Recognition of Orthoptera species by means of their song is widely used in field work but requires expertise. It is now possible to develop computer-based systems to achieve the same task with a number of advantages including continuous long term unattended operation and automatic species logging. The system described here achieves automated discrimination between different species by utilizing a novel time domain signal coding technique and an artificial neural network. The system has previously been shown to recognize 25 species of British Orthoptera with 99% accuracy for good quality sounds. This paper tests the system on field recordings of four species of grasshopper in northern England in 2002 and shows that it is capable of not only correctly recognizing the target species under a range of acoustic conditions but also of recognizing other sounds such as birds and man-made sounds. Recognition accuracies for the four species of typically 70–100% are obtained for field recordings with varying sound intensities and background signals.

Lutzomyia longipalpis (Lutz & Neiva), the vector of American visceral leishmaniasis (AVL), is much more abundant in animal sheds than in houses on Marajó Island, Pará State, Brazil. This difference in abundance is known not to reflect host preference. We show here that it also cannot be explained in terms of variable trapping efficiency, or insecticide application, and we exclude animal sheds as important daytime resting sites. In experimental sheds, the number of L. longipalpis increased markedly with the openness of the walls, though artificially large aggregations of flies could be generated in closed houses by using caged flies and hosts as attractants. We conclude that L. longipalpis tend to congregate at sites outdoors, including animal sheds, because these are the places where leks can most easily form on abundant, stationary (sleeping) and accessible hosts. These results help to explain why the seroprevalence of Leishmania chagasi infection is generally much higher among dogs than humans. They also indicate that human exposure to sandfly bites varies with the quality of house construction.

Experiments were conducted to investigate the role of pubescence in the resistance of two wild cowpea varieties, TVNu 72 and TVNu 73, to feeding and damage caused by two cowpea pests, Maruca testulalis (Geyer) and Clavigralla tomentosicollis Stål. The fine structure of the trichomes was also studied by electron microscopy in order to try to determine the role played by trichomes in the resistance of these varieties to both pests. Feeding and development were deterred in both insects on pods of TVNu 72 and TVNu 73 with or without trichomes compared to the susceptible variety, IT84E-124. In M. testulalis, the same effect was observed on seeds and flowers. However, M. testulalis larvae fed and developed better, as indicated by the higher growth index values, when trichomes were removed. Growth index estimates showed a 13-fold decrease when trichomes were left intact on both TVNu 72 and TVNu 73 compared to the cultivated susceptible control. It was concluded that resistance to M. testulalis was based on trichomes in the first instance (as a first line of defence) and phytochemicals. Survival of C. tomentosicollis nymphs was not affected by trichome removal even though adult feeding damage was slightly increased. This is explained in line with previous reports which indicate that phytochemicals may be the principal factor in the resistance of TVNu 72 and TVNu 73 to this species. Glandular and non-glandular trichomes were found to be present on both the cultivated and wild cowpea. Trichomes in the two types of cowpea differ significantly only in trichome number (susceptible cultivated cowpeas have more) and non-glandular trichome length (those on wild cowpea are ca 20 times longer). Trichome length and angle to pod surface seemed to be more important than density per se.

