range of humidities at 25°C. Maximum fecundity was obtained at 90 and 93.5% RH. Immature stages were ejected from the berry at 84% RH and above, which is interpreted as a form of brood hygiene.
The effect of elevated UV‐B radiation on herbivory of pea by Autographa gamma
Authors: Hatcher Paul E. , Paul Nigel D.
Published: April 2011

Leaves exposed to above‐ambient fluxes of ultraviolet‐B (UV‐B) radiation commonly contain increased concentrations of phenolic compounds which may influence herbivores. However, the hypothesis that elevated UV‐B modifies herbivory, whether mediated by phenolics or other plant constituents, has rarely been studied experimentally. We investigated the responses of the moth Autographa gamma L. (Lepidoptera: Noctuidae) to pea (Pisum sativum L.) grown at a range of plant‐effective UV‐B fluxes. Although total phenolics did increase significantly with increasing UV‐B, this change had little deleterious effect on the 5th instar larvae of A. gamma. However, tissue nitrogen also increased with increasing UV‐B. Increased nitrogen was correlated with an increase in the efficiency with which larvae utilized their food and in larval growth rate, but in a reduction in the amount of plant material consumed. The apparently major role of nitrogen in determining herbivore responses to changing UV‐B demonstrates the risks in predicting such responses soley on the basis of changes in phenolics and other secondary metabolites.
Variation in phenology and nutritional quality between host plants and its effect on larval performance in a specialist butterfly, Zerynthia rumina
Authors: Jordano Diego , Gomariz Ginés
Published: April 2011

The main host plants of the butterfly Zerynthia rumina L. (Lepidoptera: Papilionidae) in southern Spain occur in different habitats and in general do not grow sympatrically. Therefore, each single local butterfly population uses the particular host available within its range. Aristolochia longa L. is a tuberous perennial herb available only in the spring, while A. baetica L. is an evergreen perennial vine with indeterminate growth. However, because of the toughness of older leaves, newly hatched larvae feed only on new leaves of A. baetica, and most of these leaves are produced well before the larvae hatch. In laboratory experiments, caterpillars feeding on either new or mature A. longa leaves grew faster and converted food into biomass more efficiently than those feeding on new A. baetica leaves. These differences are related to variation in nutritional quality among the host plants. Estimates of butterfly abundance were lower in sites where Z. rumina uses A. baetica, compared with those where the host is A. longa. The potential differential effect of these two food plants on the densities of local butterfly populations relying on them is discussed here.
An in vitro rearing system for the propagation of the ectoparasitoid Catolaccus grandis
Authors: Guerra Antonio A. , Martinez Susana
Published: April 2011

An experimental ‘closed’ rearing system, where egg and larval manipulations were eliminated, was developed for the in vitro rearing of Catolaccus grandis (Hymenoptera: Pteromalidae) Burks, an important ectoparasitoid of the cotton boll weevil, Anthonomus grandis Boheman. In this rearing model, n‐hexane (a synthetic ovipositional stimulant for this parasitoid), was smeared on the Parafilm® cover of a modified rearing chamber (a Multiwell®) tissue culture plate) to induce the deposition of uncontaminated eggs, on the inner side of this waxy membrane, and on or around an agar retained diet that had been dispensed into the individual chamber wells. When the efficiency of the in vitro rearing system was compared to the current in vivo rearing method for this species, the duration of the life cycle was significantly shorter in parasitoids reared in vivo, but this difference was less than one day (17.8 vs 17.1 days, respectively). On the other hand, the number of eggs laid in the in vitro rearing chamber during a 4 h period was c. 2.5 times greater than in the conventional in vivo rearing apparatus, and adult yields were c. 25% greater when using the in vitro closed rearing method. Male to female ratios were c. 1:9 when reared in vitro as compared to 1.0:1.5 for those reared in vivo. There were no apparent adverse effects of this in vitro rearing system on the parasitoid's general behavior and reproduction after two consecutive generations.
Insect growth regulating effects of neem extract and azadirachtin on aphids
Authors: Lowery D. Thomas , Isman Murray B.
Published: April 2011

