The systematics of the hymenopterous parasitoids associated with Phoracantha spp. in Australia are reviewed. An illustrated key to species is presented to facilitate their identification as part of ongoing attempts for the biological control of P. semipunctata (Fabricius), an exotic pest on eucalypt trees. Information on the taxonomy, distribution and biology of 18 species of primary and hyperparasitoids associated with Phoracantha spp. are presented. A new braconid genus, Jarra, is described to accommodate three new species, J. phoracantha, J. maculipennis and J. bicolor, and Doryctes diadoxi Nixon (Doryctinae), the latter associated with a buprestid host. Two other new species, Heterospilus nukunu (Doryctinae) and Callibracon moorei (Braconinae) are also described; Iphiaulax morleyi Froggatt is synonymized with Atanycolus tomentosus Szépligeti and I. rubriceps Froggatt is synonymized with Syngaster lepidus Brullé lectotypes are designated for I. morleyi, I. rubriceps and I. phoracanthae Froggatt; and Ipobracon fleviceps flaviceps (Cameron) and I. flaviceps mackayensis Turner are transferred to Callibracon. The encyrtid genus Aventianella is recorded from Australia for the first time and the egg parasitoid of P. semipunctata, A. longoi Siscaro described from Italy, is postulated to be endemic to Australia.

The responses of adult females of Hypothenemus hampei (Ferrari) from New Caledonia, which were either resistant or susceptible to endosulfan, were compared to a range of insecticides. High levels of cross resistance were present to organochlorines (aldrin, dieldrin and lindane). No cross resistance was evident to carbaryl or organophosphates (descending order of toxicity: fenitrothion > pirimiphos-methyl > chlorpyrifos > diazinon=malathion). Carbaryl, a carbamate, was the least toxic, and avermectin, a macrocyclic lactone, was the most toxic insecticide tested on H. hampei. No evidence of synergy from esterase (DEF) or microsomal oxidase (piperonyl butoxide) inhibitors was present.

Two acetylcholinesterase (AChE) variants, differing in sensitivity to inhibition by the organophosphorus (OP) insecticide paraoxon were identified in a population of Bemisia tabaci (Gennadius) from cotton in Israel using a single insect kinetic microplate assay. Two strains were established, homogeneous for one or other of the two variants, by isolating mated females from the field population onto individual cotton leaves, and testing a proportion of their female offspring to identify their AChE genotype. Polyacrylamide gel electrophoresis of their I-naphthyl butyrate hydrolyzing esterases showed that all insects contained esterase E0 14, which is indicative of B-type whiteflies, although the staining intensity of this band differed. Resistance to the OPs monocrotophos, profenofos and chlorpyrifos in leaf dip bioassays was consistent with the presence of the insensitive AChE. The data also indicated that separate mechanisms conferred resistance to the two pyrethroids cypermethrin and bifenthrin. The former, when used in a mixture with profenofos, was no more toxic than when the OP was used alone, and resistance to the mixture was largely dependent on the presence of the insensitive AChE.

Host characteristics, hyperparasitism, larviposition behaviour and generation time of Sarcophaga penicillata Villeneuve a parasitoid of the conical snail, Cochlicella acuta Müller (Mollusca: Helicidae) in southern France are described. Only snails which aestivated on vegetation were found to be parasitized by S. penicillata. Sarcophaga penicillata preferred C. acuta which were both significantly higher off the ground and larger in size than the population averages. Of the 2768 snails collected at the study site, 4% (112) were parasitized by S. penicillata, of which 36.6% (41) failed to emerge while 34% (38) were hyperparasitized. The predominant hyperparasite was Novitzkyanus cryplogaster Bouček (Hymenoptera: Pteromalidae) which was responsible for 79% (30) of the hyperparasitism. Larvipositing S. penicillata were observed to fabricate a hole in the epiphragm of resting snails in which they deposited one larva. After larviposition, female S. penicillata remained with the freshly parasitized snail a mean time ± SE of 25.2 ± 10.3 min. It is suggested that this may be an adaptive response to avoid superparasitism. The mean generation time of S. penicillata when reared in the laboratory was 18 days, indicating that more than six generations are possible during summer in the south of France. During winter, S. penicillata enters diapause in the pupal stage within a host snail for up to 6 months. The possible utility of S. penicillata as a biological control agent of introduced conical snails is discussed.

