Analysis of published data on catches of insects in light-traps with a variety of light sources and of different designs showed that all conformed to the previously proposed model describing the functioning of a light-trap: catch = constant × where W = trap illumination and I = background illumination. Light-trap catches in differing cloud conditions and in open and woodland situations also varied as predicted by the model. A table of correction factors for different amounts of cloud cover is provided. The results are discussed in relation to use of light-traps and interpretation of light-trap data.

Over the past 30 years the coconut mite Aceria guerreronis Keifer has emerged as one of the most important pests of coconut and has recently spread to most coconut production areas worldwide. The mite has not been recorded in the Indo-Pacific region, the area of origin of coconut, suggesting that it has infested coconut only recently. To investigate the geographical origin, ancestral host associations, and colonization history of the mite, DNA sequence data from two mitochondrial and one nuclear region were obtained from samples of 29 populations from the Americas, Africa and the Indo-ocean region. Mitochondrial DNA 16S ribosomal sequences were most diverse in Brazil, which contained six of a total of seven haplotypes. A single haplotype was shared by non-American mites. Patterns of nuclear ribosomal internal transcribed spacer (ITS) variation were similar, again with the highest nucleotide diversity found in Brazil. These results suggest an American origin of the mite and lend evidence to a previous hypothesis that the original host of the mite is a non-coconut palm. In contrast to the diversity in the Americas, all samples from Africa and Asia were identical or very similar, consistent with the hypothesis that the mite invaded these regions recently from a common source. Although the invasion routes of this mite are still only partially reconstructed, the study rules out coconut as the ancestral host of A. guerreronis, thus prompting a reassessment of efforts using quarantine and biological control to check the spread of the pest.

Several species of Tribolium are important primary and secondary pests of various kinds of cereal products and for this reason have long attracted the attention of entomologists. Some of the species are easily cultured in the laboratory and have therefore become favoured animals for experiments not particularly concerned with their rôle as pests. As a result of the two avenues of approach, a very impressive amount of information has now been accumulated concerning the habits and physiology of a few of the species.

The subterranean termites in the genus Reticulitermes have a complex and plastic life cycle, which has been the subject of a number of publications over the past century. Given the inherent difficulties in studying such cryptic, eusocial organisms it is not perhaps surprising that the literature on their biology has failed to reach a consensus. An overview of the literature is given, which is followed by a discussion of the various theories on the life cycle of Reticulitermes spp. A substantial proportion of the review focuses on the French literature, which constitutes the majority of the primary sources and can be difficult to access. There are many discrepancies in the literature in terms of the number of instars, the definition of workers and the question of whether they should be termed pseudergates or, potentially, an additional terminology used to differentiate between pseudergates and the true workers seen in the higher termites (Isoptera: Termitidae). It remains very difficult to compare publications as there is little conformity; a problem that is aggravated by a general absence of drawings of the relevant instars. Further work on the biology of Reticulitermes is clearly required. There is also a need for researchers to agree on a standard terminology for this genus. A glossary is provided for the various synonyms and definitions.

Collections of Anopheles gambiae Giles complex, A. funestus Giles group and other mosquitoes were made by spray-catch from twelve catching stations indoors and by hand-catch from pit shelters at two catching stations at Segera, Tanzania, between January 1970 and June 1971. Females of A. gambiae were identified cytotaxonomically as sibling species A or B of the complex. In houses during 1970, A. gambiae species B was more numerous at first than A, but A became predominant during the long rains of March-May. In the cool dry weather of June-November both A and B densities declined and the A:B ratio surpassed 50:1. The short rains in December produced a population explosion of species B and less multiplication of species A, the B:A ratio reaching >11:1. In 1971, hot dry weather during January-March caused declines of species A and B with a maximum B: A ratio of 13:1. Long rains, coming in late March, provoked a resurgence of A and a concurrent decline of B, so that the A:B ratio again reached 20:1 in June. Similar cycles of species A and B were observed outdoors, although the relative numbers outdoors/indoors averaged 2·3 times more for species B than for species A. In A. funestus, A. gambiae species A and A. gambiae species B Human Blood Indices were 97·5%, 91·2% and 60·9% indoors and 24%, 2% and 7% outdoors, respectively. Respective malaria sporozoite rates were 1·62%, 4·23% and 0·32% and minimum rates of stage-Ill filarial infection were 0·33%, 0·44% and 0·57%. Sporozoite-positive and sporozoite-negative mosquitoes exhibited similar HBF's in species A and discrepant HBI's in species B. The HBI's were higher in filariapositive A and B females than in filaria-negative females. Gregarines occurred in 1·36% of species A and 0·38% of species B. Trematode cysts were seen in two specimens of species A.

