The common bed bug, Cimex lectularius (Hemiptera: Cimicidae), has recently re-emerged in increasing numbers, distribution and intensity of infestation in many countries. Current control relies on the application of residual pesticides; but, due to the development of insecticide resistance, there is a need for new tools and techniques. Semiochemicals (behaviour and physiology modifying chemicals) could be exploited for management of bed bugs. However, in order to identify semiochemicals that can be utilised in monitoring or control, a suitable olfactometer is needed that enables the study of the responses of bed bugs to volatile chemicals. Previous studies have used olfactometers that do not separate olfactory responses from responses to physical contact. In this study, a still-air olfactometer was used to measure behavioural responses to different bed bug-derived volatiles presented in an odour pot. Bed bugs were significantly more likely to visit the area above the odour pot first, and more frequently, in the presence of volatiles from bed bug-exposed paper but not in the presence of volatiles from conspecific bed bugs. Bed bug activity was found to be dependent on the presence of the volatiles from bed bug-exposed paper, the time during the scotophase and the sex of the insect being tested. The still-air olfactometer could be used to test putative semiochemicals, which would allow an understanding of their behavioural role in bed bug ecology. Ultimately, this could lead to the identification of new semiochemical tools for bed bug monitoring and control.

Pheromone and light traps have often been used in ecological studies of two major noctuid pests of agriculture in Australia, Helicoverpa armigera and H. punctigera. However, results from these two methods have rarely been compared directly. We set pheromone and light traps adjacent to or amongst cotton and various other crops for 10–11 years in the Namoi Valley, in northern New South Wales, Australia. Catches in pheromone traps suggested a major peak in (male) numbers of H. punctigera in early spring, with relatively few moths caught later in the summer cropping season. In contrast, (male) H. armigera were most abundant in late summer. Similar trends were apparent for catches of both male and female H. armigera in light traps, but both sexes of H. punctigera were mostly caught in mid-summer. For both species, males were more commonly caught than females. These catch patterns differed from some previous reports. At least three generations of both species were apparent in the catches. There was some evidence that the abundance of later generations could be predicted from the size of earlier generations; but, unlike previous authors, we found no positive relationships between local winter rainfall and subsequent catches of moths, nor did we find persuasive evidence of correlations between autumn and winter rainfall in central Australia and the abundance of subsequent 1st generation H. punctigera moths. Female H. punctigera were consistently more mature (gravid) and more frequently mated than those of H. armigera. Overall, our results highlight the variability in trap catches of these two species and question the use of trap catches and weather as predictors of future abundance in cropping regions.

The laboratory studies were conducted to uncover the correlation between the levels of pyrethroid resistance and the reproductive potential of parent (SS) and resistant strains of Culex quinquefasciatus (RR) originating from Delhi, India and selected with deltamethrin (RDL) or the combination of deltamethrin and PBO (1:5) (RDP) at the larval stage and selected with deltamethrin at the adult stage (RDA). The reproductive potential was evaluated in terms of fecundity, fertility, egg hatchability and longevity of gonotrophic cycles. The RR strains exhibited 68–74% reduced duration of the gonotrophic cycles when compared with that of SS strain. The considerable decrease in the egg production, ranging from 45.4% to 61.6%, observed in the selected strains as compared to the SS strain, indicates the possible positive correlation between the levels of deltamethrin resistance and the reproduction disadvantage. This correlation was further confirmed by 24.6% to 53.6% decrease in the hatchability of eggs of the selected strains with respect to that of the parent strain. A worth-mentioning observation of the reduced reproductive fitness in RDP strains suggests the effectiveness of synergized deltamethrin selections in reducing the frequency of resistant individuals. The reproductive disadvantage in adult-selected strains possessing negligible resistance to deltamethrin implicates the efficacy of deltamethrin as an adulticide rather than as a larvicide against Cx. quinquefasciatus. The results suggest that the reduced reproductive fitness of resistant genotypes in the population can eliminate heterozygotes and resistant homozygotes by implementing different resistance-management strategies against Cx. quinquefasciatus.

Life table studies of sunn pest were carried out in Varamin, Iran, from 1998–2001 in order to determine stage-specific mortalities and the impact of specific natural enemies on population dynamics. Populations were sampled 2–3 times weekly in agricultural fields during the growing season and monthly during the period of dormancy at resting sites in nearby mountains some 30 km away from cereal fields. Adults spend a period of 9–10 months in diapause and suffered overcompensatory, density-dependent mortality during this period. Variation in adult overwintering survival was inferred to be largely a function of the physiological condition of bugs that is reduced in a density-dependent manner by intraspecific competition for food among newly molted adults prior to migration to resting sites. Adult mortality emerged as the primary factor in key factor analysis, contributing 73% of the total variance in mortality. Other important factors were egg parasitism by Trissolcus vassilievi Mayr and adult parasitism by several species of Tachinidae. Although T. vassilievi made only a minor contribution to overall variance in total mortality, it had a significant effect on the number of newly molted adults, the life stage that is most damaging to cereal crops. The equilibrium level of the pest population in wheat fields was inferred to be ca. 72.6 adults m−2, a number that substantially exceeds the economic threshold that ranges from 3–5 adults m−2.

