A novel F2 screening technique was developed for detecting resistance in sugarcane borer, Diatraea saccharalis (F.), to transgenic Bacillus thuringiensis (Bt)-maize expressing the Cry1Ab insecticidal protein. The F2 screening method involved (i) collecting larvae from maize fields; (ii) establishing two-parent families; (iii) screening F2 neonates for survival on Bt-maize leaf tissues; and (iv) confirming resistance on commercial Bt-maize plants. With the F2 screening method, 213 iso-line families of D. saccharalis were established from field collections in northeast Louisiana, USA and were screened for Bt resistance. One family was confirmed to carry a major Bt resistance allele(s). In a laboratory bioassay, larval mortality of the Bt-resistant D. saccharalis on Bt-maize leaf tissues was significantly lower than that of a Bt-susceptible strain. This Bt-resistant D. saccharalis population is the first corn stalk borer species that has completed larval development on commercial Bt-maize. The F2 screening protocol developed in this study could be modified for detecting Bt resistance alleles in other similar corn stalk borers, such as the European corn borer, Ostrinia nubilalis (Hübner), and the southwestern corn borer, D. grandiosella Dyar.

The horse-chestnut leaf miner, Cameraria ohridella, is an invasive alien species defoliating horse-chestnut, a popular ornamental tree in Europe. This paper presents quantitative data on mortality factors affecting larvae and pupae of the leaf miner in Switzerland and Bulgaria, both in urban and forest environments. Two sampling methods were used and compared: a cohort method, consisting of the surveying of pre-selected mines throughout their development, and a grab sampling method, consisting of single sets of leaves collected and dissected at regular intervals. The total mortality per generation varied between 14 and 99%. Mortality was caused by a variety of factors, including parasitism, host feeding, predation by birds and arthropods, plant defence reaction, leaf senescence, intra-specific competition and inter-specific competition with a fungal disease. Significant interactions were found between mortality factors and sampling methods, countries, environments and generation. No mortality factor was dominant throughout the sites, generations and methods tested. Plant defence reactions constituted the main mortality factor for the first two larval stages, whereas predation by birds and arthropods and parasitism were more important in older larvae and pupae. Mortality caused by leaf senescence was often the dominant mortality factor in the last annual generation. The cohort method detected higher mortality rates than the grab sampling method. In particular, mortality by plant defence reaction and leaf senescence were better assessed using the cohort method, which is, therefore, recommended for life table studies on leaf miners.

The emergence of resistance mechanisms to, and revocation of, many insecticides used in the control of the polyphagus aphid pest, Myzus persicae (Sulzer), has increased the pressure to develop novel approaches for the control of the pest in many crops. Kaolin-based particle films provide a physical barrier against insect pests and show considerable potential for controlling M. persicae. We conducted a series of laboratory experiments to investigate the mode of action of kaolin against aphids. The material appeared to have no direct effect on M. persicae; spraying adult aphids with aqueous kaolin suspension had no significant impact on their subsequent survival or reproduction on untreated plants. Similarly, when aphids were placed on kaolin-treated host-plants (Brassica oleracea), their performance (survival, growth rate and reproduction) was not significantly different from aphids on untreated plants. However, when M. persicae were given a choice between kaolin-treated and untreated (or water solvent-treated) leaf areas, both adults and nymphs exhibited a significant preference for non-kaolin-treated host-plant material. Rejection of kaolin-treated plant material occurred very rapidly (within 20 min) and this behavioural effect may be related to the efficacy of kaolin in controlling aphids under field conditions.

A quick and developmental-stage non-limiting method of the identification of vectors of tospoviruses, such as Thrips tabaci and T. palmi, is important in the study of vector transmission, insecticide resistance, biological control, etc. Morphological identification of these thrips vectors is often a stumbling block in the absence of a specialist and limited by polymorphism, sex, stage of development, etc. Molecular identification, on the other hand, is not hampered by the above factors and can easily be followed by a non-specialist with a little training. The mitochondrial cytochrome oxidase I (mtCOI) exhibits reliable inter-species variations as compared to the other markers. In this communication, we present the differences in the mtCOI partial sequence of morphologically identified specimens of T. tabaci and T. palmi collected from onion and watermelon, respectively. Species-specific markers, identified in this study, could successfully determine T. tabaci and T. palmi, which corroborated the morphological identification. Phylogenetic analyses showed that both T. tabaci and T. palmi formed different clades as compared to the other NCBI accessions. The implication of these variations in vector efficiency has to be investigated further. The result of this investigation is useful in the quick identification of T. tabaci and T. palmi, a critical factor in understanding the epidemiology of the tospoviruses, their management and also in quarantine.

