In order to evaluate Morris traps as a method of investigating populations of Glossina pallidipes Aust., and to compare them with fly-rounds, a series of catches was made by both methods in and adjacent to an area of evergreen thicket covering about three sq. miles in the Lambwe Valley, South Nyanza District, Kenya. During the period of the investigations (February 1955-February 1958), the mean monthly apparent density (catches of non-teneral males per 10,000 yd. traversed) determined from a fly-round 5,200 yd. long traversing the thicket varied from 70 to 1,300, and the mean monthly trap catch, determined from 26 traps along a similar traverse but over a shorter period, varied from 190 to 670. Catches by the two methods showed similar fluctuations but were not significantly correlated, and it is not certain that real changes in population occurred. The distribution of G. pallidipes between the three main vegetation communities sampled appeared different when studied by traps, or by other methods (fly-rounds, and searching for resting flies). The two latter methods were in agreement, but traps gave different results, perhaps because one of the vegetation communities may have had a high proportion of productive trapping sites.

Dispersal of G. pallidipes into the surrounding, sparsely wooded grassland was studied by traps arranged in lines extending east and west of the thicket and at right angles to its edge. Traps appeared not to attract flies over a distance as great as 100 yd., but to catch only those that chanced to be in their immediate vicinity. Total catches in three traps over 10 months at distances of 5–100–300–500 and 900 yd. west of the thicket edge were 15,417–965–153–89 and 56, respectively; smaller numbers were taken up to 2,500 yd., the greatest distance investigated. Dispersal was greatest in the wet, cool half of the year.

In catches of G. pallidipes made in six consecutive two-hour periods daily for one year in two batteries, each of seven traps, and on two short fly-rounds, one of each along the east and the other along the west edge of the thicket, the traps yielded 78 per cent, females and the fly-rounds only 17 per cent. There was a marked tendency for females to be caught earlier in the day than males by either method, and for the pattern of catches to be earlier on fly-rounds than in traps. No difference in age, estimated by wing fray, was found between flies caught, by either method, at different times of day.

The total number of G. pallidipes caught by two traps operating 11 hours per day for 10 days at the thicket edge was over four times that caught there concurrently by a stationary party of three men.

It is concluded that traps are valuable because they catch a high proportion of females, thus affording information not given by fly-rounds, and operate continuously, at a higher over-all catching rate than that of men, thus facilitating the study of sparse populations. Nevertheless, site effects and day-to-day variability are both large with traps, so that reproducible results are difficult to obtain.

The effect of delayed mating on reproductive potential, longevity and oviposition period of female redbanded leafroller, Argyrotaenia velutinana (Walker) and Pandemis leafroller, Pandemis pyrusana Kearfott, was investigated in the laboratory. Virgin female or male moths of each species were held for 1, 2, 4, 6 or 10 days prior to pairing with one-day-old virgin conspecifics of the opposite sex. In addition, reproductive potential was assessed when both sexes of each species were aged for those periods prior to pairing. The expected reproduction of female A. velutinana was reduced by 34, 53, 71 and 81% for 2, 4, 6 and 10-day delays in female mating, respectively. For P. pyrusana, expected reproduction was reduced by 47, 74, 85 and 93% for 2, 4, 6 and 10-day delays in female mating, respectively. Increasing male age at mating in both species had a lesser effect on female reproductive output compared with increasing female age at mating. As male A. velutinana age at mating increased, the expected reproduction of female A. velutinana was reduced by 15, 45, 54 and 70% for 2, 4, 6 and 10-day delays, respectively. Comparing male P. pyrusana of various ages at mating, expected reproduction was reduced by 14, 42, 64 and 79% for 2, 4, 6 and 10-day delays in mating, respectively. The decrease in female reproduction when both sexes were aged prior to mating was higher than when either sex alone was aged prior to pairing with a one-day-old virgin of the opposite sex. The expected reproduction of female A. velutinana was reduced by 60, 83, 96 and 98% for 2, 4, 6 and 10-day delays in mating of both sexes, respectively. Only 7.5% of female eggs hatched when both sexes of A. velutinana were aged ten days prior to mating. When simultaneously aging both sexes of P. pyrusana prior to mating, expected reproduction was reduced by 71, 93, 96 and 99% for 2, 4, 6 and 10-day delays in mating, respectively. No P. pyrusana eggs hatched after a ten-day delay of mating for both sexes. For both species, female longevity increased and duration of oviposition period decreased with increasing female age at mating. Our results demonstrate that delayed mating in both females and males negatively affects female reproductive output in both species and that simultaneous aging of both sexes prior to mating has a greater effect than aging either sex alone. Our results suggest that laboratory studies that have paired aged females or aged males with conspecifics of optimal reproductive maturity have likely underestimated the effects of delayed mating on reproductive output.