Of A and B females 28% and 4%, respectively, had four-banded palps. It is shown mathematically that the discrepant malaria sporozoite rates in species A and B may be explained by extrapolating from the man-biting rate and probable daily survival rate for each species. This implies that no unrecognised factors play a major role in causing the contrasting efficiency of these two sibling species as malaria vectors.

Life history parameters of the pea aphid, Acyrthosiphon pisum were studied at five constant temperatures on two cultivars of peas, Scout and Sancho. The development and mortality of juveniles and the life-span, age-specific fecundity and survivorship of adult aphids were recorded and used to construct life tables. The juvenile development period (from birth to adulthood) was longest at 11.9°C (16.8 days on cv. Scout and 16.2 days on cv. Sancho) and shortest at 26.7°C (8.5 days on cv. Scout and 8.8 days on cv. Sancho). At all temperatures, except 26.7°C, juveniles developed faster on cv. Sancho than on cv. Scout. On both pea varieties juvenile mortality was highest at temperatures above 19.6°C and lowest at 19.6°C. Highest cumulative juvenile mortality was recorded on cv. Scout at 26.7°C when only 9% of aphids survived from birth to reproductively mature adults. Fecundity rates were unaffected by temperature in the range tested on cv. Sancho but increased with increasing temperatures between 11.9 and 19.6°C on cv. Scout. These differences in life history parameters were reflected in the population growth (rm) of aphids on both pea cultivars which increased with increasing temperatures between 11.9 and 23.1°C on cv. Sancho and 11.9 and 19.6°C on cv. Scout, declining thereafter. Population growth was consistently greater at all temperatures for aphids reared on cv. Sancho than those reared on cv. Scout.

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.

Five aspects of the behaviour of the Triatominae are reviewed: hostfinding, defence from predators, habitat selection, activity patterns and substrate preferences, and mating and oviposition behaviour. It is emphasised that knowledge of behaviour is largely restricted to the three species Triatoma infestans (Klug), Rhodnius prolixus Stål and Panstrongylus megistus (Burm.) and that the behaviour of other species, particularly those with predominantly sylvatic habits, may be quite different in some respects.

An incomplete ring of electrocuting nets was placed round various mammals stationed singly in woodland infested with Glossina morsitans morsitans Westw. and G. pallidipes Aust. in the Zambezi Valley in Rhodesia. Catches of fed and unfed flies made on the inside and outside faces of the nets were used to estimate the number and nutritional status of flies travelling to and from the baits. The validity of these assessments was investigated by studying the responses of the flies to the netting frame, and the effects of different heights and arrangements of nets. The percentages of recently fed flies in samples leaving various mammals were: ox 33–61, donkey 51, sedated ox 42, kudu 41, washed ox 34, warthog 19, sedated goat 15, ox with three men 12, bushpig 8, buffalo 5, ox sprayed with repellent 4, bushbuck 2, goat 1, sheep 1, impala 0. With the ox, the proportion of fed flies fell by one-third when the number of tsetse attracted to the ox increased 4·5-fold to the point where the ox became intolerant. Effects of time of day and season on the proportion of flies feeding are discussed.