In a survey of adult ticks infesting livestock in Ethiopia, 33 species and subspecies were identified. The distribution and abundance of each are discussed in relation to ecology (altitude, climate and vegetation). Amblyomma variegatum (F.) is the most widespread and abundant tick parasitising cattle. A. cohaerens Dön. is common on cattle in wetter western habitats but is replaced by A. gemma Dön. in drier eastern areas. A. lepidum Dön. occupies intermediate habitats. The distribution of Boophilus decoloratus (Koch) is similar to that of A. variegatum. Hyalomma truncatum Koch and H. marginatum rufipes Koch are both common except in extremely arid and humid zones. H. anatolicum anatolicum Koch, H. anatolicum excavatum Koch, H. dromedarii Koch, H. erythraeum Tonelli-Rondelli, and H. impeltatum Schulze & Schlottke are usually associated with camels in semi-arid areas of eastern Ethiopia. Rhipicephalus evertsi evertsi Neum., R. sanguineus (Latr.) group and R. simus Koch do not display marked ecological preferences. East of the Rift Valley in semi-arid areas below 2000 m, R. pulchellus (Gerst.) is abundant on cattle and camels. R. longicoxatus Neum. and R. pravus Dön. inhabit drier localities, but R. lunulatus Neum. occurs only in wetter western areas. Species taken infrequently were A. nuttalli Dön., A. sparsum Neum., B. annulatus (Say), Haemaphysalis aciculifer Warb., H. leachii (Aud.), H. parmata Neum., H. spinulosa Neum., Hyalomma marginatum marginatum Koch, H. marginatum turanicum Pom., H. punt Hoogst., Kaiser & Pedersen, Ornithodoros savignyi (Aud.), R. longus Neum., R. muhsamae Morel & Vassiliades, and R. senegalensis Koch. The seasonal dynamics of the common species and observations on their relationships to tick-borne diseases of man and domestic animals are discussed.

The growth of populations of Triatoma infestans (Klug) depends on temperature and blood-intake. Experiments are described which demonstrated the density-dependent relationship between population size, blood intake and population growth at different temperatures. The number of bugs feeding and their mean blood intake was lower at high bug densities than at low ones, both with restrained chickens and with unrestrained mice as hosts. When blood intake was restricted, the development times of all nymphal stages were increased, and female fecundity was decreased. Previous work showed also that reduced blood intake led to an increased tendency for adult flight. It is thought that at high bug density the three factors, increased development times, decreased fecundity and increased flight, operate to restore the population to a stable density without promoting an increase in mortality. The mechanism linking population density to nutritional status seemed to depend on host irritability, which interrupted the bugs' feeding. Bugs which passed a certain threshold meal size would not resume feeding if interrupted, even though their blood intake was well below normal. The difference between the minimal threshold meal and a normal meal is thought to provide the nutritional elasticity within which the development processes are regulated. It is suggested that this mechanism is characteristic of K-strategists, whereas r–strategists such as mosquitoes tend to continue attacking, even if interrupted, until they achieve a normal meal.

In Nigeria, shelled groundnuts are stored in sacks in covered warehouses and as pyramids in the open air. At the beginning of storage the nuts comprise approximately equal quantities of whole, split and broken nuts of a moisture content of 3·4 per cent. The sacks are exposed to direct hot sun whilst stacking.

The mean monthly maximum shade temperature in Kano ranges from 101°F. in April to 85°F. in January and August and the mean monthly minimum from 75°F. in May to 56°F. in January. Monthly maximum relative humidities range from 100 per cent, in August and September to 45 per cent, in February, and the monthly minimum from 71 per cent, in August to 12 per cent, in February. The range of mean relative humidity is 81 per cent, in August and 18 per cent, in February. Rains fall between April and September, 70 per cent, falling in July and August. Heavy falls are recorded on about 25 days.

Inside warehouses, the maximum monthly temperatures are 102°F. in May and 79°F. in January and February, and minimum temperatures are 81°F. in June, and 58°F. in February. In August the mean relative humidity range is 93 per cent, to 70 per cent. In December it is 34 per cent. to 20 per cent.

Just under the roof of a warehouse and on the surface of pyramids the diurnal range is very large.

In laboratory experiments in Australia under standard conditions, densities of the dung beetle Euoniticellus intermedius (Reiche) exceeding 150/1-litre pad of cattle dung were shown to suppress breeding of Musca vetustissima Wlk. The experiments also suggested that it was the effect of dung disturbance on the survival of eggs of the fly that led to suppression. Natural vaiation in the quality of cattle dung obscured but did not alter the effects of high beetle densities. The mobility of M. vetustissima in particular, obscured the relationship of its abundance to dung beetle numbers in the field in 1974–75 and 1975–77 an intial high level of flies was apparently reduced and suppressed by a seasonally late but otherwise similar level of beetle attack on dung pads.