Rapidly changing environments and an increase in human movement around the globe have contributed to a rise in new and emerging diseases, many of which are arthropod borne. The threat posed to the United Kingdom by such diseases is uncertain, and there is a real need to understand the distribution, seasonality and behaviour of potential vectors in the country. At present, there is no standard method for routine mosquito surveillance in the UK. Here we compared the catching efficiency of two carbon dioxide-baited traps, the CDC light trap and the MosquitoMagnet® Pro trap, for collecting British mosquitoes. Two of each type of trap were operated at four sites in central and southern England from June to September, 2003. To determine whether trap height affected collections, three light traps were operated at 1, 2.5 and 5 m above the ground in one site in 2004. Both types of trap were efficient at catching mosquitoes, collecting 5414 mosquitoes of 16 species. MosquitoMagnet® traps caught 2.7 times more mosquitoes than CDC light traps (P<0.001) and a wider range of species (16 species vs 11) than CDC light traps. Four to six times more female Culex pipiens s.l. were collected in light traps at 5 m (P<0.001) compared with traps at lower heights. MosquitoMagnet® traps ran continuously for up to 8 weeks, whilst the battery of a CDC light trap had to be replaced every 24 hrs. Although MosquitoMagnets® collected more specimens and a greater range of mosquito species, they were considerably more expensive, prone to breakdown and incurred higher running costs than the CDC light traps. MosquitoMagnets® are useful tools for collecting mosquitoes during longitudinal surveys during the summer months, whilst CDC light traps are to be preferred for rapid assessments of the presence or absence of mosquitoes, particularly the important species Culex pipiens.

Aedes aegypti (L.) (Diptera: Culicidae), the main vector of dengue and urban yellow fever in the world, is highly adapted to the human environment. Artificial containers are the most common larval habitat for the species, but it may develop in tree holes and other phytotelmata. This study assessed whether tree holes in San Ramón de la Nueva Orán, a city located in subtropical montane moist forest where dengue outbreaks occur, are relevant as larval habitat for Ae. aegypti and if the species may be found in natural areas far from human habitations. Water holding tree holes were sampled during 3 years once a month along the rainy season using a siphon bottle, in urban and suburban sites within the city and in adjacent forested areas. Larvae and pupae were collected and the presence and volume of water in each tree hole were recorded. Finding Ae. aegypti in forested areas was an isolated event; however, the species was frequently collected from tree holes throughout the city and along the sampling period. Moreover, larvae were collected in considerably high numbers, stressing the importance of taking into account these natural cavities as potential reinfestation foci within dengue control framework.

Applying microsatellite DNA markers in population genetic studies of the pest moth Helicoverpa armigera is subject to numerous technical problems, such as the high frequency of null alleles, occurrence of size homoplasy, presence of multiple copies of flanking sequence in the genome and the lack of PCR amplification robustness between populations. To overcome these difficulties, we developed exon-primed intron-crossing (EPIC) nuclear DNA markers for H. armigera based on ribosomal protein (Rp) and the Dopa Decarboxylase (DDC) genes and sequenced alleles showing length polymorphisms. Allele length polymorphisms were usually from random indels (insertions or deletions) within introns, although variation of short dinucleotide DNA repeat units was also detected. Mapping crosses demonstrated Mendelian inheritance patterns for these EPIC markers and the absence of both null alleles and allele ‘dropouts’. Three examples of allele size homoplasies due to indels were detected in EPIC markers RpL3, RpS6 and DDC, while sequencing of multiple individuals across 11 randomly selected alleles did not detect indel size homoplasies. The robustness of the EPIC-PCR markers was demonstrated by PCR amplification in the related species, H. zea, H. assulta and H. punctigera.