A field trial was carried out in a Maasai group ranch to assess the use of odour-baited traps for suppression of a population of the tsetse fly Glossina pallidipes Austen. In January, 1987, local people made 100 NG2B traps in their homesteads. These were then deployed within the suppression zone of about 100 km2, primarily in the areas of woodland where flies aggregate in the dry season. Traps were baited with acetone (ca. 150 mg/h) and cow urine (ca. 1000 mg/h) and checked at monthly intervals in order to replenish odours and repair damage. A further 90 traps were added between October and December to enlarge the suppression area slightly and to strengthen the trap barriers. The population was monitored using biconical and NG2B traps as well as by mark-release-recapture estimates of population size. By October the number of G. pallidipes in the suppression zone was reduced by 98–99% relative to the number 3 km outside the suppression zone. Some reinvasion, mainly of parous females, occurred in November during the short rains but these flies were rapidly trapped out again. Average mortality rates due to trapping were estimated at 4–5% per day, which, combined with the natural mortality, reduced the adult population at a rate of about 2.6% per day during the dry season. The traps had less effect on the smaller population of G. longipennis Corti but still gave a reduction of up to 90% in the dry season. The use of this low technology approach offers good prospects for future community-based tsetse control operations.

A significant reduction in age of mating occurred during the first four generations (G1–G4) of laboratory adaptation of wild Bactrocera tryoni (Froggatt) and this was associated with the earlier attainment of peak egg load although no significant differences were detected in the peak egg load itself. A long term laboratory (LTL) strain had a significantly earlier mating age and higher peak egg load than flies of wild origin or those from the first four laboratory generations. The amount of protein consumed by females in the first week of adult life was significantly higher in the LTL strain than in flies of wild origin or G1–G4 but there were no significant changes (or only slight changes) with laboratory adaptation in the amounts of protein consumed up to the ages of mating and peak egg load. Laboratory adaptation resulted in no significant changes in egg size, egg dry weight, puparial fresh weight and the dry weight of newly emerged females. The large increase in fecundity with laboratory adaptation is associated with a 4- to 5-fold increase in the rate of conversion of dietary protein to eggs (i.e. eggs produced per mg of protein consumed).

Field experiments were conducted in the Gambia to measure the convergence of mosquitoes towards single bait-animals (calf or man) or to an equivalent source of carbon dioxide, the mosquitoes being caught in ramp-traps. Catches of unfed females of Anopheles melas Theo. fell off steeply with increasing distance up to 15 yd from animal bait; with carbon dioxide as bait, raised catches were only recorded out to 10 yd. Catches of other Anopheles spp. with calf-bait gave similar results to those for A. melas. A positive effect of the calf on densities at 15 yd was obtained for Culex tritaeniorhynchus Giles but this was less clear-cut in the case of C. thalassius Theo.; with carbon dioxide as bait, raised catches of both species were recorded at 10 yd but not at 15 yd. Both types of bait gave raised catches of the C. decens group only at 5 yd. It is concluded that A. melas and other Anopheles spp. were detecting and responding to the single animal bait from 15–20 yd, C. tritaeniorhynchus and C. thalassius from 10–20 yd, and the C. decens group from 5 yd. In all except the last named group, as also for the other Anopheles spp., on which data are lacking, the range of attraction of carbon dioxide was less than 15 yd. Olfactory cues were therefore held to be responsible for long-range orientation in these three species of mosquitoes, the effect being most marked with A. melas.

Two Dermestid beetles, Trogoderma granarium Everts and T. versicolor (Creutz.) have been recorded on a variety of stored products. In England, T. granarium is a serious pest only in maltings. The life-history is described. The larvae are responsible for the damage to stored products, and their hairy nature facilitates the spread of infestations on sacking and clothing.

All stages in the life-cycle are resistant to heat and dryness.

