Plutella xylostella (L.) is the most important pest of Brassicaceae worldwide, with a recent estimate of US$ 4–5 billion expenditure for the control of this insect. A case of very high resistance of this pest to chlorantraniliprole was recently associated with reduced efficacy in a Brazilian field of Brassica spp. Although diamide resistance has been characterized, the fitness of insects due to such resistance has yet to be examined. Therefore, in this study, biological parameters were assessed in both susceptible and resistant strains of P. xylostella subjected to sublethal chlorantraniliprole concentrations. The field strain showed high resistance to chlorantraniliprole (RR50=27,793-fold), although resistance rapidly decreased in the first generations, showing instability. The exposure of susceptible and resistant larvae to their respective LC1, LC10, and LC25 values led to an increased duration of the larval and pupae phases and reduced weight in both strains; however, no significant differences in pupal viability across the treatments were observed. The resistant insects presented significantly lower larval weight and fecundity and higher larval and pupal periods, hatchability, and male longevity when not exposed to chlorantraniliprole, suggesting a fitness cost associated with resistance. In addition, resistant females showed a significantly higher egg-laying period and longevity at LC25, whereas the males lived longer at LC1. Chlorantraniliprole negatively impacted the biological parameters of both strains tested, although these effects were more relevant to the resistant insects. Resistant P. xylostella showed negative and positive biological trade-offs when compared with the susceptible individuals in both the absence and presence of chlorantraniliprole. Despite the important role that these trade-offs may play in the evolution of resistance to chlorantraniliprole, practical applications still depend on such information as the dominance of fitness costs and resistance.

The weight of fresh grass eaten by Schistocerca gregaria (Forsk.) on each day of its development from hatching until maturation of the adults was investigated. Hoppers in all instars ate on the average about one gram per gram body-weight per day on the middle days of the instars and the adults ate approximately half-a-gram per gram body-weight each day. The percentage of food assimilated, calculated from the dry faeces and estimated dry weight of food eaten, falls from about 78 in the first to 35 in the fifth instar. There were some indication that the food consumption per hopper increases with the number of hoppers per cage.

The weight of wheat bran eaten by hoppers was also investigated. The amount eaten by hoppers on the middle day of the first instar is approximately the same, in relation to their body weight, as that eaten per day just before and just after moulting by those in the fourth and fifth instars. More is eaten in the middle of these instars.

Measurements of weights and lengths of males and females in the hopper instars and of the weights of adults showed that in the course of their development females become progressively heavier and larger than males. The weight of a newly-hatched hopper is about 10 mg.; a female fledgling weighs about 2 gm. and a male 1·5 gm. Hoppers are approximately 1 cm. long on hatching, and males on reaching maturity are about 4·5 cm. long and females about 5.0 cm.

Generalist insect predators can significantly impact the dynamics of pest populations; and, using alternative prey, they can rapidly establish in disturbed agroecosystems. However, indirect interactions between prey can occur, leading to either increased or decreased predation on focal prey. The present paper demonstrates how alternative prey can disrupt predation by the hemipteran Orius insidiosus on the soybean aphid Aphis glycines via short-term indirect interactions. We used laboratory microcosms to measure the impact of the predator on the population growth of the aphid in the presence of alternative prey, soybean thrips Neohydatothrips variabilis, and we characterized the foraging behaviour of the predator to assess prey preference. We showed that O. insidiosus predation on aphids was reduced in the presence of thrips and that this positive impact on aphids increased as thrips density increased. Results from the behavioural experiment support the hypothesis of a prey preference toward thrips. When prey-pest ratio is aphid-biased, short-term apparent commensalism between prey occurs in favour of the most abundant prey (aphids) with no switching behaviour appearing in O. insidiosus. These results demonstrate that potential indirect interactions should be taken into account when considering O. insidiosus as a biocontrol agent against the soybean aphid.

