The reproductive phenology of Listronotus bonariensis (Kuschel) in the north of North Island, New Zealand, was studied by dissection of adults collected at intervals from several sites. First-generation adults exhibited reproductive development and activity, followed by gonad atrophication and death. Most second-generation adults entered directly into oligopause in the autumn. Some early emergent weevils of this generation oviposited before onset of winter and reproductive dormancy. Oligopause was not intense, and reproductive maturity was gradually attained over the winter, with resumption of egg laying in early spring. These results are discussed in relation to population reproductive biology and survival.

Suction traps sampling at a height of 12·2 m have been operated by the Rothamsted Insect Survey since 1964 to monitor the aerial movement of aphids and other insects. Many variants of the trap have evolved in other countries due to the lack of a detailed published description. A standard for a low maintenance structure of the ‘12-metre' suction trap now being adopted by the Rothamsted Insect Survey and some other users is described. This should lead to better uniformity and comparability of data from such traps.

In Zimbabwe, catches of Glossina morsitans morsitans Westwood and G. pallidipes Austen in traps baited with acetone and 1-octen-3-ol were increased by the addition of the synthetic mixture of eight phenols found in cattle urine to a level equal to or greater than those with natural urine. The addition of natural urine to the synthetic mixture did not increase catches further, indicating that the phenols account for essentially all the attractiveness of cattle urine. 4-Methylphenol and 3-n-propylphenol were shown to be the naturally-occurring components essential for attractiveness, and 2-methoxyphenol was found to reduce attractiveness. 4-Methylphenol alone was slightly attractive to both species, but only for males, increasing catches by approximately 30%. Catches of both species were increased by approximately 50% by 3-n-propylphenol. The addition of 4-methylphenol increased catches of G. pallidipes by up to a further four times, but catches of G. m. morsitans were decreased. Of 14 other phenols tested, phenol, 3-methylphenol and 4-ethylphenol increased the attractiveness of 3-n-propylphenol to G. pallidipes without decreasing the attractiveness to G. m. morsitans; (E)- and (Z)-3-(1-propenyl)phenol, potential contaminants in 3-n- propylphenol, did not reduce the attractiveness of mixtures of 3-n-propylphenol and 4-methylphenol, and the E and, to a lesser extent, the Z isomer could substitute for 3-n-pro-pylphenol in these mixtures. Mixtures of phenols which increased the attractiveness of traps to tsetse showed similar effects with targets but at a slightly reduced level.

Aerial sampling for Nysius vinitor Bergroth was undertaken in the surface and upper air, at altitudes of 2 and 100-300 m, respectively, at Trangie in central New South Wales and at Corny Point, Yorke Peninsula, South Australia. Insects were sampled for 15 periods, each of 3-11 days, between October 1979 and February 1984, covering all months except January, March and May. N. vinitor was one of the most abundant insects caught in the upper air during the day and night (mean density of 652/106 m3), while the congeneric N. clevelandensis Evans was rarely caught at any time. N. vinitor was caught in all months sampled except for the winter months of July and August, and the largest daily catches occurred in September. Females were generally less common than males, although the relative incidence in the upper air catches frequently increased significantly from day to night. Fewer mature females were caught in the upper air (0-16·8%) than at the surface (0-48·4%). Densities were generally much greater in the surface air than in the upper air, although during the major flights of spring, there was less than a two-fold difference, indicating increased migratory activity. Migration occurred in a range of synoptic conditions resulting in the displacement of individuals in a variety of directions and distances depending on synoptic flow at the time of flight. Major migrations occurred at night, following dusk take-off, in disturbed weather associated with prefrontal airflows. These resulted in net southward displacements of ca 200-300 km depending on flight duration. It is suggested that major immigration flights into central-western New South Wales and regions to the south regularly occur in early spring (September-October) and probably arise from breeding areas in subtropical latitudes.

The landing preferences of fed males of Glossina morsitans morsitans Westwood and Stomoxys calcitrans (L.) were measured under constant conditions in a two-choice situation. Pairs of black-and-white landing targets were presented on the grey walls of an arena ca 60 cm in diameter. In a simple choice of blackness vs whiteness, G. m. morsitans showed a ninefold greater preference for black; S. calcitrans displayed no preference. G. m. morsitans landed twice as frequently on a 15×30-cm vertical black stripe as on a horizontal one, but S. calcitrans preferred the horizontal one. Comparisons between a vertical stripe (or a horizontal one) and similar stripes sloping at various angles indicated that at about 50° G. m. morsitans distinguished the sloping stripe from the vertical (or the horizontal), but did not well distinguish slopes closer to the vertical (or horizontal). Tests with multiple vertical stripe patterns indicated that G. m. morsitans did not significantly distinguish between a single 15-cm stripe and two- or three-striped targets of the same total black area, but landed significantly less frequently on targets of four or five stripes, implying an angular, behavioural visual ‘resolution' of roughly 17°; S. calcitrans responded similarly. Both species showed a marked preference for landing near the edge of the black on all targets, with G. m. morsitans strongly biassed to the black side of an interface.

