Eupelmus orientalis (Crawford) (Hymenoptera: Eupelmidae) is a solitary ectoparasitoid of the larvae and pupae of West African bruchids. Since the biology of this species was unknown, studies were carried out on its reproductive biology. The age-dependent fecundity and offspring production of virgin and mated females of E. orientalis were determined under laboratory conditions at 33°C:23°C, 50%:80% r.h., L:D 12:12 on its host Callosobruchus maculatus (Fabricius) (Coleoptera: Bruchidae) during the first 15 days of the life cycle. No differences were found between virgin and mated females for any parameter. A study of the age-dependent fecundity and offspring production was also carried out under the same conditions over the entire life cycle of mated females. The resulting data were used to determine the longevity and reproductive potential of the species, particularly through the calculated life tables and estimation of the intrinsic rate of increase. With ten hosts per female per day, E. orientalis females had a mean longevity of 45.75±5.09 days. They laid an average of 219.91±39.08 eggs, parasitized 154.27±26.17 hosts, and produced 166.77±9.41 offspring, consisting of 80.46±14.10 males and 86.31±10.04 females. The total mean developmental time was 18.58±0.22 days for males and 20.03±0.21 days for females. The net reproductive rate (Ro) was 62.33 female progeny per adult female, and the intrinsic rate of population increase (rm) was 0.1389 per day. The generation time (G) was 29.76 days and the doubling time (DT) 4.99 days. These results constitute the first step to determine the potential of E. orientalis as an agent for the biological control of bruchidae, especially C. maculatus.

A method for the purification of elevated esterase B2 from the Sri Lankan Pel RR strain of Culex quinquefasciatus (Say) has been developed, using sequential column chromatography. The pure enzyme is stable, with no decrease in specific activity after several months, if stored in the presence of 25 mM dithiothreitol and 50% glycerol at –20°C. The enzyme has a pl of 5 and an estimated molecular weight for the monomeric enzyme of 63 kD from SDS-PAGE. In all Culex strains with elevated B2, another esterase (A2) is always co-elevated. The strains with these esterases are resistant to a broad range of organophosphorus insecticides. The previous purification and characterization of A2 from Pel RR indicated that the role of this enzyme was primarily to sequester rather than metabolize organophosphates. Purified B2, rapidly binds malaoxon, the activated form of malathion, but not malathion itself. The turnover rate of bound malaoxon is slow, suggesting that the role of this esterase in malathion resistance is also sequestration. The similar bimolecular rate constants for both A2 and B2 with malaoxon suggest both esterases are important in resistance, which may explain the almost complete linkage disequilibrium that the elevated forms of these two esterases are maintained in when under pesticide selection pressure.

The introduced pollinating weevil, Elaeidobius kamerunicus Faust, established itself well in the oil palm plantations in India, but the population fluctuated between seasons reaching its lowest level during the dry season. The wet season was more favourable for the population build-up of E. kamerunicus. As the weevil population in the male inflorescence did not represent the actual numbers present at a given time, an estimation of pollinator force as well as the population size is recommended. Fruitset increased significantly after the introduction of E. kamerunicus, but fluctuated widely between seasons. However, the fluctuation in populations in the male inflorescences, as well as the variation in the number visiting the female inflorescences, did not have any impact on the fruitset. During the dry season when the weevil population was very low, fruitset was high, but during the wet season when the weevil population was very high, the fruitset was lower. Availability of male inflorescences as well as climatic factors such as rainfall, number of rainy days and relative humidity affected the pollinating efficiency of the weevil by reducing the pollen load and its viability. Even though there was a population decline of E. kamerunicus during the dry season there was no reduction in pollinating efficiency and hence there is no need to introduce additional pollinators such as E. subvittatus Faust, which is more efficient during dry seasons.

The efficiency of electrocuting devices currently used for sampling tsetse flies (Glossina spp.) and similar insects, was studied in Zimbabwe by recording approaches, kills, and escapes, with video. The kill rate of an electrified netting screen increased with the discharge frequency of the device up to 200 Hz (ca the highest practicable frequency) reaching ca 90% at best. The same kill rate was achieved by an electrified black cloth target. However, ‘two-choice’ comparisons of electric nets and their components showed avoidance by the tsetse of the black mosquito netting between the electric wires, and even of the electric wires on their own, though probably not of the black metal frame that supported them. The proportion of tsetse avoiding a standard electric net was ca 27% in full sun, ca 40% in shade, implying an overall sampling efficiency of, at best, ca 65% at the optimum 200 Hz discharge rate in sunshine, and ca 40–50% with the 67 Hz nets used currently in Africa. Potential for improvements therefore lies mainly in reducing the visibility of the nets; suggestions are offered.