Neem, Azadirachta indica (A. Juss.), seed oil (NSO) applied to leaf discs at a concentration of 1.0% resulted in 94% to 100% mortality of second instar nymphs of currant‐lettuce aphid, Nasonovia ribis‐nigri (Mosley), and green peach aphid, Myzus persicae (Sulzer), after nine days. The equivalent amount of pure azadirachtin (AZA) (ã40 ppm), the principle active ingredient of neem, was as effective as NSO. The survival of adult aphids was unaffected by NSO or AZA, but the survival of offspring from treated adult M. persicae and N. ribis‐nigri was reduced significantly. The lethal concentration of AZA resulting in 50% mortality of second instar nymphs of nine species of aphids ranged from 2.4 ppm for M. persicae on pepper to 635.0 ppm for the strawberry aphid, Chaetosiphon fragaefolii (Cockerell), on strawberry. For M. persicae, the growth regulating effect of AZA was influenced by the host plant and the nymphal instar treated.
Isolation of a chitin‐binding lectin, with insecticidal activity in chemically‐defined synthetic diets, from two wild brassica species with resistance to cabbage aphid Brevicoryne brassicae
Authors: Cole R. A.
Published: April 2011

A lectin, with a chitin‐binding domain and chitinase activity, is present in significant quantities in the wild brassica species B. fruticulosa and B. spinescens but at low levels in cultivated cabbage cv. Offenham Compacta. The lectin, purified > 1000 fold after binding to chitin, migrated on SDS ‐ PAGE gels as a single band with a Mr of 14.500. The amino acid composition of the lectin from B. spinescens indicated high concentrations of asparagine/aspartic acid, glycine, leucine and serine in common with other chitin‐binding lectins with insecticidal and antifungal activities. Brassica lectin and the closely related agglutinin from wheatgerm and nettle show significant insecticidal activity when presented to Brevicoryne brassicae in chemically‐defined synthetic diets.
Behavioral responses of Colorado potato beetle larvae to combinations of temperature and insolation, under field conditions
Authors: Lactin Derek J. , Holliday N. J.
Published: April 2011

In short‐term field trials at combinations of ambient temperature (°C) and insolation (W·m−2), larval Colorado potato beetles (Leptinotarsa decemlineata [Say] [Coleoptera: Chrysomelidae]) were observed after their release on the adaxial surface of leaflets on potato plants (Solanum tuberosum L. Solanaceae). The larvae either began feeding or moved under the leaflet; mean interval from release to expression of these behaviors (2.9 ± 0.05 min [n = 358]) was independent of air temperature and insolation. Proportion of larvae moving under the leaflet increased logistically with both air temperature and insolation. A 1 W·m−2 change in insolation (P) evoked the same effect on this proportion as a 0.0838 °C change in air temperature (Ta), so the two quantities were combined as T* = Ta + P · 0.0838 °C/(W·m−2), which has units of °C. The proportion of larvae moving under the leaflet increased logistically with T*.

In 1‐day field trials we monitored air temperature, insolation and proportion of larvae under the leaflet, and compared the latter to predictions from the logistic regression derived from the short‐term trials. Consistently more larvae occurred under leaflets than predicted from the logistic regression; this bias diminished as T* increased until at T* > 40 °C, observed and predicted proportions were equal. This pattern of deviation from the predictions of the logistic regression is consistent with a thermoregulatory strategy in which larvae move away from hostile conditions, rather than seek optimal conditions.
Sex differentiation studies relating to releaser aggregation pheromones of the desert locust, Schistocerca gregaria
Authors: Obeng‐Ofori D. , Njagi P. G. N. , Torto B. , Hassanali A. , Amiani H.
Published: April 2011