The European cherry fruit fly, Rhagoletis cerasi (Diptera: Tephritidae), is a major pest of cherries in Europe and parts of Asia. Despite its big economic significance, there is a lack of studies on the genetic structure of its natural populations. Knowledge about an insect pest on molecular, genetic and population levels facilitates the development of environmentally friendly control methods. In this study, we present the development of 13 microsatellite markers for R. cerasi, through cross-species amplification. These markers have been used for the genotyping of 130 individuals from five different sampling sites in Greece. Our results indicate that (i) cross-species amplification is a versatile and rapid tool for developing microsatellite markers in Rhagoletis spp., (ii) the microsatellite markers presented here constitute an important tool for population studies on this pest, and (iii) there is clear structuring of natural European cherry fly populations.

The flight distance, flight time and individual flight activities of males and females of Dendroctonus armandi were recorded during 96-h flight trials using a flight mill system. The body weight, glucose, glycogen and lipid content of four treatments (naturally emerged, starved, phloem-fed and water-fed) were compared among pre-flight, post-flight and unflown controls. There was no significant difference between males and females in total flight distance and flight time in a given 24-h period. The flight distance and flight time of females showed a significant linear decline as the tethered flying continued, but the sustained flight ability of females was better than that of males. The females had higher glycogen and lipid content than the males; however, there was no significant difference between both sexes in glucose content. Water-feeding and phloem-feeding had significant effects on longevity, survival days and flight potential of D. armandi, which resulted in longer feeding days, poorer flight potential and lower energy substrate content. Our results demonstrate that flight distances in general do not differ between water-fed and starved individuals, whereas phloem-fed females and males fly better than water-fed and starved individuals.

Control of Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), populations or outbreaks may be achieved through the mass-rearing and inundative release of sterile B. tryoni. An alternative release method is to release chilled adult sterile fruit flies to decrease packaging and transport requirements and potentially improve release efficiencies. Two trials were conducted to determine the effect of chilling on the performance of two separate batches of adult B. tryoni, fed either a protein and sucrose diet or sucrose only diet. The first trial compared chill times of 0, 0.5, 2 and 4 h; the second trial compared chill times of 0, 2, 4, 8 and 24 h. Overall, there was little or no affect of chilling on the recovery, longevity and flight ability of B. tryoni chilled at 4°C. Recovery time can take up to 15 min for chilled adult flies. There was no effect of chill time on longevity although females generally had greater longevity on either diet compared with males. Propensity for flight was not adversely affected by chilling at the lower chill times in trial 1; however, in trial 2, adults fed on a protein and sucrose diet had a decreased tendency for flight as the chilling time increased. Fly body size did not affect recovery times although the smaller adult B. tryoni in trial 1 had significantly reduced longevity compared to the larger adults in trial 2. Implications of these findings for B. tryoni SIT are discussed.

Two novel full-length P450 cDNAs, CYP6CS1 and CYP6CW1, were cloned from the fourth instar nymphs of brown planthopper Nilaparvata lugens Stål (Hemiptera: Delphacidae) reared on its susceptible rice variety Taichung Native 1 (TN1) plants. The deduced proteins are typical microsomal P450s sharing conserved structural and functional domains with other insect CYP6 members. Temporal expression analysis by northern blot hybridization indicated pre-exposure to N. lugens moderately resistant rice Minghui 63 (MH63) seedlings caused a time course-dependent induction of CYP6CS1 which peaked after 24 h of treatment; in contrast, CYP6CW1 was induced and remained at a constant time course from 0–72 h. CYP6CS1 and CYP6CW1 are dramatically induced in gut tissues and, slightly upregulated in carcass and fat bodies as revealed in spatial gene expression analysis. Whole mount in situ hybridizaion revealed that the two genes are expressed at a basal level in gut tissue and Malpighian tubules in nymphs fed with TN1 rice. After exposure to MH63, the expression of CYP6CW1 was found to be high in the whole gut, including Malpighian tubules. Expression of CYP6CS1 was significantly increased in midgut, and slightly increased in foregut, hindgut and Malpighian tubules. These data suggest a potential role of the two P450s in determining patterns of N. lugens-rice relationships through allelochemical detoxification.

The tobacco whitefly, Bemisia tabaci (Gennadius), causes severe crop losses in many agricultural systems. The worst of these losses are often associated with the invasion and establishment of specific whitefly biotypes. In a comprehensive survey of biotypes present in central China between 2005 and 2007, we obtained 191 samples of B. tabaci from 19 districts in Hubei province and its surrounds. Biotypes were identified by RAPD-PCR and by sequencing the mitochondrial cytochrome oxidase I gene (mtCO1). We determined that these central Chinese haplotypes included the world's two most invasive B. tabaci biotypes (B and Q) and two indigenous biotypes (ZHJ1 and ZHJ3). The B biotype shared >99.7% identity with other Chinese B biotypes and the Q biotype shared >99.5% of its identity with Q samples from the Mediterranean, USA, Africa and East Asia. By 2007, the Q biotype was dominant over much of Hubei province and appeared to be supplanting all other biotypes, although both the invasive and indigenous biotypes existed in sympatry in some regions. The invasion and rapid establishment of the Q biotype in China mirrors events elsewhere in the world, and we suggest that this is a consequence of its reproductive isolation, its polyphagous nature and its broad-spectrum resistance to insecticides. Its dominance has severe implications for the sustainability of some insecticide groups and for the production of a number of crops.