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.

The responses of female Aedes aegypti (Linnaeus) to a variety of stimuli were studied using an olfactometer bioassay. Mosquitoes responded significantly to convection currents produced by a human hand. The addition of water vapour to convection currents enhanced significantly the mosquitoes' response. Lactic acid, either alone or in combination with water vapour or/and convection currents however, did not increase the response level. Sweat extract elicited higher response than convection currents, water vapour and lactic acid. Human hands elicited significantly higher responses than any other stimuli. The presence of active chemicals other than lactic acid in human odour extract is discussed.

The morphology and ultrastructure of aphid mummies formed by diapausing and non-diapausing larvae of Aphidius rhopalosiphi De Stefani Perez, are described. Two types of silk thread were present in both types of cocoons: well-structured rounded threads, and flat threads which form a gum coating. Differences in thecocoon weight were observed depending on parasitoid development. A morphometric characterization of the two groups of mummies is given.

Some rose cultivars such as City of Belfast are more resistant to the western flower thrips, Frankliniella occidentalis (Pergande) than others. Data from life tables and behavioural studies indicate that the reason for resistance may be physiological-chemical as well as the physical structure and colour of the flower. Some rose odours repelled F. occidentalis.

Two new species of Eulophidae, which are potential biological control agents of economically important pests, are described from China. Aprostocetus prolixussp. n. (Tetrastichinae) is an egg-parasitoid of Apriona germarii (Hope) (Coleoptera: Cerambycidae), and Hyssopus grossorissp. n. (Eulophinae) is a larval parasitoid of Paranthrene tabaniformis (Rottenburg) (Lepidoptera: Sesiidae). The species Elachertus pallidus Askew is transferred to Hyssopus, comb. n.

The number of wind-borne female Simulium damnosum Theobald sensu lato migrating across territory devoid of breeding populations (the Onchocerciasis Control Programme, OCP) were monitored daily at widely separated sites downwind. The seasonal curves of numbers recorded each day were remarkably similar in pattern at each site with little blurring (although numbers lessened as distance from source increased). The uniformity suggests that each daily batch of S. damnosum moved downwind en bloc with but a small proportion of laggards. To test this hypothesis, model curves were generated, with different proportions of daily laggards, from the data at each sampling site and compared by chi-squared tests with the observed curve at the next site downwind. It was found that, in general, those models that most closely resembled the downwind curves were those with the smallest proportion of laggards. Other aspects of the migration were also considered, notably the factors affecting loss of numbers as distance increased and the interaction between laggards and loss where it was shown that the greater the proportion of laggards the greater will be the daily loss.

In the ichneumonid wasp Diadromus pulchellus (Wesmael), diploid males may regularly be produced in laboratory populations by inbreeding. They are viable, produce diploid sperm and are equally capable of multiple inseminations as are haploid males. Their spermatozoa are also able to penetrate the oocyte. Progeny sired by diploid males are essentially haploid sons with only a few daughters. The sons are normal haploid individuals, produced in a frequency significantly higher than in crosses between females and haploid males. The daughters are normal diploid females probably resulting from the fertilization of an oocyte by an exceptional haploid sperm rarely produced by diploid males. Triploid individuals were not observed and their absence was correlated with the high mortality observed during the first developmental stages. The death of these individuals is discussed in the light of the phenomenon of superparasitism to explain the increase in the frequency of sons produced in crosses with diploid males. Despite their viability, their ability to produce sperm and their normal potential insemination, diploid males of Diadromus pulchellus are therefore almost sterile.

An account is given detailing some aspects of the biology and economic importance of Psalydolytta pilipes Maklin in pearl millet (Pennisetum glaucum) fields in north-west Mali. Descriptions of the triungulin larval stage, together with drawings of larval development from the first grub stage to the coarctate larval stage, are given for two Psalydolytta species, P. pilipes and P. vestita Dufour. First grub phase larvae were successfully reared through to coarctates from eggs obtained from field captured adult beetles, on egg-pods obtained from a selection of commonly occurring grasshopper species. Yield losses resulting from cage trial experiments showed that whole millet candles can be destroyed during one night's feeding at densities approaching 12 beetles per head.