In laboratory and field trials in the UK, larvae of Pieris rapae (L.) from the UK survived better than larvae from the Mediterranean region on Brussels sprouts, broccoli and field kale. A similar difference, associated with latitude, was found in Australia. The implications of these results are discussed.

Metaphycus baruensis sp. n., an encyrtid parasitoid of Coccus spp. on coffee in Kenya, is described and compared with related species. The parasitoid is to be introduced into Papua New Guinea in an attempt to control green scales which are serious pests of coffee there.

In southern Brazil, adults and larvae of the halticine beetle Alagoasa parana Samuelson fed on the foliage and flowers of Lantana tiliaefolia and L. glutinosa (Verbenaceae). The life-cycle of this univoltine species from egg to adult emergence took 80-90 days between October and April. The abundance varied seasonally from four to eight adults per 100 branches. Larvae remained on the foliage during development and pupated in moist, loose, friable soil within a cocoon at the base of the host-plant. Adults overwintered and oviposited in litter at the base of the host-plant. In multiple-choice host- specificity studies in Australia, adults fed lightly on Verbena bonariensis and Clerodendrum speciosissimum (Verbenaceae) and produced minute scars on leaves on unrelated passion fruit (Passiflora edulis) and sunflower (Helianthus annuus). However, A. parana completed immature development only on L. camara among the 55 plants tested. The potential of A. parana as a biological control agent for L. camara in Australia is discussed.

Introduction of parasitoids gave improved biological control of Planococcus citri (Risso) in a large glasshouse stocked with a variety of ornamental plants, supplementing that achieved by the predator Cryptolaemus montrouzieri Mulsant. Following parasitoid release, there was evidence of pest population regulation on guava and coffee bushes with reduced and stabilized mealybug numbers and stable percentage parasitism. The mean temperature during one sampling period was significantly correlated with the percentage parasitism two months later, indicating that temperature has a major impact on parasitoid efficiency. Leptomastidea abnormis (Girault) was responsible for about 90% of the parasitism observed; the remainder was by Leptomastix dactylopii Howard. The effects of supplementary inoculative releases of Leptomastidea abnormis were variable, but resulted in increased percentage parasitism only when the number released contributed significantly to those already established. No evidence of pest population regulation was found on Aristolochia or Passiflora vines nor on potted Gesneriaceae plants of the genera Streptocarpus and Saintpaulia. Peak mealybug populations on these last plants coincided with periods of new growth, fruiting or flowering. Host-plant quality thus seems to be a major factor inducing mealybug outbreaks.

Gyranusoidea tebygi sp. n., an encyrtid parasitoid of Rastrococcus on mango in India, is described and compared with related species. The parasitoid is to be introduced into West Africa in an attempt to control the mealybug, which is a serious pest of mango and citrus in some West African countries.

The species of the cixiid genus Myndus occurring in the Solomon Islands and Vanuatu are reviewed. M. macfarlanei sp. n. is described from Santa Cruz Islands. It is distinguished from M. mavors Fennah and M. taffini Bonfils, both of which are redescribed and illustrated. All species have been collected from coconut palms, and M. macfarlanei also from areca palm (Areca catechu). M. taffini has been previously confirmed as the vector of foliar decay of coconut palms in Vanuatu.

Populations of Nysius vinitor Bergroth were studied from 1979 to 1982 in two weed hosts, Arctotheca calendula and Polygonum aviculare, and eight irrigated sunflower crops in a summer cropping area of northern Victoria, Australia. The spring generation began with the adults colonizing flowering A.calendula plants in September and concluded with the rapid development of late stage nymphs and an exodus of adults from these plants from mid-November to December. Gradual invasion of sunflowers occurred mostly in late December and reached a peak at flowering, after which nymphs appeared. P. aviculare attracted adults from February and hosted a number of overlapping generations until winter. The weed sustained diminishing numbers of adults through the winter, except in 1982, when a further generation produced an early spring peak. Immigrant populations were regarded as a common source of adults for initiating the spring and summer generations. The rate of development of N. vinitor in spring was more rapid than that predicted by phenological simulation based on ambient temperatures and laboratory-derived day-degree estimates. This was attributed to increased body temperatures through absorption of solar radiation, and the simulation model was adjusted by increasing daily minimum and maximum temperatures by 1·3 and 5·5°C for young and older instars, respectively. This suggested that older nymphs have lower developmental thresholds or are better able to optimize body temperatures.

Chironomid midges have been known to include parthenogenetic species for over a century. One of these species, Paratanytarsus grimmii (Schneider), cited under several different names here shown to be junior synonyms, has attained some notoriety as a pest. Its occurrence as a supposedly paedogenetic (actually pharate adult parthenogenetic) inhabitant of water distribution systems is discussed and related to its more usual occurrence in a variety of small water bodies including aquaria. New synonymy is proposed and a lectotype designated.