The effects of nitrogen and silica application to maize plants on various aspects of the bionomics of the maize stem borer, Sesamia calamistis Hampson, were studied in the laboratory. Increasing nitrogen doses significantly increased larval survival (from 18.7% (control) to 37.3% at 2.25 g N/plant), larval weight (from 49.0 mg (control) to 99.5 mg at 2.25 g N/plant), and female fecundity (from 77 eggs per female (control) to 365 eggs per female at 1.69 g N/plant). A significant, positive relationship was found between moth fecundity and female pupal weight. Nitrogen had no effect on larval and pupal developmental time but increased adult longevity. Intrinsic rate of increase, rm, and the net reproductive rate, Ro, were positively related to leaf and stem nitrogen, while generation time, G, was negatively related. Silica had the opposite effect from nitrogen on larval survival. Increasing silica supply reduced ultimate larval survival from 26.0% (control) to 4.0% at 0.56 g Si/plant. Immature developmental time, larval and pupal weight, pupal survival, female fecundity, egg viability and adult longevity of S. calamistis were not affected by silica application.

Genetic (electrophoretic) variation was examined in the two pest species of Heliothis found in Australia, H. armigera (Hübner) and H. punctigera Wallengren. They could be differentiated by seven loci which enabled identification of individual eggs and small larvae not normally distinguishable by their morphology. The traditional criteria for distinguishing the larger larvae of the two species were shown to be unreliable. The genetic distance between the two species was 0·34 ± 0·02. The percentage of loci polymorphic in both species, 32%, and the mean heterozygosities, 11·3% for H. armigera and 10·8% for H. punctigera, are lower than those reported in the American species, H. virescens (F.) and H. zea (Boddie). Populations throughout Australia were differentiated from each other, but there did not appear to be a marked geographic pattern to the variation. Genetic distances between populations of H. armigera were low (<0·01). It was concluded that the effective population size of Heliothis is large and that significant gene flow probably occurs between widely separated regions.

Many hemipteroids are major pests and vectors of microbial pathogens, infecting crops. Saliva of the hemipteroids is critical in enabling them to be voracious feeders on plants, including the economically important ones. A plethora of hemipteroid salivary enzymes is known to inflict stress in plants, either by degrading the plant tissue or by affecting their normal metabolism. Hemipteroids utilize one of the following three strategies of feeding behaviour: salivary sheath feeding, osmotic-pump feeding and cell-rupture feeding. The last strategy also includes several different tactics such as lacerate-and-flush, lacerate-and-sip and macerate-and-flush. Understanding hemipteroid feeding mechanisms is critical, since feeding behaviour directs salivary composition. Saliva of the Heteroptera that are specialized as fruit and seed feeders, includes cell-degrading enzymes, auchenorrhynchan salivary composition also predominantly consists of cell-degrading enzymes such as amylase and protease, whereas that of the Sternorhyncha includes a variety of allelochemical-detoxifying enzymes. Little is known about the salivary composition of the Thysanoptera. Cell-degrading proteins such as amylase, pectinase, cellulase and pectinesterase enable stylet entry into the plant tissue. In contrast, enzymes such as glutathione peroxidase, laccase and trehalase detoxify plant chemicals, enabling the circumvention of plant-defence mechanisms. Salivary enzymes such as M1-zinc metalloprotease and CLIP-domain serine protease as in Acyrthosiphon pisum (Aphididae), and non-enzymatic proteins such as apolipophorin, ficolin-3-like protein and ‘lava-lamp’ protein as in Diuraphis noxia (Aphididae) have the capacity to alter host-plant-defence mechanisms. A majority of the hemipteroids feed on phloem, hence Ca++-binding proteins such as C002 protein, calreticulin-like isoform 1 and calmodulin (critical for preventing sieve-plate occlusion) are increasingly being recognized in hemipteroid–plant interactions. Determination of a staggering variety of proteins shows the complexity of hemipteroid saliva: effector proteins localized in hemipteran saliva suggest a similarity to the physiology of pathogen–plant interactions.

A species in the Bactrocera dorsalis (Hendel) complex was detected in Kenya during 2003 and classified as Bactrocera invadens Drew, Tsuruta & White. Having spread rapidly throughout Africa, it threatens agriculture due to crop damage and loss of market access. In a recent revision of the B. dorsalis complex, B. invadens was incorporated into the species B. dorsalis. The potential distribution of B. dorsalis has been previously modelled. However, previous models were based on presence data and did not incorporate information on the seasonal phenology of B. dorsalis, nor on the possible influence that irrigation may have on its distribution. Methyl eugenol-baited traps were used to collect B. dorsalis in Africa. Seasonal phenology data, measured as fly abundance throughout the year, was related to each location's climate to infer climatic growth response parameters. These functions were used along with African distribution records and development studies to fit the niche model for B. dorsalis, using independent global distribution records outside Africa for model validation. Areas at greatest risk of invasion by B. dorsalis are South and Central America, Mexico, southernmost USA, parts of the Mediterranean coast, parts of Southern and Eastern Australia and New Zealand's North Island. Under irrigation, most of Africa and Australia appear climatically suitable.