Behavioural responses of nymphs and adults in the gregarious phase of the desert locust, Schistocerca gregaria (Forskal) (Orthoptera: Acrididae) were investigated in a single‐chamber bioassay system to a choice of two columns of air, one permeated with airborne volatiles emanating from either sex of nymphs or adults and the other untreated. There was no sexual differentiation in the production of or response to nymphal volatiles. Young adults of either sex did not produce a stimulus with significant activity. Of the older adults, only the males produced the aggregation stimulus to which both sexes were equally responsive. Charcoal‐trapped volatiles from the two sexes of nymphs and adults evoked similar aggregation responses. Antennae of the older adults showed significantly higher EAG responses than those of fifth instar nymphs to all four volatile collections, of which volatiles from older adult males were the most stimulatory and evoked the highest EAG amplitudes.
Composition and variability of the saliva of coreids in relation to phytoxicoses and other aspects of the salivary physiology of phytophagous Heteroptera
Authors: Taylor G. S. , Miles P. W.
Published: April 2011

In the saciform, principal salivary glands of Mictis profana (Fabr.) (Coreidae: Heteroptera, Pentatomorpha), the contents of all lobes other than the posterior form gels consistent with their contributing to the solidifying saliva (stylet sheath); the posterior lobe secretes most if not all of a sucrose‐hydrolysing enzyme that occurs in the nongelling (watery) saliva. Evidence for the occurrence of such an enzyme in the saliva of other coreids is presented. That in M. profana has a pH optimum near neutral and a substrate specificity consistent with sucrase (sucrose α ‐D‐glucohydrolase, EC 3.2.1.48) as distinct from plant invertase (β ‐D‐fruccofuranosidase, EC 3.2.1.26). Apart from some maltose‐hydrolysing activity in the salivary glands, also consistent with sucrase, no other carbohydrases and neither proteinase nor lipase were detected. Phosphatases were found in gland extracts but not in secreted saliva. The saliva contains catechol oxidase (EC 1.10.3.1) from the accessory gland and ducts. Topical application of pilocarpine caused individual M. profana to secrete up to 58 μl watery saliva which showed continuous and independent variation of sucrase activity (up to ca 0.012 Units/μl) and pH (6–8), although high sucrase content tended to coincide with high pH. Total protein varied up to 10 μg/μl, and free amino acids up to 1.8 μg/μl leucine eq. Of the many proteins and/or protein subunits separable by electrophoresis of gland contents and saliva, four had sucrase activity, the most mobile with MW ca 66000. TLC indicated inter alia phenyl alanine and tyrosine, but no DOPA nor other diphenolic substrates of the catechol oxidase in the watery saliva. The soluble components of the saliva, which also has marked surfactant properties, are discussed in relation to the feeding process of coreids and the characteristic lesions they produce in their food plants.
Effects of intercropping white cabbage with clovers on pest infestation and yield
Authors: Theunissen J. , Booij C. J. H. , Lotz L. A. P.
Published: April 2011

During two consecutive years the effects of intercropping fresh market white cabbage with two species of clover on pest populations and yield were studied. White cabbage cv. Minicole was intercropped with Trifolium repens (white clover) and Trifolium subterraneum (subterranean clover) as compared to the monocrop. During the season observations were made on pest population developments, especially of Mamestra brassicae L. (cabbage moth), Brevicoryne brassicae L. (cabbage aphid), Delia brassicae L. (cabbage root fly), and evaluation of caterpillar feeding injury. At harvest the yield in quantity and quality was determined to be able to assess the gross financial result. Intercropping effects in terms of suppression of oviposition and larval populations of various pests were found. Although no pesticides were used and competition reduced the weight, the quality of the intercropped cabbages lead to a better financial result compared to the monocropped cabbage crop. The results are discussed in the perspective of the practical implications in the context of IPM.
Plant growth stage effects on the feeding and growth responses of the bertha armyworm, Mamestra configurata to canola and mustard foliage
Authors: McCloskey Catherine , Isman Murray B.
Published: April 2011