If species-specific male genitalia are courtship devices under sexual selection by cryptic female choice, then species-specific aspects of the morphology and behaviour of male genitalia should often function to stimulate the female during copulation. The morphology and behaviour of the complex, species-specific male genitalia of the tsetse fly, Glossina pallidipes Austen, were determined from both direct observations and dissections of flash-frozen copulating pairs; we found that some male genitalic traits probably function to stimulate the female, while others function to restrain her. The male clamps the ventral surface of the female's abdomen tightly with his powerful cerci. Clamping does not always result in intromission. Clamping bends the female's body wall and her internal reproductive tract sharply, posteriorly and dorsally, and pinches them tightly. The male performed sustained, complex, stereotyped, rhythmic squeezing movements with his cerci that were not necessary to mechanically restrain the female and appeared instead to have a stimulatory function. Six different groups of modified setae on and near the male's genitalia rub directly against particular sites on the female during squeezing. The designs of these setae correlate with the force with which they press on the female and the probable sensitivity of the female surfaces that they contact. As expected under the hypothesis that these structures are under sexual selection by female choice, several traits suspected to have stimulatory functions have diverged in G. pallidipes and its close relative, G. longipalpis. Additional male non-genitalic behaviour during copulation, redescribed more precisely than in previous publications, is also likely to have a courtship function. The elaborate copulatory courtship behaviour and male genitalia may provide the stimuli that previous studies showed to induce female ovulation and resistance to remating.

Information relevant to invasion processes and invasive alien insect species management in Central Europe was extracted from two databases: a compilation of two inventories of alien insects in Austria and Switzerland, and a list of interceptions of non-indigenous plant pests in Europe gathered by the European and Mediterranean Plant Protection Organisation (EPPO) for the period 1995–2004. For one-third of the insects established in Switzerland and Austria, the region of origin is unclear. Others come mainly from North America, Asia and the Mediterranean region. Among the intercepted insects, 40% were associated with commodities from Asia, 32% from Europe and only 2% from North America. Sternorrhyncha, Coleoptera and Psocoptera were particularly well represented in the alien fauna compared to the native fauna. In the interception database, Sternorrhyncha were also well represented but Diptera accounted for the highest number of records. Sap feeders and detritivores were the dominant feeding niches in the alien insect fauna. In contrast, external defoliators, stem borers, gall makers, root feeders, predators and parasitoids were underrepresented. Nearly 40% of the alien insects in Switzerland and Austria live only indoors. Another 15% live outdoors but exclusively or predominantly on exotic plants. Less than 20% are found mainly in ‘natural’ environments. The majority of introductions of alien insects in Europe are associated with the international trade in ornamental plants. An economic impact was found for 40% of the alien insects in Switzerland and Austria, whereas none is known to have an ecological impact. The implications of these observations for further studies and the management of alien species in Europe are discussed.

The aim of this study was to develop and optimize silverleaf bioassay, esterase analysis and PCR-based techniques to distinguish quickly and reliably biotype B of the whitefly, Bemisia tabaci (Gennadius), from Indian indigenous biotypes. Zucchini and squash readily develop silverleaf symptoms upon feeding by the B biotype, but they are not readily available in Indian markets. A local pumpkin variety ‘Big’ was, therefore, used in silverleaf assay, which developed symptoms similar to those on zucchini and squash and can be used reliably to detect B biotype. Analysis of non-specific esterases of B and the indigenous biotypes indicated both quantitative and qualitative differences in esterase patterns. Two high molecular weight bands were unique to B biotype and they occurred in abundance. These esterases were used to develop quick and field-based novel detection methods for differentiating B from the indigenous biotypes. Development of these simple and cost-effective protocols has wider application as they can be potentially used to identify other agricultural pests. Mitochondrial cytochrome oxidase I gene sequences and randomly amplified polymorphic DNA (RAPD) polymorphisms, generated using the primer OpB11, were also found useful for detecting B. tabaci biotypes. A B biotype-specific RAPD band of 800 bp was sequenced, which was used to a develop sequence characterized amplified region (SCAR) marker. The SCAR marker involved the development of B biotype-specific primers that amplified 550 bp PCR products only from B biotype genomic DNA. Silverleaf assay, esterases, RAPDs or a SCAR marker were used in combination to analyse whitefly samples collected from selected locations in India, and it was found that any of these techniques can be used singly or in combination to detect B biotype reliably. The B biotype was found in southern parts of India but not in the north in 2004–06.