The Asian citrus psyllid, Diaphorina citri Kuwayama, vectors Candidatus Liberibacter asiaticus (Las) and Candidatus Liberibacter americanus (Lam), the presumed causal agents of huanglongbing. D. citri generally rely on olfaction and vision for detection of host cues. Plant volatiles from Allium spp. (Alliaceae) are known to repel several arthropod species. We examined the effect of garlic chive (A. tuberosum Rottl.) and wild onion (A. canadense L.) volatiles on D. citri behaviour in a two-port divided T-olfactometer. Citrus leaf volatiles attracted significantly more D. citri adults than clean air. Volatiles from crushed garlic chive leaves, garlic chive essential oil, garlic chive plants, wild onion plants and crushed wild onion leaves all repelled D. citri adults when compared with clean air, with the first two being significantly more repellent than the others. However, when tested with citrus volatiles, only crushed garlic chive leaves and garlic chive essential oil were repellent, and crushed wild onions leaves were not.

Analysis of the headspace components of crushed garlic chive leaves and garlic chive essential oil by gas chromatography-mass spectrometry revealed that monosulfides, disulfides and trisulfides were the primary sulfur volatiles present. In general, trisulfides (dimethyl trisulfide) inhibited the response of D. citri to citrus volatiles more than disulfides (dimethyl disulfide, allyl methyl disulfide, allyl disulfide). Monosulfides did not affect the behaviour of D. citri adults. A blend of dimethyl trisulfide and dimethyl disulfide in 1:1 ratio showed an additive effect on inhibition of D. citri response to citrus volatiles. The plant volatiles from Allium spp. did not affect the behaviour of the D. citri ecto-parasitoid Tamarixia radiata (Waterston). Thus, Allium spp. or the tri- and di-sulphides could be integrated into management programmes for D. citri without affecting natural enemies.

The diamondback moth (DBM, Plutella xylostella L. (Lepidoptera: Plutellidae)) consumes a wide variety of brassicaceous host plants and is a common pest of crucifer crops worldwide. A highly unusual infestation of a sugar pea crop was recorded in Kenya in 1999, which persisted for two consecutive years. A strain (DBM-P) from this population was established in the laboratory and is the only one of several strains tested that can complete larval development on sugar peas. The oviposition acceptance and preference of the DBM-P strain was assessed in the presence of cabbage plants, sugar pea plants or both, in comparison to another strain (DBM-Cj) that was collected from cabbage and is unable to grow on pea plants. As expected, DBM-Cj females preferred to oviposit on cabbage plants. Surprisingly, DBM-P females also laid most eggs on cabbage and very few on peas. However, they laid significantly more eggs on the cabbage plant when pea plants were present. Our findings suggest that DBM-P manifested the initial stages of an evolutionary host range expansion, which is incomplete due to lack of oviposition fidelity on pea plants.

The role of pathogens in insect ecology is widely appreciated but remains insufficiently explored. Specifically, there is little understanding about the sources of the variation in the outcome of insect-pathogen interactions. This study addresses the extent to which immune traits of larvae and pupae of the moth Orgyia antiqua L. (Lepidoptera: Lymantriidae) depend on the host plant species and individual condition of the insects. The two host plants, Salix myrsinifolia Salisb. and S. viminalis L., were chosen because they differ in the concentration of phenolic glycosides, harmful to most polyphagous insects. Individual condition was assumed to be reflected in body weight and development time, and was manipulated by rearing larvae either singly or in groups of four. The resistance traits recorded were survival and time to death after fungal infection in the larval stage and the efficiency of encapsulating a nylon implant by the pupae. The survival of the infected larvae was mainly determined by the species of the host plant. Encapsulation response was not associated with the resistance to the pathogen, suggesting that the host plant affected the pathogen rather than the immune system of the insect. Interestingly, the host plant supporting better larval growth led to inferior resistance to the pathogen, indicating a trade-off between different aspects of host plant quality.

We performed molecular and morphological analyses to determine the generic limit of the genus Aulacorthum, including several species with controversial taxonomic histories. The sequences of four mitochondrial genes, COI, COII, srRNA and lrRNA, and one nuclear gene, EF1a, implied that Aulacorthum is not monophyletic, with Aulacorthum magnoliae and Aulacorthum nipponicum forming a clade that is not sister to other currently recognized Aulacorthum species. Morphometric analysis based on 20 morphological characters also showed that A. magnoliae and A. nipponicum exhibited morphological characteristics distinct from congeneric species. Based on these results, we propose a new genus, Neoaulacorthum ge. n., for A. magnoliae and A. nipponicum.