A juvenile hormone mimic (pyriproxyfen) was used with odour-baited targets to assess its suitability for controlling tsetse flies (Glossina spp.). In August 1991, 41 odour-baited targets identical to those used with insecticide in tsetse control operations, were each treated with 4 g of pyriproxyfen and deployed near Rekomitjie Research Station, Zambezi Valley, Zimbabwe, in a 12.3 km2 block of woodland habitat of Glossina morsitans morsitans Westwood and G. pallidipes Austen. After three months, emergence rates from puparia of the two species collected in the block fell to 34% and 20% of control levels; 50 and 70%, respectively, of puparia of the two species collected were found, on dissection, to show arrested development. Changes in mean ovarian age and wing-fray category in the tsetse population during the trial were due partially to the pyriproxyfen and partially to high mortality, in the larval/pupal stages and in young adult flies, which occurs each year in the hot/dry season. Chemical analysis of cloth samples indicated that after four months 68–85% of the pyriproxyfen had been lost, a large proportion apparently dripping off the bottom of the target. If the technical problem of persistence can be solved pyriproxyfen could substitute for pesticides in target-based tsetse control operations.

The results of sixty 24-hour catches of mosquitos carried out with man as bait in the forest canopy at Zika, central Uganda, are discussed. In these catches the arrival of mosquitos was recorded to the nearest minute.

The rapid changes of light intensity in the equatorial twilight are discussed in relation to a series of readings made at Entebbe.

It is shown that among species that show a crepuscular peak of biting activity (Aedes ingrami Edw., A. africanus (Theo.), Mansonia fuscopennata (Theo.) and M. aurites (Theo.)) the peaks do not all occur at the same time, but form a succession.

Moonlight (at least in the forest canopy) has no apparent effect on the timing of these crepuscular surges of biting activity.

One species (M. fuscopennata) also shows a peak of biting activity before sunrise. This peak is closer to sunrise than the evening peak is to sunset. A brief reference to current work carried out above the canopy, where foliage, shadows, etc., do not complicate the environment, shows that this phenomenon occurs in other species also. It is concluded that in these species the morning peak must almost certainly occur in light of much greater intensity than the evening peak.

The implications of these findings are discussed with reference to the questions of endogenous rhythm and exogenous stimuli.

During studies on yellow fever in Bwamba county, Western Uganda, five non-stop series, each of six 24-h catches, were carried out in an uninhabited area of dense rainforest. All these yielded very large numbers of mosquitoes belonging to the Anopheles gambiae Giles complex. Measures of the central tendency, applied to summed results, show a “typical” pattern with a peak in the second half of the night. Examination of the results in detail reveals great variations in the biting pattern from day to day. These cannot be correlated with local weather conditions and their existence shows that considerable caution must be used in this type of analysis, except in well synchronised biting patterns.

Studies on the biology of Acanthomia tomentosicollis (Stål) at Ibadan, Nigeria, showed that the periods of development in the field and the insectary averaged 17 and 18 days, respectively. The hemispherical, hexagonally sculptured eggs were laid in batches of 2.99 (mean=7 eggs per batch in the insectary and 20 in the field). Preoviposition periods were 11–22 days in unmated and 6–9 days in mated females. The mean number of eggs deposited by mated females (202) was significantly higher than that deposited by unmated females (135), although the average oviposition period of 16 weeks in unmated females was three weeks longer than in mated females. Unmated males and females were longer-lived than their mated counterparts, and females generally lived longer than males. These results and other observations on 'the biology of A. tomentosicollis are discussed in the context of its seasonal biology and the pattern of infestation of pigeon pea (Cajanus cajari), its main host plant.