A dual port olfactometer was used to study the response of Anopheles gambiaeGiles sensu stricto to odours of human and animal origin. Human odour consisted of human skin emanations collected on a nylon stocking, which was worn for 24 h. This was tested alone or together with 4.5% carbon dioxide, the concentration in human and cattle breath. Cattle odours consisted of cow skin emanations and/or carbon dioxide. Cow skin emanations were collected by tying a nylon stocking (‘cow sock’) around the hind leg of a cow for 12 h. Anopheles gambiae s.s. was consistently highly attracted by human odour, which is consistent with the high degree of anthropophily in this mosquito. Anopheles gambiae s.s. was not attracted by human or cattle equivalent volumes of carbon dioxide and this gas did not enhance the effect of human skin residues. Furthermore, A. gambiae s.s. showed a high degree of aversion to cow odour. When human odour and cow odour were tested together in the same port, mosquitoes were still highly attracted, indicating that whilst cattle odour may deter A. gambiae s.s., these mosquitoes can detect human odour in the presence of cattle odour. It was concluded that carbon dioxide plays a minor role in the host seeking behaviour of A. gambiae s.s., whilst host specific cues such as human skin residues play a major role and very effectively demonstrated anthropophilic behaviour in the laboratory.

Insects immersed in oils exude minute droplets of water over the surface of the cuticle. These appear more rapidly in light oils than in heavy oils and are more numerous in young insects than in old. Immersed in mixtures of oils and alcohols which separate in contact with water they show a vigorous effervescence at those regions where the mixture penetrates most rapidly to the water in the cuticle. There is a delay of varying duration at different parts of the cuticle when heavy oils are used. This delay disappears if the lipoid layer is first extracted with petroleum ether.

Factors controlling the rate of entry of pyrethrum through the cuticle have been studied by the application of pyrethrum in oil to a restricted area of the abdomen of nymphs and adults of Rhodnius. Entry is more rapid in light than in heavy petroleum oils ; it is much accelerated if the cuticle is first treated with petroleum ether. Entry is very slow in vegetable oils. There are great individual variations, due chiefly to the thickness of the endocuticle, which in turn is determined by the size of meal taken before moulting, the age and the amount of food taken after moulting, and the degree of stretching of the cuticle. There is evidence that the pore canals are important in the passage of pyrethrum through the endocuticle.

Histological examination of the integument shows that in the nymph of Rhodnius oils are taken up first by the epidermal cells in the zone around the bristles ; later by the general epidermis. The uptake of oil is greatly increased if 5 per cent. of oleic acid is added to refined petroleum. In the adult Rhodnius soon after moulting, oils are taken up by the general epidermis. In old insects they are taken up solely by the dermal glands. There is no visible entry through the sockets of the bristles.

The entry of pyrethrum in oils is accelerated by the addition of oleic or other fatty acids.

Changes in numbers of adult Coccinellids on nettles infested with Microlophium evansi (Theo.) and on three experimental bean plots infested with Aphis fabae Scop. are described for the spring and summer of 1952 at Rothamsted. Of the three common species, Adalia bipunctata (L.), Coccinella septempunctata L. and Propylea quatuordecimpunctata (L.), the first was always the most abundant.

The overwintered Coccinellids produced two broods: one on nettles in the spring and one on beans in early summer.

On bean plots, changes in numbers of the adult insects occurred in three phases: (1) overwintered ladybirds, dispersing from nettles and other places, accumulated on the beans in the early stages of the infestations by Aphis fabae; (2) ladybirds, which had developed from eggs laid by the overwintered insects on nettles, emigrated from nettles and accumulated on the beans when A. fabae populations were at their height; (3) ladybirds, developed from eggs laid on the beans also by the overwintered insects, reached the adult stage when the bean aphid infestations had finished. The rise and fall of the A. fabae populations are discussed.