The Australian cotton industry relies almost exclusively on synthetic insecticides for control of early season pests. These insecticides often disrupt predatory insect activity in the field. Potential predators of the twospotted spider mite, Tetranychus urticae Koch, in cotton, identified in field and confirmed in laboratory experiments, included a theridiid spider, a phytoseiid mite, a lacewing larva, predatory thrips, several Coccinellidae and several Hemiptera. These predators were mostly generalists, having previously been reported as predators of aphids or caterpillars of Helicoverpa spp. The effect of insecticides on T. urticae and its predators was evaluated in three field experiments. Cotton was artificially infested with T. urticae then sprayed five times at seven to ten day intervals with either dimethoate (140 g ai/ha), thiodicarb (750 g ai/ha and 187.5 g ai/ha), endosulfan (735 g ai/ha and 367.5 g ai/ha), methomyl (169 g ai/ha) or amitraz (400 g ai/ha). Tetranychus urticae populations reached higher densities in dimethoate, thiodicarb and methomyl treated cotton than in untreated cotton. Population densities of T. urticae in cotton treated with low rates of endosulfan or thiodicarb were similar to controls, while those in cotton treated with amitraz were lower. All insecticides caused significant reductions in at least one predator group. Significant negative relationships were found between early season abundance of predators and the mid-season abundance of T. urticae and positive relationships between predators and the lag-period for T. urticae outbreaks to develop. Predation is implicated as a key factor influencing the early season survival of T. urticae. The implications for developing integrated pest management strategies in cotton are discussed.

Energy values for Glossina morsitans morsitans Westw. and for the vertebrate blood which constitutes its food were determined. On this basis, energy budgets for the hunger cycle were drawn up over a range of temperatures. The results indicate that daily flight duration for females is limited to a few minutes, while for males it averages about 15 min in the hot season and more than twice as long in the cold season.

All available records showed that Eldana saceharina Wlk. occurs in wild plants in all suitable areas of Africa south of the Sahara. Until a few years ago, it was only of economic importance in West Africa as an occasional pest of maize and sugar-cane, but a crop-feeding form has recently appeared in East Africa. Biological studies were carried out in the field and laboratory at Kawanda, Uganda, between 1970 and 1972 using natural and artificial larval diets. The life-cycle lasted 2–3 months, depending on temperature, and the number of larval instars depended partly on the diet. The adults lived for two weeks, during which time the females each laid 400–600 eggs. The majority of eggs and small larvae were taken by ants, but sufficient larvae survived to cause considerable damage. The pupae and larger larvae lacked efficient natural enemies in East Africa, and the introduction of parasites is suggested to prevent serious crop damage. The relatively evenly spread rainfall at Kawanda allowed maize to be planted every month so that field populations of E. saccharina and the other stem-borers Chilo partellus (Swinh.), Busseola fusca (Fuller) and Sesamia calamistis Hmps. could be studied throughout the year. Collections from maize, sorghum and sugar-cane showed that, although the four species attack the same host-plants, they occupy different ecological niches.