Mamestra configurata (Walker) (Lep., Noctuidae) larvae were fed excised Brassica juncea (commercial brown mustard) or B. rapa cv. Tobin (Canola) foliage of three plant growth stages ‐ rosette (stage 2), stem elongation (stage 3) and flowering (stage 4). Relative consumption rates (RCRi) were not significantly different between the plant species. Within the B. juncea treatments, there were no significant growth stage differences in RCRi. However, within B. rapa, RCRi increased with advancing plant growth stage. Larvae fed B. juncea foliage had significantly reduced relative growth rates (RGRi) compared to larvae fed B. rapa foliage. Within the B. juncea treatments, RGRi decreased with advancing plant growth stage. There were no significant growth stage differences in RGRi in the B. rapa treatments. RGRi was inversely proportional to the levels of isothiocyanate‐releasing glucosinolates in the B. juncea treatments. RCRi was inversely proportional to the levels of indolyl glucosinolates in the B. rapa treatments. Levels of total phenols and catechols in B. juncea did not show any trend which could be related to growth stage effects in the insect nutritional indices. In B. rapa, levels of phenols and catechols in stage 3 and 4 foliage were lower than that of stage 2 foliage. Analyses of total nitrogen in field‐grown plants showed reductions in percent nitrogen from rosette to flowering stage foliage. The response of M. configurata to different growth stages of its host plants are discussed in relation to changing levels of allelochemicals and nitrogen.
The effect of host instar on the size and sex ratio of the endoparasitoid Dacnusa sibirica
Authors: Croft P. , Copland M. J. W.
Published: April 2011

Older instars of the leafminer host Chromatomyia syngenesiae Hardy (Diptera: Agromyzidae) at parasitization resulted in larger female adults of the larval‐pupal endoparasitoid Dacnusa sibirica Telenga (Hymenoptera: Braconidae). The sex ratio in the parasitoid offspring became increasingly female biased and development period decreased with increasing age of the host at parasitization. Older host instars were therefore considered to produce a fitter parasitoid.
Variation among Eucalyptus species in resistance to eucalyptus longhorned borer in Southern California
Authors: Hanks Lawrence M. , Paine Timothy D. , Millar Jocelyn G. , Hom John L.
Published: April 2011

Eucalyptus L'Héritier (Myrtaceae: Leptospermoideae) species are native to the Austro‐Malaysian region, but have been widely planted in temperate and subtropical regions around the world. In most regions where Eucalyptus have been imported, the Eucalyptus Longhorned Borer (Phoracantha semipunctata F.) (Coleoptera: Cerambycidae) has been accidently introduced. Larvae of the beetle bore through the bark and mine along the cambium of stressed trees, usually killing their host. We report here the relative susceptibilities of 12 Eucalyptus species in two mixed‐species plantations in California, USA. These trees were stressed by water deficit resulting from a prolonged drought. Eucalyptus species that appeared resistant to the borer included E. camaldulensis Dehnhardt, E. cladocalyx F. Muller, E. sideroxylon A. Cunn. ex Woolls, and E. trabutii (an E. camaldulensis hybrid). Species that were more susceptible to attack were E. diversicolor F. Mueller, E. globulus LaBillardière, E. grandis Hill ex Maiden, E. nitens (Deane & Maiden), E. saligna Sm., and E. viminalis LaBillardière. Survival of trees was influenced by fine‐scale moisture variation resulting from slope and irrigation effects. Resistance characteristics of these Eucalyptus species did not correlate with taxonomic relatedness or bark characteristics, but did correspond to drought tolerance traits in their native habitat. Eucalyptus species that were resistant to attack by P. semipunctata were those that are most tolerant of drought in Australia.
Identification and field optimisation of the female sex pheromone of the rice leaffolder, Cnaphalocrocis medinalis in India
Authors: Rao A. Ganeswara , Reddy D. D. R. , Krishnaiah K. , Beevor P. S. , Cork A. , Hall D. R.
Published: April 2011