One of the bean plots had always a high population of Coceinellids, which was attributed to its situation between two of the nettle sites. The other two bean plots were remote from nettles and one was sheltered by trees and buildings; their coccinellid populations were much lower.

Callosobruchus maculatus (Fabricius) develops in the seeds of Vigna unguiculata in the Sahel region of Africa. The reproductive activity of this species and the development of its offspring were studied during the dry season at Ouagadougou and Bobo Dioulasso (Burkina Faso), two zones with different climatic conditions. The length of imaginal life of the females and the developmental time varied with changes in climatic conditions, the lowest values for both parameters being found at the end of the dry season when temperature and humidity increased. In the two zones, variations in the density of the bruchid populations have been studied in experimental stores. The density of the bruchid population was low at the beginning of the study and increased when temperature and humidity rose. The introduction of Dinarmus basalis (Rondani) adults to the stores caused a significant reduction in the numbers of C. maculatus adults. The density of the D. basalis populations was low from December to February and increased when temperatures and then humidity became higher. The increase of the D. basalis population and the rate of parasitism were greater at Bobo Dioulasso than at Ouagadougou. Laboratory studies have demonstrated that fecundity, duration of adult life and developmental times depend on humidity. This study has shown the importance of local climatic conditions on parasitoid reproduction and development and also in the control of bruchid populations in stores.

1. Tsetse-flies have been divided into four stages of hunger by their external appearance. These stages have been correlated with the internal appearance determined by dissection. It was found that the fat-bodies became maximally developed shortly after a meal, and thereafter diminished rapidly in bulk. Hunger of flies in samples is expressed as the Mean Hunger Stage (M.H.S.).

2. Flies in different stages of hunger showed different behaviour in the field. Thus hungry flies usually attacked head-upwards, replete flies, if attacking, tending to adopt a head-down attitude. Most replete flies preferred to settle on the ground, or on objects other than the members of the catching party. Hungry flies were the most persistent followers.

3. The true habitats and feeding-grounds of Glossina morsitans, G. swynnertoni, and G. palpalis are described, so far as they are known to the writer.

4. Confirmation of the feeding-ground theory was obtained for G. swynnertoni by an analysis of the to-and-fro movements of marked flies.

5. Considerable independent movement of flies was shown to occur in the absence of carriage on man or game. Some flies under such conditions travelled over 2 miles in 3 hours.

Between October 1999 and April 2000, nearly 4000 ha of nymphal bands and adult swarms of Chortoicetes terminifera (Walker) were aerially treated using a ULV oil formulation of strain FI-985 of Metarhizium anisopliae var. acridum. During the mild weather (maxima 22–30°C) of spring (October), there was little change in nymphal bands during the first week but at all doses between 25–100 g (1–4 × 1012 conidia) ha−1, the bands rapidly declined 9–12 days after treatment reaching > 90%mortality by 14 days. Metarhizium persisted for some time as there was 50% mortality of locusts fed vegetation collected from the treated blocks seven days after treatment. Persistence was confirmed by the high mortality of bands that invaded from untreated areas and of nymphs that hatched on the plot five to seven days after treatment, though mortality was then delayed until early in the third week. During summer (January), temperatures were high (maxima 36–42°C), and at all doses between 25 and 125 g (1–5 × 1012 conidia) ha−1, there was a rapid decline seven to ten days after treatment. By 12–14 days, there was a > 90% decline in numbers in most blocks which was confirmed by helicopter surveys two weeks after treatment that found very few adults within or near treated areas. Mortality was delayed in the high dose where there were blockages of spray equipment during treatment. The clear demonstration that Metarhiziumcan suppress small local populations of C. terminifera led to the limited operational use of Metarhizium on an organic farm and in a National Park where nearly 2500 ha of bands and swarms were treated. Continued research is needed to develop a commercially viable product so that Metarhizium can form a significant part of a programme of integrated pest management of locusts in Australia.