In the presence of the odour of carbon dioxide and acetone, an electrified net adjacent to a stationary cylindrical black model in the Zambezi Valley, Zimbabwe, in the hot dry season caught more adults of Glossina morsitans morsitans Westw. and G. pallidipes Aust. than in the absence of odour. In the absence of odour, a moving model attracted more G. m. morsitans males than did a stationary model. Between 20 and 50% of males of G. m. morsitans but only 0 to 12% of males of G. pallidipes near a model were caught by electrified decoys (surrogate females) on the model. Hidden observers recorded the numbers of flies copulating with decoys baited with pheromone or pheromone plus bisazir (P, P-bis(1-aziridinyl)-N-methylphosphinothioic amide) on a stationary model with odour between 16.00 and 19.00 h daily. Males of G. m. morsitans contacted the decoys with much greater frequency than did males of G. pallidipes although the latter species was the more abundant. The numbers of copulatory attempts by G. m. morsitans males during each 10 min suggested that changes were a function of the total numbers of flies attracted to the model. At all times of the day, the average duration of copulation was 37–40 s. However, approximately 50% of responses were of 10 s duration or less and fewer than 10% endured for longer than 3 min. The presence of bisazir on the decoys did not influence the response duration or the total numbers of flies responding. A comparison with laboratory data suggested that further refinement of technique will allow pheromone-baited decoys to be used in the autosterilisation of G. m. morsitans males with bisazir in the field.

The efficiencies of five mechanical traps and an electric trap for tsetse flies were measured by estimating the numbers of flies which approached the devices but were not captured by them. With this method, it was possible to discern significant differences in efficiencies even if the means differed by as little as 25%. Three biconical traps had estimated efficiencies of 40–70% for Glossina morsitans morsitans Westw. and 50–80% for G. pallidipes Aust. when used in the presence of the odour of one ox. The efficiency of a small electric net was estimated at 70–75% for all tsetse under this test condition, and a modification of one of the biconical traps had an estimated efficiency of 55–85%. The efficiency of this trap increased by a factor of 1·2–2·2 when used with the odour of six oxen, compared to the efficiency in the absence of host odour. Preliminary results suggested that, when used in the presence of ox odour, the efficiency of this trap for teneral tsetse was at least as high as for mature flies.

Among the diverse forms of insect life infesting stored agricultural products in South India those belonging to the Lepidoptera are by no means unimportant. Though no accurate estimates of the annual losses in value of grain, pulses, etc., due to their depredations are available in this country, it has to be admitted that the extent of the damage may occasionally be considerable. It is, therefore, unfortunate that these insects have not attracted sufficient attention at the hands of Economic Entomologists in this country; consequently very little information is available as to the exact identity of the species, their relative importance, or their life-histories. The present investigation was undertaken to make a detailed study of this problem in South India with a view to elucidating the points just raised.

A key is provided to distinguish the three species of Planococcus occurring in the Mediterranean Basin, P. citri (Risso), P. ficus (Signoret) and P. vovae (Nasonov), and their nomenclatural histories are reviewed. Notes on economic importance, host preferences, distribution and taxonomy are given for each species. Pseudococcus citrioides Ferris is synonymized with Planococcus ficus (Signoret), Pseudococcus lindingeri Bodenheimer is transferred to Planococcoides, Pseudococcus inamabilis Hambleton is synonymized with Planococcus vovae, and Allococcus Ezzat & McConnell is regarded as a subjective junior synonym of Planococcus Ferris. A new genus, Delottococcus, is erected to contain a group of species previously placed in Allococcus.

In this study, we use DNA barcodes for species delimitation to solve taxonomic conflicts in 86 specimens of 14 species belonging to the Corynoneura group (Diptera: Chironomidae: Orthocladiinae), from the Atlantic Forest, Brazil. Molecular analysis of cytochrome c-oxidase subunit I (COI) gene sequences supported 14 cohesive species groups, of which two similar groups were subsequently associated with morphological variation at the pupal stage. Eleven species previously described based on morphological criteria were linked to DNA markers. Furthermore, there is the possibility that there may be cryptic species within the Corynoneura group, since one group of species presented internal grouping, although no morphological divergence was observed. Our results support DNA-barcoding as an excellent tool for species delimitation in groups where taxonomy by means of morphology is difficult or even impossible.