Analysis of ovipositor washings from virgin female Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae) of Indian origin by linked gas chromatography and electroantennography indicated the presence of three electrophysiologically‐active compounds. These were identified on the basis of their gas chromatographic retention times and mass spectra as (Z)‐11‐hexadecenyl acetate, (Z)‐13‐octadecenyl acetate and (Z)‐13‐octadecen‐1‐ol with (Z)‐13‐octadecenyl acetate present in amounts of between 0.25 and 1.5 ng per ovipositor and the other two components at less than 10% of this. Trace quantities of octadecyl acetate were identified by mass spectrometry but no electroantennographic responses were observed to this compound. Field trials conducted with a range of blends of the three electrophysiologically‐active compounds showed that blends containing between 5% and 30% (Z)‐11‐hexadecenyl acetate in (Z)‐13‐octadecenyl acetate dispensed from either white rubber septa or polythene vials were more attractive to male moths than a virgin female moth. Addition of (Z)‐13‐octadecen‐1‐ol reduced attractiveness to male moths in the blends and concentrations tested.
The use of visual cues in host evaluation by aphidiid wasps
Authors: Michaud J. P. , Mackauer M.
Published: April 2011

We examined host evaluation behaviour in three species of aphid parasitoids, Ephedrus californicus Baker, Monoctonus paulensis (Ashmead), and Praon pequodorum Viereck (Hymenoptera: Aphidiidae). Mated females were provided with pairwise choices among three kinds of hosts in the laboratory: (green) pea aphid, Acyrthosiphon pisum (Harris), and a green and a pink colour morph of alfalfa aphid, Macrosiphum creelii Davis. Patterns of attack and host acceptance were species‐specific. Females of E. californicus did not respond to the presence of aphids prior to making antennal contact. Variations in rates of parasitization (pea aphid>green alfalfa aphid>pink alfalfa aphid) were consistent with differences in aphid defensive behaviours; no ‘preference’ for any host type was evident when aphids were anaesthetized with carbon dioxide. In M. paulensis, the order of preference (pea aphid>green alfalfa aphid>pink alfalfa aphid) did not vary when aphids were immobilized, or presented in the dark, or both. Host movement did not influence the rate of attack by M. paulensis. In contrast, the ranked order of preference in P. pequodorum varied with circumstance. In the light, females attacked pea aphid and green alfalfa aphid with equal frequency, but parasitized significantly more of the former; both kinds of aphids were attacked and parasitized at higher rates than pink alfalfa aphid. In the dark, P. pequodorum females parasitized green and pink alfalfa aphids equally and at higher rates than pea aphids. Whereas E. californicus was more successful ovipositing in immobilized hosts, P. pequodorum females attacked and laid more eggs in normal than anaesthetized aphids. Patterns of host recognition and evaluation are compared across six species representing four genera in the family Aphidiidae.
Does time spent on adult bees affect reproductive success of Varroa mites?
Authors: Boot Willem J. , Calis Johan N. M. , Beetsma Joop
Published: April 2011

Reproduction of Varroa jacobsoni Oudemans (Acari: Varroidae) and the number of Varroa mites that were found dead on the bottom board of the hive, were studied in relation to the period the mites spent on adult honey bees, Apis mellifera L. (Hymenoptera: Apidae), prior to invasion into brood cells. The maximum period on adult bees was 23 days. To introduce mites, combs with emerging worker brood, heavily infested with mites, were placed into a colony and removed the next day. At the beginning of the first day following emergence from brood cells, 18% of the mites introduced into the colony was found on the bottom of the hive. Part of these mites may already have died inside the capped brood cells, and then fallen down after cleaning of cells by the bees. At the second and third day following emergence, respectively 4% and 2% of the mites on adult bees at the previous day was recovered on the bottom, whereas from the fourth day on only 0.6% of the mites on adult bees was recovered on the bottom per day. After invasion into brood cells, 8–12% of the mites did not produce any offspring. Of the mites that did reproduce, the total number of offspring was 4.0–4.4 per mite during one reproductive cycle, part of which may reach maturity resulting in 1.2–1.3 viable daughters, and 8–10% of the mites produced only male offspring. Reproduction was independent of the period the mites had spent on adult bees prior to invasion into brood cells.
Quality assessment of Trichogramma brassicae in the laboratory
Authors: Cerutti F. , Bigler F.
Published: April 2011