Gravid females of Culex quinquefasciatus Say from a laboratory strain originating in Nigeria orientated to a source of the main volatile pheromone component, erythro-6-acetoxy-5-hexadecanolide, isolated from the apical droplets of the egg rafts. Significantly more egg rafts were laid around polystyrene discs treated with the synthetic compound than around untreated discs, and modification of the chemical structure destroyed its biological activity. The response was found at a dose of 0·02μg of the synthetic compound, which is equivalent to one-sixteenth of the total acetoxyhexadecanolide found in an egg raft, and above. Although the apical droplets were contaminated by bacteria, these did not contribute to the production of the acetoxyhexadecanolide, which was present in the eggs before they were laid. It is concluded that the pheromone is released slowly from the apical droplets into the air above the water surface, attracting other gravid females to oviposit around previously laid egg rafts, and there is evidence of attraction over a distance of 5·5 cm.

Laboratory bioassays were carried out with four neonicotinoid insecticides on multiple strains of Bemisia tabaci (Gennadius) to evaluate resistance and cross-resistance patterns. Three imidacloprid-resistant strains and field populations from three different locations in the southwestern USA were compared in systemic uptake bioassays with acetamiprid, dinotefuran, imidacloprid and thiamethoxam. An imidacloprid-resistant strain (IM-R) with 120-fold resistance originally collected from Imperial Valley, California, did not show cross-resistance to acetamiprid, dinotefuran or thiamethoxam. The Guatemala-resistant strain (GU-R) that was also highly resistant to imidacloprid (RR = 109-fold) showed low levels of cross-resistance when bioassayed with acetamiprid and thiamethoxam. However, dinotefuran was more toxic than either imidacloprid or thiamethoxam to both IM-R and GU-R strains as indicated by low LC50s. By contrast, a Q-biotype Spanish-resistant strain (SQ-R) of B. tabaci highly resistant to imidacloprid demonstrated high cross-resistance to the two related neonicotinoids. Field populations from Imperial Valley (California), Maricopa and Yuma (Arizona), showed variable susceptibility to imidacloprid (LC50s ranging from 3.39 to 115 μg ml–1) but did not exhibit cross-resistance to the three neonicotinoids suggesting that all three compounds would be effective in managing whiteflies. Yuma populations were the most susceptible to imidacloprid. Dinotefuran was the most toxic of the four neonicotinoids against field populations. Although differences in binding at the target site and metabolic pathways may influence the variability in cross-resistance patterns among whitefly populations, comparison of whitefly responses from various geographic regions to the four neonicotinoids indicates the importance of ecological and operational factors on development of cross-resistance to the neonicotinoids.

Larval populations of the Anopheles gambiae Giles complex (species A and B) were sampled in Kenya, and from the frequencies of the age distribution of the immature stages time-specific life-tables were constructed. Daily survival rates and instar mortalities showed that there was high mortality amongst fourth-instar larvae, due at least in part to infections of larval nematodes, Coelomomyces and epibionts. Antiserum to the A. gambiae complex was prepared in rabbits so that the precipitin test could be employed to detect the presence of A. gambiae in gut smears taken from possible predators. By this serological technique various spiders, Diptera, Coleoptera and amphibia were identified as predators. These may be very important in regulating populations of A. gambiae even in small collections of water.

Experimental huts in Côte d’Ivoire were used to evaluate the pyrethroid alpha-cypermethrin, the non-ester pyrethroid etofenprox, the organophosphate pirimiphos-methyl and the carbamate carbosulfan on bednets against pyrethroid-resistant Anopheles gambiae Giles. To test for selection for the resistance gene by the treated nets, A. gambiae collected live or dead from the huts were kept and analysed for the presence of the kdr gene using a new polymerase chain reaction followed by sequence-specific oligonucleotide probing (PCR–SSOP) for kdr-genotyping. Deliberately holed bednets freshly treated with pirimiphos-methyl or carbosulfan caused over 90% kill of A. gambiae s.s. and Culex spp. However, the mortality with alpha-cypermethrin or etofenprox treated nets was similar to that with untreated nets. Bloodfeeding of A. gambiae s.s. on the sleepers under the nets was only significantly reduced by alpha-cypermethrin and carbosulfan. Tests of the residual activity of the bednets after seven months showed that pirimiphos-methyl had lost its efficacy while carbosulfan still performed well. Once again the pyrethroid treated nets gave similar results to the untreated nets. Selection for the kdr-allele by alpha-cypermethrin and etofenprox, but not by carbosulfan, was indicated by PCR–SSOP genotyping of mosquitoes. Thus carbamates such as carbosulfan, or organophosphates of longer persistence than pirimiphos-methyl and of low mammalian toxicity, would seem to be a promising alternative to be used on bednets, particularly in areas of pyrethroid resistance.