Parasitoids employ different types of host-related volatile signals for foraging and host-location. Host-related volatile signals can be plant-based, originate from the herbivore host or produced from an interaction between herbivores and their plant host. In order to investigate potential sex- and species-related differences in the antennal response of parasitoids to different host-related volatiles, we compared the electroantennogram (EAG) responses of both sexes of the specialist parasitoid, Microplitis croceipes (Cresson), and the generalist, Cotesia marginiventris (Cresson), to varying doses of selected plant-based host-related volatiles: two green leaf volatiles (cis-3-hexenol and hexanal) and three inducible compounds (cis-3-hexenyl acetate, linalool, and (E,E)-α-farnesene). Mating had no significant effect on EAG response. Females of both species showed significantly greater EAG responses than conspecific males to green leaf volatiles, which are released immediately after initiation of herbivore feeding damage. In contrast, males showed greater responses than conspecific females to inducible compounds released much later after initial damage. Cotesia marginiventris females and males showed greater EAG responses than counterpart M. croceipes to the tested compounds at various doses, suggesting that the generalist parasitoid shows greater antennal sensitivity than the specialist to the tested host-plant volatiles. These results are discussed in relation to the possible roles of green leaf volatiles and inducible compounds in the ecology of female and male parasitoids.

The aim of this study was to determine which Arabidopsis thaliana (L.) genes had significantly altered expression following 2–36 h of infestation by the aphid Myzus persicae (Sulzer). Six biological replicates were performed for both control and treatment at each time point, allowing rigorous statistical analysis of any changes. Only two genes showed altered expression after 2 h (one up- and one down-regulated) while two were down-regulated and twenty three were up-regulated at 36 h. The transcript annotation allowed classification of the significantly altered genes into a number of classes, including those involved in cell wall modification, carbon metabolism and signalling. Additionally, a number of genes were implicated in oxidative stress and defence against other pathogens. Five genes could not currently be assigned any function. The changes in gene expression are discussed in relation to current models of plant-insect interactions.

Nilaparvata lugens Stål, the Brown Planthopper (BPH), is a major pest in rice. The lycosid Pardosa pseudoannulata (Bösenberg & Strand) and the linyphiid Atypena formosana (Oi) are the early dominant predators in irrigated rice. Later, predatory bugs, including the mirid Cyrtorhinus lividipennis Reuter, become dominant. In unsprayed rice, BPH numbers normally remain low. While P. pseudoannulata is known to be a key natural enemy of BPH, the contribution to BPH reduction by the smaller A. formosana is less well known. Due to the size difference, A. formosana may also be an intraguild prey of P. pseudoannulata. To investigate predation on BPH by the two spider species alone, together and in combination with C. lividipennis, two cage experiments were conducted, the first with adult spiders, the second with immature/unmated spiders. In the latter, spiders were introduced with a delay to allow a better establishment of C. lividipennis. In both experiments, BPH numbers were lowest in treatments with more than one predator species present. Intermediate BPH reduction was obtained with P. pseudoannulata followed by A. formosana and C. lividipennis. While P. pseudoannulata can prey upon large nymphs and adult BPH, A. formosana favour early instar BPH, leading to a more even control across instars in treatments with both spider species. Pardosa pseudoannulata numbers increased more with A. formosana or A. formosana and C. lividipennis present. In contrast, P. pseudoannulata reduced A. formosana and C. lividipennis numbers. The presence of C. lividipennis apparently lessened intraguild predation on A. formosana and may be an intraguild prey of A. formosana. Competition for prey may have added to the antagonistic interactions found. From a biological control perspective, the presence of both spiders in early rice is an advantage for the biological control of BPH in rice. In early rice, results show that A. formosana is an important predator of BPH and, like C. lividipennis, can complement control by P. pseudoannulata and serve as intraguild prey for the latter species.