The quality of 52 populations of the egg‐parasitoid Trichogramma brassicae Bezdenko (Hymenoptera, Trichogrammatidae) (synonymous to T. maidis Pint. et Voegele) has been compared by investigating seven parameters in each population. The parameters assessed were: emergence rate, sex ratio, ratio of deformed females, life‐span, walking activity, fecundity on the factitious host eggs and fecundity on the natural host eggs. The last parameter is used as an indirect measure of the acceptance and suitability of the natural host eggs. Origin, history and treatment of each population were known and used as information for interpreting the quality. For computing and presenting the data classical descriptive statistics as well as graphical methods (profile symbol) were applied. Principal Component Analysis and cluster analysis were used for dividing the populations into groups with similar properties.

From the results we conclude: a) Strains of the same species, reared under similar conditions, differ in quality. b) Storage and shipment often have a negative impact on quality. c) Crossbred isolated populations showed a lower quality than the parental populations.

A synoptical presentation of many parameters assessed on a high number of populations (strains, biotypes, species) is best accomplished by combining profile symbol plots, Principal Component Analysis and cluster analysis.
Evaluation of four aphidiine parasitoids for biological control of Aphis gossypii
Authors: van Steenis M. J.
Published: April 2011

Four aphidiine parasitoid species (Hymenoptera: Braconidae) were evaluated with respect to their potential to control Aphis gossypii Glover (Homoptera: Aphididae) in glasshouse cucumbers. In a laboratory experiment thirty cotton aphids were offered to individual females for two hours. Aphidius matricariae Haliday parasitized less than six percent of the aphids and was ruled out as potential biological control agent. Ephedrus cerasicola Starý and Lysiphlebus testaceipes Cresson parasitized 23 and 26 percent of the aphids, respectively. Aphidius colemani Viereck parasitized 72 to 80 percent of the aphids.

With the latter three species, experiments were performed in small glasshouses with cucumbers (Cucumis sativus L. cv. ‘Aramon’). As in the laboratory test A. colemani performed best; significantly more colonies were found and parasitization rates in the colonies were higher by A. colemani than by E. cerasicola and L. testaceipes.

Because of the good correspondence between laboratory and glasshouse experiments, it is suggested that bad performance of an aphid parasitoid species in a simple laboratory trial might be sufficient evidence to disregard this species for further tests.
Decay rates for slug antigens within the carabid predatorPterostichus melanariusmonitored with a monoclonal antibody
Authors: Symondson W. O. C. , Liddell J. E.
Published: April 2011

The rate at which prey antigens decay within a predator during digestion must be calibrated, for a given assay system, in order to define the period within which predation must have occurred. Monoclonal antibodies have great advantages in terms of target specificity, but have often in the past demonstrated impractically abbreviated antigen detection periods. However, the DrW‐2D11 monoclonal antibody, which detects all three genera of pest slugs (Mollusca: Pulmonata) in Britain, could clearly identify predation byPterostichus melanariusIlliger (Coleoptera: Carabidae) after 2.5 days at 16 °C, a longer interval than has been recorded for any other monoclonal antibody used in predation studies. The half‐life, detection period and decay rate were calibrated with and without subsequent feeding on alternative prey. Unrestricted feeding on earthworm, following consumption of the slugDeroceras reticulatum(Müller), significantly reduced the decay rate of slug antigens. These results appear to contradict the assumptions, based on previous studies, that indicate reduced digestion rates in response to starvation. Possible reasons for this failure to comply with the predictions of optimal foraging theories are discussed.
Evaluation of neem Azadirachta indica seed extracts and oils as oviposition deterrents to noctuid moths
Authors: Naumann Ken , Isman Murray B.
Published: April 2011