Females of Glossina tachinoides Westwood captured three-hourly in biconical traps deployed from 16.30 to 18.30 h weekly in three peridomestic agroecosystems in southern Nigeria from April 1984 to March 1987, were dissected and classified as nulliparous, pregnant, aborted or parous-but-not-pregnant. In all three tsetse populations, the monthly pregnancy rate ranged from 76 to 94% and the abortion rate from 3 to 8% throughout the year. No seasonal or locational differences or evidence of seasonal increase, reduction or cessation in breeding were demonstrated. A significant difference between years with respect to monthly abortion rate during the wet season was possibly due to changes in vegetation structure which is dependent on crop types. It is concluded that the low population density and pattern of seasonal fluctuation in apparent density of G. tachinoides in these peridomestic agroecosystems are due to causes other than seasonal differences in its breeding rate.

A series of host-transfer trials using both laboratory-cultured and field-collected individuals of the aphid parasitoids Aphidius ervi Haliday and A. rhopalosiphi De Stefani Perez were done in order to clarify inconsistent results from several previous studies. A. ervi cultured on Acyrthosiphon pisum (Harris) produced very few mummies when confined with Microlophium carnosum (Buckton), whereas those cultured on M. carnosum produced as many mummies on A. pisum as they did on their original host. Mummy production was correlated with the attack rate of adult parasitoids on potential hosts. The production of mummies on M. carnosum by parasitoids reared on A. pisum was often greatly improved if their male parent had been reared on M. carnosum, suggesting that genotype strongly influences host preference. Aphidius rhopalosiphi from laboratory cultures produced significantly more mummies on Metopolophium dirhodum (Walker) than on Sitobion avenae (F.) regardless of their original host, but this preference was not shown by parasitoids from field populations. It is concluded that inadvertent selection occurs in laboratory cultures of aphid parasitoids as a result of low founder numbers, genetic drift and genetic bottlenecks and that this can strongly influence experimental results in biology and behaviour studies, which has important implications for biological control workers.

Densities of four herbivorous insect species were compared on field beans (Phaseolus vulgaris) grown in monoculture and those grown in relay intercropping with winter wheat. In three years of study in New York State, population densities of Empoasca fabae (Harris) and Aphis fabae Scopoli were significantly less in plots intercropped with winter wheat than in those grown in monoculture. In contrast, intercropping was associated with greater densities of Lygus lineolaris (Palisot de Beauvois) and Systena frontalis (F.). An increased density of L. lineolaris may be an economic risk factor in beans intercropped with wheat because only this species of the four studied feeds exclusively on the flowers and developing seed pods.

Rastrococcus invadens Williams has been the most important polyphagous pest of horticultural crops since 1982 in some West African countries. It originated in South-East Asia and was probably introduced on infested plant material. The pest has been reported up to 150 km north of the coast of Benin and 500 km north from the coast in Togo. Although the species is polyphagous, mango, citrus, breadfruit, banana, frangipani (Plumeria alba) and species of Ficus are among the most attacked hosts. Several indigenous natural enemies were identified, but their ability to regulate the populations of R. invadens is very low. The most important among the predators were the coccinellids Chilocorus nigrita (F.), Exochomus promtus Weise and E. troberti Mulsant and the lycaenids Spalgis spp. In Togo, an indigenous parasitoid, Anagyrus sp. ?nr aurantifrons Compere, has become adapted to the pest.

A rapid technique is described for characterizing and monitoring, in single insects, the insensitivity of acetylcholinesterase (AChE) to organophosphorus and carbamate insecticides. Ninety-six insects are homogenized simultaneously in a microtitre plate and portions (e.g. 0·05 for Musca domestica L.) assayed colorimetrically with acetylthiocholine in the presence and absence of diagnostic concentrations of insecticide. Reactions are monitored by a kinetic microplate reader linked to a microcomputer that determines mean AChE activities automatically by linear regressions of absorbance-time data. Mean inhibited activity is then expressed as a percentage of uninhibited activity. Several inhibitors can be tested against the same insect to yield an ‘insensitivity profile‘ of individuals and strains. In tests on M. domestica adults of known AChE genotype, the assay clearly distinguished not only between a sensitive and two slightly (3-15-fold) insensitive AChE variants but between all six genotypic combinations of these three alleles.

A quantitative analysis of the foraging behaviour of Acromyrmex octospinosus (Reich) from three nests on 27 yam varieties of nine species was undertaken in Guadeloupe using a video-microcomputer device. In ants with no previous experience of the variety, foraging inhibition appeared only after at least a whole day of contact with resistant yam leaves. There was a negative correlation between leaf saponin content of the yam species and foraging intensity; however, the main yam sapogenin, the steroid diosgenin, had no effect on foraging behaviour, and tomatin, a steroid-alkaloidal saponin, induced only long-term deterioration of the fungus garden when incorporated in the nest. The saponins tested are thus not detected by the ants and are therefore unable to initiate the strong and rapid foraging inhibition observed with resistant yams.

The shoot-fly Atherigona ramu sp. n. is described from Papua New Guinea. It was reared from sugarcane at the agronomy centre of Ramu Sugar Ltd, Gusap, Papua New Guinea, and is also known from other parts of Papua New Guinea.