Three plant spacings, 30 cm, 7·5 cm and 2·5 cm within rows 90 cm apart, equivalent to about 36, 143 and 430 thousand plants/ha respectively, were used in three field trials on the population dynamics of Aphis craccivora Koch on groundnuts at Chitedze, Malawi in 1964–1967. Aphid density per infested plant was consistently higher, while numbers of aphid-infested plants per unit area were consistently lower, in 30 cm than in 2·5 cm spacing. Aphid numbers per unit area increased to similar levels at all spacings in crops under 40–50 days old, but subsequently aphid density was consistently lower in 2·5 cm than in 30 cm spacing. This effect could not be related to the intensity of fungus disease infection, parasitism, predation, the availability of feeding sites or the rate of emigration. Aphid groups were, however, consistently smaller in 2·5 cm than in 30 cm spacing in one trial. The potential rate of increase was studied in two trials using the methods of Hughes (1962), and was found to be consistently lower in 2·5 cm than in 30 cm spacing. The rate of plant growth was relatively depressed in 2·5 cm spacing, particularly after 40 days. The effect of spacing on aphid numbers was attributed to the effect of host-plant condition on the potential rate of increase.

Chaetorellia acrolophi sp. n. is associated with some European species of the subgenus Acrolophus of Centaurea. It is a potential biocontrol agent of some Acrolophus species that are adventive noxious weeds in North America. Ch. acrolophi sp. n. is described, and a key is provided to all nine species. The confirmed host-plants, knapweed, starthistles and related plants, belong to the genera Centaurea, Carthamus and Chartolepis (Asteraceae), and these are listed. Available biological data are reviewed, and some details of egg, larval and pupal morphology are described. Host-plant choice tests and canonical variates analysis were used to justify the separation of some species and to help identify some populations. The following nomenclatural changes are made (junior synonyms in brackets): Chaetorellia conjuncta (Becker) is removed from synonymy with Ch. succinea (Costa); Ch. hexachaeta australis Hering is raised to specific status; Ch. hestia Hering (=Ch. nigropicta Hering); Ch. loricata (Rondani) (= Ch. mara Hering and Ch. loricata septentrionalis Hering). Questionable synonyms include: Ch. australis Hering (?=Trypeta hexachaeta Loew); Ch. hestia (?= T. vittata Rondani); Chaetostomella cylindrica (Robineau-Desvoidy) (?= Tephritis algira Macquart, which is removed from Chaetorellia).

Phymastichus coffea, a new genus and species of tetrastichine Eulophidae, is described. This species is parasitic on the coffee berry borer, Hypothenemus hampei (Ferrari), in Africa and is currently under investigation as a possible biological control agent for this borer

The peritrophic matrix is a chitin-protein structure that envelops the food bolus in the midgut of the majority of insects, but is absent in some groups which have, instead, an unusual extra-cellular lipoprotein membrane named the perimicrovillar membrane. The presence of the perimicrovillar membrane (PMM) allows these insects to exploit restricted ecological niches during all life stages. It is found only in some members of the superorder Paraneoptera and many of these species are of medical and economic importance. In this review we present an overview of the midgut and the digestive system of insects with an emphasis on the order Paraneoptera and differences found across phylogenetic groups. We discuss the importance of the PMM in Hemiptera and the apparent conservation of this structure among hemipteran groups, suggesting that the basic mechanism of PMM production is the same for different hemipteran species. We propose that the PMM is intimately involved in the interaction with parasites and as such should be a target for biological and chemical control of hemipteran insects of economic and medical importance.

The recognized importance of coffee alkaloids and phenolics mediating insect-plant interactions led to the present investigation aiming to test the hypothesis that the phenolics chlorogenic and caffeic acids and the alkaloid caffeine and some of its derivatives present in coffee leaves affect egg-laying by the coffee leaf miner Leucoptera (=Perileucoptera) coffeella (Guérin-Méneville & Perrottet) (Lepidoptera: Lyonetiidae), one of the main coffee pests in the Neotropical region. These phytochemicals were, therefore, quantified in leaves from 12 coffee genotypes and their effect on the egg-laying preference by the coffee leaf miner was assessed. Canonical variate analysis and partial canonical correlation provided evidence that increased leaf levels of caffeine favour egg-laying by the coffee leaf miner. An egg-laying preference bioassay was, therefore, carried out to specifically test this hypothesis using increasing caffeine concentrations sprayed on leaves of one of the coffee genotypes with the lowest level of this compound (i.e. Hybrid UFV 557-04 generated from a cross between Coffea racemosa Lour. and C. arabica L.). The results obtained allowed the recognition of a significant concentration-response relationship, providing support for the hypothesis that caffeine stimulates egg-laying by the coffee leaf miner in coffee leaves.