Applications of three concentrations of oil‐free neem seed extracts (Azadirachta indica A. Juss; Meliaceae) to cabbage plants in cages did not deter oviposition by individuals of three species of noctuid moths, Trichoplusia ni, Peridroma saucia, and Spodoptera litura. The concentrations used corresponded to 10, 50, and 100 ppm of the main active ingredient, azadirachtin. The total number of eggs laid per female, female longevity, and median day of oviposition were not affected. Sprays of the neem oil‐based insecticide Margosan‐OR, and a 1% aqueous emulsion of a refined neem seed oil similarly had no effect on any of the parameters studied. However, a 1% crude oil emulsion significantly reduced the proportion of eggs laid by S. litura on treated plants. Our results suggest that literature reports of significant neem‐based oviposition deterrence to S. litura are the result of compounds that are removed by higher levels of processing and thus not likely to be found in most commercial neem seed formulations. Sprays consisting of highly processed neem seed extracts, used at concentrations that provide larval control, are unlikely to be generally effective as oviposition deterrents to noctuid pests.
Influence of host plant on the mango mealybug, Rastrococcus invadens
Authors: Boavida C. , Neuenschwander P.
Published: April 2011

Life history traits of the mango mealybug, Rastrococcus invadens Williams, were compared between two neighboring mango trees (Mangifera indica L.), one of which was heavily infested and the other slightly infested. On the infested tree, mealybug survival was high because of good feeding conditions and low escape. The pre‐reproductive period of mealybugs on the heavily infested tree was shorter and total offspring production higher than that of mealybugs on the uninfested tree. This significantly affected the intrinsic rate of natural increase and explained the observed differences in population densities among the trees. The results obtained from an additional experiment using juvenile clones from the same two mango varieties, in which environmental factors were uniform, demonstrated the importance of plant genotype on mealybug size and survival.
Transport and kinetics of diflubenzuron and pyriproxyfen in the beet armyworm Spodoptera exigua and its predator Podisus maculiventris
Authors: De Clercq P. , Viñuela E. , Smagghe G. , Degheele D.
Published: April 2011

Transport and retention of the insect growth regulators (IGRs) diflubenzuron and pyriproxyfen in larvae of the beet armyworm Spodoptera exigua (Hübner) and in nymphs of the predatory bug Podisus maculiventris (Say) were investigated. In a first experiment, the retention of orally administered [14C]radiolabeled isotopes of both compounds in fifth‐instar larvae of the beet armyworm was studied. Rate of excretion of both IGRs in S. exigua caterpillars was high, with a 50% excretion time of approximately 6 h after intake. In a second experiment, the transport of the compounds from prey to predator and their retention inside the predator were studied. Fifth‐instar nymphs of P. maculiventris were allowed to feed on caterpillars that had been given contaminated food. For both diflubenzuron and pyriproxyfen, more than 80% of the amount of radiolabel applied was recovered in consumed prey. Low levels of radioactivity (c. 3% of the applied amount of radiolabel) were also found in the fluid regurgitated by the prey larvae when attacked by the predatory bugs. Relatively small amounts of radiolabel (c. 8 and 15% of the amount orally applied to the prey for diflubenzuron and pyriproxyfen, respectively) were ingested by P. maculiventris nymphs when feeding on beet armyworm caterpillars. The data suggest that the predators did not use gut content as food. The pattern of excretion in nymphs of P. maculiventris differed between compounds. For diflubenzuron, there was a drastic decrease of radioactivity inside the predator body of around 40% within the first 6 h and then the level of retained radiolabel remained stable at 3–4% up to 72 h. For pyriproxyfen, a slow decrease of radioactivity inside the body was observed and at 72 h only 2% of the applied quantity was detected. Results of this study are discussed in relation to the findings from previous studies on the toxicity of both IGRs to P. maculiventris.
Sensilla basiconica (grooved pegs) on the antennae of female mosquitoes: electrophysiology and morphology
Authors: Bowen M. F.
Published: April 2011

The sensilla basiconica or grooved pegs of mosquitoes consist of two morphologically and functionally distinct classes. Short grooved pegs house sensory cells that are excited by lactic acid whereas lactic acid‐excited cells are absent in long grooved pegs. This correlation was found in four species of mosquito examined: Aedes aegypti, Aedes atropalpus, Aedes epactius, and Culex pipiens. In Aedes epactius, both short and long grooved pegs house receptors that are sensitive to butyric acid.