Temperature and food quality can both influence growth rates, consumption rates, utilization efficiencies and developmental time of herbivorous insects. Gravimetric analyses were conducted during two consecutive years to assess the effects of temperature and food quality on fourth instar larvae of the forest tent caterpillar Malacosoma disstria Hübner. Larvae were reared in the laboratory at three different temperatures (18, 24 and 30°C) and on two types of diet; leaves of sugar maple trees Acer saccharum Marsh. located at the forest edge (sun-exposed leaves) or within the forest interior (shade-exposed leaves). In general, larvae reared at 18°C had lower growth rates and lower consumption rates than larvae reared at the warmer temperatures (24 and 30°C). Moreover, the duration of the instar decreased significantly with increasing temperatures. Type of diet also affected the growth rates and amount of food ingested by larvae but did not affect the duration of the instar. Larvae fed sun-exposed leaves consumed more food and gained higher biomasses. Values of approximate digestibility and efficiency of conversion of ingested food were also higher when larvae were fed sun-exposed leaves. Higher growth rates with increasing temperatures were primarily the result of the shorter stadium duration. The higher growth rates of larvae fed sun-exposed leaves were possibly the result of stimulatory feeding and consequently greater food intake and also a more efficient use of food ingested. This study suggests that the performance of M. disstria caterpillars could be enhanced by warmer temperatures and higher leaf quality.

Twelve Trichogramma spp. are redescribed. These are: T. australicum Girault, T. dendrolimi Matsumura, T. euproctidis (Girault), T. evanescens Westwood, T. fasciatum(Perkins), T. japonicum Ashmead, T. minutum Riley, T. perkinsi Girault, T. pretiosum Riley, T. retorridum (Girault), T. semblidis (Aurivillius) and T. semifumatum(Perkins). Differences in male genitalia are emphasised, being most stable and reliable, and pigmentation as well as wing and antennal trichiation are described, being characters of supplementary importance for species diagnosis. Host and distribution records are also given. In the male genitalia, the shape of the dorsal expansion of the gonobase differs considerably in some species and the position of the chelate structures with respect to the tips of the gonoforceps also varies; the median ventral projection is large in some species, reduced in some and almost absent in others. A comparative account of the most distinguishing characters of the different species is included and a key to 15 species is provided

Species richness and abundance of staphylinid and carabid beetles overwintering in winter wheat fields and 1- to 3-year-old wildflower areas were investigated during 2000/2001 on 16 study sites in Switzerland. Abundance and species richness of overwintering staphylinids significantly increased with successional age of the wildflower areas and were always higher in older wildflower areas than in winter wheat. A similar but less distinct pattern was observed for the abundance and species richness of carabid beetles. The influence of habitat parameters (vegetation cover, fine sand content, organic matter, pH, soil pore volume, surrounding landscape structure, habitat area) on the staphylinid and carabid assemblages based on the number of individuals per species and site was analysed using canonical correspondence analysis. Vegetation cover was the most significant parameter significantly characterizing both staphylinid and carabid assemblages. The amount of vegetation cover explained 15.7% of the variance, fine sand content accounted for 13.3% and surrounding landscape structure for 10.9% of the variance in the staphylinid assemblage. In the carabid assemblage, vegetation cover was the only significant factor, explaining 24.7% of the variance. This study showed for the first time that the significance of wildflower areas as a reservoir for hibernation for generalist predatory beetles increases with progressing successional age.