This paper presents a thorough review and a complete amalgamation, with some modification, of the internal classification of the genus Anopheles. Both formal and informal taxa are included. The classification is intended to aid researchers and students who are interested in analysing species relationships, making group comparisons and testing phylogenetic hypotheses. The genus includes 458 formally named and provisionally designated species divided among six subgenera. The largest subgenera, Anopheles, Cellia and Nyssorhynchus, are further divided into various descending informal groupings down to species level. These groupings include Sections, Series, Groups, Subgroups and Complexes. Other terms applied by some authors to levels of classification represented by these categories have been changed in order to establish a degree of uniformity in the application of informal group names within the genus. A few changes involving groups and species assignments have been made to eliminate duplicity or clarify concepts.

During investigations on the phytophagous mite fauna of Mauritius, of which up to the present five species only had been recorded, 21 species were collected, of which ten species belong to the TETRANYCHIDAE. In addition, nine species, of which the majority are believed to be predacious, were observed.

An annotated list of the species, together with their food-plants, their geographical distribution and the countries from which they might have been introduced into Mauritius, is given.

Of the species of economic importance the following are worthy of mention: — In the TETRANYCHIDAE: Eutetranychus banksi (McG.) on Citrus, Oligonychus biharensis (Hirst) and Oligonychus mangiferus (Rahm. & Sapra) on various fruit trees, including avocado, mango and litchi, Oligonychus sp. (pratensis (Banks) group) on sugar-cane, Tetranychus marianae McG. and Tetranychus sp. (ludeni Zacher group) on many vegetable crops, including bean, egg-plant, tomato, etc. In the ERIOPHYIDAE: Phyllocoptruta oleivora (Ashm.) and Tegonotus sp., which are potential enemies of Citrus and tomato, respectively. In the TENUIPALPIDAE: Brevipalpus phoenicis (Geijskes) has a very wide range of food-plants and its future importance in the cultivation of tea and Citrus are mentioned, whilst Raoiella indica Hirst is an important pest of coconut plantations. In the TARSONEMIDAE: Hemitarsonemus latus (Banks) ranks as an important pest of a large number of economic plants including bean, tea and water-cress.

Only two predatory mites of great economic importance are recorded, viz.:— Typhlodromus caudatus (Berl.) and T. ovalis Evans. The bionomics of the former species are fully described and its relation to Raoiella indica on coconut is discussed. The life-cycle of T. caudatus from egg to adult varies from 4–8 days, in summer to 13–18 days in winter.

Results are given of a survey of the predatory insects associated with the phytophagous mites. The most important predators on Tetranychus spp. are the Coccinellid, Stethorus vinsoni Kapur, and the Cecidomyiid, Feltiella sp. near tetranychi Rübs. The daily mite consumption of these predators is given. Other predators of secondary importance are Oligota pallidicornis Cam. and Scolothrips sp. near indicus Priesn.

The bionomics of T. marianae on tomato and of Raoiella indica on coconut were studied. Duration of the life-cycle of the former species varies from 4–9 days in summer to 15–22 days in winter. Twenty four to 30 generations of this species are estimated to occur in a year. Raoiella has a development period of 18–26 days from egg to adult in summer and of 30–36 days in winter.

A biological study of the predatory insects, Stethorus vinsoni and Feltiella, sp., is given. Their beneficial effect is discussed. These two predators do not exert a control in time to check the build-up of the mite population. Their abundance is directly proportional to the incidence of the mite and the peak is generally only attained when the depredations of the latter have reached a disastrous level.

The various possible factors which have contributed to the sudden increase in the mite population on tomato during the last 6–8 years are discussed. Amongst the important factors are the following: —

(a) Absence of cyclonic disturbances with their heavy rains and violent gales which generally upset considerably the development of the mite population and reduce it to a minimum each year.

(b) Dressing of tomato and other vegetable crops with nitro-phosphatic fertilisers which were not applied until 10 years ago and which, it is thought, may have favoured an increase in the mite population.

(c) The abundance of natural reservoirs of wild food-plants that harbour Tetranychus spp. from which the subsequent spread results in the building up of mite colonies in cultivated areas.

(d) The ineffectiveness of Stethorus vinsoni as a predator on infested tomato plants.