We have identified the following three taxa related to the Aphidius colemani species group, which are important biological control agents: Aphidius colemani, Aphidius transcaspicus and Aphidius platensis. Using partial sequences of the mitochondrial cytochrome oxidase subunit I (mtCOI) gene and geometric morphometric analysis of the forewing shape, we have explored the genetic structure and morphological variability of the A. colemani group from different aphid host/plant associations covering a wide distribution area. The topology of the maximum parsimony and maximum likelihood trees were identical with 98–100% bootstrap support, clustering A. colemani, A. platensis and A. transcaspicus into separate species. The distances among the taxa ranged from 2.2 to 4.7%, which is a common rate for the between-species divergence within the subfamily Aphidiinae. Differences in the shape of the forewing investigated within the biotypes of A. colemani group are congruent with their genetic diversification. Both A. platensis and A. colemani share a common host range pattern, and it would be interesting to estimate and compare the role of these two species in future biological control strategies against aphids of economic importance. Our results indicate that ‘genetic screening’ is a reliable approach for identification within the A. colemani group. The high variation in the wing shape among species, including a significant divergence in the wing shape among specimens that emerged from different hosts, makes the forewing shape and wing venation less reliable for species determination. Aphidius platensis is diagnostified and redescribed, and the key for the A. colemani group is presented.

The entomology of swollen shoot of cacao is a complex and unique problem involving the inter-relations in the field of over 120 insect species of four insect and two arachnoid orders. Briefly, there are 17 species of pseudococcids, 75 species of ants, 16 species of hymenopterous parasites, three predatory beetles, one predatory dipteran, and three arachnid species involved in vector relationships directly, with a further 18 Coccid species involved indirectly (it is possible, of course, that further work will show that some of these 18 species are directly concerned as vectors).

In the present paper an attempt has been made to reduce this assemblage of insect material to some semblance of order. The Coccid species are named and a series of preliminary observations on their biology and field behaviour detailed. The ant species, some of which are obligatorily associated with certain vector species, have been sorted into groups where specific determination has proved impossible or unnecessary and information has been included on their field habits and relative abundance.

There are three distinct but complementary ecological niches involved in the problem. The first, and most important, is the association between the mealybug virus vectors and the Myrmicine coccid-tending ants. The second is the association between mealybugs of the genera Paraputo and Formicococcus and the wild forest tree hosts of swollen shoot virus, and the third is the negative association between the mealybug tending Myrmicine ants and Oecophylla and Macromischoides, the latter species acting in certain circumstances as barriers to the spread of the mealybugtending species and hence to the spread of mealybugs and virus. These problems will be dealt with on a quantitative basis in a further paper.

Anthrenus verbasci (L.) (Col., Dermestidae) is a pest of dried animal materials and is widely distributed in temperate regions.

The effects of temperature and relative humidity on development have been studied. It is shown that the periods of incubation and pupation decrease with increase of temperature, the former from 54 days at 15°C. to 12 days at 30°C., and the latter from 89 days at 10°C. to 9 days at 25°C. Humidity differences have little effect.

The larval development is exceptional in that under constant physical conditions in the laboratory there is a rhythmical onset of the larval diapause, i.e., development is regulated into one or more cycles, each comprising a period of active growth followed by diapause. The length of this cycle under constant conditions is considerably less than a year. Larval development may extend over one or two cycles depending mainly upon the temperature. At low temperatures of 15°C., development extends over two cycles; at 20°C. and above, only one cycle is needed; at the intermediate temperature of 17·5°C., half the larvae require one and half require two cycles in which to complete their development.

When the larvae developed under constant physical conditions with malnutrition the rhythm of development was maintained, but the larvae tended to require an extra cycle for development compared with those fed on an adequate diet.

Under three sets of controlled alternating temperatures (ranging from 18 to 33°C.) the rhythm of development was similar to that which occurred in constant conditions at a temperature equal to the mean.

The number of larval moults increased both with temperature and the time spent as a larva. At the unfavourably high temperatures of 30 and 35°C., larvae moulted an excessive number of times; one larva at 30°C. moulted 19 times after the fully grown stage was reached; and, at 35°C., 30 per cent. R.H., 13 out of 20 larvae gradually decreased from about 5 mm. (the length when first put to 35°C.) to 2 mm., moulting a number of times in the process.

Under outdoor fluctuating conditions, the resting period in the cycle is extended, due to the winter temperatures prevailing for some time after the end of diapause. Active development commences again in the spring when the temperature rises, and in this way the cycle is synchronised with the seasons into an annual rhythm of development. The life-cycle under outdoor conditions may take one, two or more years to complete.