Cross-resistance spectra were determined in strains of the Australian sheep blowfly, Lucilia cuprina (Wiedemann), which had been pressured for several years in the laboratory with diflubenzuron, butacarb or deltamethrin. Each strain was highly resistant to its selecting chemical (resistance factors > 1000-fold), however, cross-resistance levels were variable and often low. In particular, strains selected with diflubenzuron and butacarb showed very little resistance to deltamethrin (resistance factors <7-fold). Each strain showed resistance levels to diazinon only slightly higher than the highest levels currently detected in field strain larvae. Piperonyl butoxide and triphenyl phosphate significantly synergized each pressured strain with its selecting chemical, suggesting the involvement of both monooxygenases and esterases in the observed resistances. Synergism ratios in each case were greater with piperonyl butoxide. The lack of any alteration in in vitro acetylcholinesterase sensitivity to butacarb inhibition in the butacarb-selected strain, and only low level resistance to DDT in the deltamethrin-selected strain, provided no evidence for target-site insensitivities in these strains. The low-moderate levels of cross-resistance therefore imply the existence of qualitative differences in the detoxification systems in each strain.

The host preference and acceptance behaviour of populations of Aphidius ervi Haliday and A. microlophii Pennacchio & Tremblay from southern Italy was investigated. In no host-choice conditions, A. ervi females showed significantly higher attack and oviposition rates on the natural host Acyrthosiphon pisum (Harris) than on the non-host aphid Microlophium carnosum (Buckton)(Homoptera: Aphididae). In contrast, A. microlophii, which specifically parasitizes M. carnosum in the field, attacked both aphid species. However, dissections showed that oviposition of A. microlophii occurred only in a few of the attacked Acyrthosiphon pisum and was significantly less frequent than in M. carnosum. These results were confirmed in experimental host-choice conditions, suggesting that Aphidius microlophii oviposition is possibly regulated by a host haemolymphatic kairomone. Hybrids obtained by crossing A. ervi females with A. microlophii males attacked and oviposited in both aphid species, suggesting that these behavioural events have a strong genetic basis. The oviposition into host or non-host aphids did not elicit an immune defence reaction. The presence of the host's food-plant had no evident close-range effects on parasitoid attack and oviposition in non-host aphids. Aphidius microlophii reared on the non-host aphid Acyrthosiphon pisum produced a significant higher number of mummies after a few generations, suggesting a possible role of larval and early adult conditioning in the host selection process. These results, together with those from previous studies, suggest that Aphidius ervi is best considered as a complex of differentiated populations, characterized by a varying degree of genetic divergence.

Isozyme polymorphism in the brown planthopper, Nilaparvata lugens (Stål) was investigated using isoelectric focusing. Four of the 18 enzyme systems assayed were polymorphic. Allelic designations could be made for two enzyme systems (PGM and AK), but not for GPI and IDH, and GPI seemed to be sex-linked. Using the two highly polymorphic enzyme systems, GPI and PGM, geographic variation was estimated among several Asian (except Japanese) laboratory populations and several Japanese wild populations. Significant variation was observed among the Asian (except Japanese) populations, but the genetic structures of Japanese populations were very similar to each other. These results are suggestive of substantial differentiation among Asian populations and large panmictic structure of the migrant population.

The life history of Frankliniella occidentalis (Pergande) was studied at six different temperatures on English cucumbers, cv. Pepinex. Life tables constructed indicate that the highest population growth rate (rm) and net reproduction rate (R0) occur at 30°C and the lowest at 15°C, where the population remains nearly stable. Generation time (T) was the shortest at 30°C and increased as temperature decreased. At 30°C oviposition increased, females matured and reproduced earlier and the time specific fecundity (mx) was higher than at lower temperatures. Adult longevity was shortest at 30°C and longest at 15°C. The threshold value for development was determined as 9.4°C. Average duration of each developmental stage and the sex ratio at six different temperatures are given.