Four Old World blow flies (Diptera: Calliphoridae), Chrysomya albiceps (Wiedemann), C. putoria Wiedemann, C. megacephala (Fabricius), and C. rufifacies (Macquart), have recently invaded the New World. The interaction of Chrysomya rufifacies (Macquart) with native carrion flies in Texas, USA, was investigated by reducing oviposition by the invader on rabbit carcasses outdoors. These carcasses produced significantly more Cochliomyia macellaria (Fabricius) adults compared to carcasses on which the invader was not reduced. The results suggest that C. macellaria populations will decline where the two species co-occur. They also support the hypothesis that the carrion community is saturated with species, and provide a mechanism for the possible elimination of Lucilia caesar (Linnaeus) in Madeira and the reduction of C. macellaria in South America by Chrysomya albiceps (Wiedemann).

Field experiments were performed in artificial ponds to evaluate how the density of predatory diving beetles (Dytiscidae) would affect the population levels of mosquito larvae (Culicidae). Mosquitoes colonizing the ponds were predominantly species of the genus Culex. In 2000, most of the dytiscids colonizing the ponds were small (Hydroporus spp.), and these predators had no impact on the size of larval mosquito populations, not even in ponds with added dytiscids. In 2001, larger beetles (Ilybius, Rhantus, and Agabus spp.) were more common, and there were significantly fewer mosquito larvae in ponds with the highest numbers of dytiscids. There was a negative correlation between numbers of diving beetles in the ponds and the mean body length of mosquito larvae. In neither year could dytiscid densities be maintained above a certain level owing to emigration. In laboratory tests, there were marked differences between three common dytiscid species in regard to preferences for Daphnia and Culex species as prey: Colymbetes paykulli Erichson chose mosquito larvae more often, whereas both Ilybius ater (De Geer) and I. fuliginosus (Fabricius) preferred Daphnia spp. All of the tested dytiscids consumed large numbers of prey. Since some dytiscid species can efficiently decrease populations of mosquito larvae, they are probably important in the natural control of these dipterans.

In the course of an experiment in malaria control in an inland region of Kenya and Tanganyika, by the use of house spraying with dieldrin, routine catches were maintained of mosquitos resting in artificial outdoor shelters. During the 18 months of the pre-spraying period, catches in the South Pare district of Tanganyika mainly consisted of the principal vectors, Anopheles gambiae Giles and A. funestus Giles, together with small numbers of A. rivulorum Leeson.

During the three years following the spraying, A. funestus disappeared almost completely from the catches, while A. rivulorum showed an increase of about seven times above its former level.

Arabica coffee was sampled from two sites in the central highlands of Kenya (Rurima, Ruiru) and one site on the western side of the Rift Valley (Koru). Three species of ceratitidine Tephritidae, Ceratitis capitata (Wiedemann), C. rosaKarsch and Trirhithrum coffeae Bezzi, were reared from sites in the central highlands, and an additional species, C. anonae Graham, was recovered from the western-most site. Ten species of parasitic Hymenoptera were reared from these tephritids. The parasitoid assemblage was dominated by koinobionts. Eight of the species are koinobiont endoparasitoids, but only one idiobiont larval ectoparasitoid was reared, and only one idiobiont pupal endoparasitoid. The effects of sampling bias on determination of parasitoid assemblage size associated with concealed hosts are discussed. The potential for use of these parasitoids in biological control is also discussed. Most of the parasitoid species recovered during this study are capable of developing on C. capitata, while several also attack C. rosa. Both flies are notorious pests of tropical and subtropical fruits.

The soybean pod gall midge is an important pest of soybean in Japan and is known to occur also in Indonesia and China. This gall midge is described from Japan as Asphondylia yushimaisp. n. and is clearly distinguished from its congeners by the arrangement of the lower frontal horns of the pupa and the sequence of the mtDNA COI region. It is concluded that Prunus zippeliana Miquel is a winter host of the soybean pod gall midge since haplotypes of the soybean pod gall midge coincide with those of the Prunus fruit gall midge that produces fruit galls on P. zippeliana. In addition, phenological and distributional information on the two gall midges and on their host plants supports the identification of the winter host. In Japan, the soybean pod gall midge overwinters as a first instar in the fruit galls on P. zippeliana and emerges as an adult from the galls in May. In summer and autumn, the soybean pod gall midge has two or more generations in the pods of soybean, Glycine max (L.) Merrill or wild fabaceous and caesalpiniaceous plants. Thus host alternation by A. yushimai is confirmed. This is the second finding of host alternation by a species of Asphondylia, the first instance being that of Asphondylia gennadii (Marchal) in Cyprus.