Field populations, developing both in attics of houses and under more outdoor conditions, pupated from January to May, the time of pupation being mainly dependent upon the ambient temperature prevailing after the termination of diapause.

Diapause is of value to A. verbasci because it induces a rhythm hi the life-cycle which synchronises with the rhythm of the seasons and ensures that the adults are present when the environment is favourable for their activity, i.e., during May and June when the maximum hours of sunshine favour flight and the preferred flowers are in bloom.

The mechanism by which the rhythmical onset of diapause is controlled has not been investigated.

The status of pyrethroid resistance in some field populations of Helicoverpa armigera (Hübner) from Pakistan was determined using an IRAC leaf-dip method. Resistance factors varied between populations, and the general trend was for a moderate to high resistance to cypermethrin and cyfluthrin; a low to moderate resistance to deltamethrin and alpha-cypermethrin; and a comparatively low resistance to bifenthrin, lambda-cyhalothrin and zeta-cypermethrin. Depending on which physiological mechanisms are shown to be present in Pakistani field strains, the latter group of pyrethroids may serve as useful tools in the management of insecticide resistance.

The aphid Therioaphis trifolii (Monell) is indigenous to the western Palaearctic region, where it colonizes lucerne (alfalfa), clovers and related legumes. A form of the species, T. trifolii f. maculata (the spotted alfalfa aphid, SAA), has been known in Australia since 1977, feeding almost exclusively on Medicago sativa (lucerne). Since 1989, T. trifolii has been found in Australia colonizing Trifolium subterraneum (subclover). We have compared samples of T. trifolii in Australia collected on lucerne and subclover using several techniques: survival and reproduction on different hosts, morphology, cuticular hydrocarbon profile, karyology, and a combination of RAPD-PCR and mitochondrial DNA (cytochrome oxidase) genetic markers. Whereas there were no distinct differences in cuticular hydrocarbons and karyology, we found significant correlated differences between the host on which aphids were collected, some morphological characters, and the genotypes of the aphids. Aphids collected from lucerne were always of one genetic type, and nearly all those from subclover were of another. Both groups of aphids are morphologically distinguishable from the yellow clover aphid (YCA), the other form of the species recognized so far. We conclude that the clover-colonizers (spotted clover aphid, SCA) and the lucerne-colonizers (SAA) are each host-restricted forms (biotypes) of T. trifolii. Estimates of mtDNA divergence are in the range of conspecific to closely congeneric, as compared with other insects including aphids. We developed simple diagnostic DNA tests to distinguish the two pest aphids.

Aphidius ervi Hal. parasitised natural populations of Acyrthosiphon pisum (Harris), Sitobion avenae (F.) and Microlophium carnosum (Buckt.) in Britain but parasitised few examples of S. avenae placed on trap plants in winter wheat, nettle-grass edge areas or lucerne-wheat strip crops. In laboratory experiments, Aphidius ervi reared from Acyrthosiphon pisum did not parasitise M. carnosum, and significantly fewer mummies were formed on S. avenae than on A. pisum. After rearing Aphidius ervi for 4–5 generations on S. avenae, similar numbers of mummies were formed on both hosts. The switch of hosts from Acyrthosiphon pisum to S. avenae was associated with the loss of certain parasitoid esterase enzyme bands revealed following electrophoretic separation of parasitoid proteins. Slow adaptation to new aphid hosts by polyphagous parasitoids such as Aphidius ervi may reduce the usefulness of reservoirs as a source of beneficial species.