The cuticular hydrocarbons of laboratory-bred and wild-caught females of Phlebotomus martini Parrot and P. celiae Minter, originating from southern Ethiopia, were used to distinguish females of the two sympatric and isomorphic species. Field-caught sandflies were dissected for parasites prior to the analysis. A high degree of separation, was achieved between the two species in both laboratory-bred (91.6%) and wild-caught (91.3%) specimens. However, the discriminating hydrocarbon peaks in laboratory reared specimens were different from those of wild-caught specimens, resulting in a high number of misclassiflcations in the pooled analysis of wild and laboratory specimens in each species. High degrees of hydrocarbon differentiation (84.7%–96.7%) between laboratory-bred and wild caught flies within each species were also obtained.

The primary coffee of commerce, Coffea arabica, has well-developed pit domatia in the primary vein axils on the undersurfaces of the leaves. In plantations near Mareeba and Daintree in far north Queensland, Australia, these morphogenetic structures are commonly occupied by mites. Mites used domatia on over 80% of all leaves examined, and 41% of all domatia had been occupied by mites (15–28% on young leaves and 54–59% on older leaves at Mareeba, and 58% overall at Daintree). At Mareeba, domatia use by mites did not differ among plants or shoots within plants but did vary significantly with leaf position within shoots, a reflection of leaf age. Domatia were important sites for mite reproduction and development; 93% of the eggs and all moulting mites on leaves were in domatia. Seven mite taxa were identified on leaves at Mareeba and nine were present at Daintree. With the exception of Fungitarsonemus sp. and Brevipalpus obovatus Donnadieu at Mareeba, all were concentrated in leaf domatia. Almost all mites in domatia were from groups in which arboreal representatives are primarily predatory (e.g., Stigmaeidae, Phytoseiidae, and Bdellidae), fungivorous (e.g., Winterschmidtiidae, Oribatida and Acaridae), or both (Tydeidae and Tarsonemidae). The data suggest that domatia influence the distribution and abundance of predatory and fungivorous mites that have the potential to affect fungal pathogens and some arthropod pests on coffee leaves.

A key is provided for the recognition of the hymenopterous parasitoids of the African white rice borer, Maliarpha separatella Ragonot, a pest of rice in Africa and Madagascar. Five species are described as new: Braconidae: Chelonus maudae Huddleston, Rhacanotus carinafus Polaszek; Ichneumonidae: Prisfomerus bullis Fitton, Prisfomerus caris Fitton, Venturia jordanae Fitton. The following synonyms are proposed: Goniozus indicus Muesebeck, G. natalensis Gordh and G. procerae Risbec are synonymized with Goniozus indicus Ashmead. Phanerotorna major Brues is synonymized with Phanerotoma saussurei Kohl. Lectotypes are designated for Goniozus procerae Risbec, Rhaconotus scirpophagae Wilkinson and Garouella ovicida Risbec. The known distributions, biologies and alternative hosts of each parasitoid are provided, and their use as biological control agents or components of integrated pest management programmes are discussed.

Similar increases in the height and aerial fresh weight of cowpeas compared with control plants were obtained when plants were sprayed with either 50 ppm a.i. (active ingredient) of the pyrethroid insecticide ‘Cymbush’® containing cypermethrin, or, the equivalent dilution of a blank formulation without the a.i. With broad beans, similar growth stimulation was obtained with the blank at the same or half dose, but not at a quarter dose. Testing the four formulation components separately showed that only the non-ionic emulsifier caused stimulation. A comparison of the stimulation of plant growth by the blank and the non-ionic emulsifier showed that plant height, shoot fresh weight, leaf fresh weight, leaf dry weight and leaf area were each equally increased by both treatments. The non-ionic emulsifier thus accounted for the entire stimulation caused by blank solution. Populations of Aphis fabae Scopoli (Homoptera: Aphididae) were twice as high on broad bean plants sprayed with the non-ionic emulsifier as on the controls. ‘Cymbush’ (the complete formulation) sprayed at 25 ppm a.i. was shown to increase the intrinsic rate of natural increase of the aphid through a 22% increase in fecundity; aphid development time was not affected. The results do, however, suggest that residual effects of cypermethrin may have partly counteracted the stimulatory effects of the non-ionic emulsifier. Nevertheless, it is possible that outbreaks of aphids and mites following pyrethroid application, and often assumed without evidence to have been due to natural enemy mortality, may at least in part reflect the plant stimulation caused by the non-ionic emulsifier in the formulation.