Resistance to chlorpyrifos and other commonly used organophosphate larvicides was found in Culex quinquefasciatus Say from several urban areas in Tanzania. Lower levels of resistance were found in laboratory strains of the complex of C. pipiens L. collected in Sri Lanka, Egypt, Liberia and Brazil. Crosses of the Tanzanian strains to a more susceptible strain gave results consistent with causation of the resistance by a single gene or closely linked group of genes. Electrophoresis of one of the Tanzanian stocks indicated two esterase bands of high activity. The resistance in Tanzania did not prevent larval killing by freshly sprayed chlorpyrifos, but it is suggested that a spraying would probably no longer remain effective for three months as reported in earlier field studies.

Click beetle larvae within the genus Agriotes (Coleoptera: Elateridae), commonly known as wireworms, are abundant ground-dwelling herbivores which can inflict considerable damage to field crops. In Central Europe up to 20 species, which differ in their distribution, ecology and pest status, occur in arable land. However, the identification of these larvae based on morphological characters is difficult or impossible. This hampers progress towards controlling these pests. Here, we present a polymerase chain reaction (PCR)-based approach to identify, for the first time, 17 Agriotes species typically found in Central Europe. Diagnostic sequence information was generated and submitted to GenBank, allowing the identification of these species via DNA barcoding. Moreover, multiplex PCR assays were developed to identify the nine most abundant species rapidly within a single-step reaction: Agriotes brevis, A. litigiosus, A. obscurus, A. rufipalpis, A. sordidus, A. sputator, A. ustulatus, A. lineatus and A. proximus. The latter two species remain molecularly indistinguishable, questioning their species status. The multiplex PCR assays proved to be highly specific against non-agrioted elaterid beetles and other non-target soil invertebrates. By testing the molecular identification system with over 900 field-collected larvae, our protocol proved to be a reliable, cheap and quick method to routinely identify Central European Agriotes species.

The size-specific fat content of tsetse flies recently emerged from their puparia was determined and by comparison with the size-specific fat content of newly deposited larvae an estimate was obtained of the consumption of fat during pupal development. Experiments with Glossina morsitans Westw. were carried out at a number of different temperatures and it was found that the amount of fat consumed was least at temperatures between 22 and 24°C.

Knowing the duration of the pupal period at different temperatures, the rate of fat consumption could be calculated and the logarithm of this rate was found to be linearly related to temperature. The occurrence of an optimum temperature in respect of fat consumption thus reflects the fact that at high temperatures the rate of fat consumption is greatly increased without a corresponding reduction in the duration of the pupal period, whereas at low temperatures the pupal period is very greatly lengthened without a corresponding decrease in the rate of fat consumption.

Both Sitobion avenae (Fabricius) and Rhopalosiphum padi (Linnaeus) are the most important pests of wheat in China and usually coexist on the late period of wheat growth. Pirimicarb was introduced into China for wheat aphid control in early 1990s, and differential susceptibilities of Sitobion avenae (Fabricius) and Rhopalosiphum padi (Linnaeus) to pirimicarb have been observed. A bioassay exhibited that Rhopalosiphum padi possessed significantly higher susceptibility to pirimicarb than Sitobion avenae. The addition of synergists DEF, an esterase inhibitor, PBO, a cytochrome P450 monooxygenase inhibitor, and DEM, a glutathione S-transferase inhibitor, resulted in apparent reductions in the differential susceptibilities, suggesting the involvement of the above three detoxification enzymes in the differential susceptibility to pirimicarb between Sitobion avenae and Rhopalosiphum padi. A biochemical analysis showed that the activities of carboxylesterases and glutathione S-transferases were significantly higher in Sitobion avenae than in Rhopalosiphum padi, consistent with the results of synergism. Acetylcholinesterase is the target enzyme of pirimicarb and the sensitivity of acetylcholinesterase to pirimicarb was significantly higher in Rhopalosiphum padi than in Sitobion avenae. The combined results suggest that multiple mechanisms are likely to be responsible for differential susceptibilities to pirimicarb between Sitobion avenae and Rhopalosiphum padi. The results obtained from this study should be helpful in the rational applications of insecticides.