Spodophagus, gen. n. (Pteromalidae: Pteromalinae), is described to include the single species S. lepidopteraecomb. n., which was originally described from Madagascar by Risbec (1952) in the genus Oxyglypta. A lectotype is selected for O. lepidopterae, and the species is redescribed and illustrated. This pteromalid is a parasitoid of Spodoptera littoralis, an important pest, which is resistant to several classes of insecticides in Madagascar. Spodophagus lepidopterae is thus a potential agent for the biological control of Spodoptera spp. in Africa and elsewhere.

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.

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.

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.

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 effects of intraplant variation of nitrogen, phosphorus, potassium and wafer content within maize plants on fitness of the African armyworm, Spodoptera exempta (Walker), were studied in three experiments by using an excised leaf system. Maize plants were phosphorus deficient in one of the experiments. Various leaf categories were distinguished differing in age and position on the plants. Leaf sections on which caterpillars fed were daily refreshed. Changes in the four plant variables measured, due to the excision and subsequent placement of the leaf sections in the excised leaf system for one day, were small and mostly insignificant. Highly significant differences were found between the composition of the various leaf categories in all three experiments. In all experiments, the nitrogen concentrations ranged from 2.4 to 4.5%, phosphorus from 0.1 to 1.3%, and potassium from 1.4 to 4.8% dry weight, while water content varied from 83 to 90% fresh weight. Of all insect fitness parameters observed, only larval growth rate was consistently and significantly affected by leaf category. Fecundity was strongly correlated with pharate adult weight. Only phosphorus was significantly and positively correlated with larval fresh weight, especially in the experiment with phosphorus deficient plants. Multiple regression models revealed that in all experiments a significant proportion of variation in larval fresh weight between leaf categories could be explained by the four plant variables. However, only phosphorus was included in all models. When all leaf categories used in the three experiments were considered simultaneously, the importance of phosphorus for larval growth rate in these experiments was again evident. The variation in nitrogen, potassium and water appeared to be of little or no significance. The consequences of these findings for outbreak development of S. exempta are discussed.

In India the cultivated oyster mushroom Pleurotus sajor-caju (Fr.) Singer is attacked by the larvae of two species of Phoridae, Megaselia pleurota Disney sp. n. and M. scalaris (Loew). The new species is described. Biological data and damage symptoms are reported for both species. Serious economic damage is also caused by a bacterium associated with M. scalaris. The identities of the two Megaselia species, previously reported attacking this fungus, are called into question.

Some physical and biological factors affecting the abundance of larvae and pupae of the Aedes simpsoni (Theobald) complex, in leaf axils of different plants at several locations in Uganda, were investigated during the rainy and dry seasons. The mean number of axils per plant, axils containing larvae and pupae, and the mean number of larvae and pupae per ml of axil water all varied between seasons and locations. The percentage of axils containing larvae and pupae increased with volume of water in the axils of the different plants. The mean number of larvae and pupae per axil containing water also increased with water content of the axils. There was more water in the axils during the rainy than during the dry seasons. The mean temperature of water was lower in Xanthosorna sagittifoliurn (20.4°C) and Colocasia esculentum (22.1°–22.7°C) than in those of banana (25.0°–27.2°C) and this affected developmental rates of larvae and pupae. The indices of association between larvae and pupae of the A. simpsoni complex and Malaya taeniarostris (Theobald) did not indicate competition and there was some habitat segregation between them. The volume and temperature of water in the axils appeared to be the major factors affecting larval and pupal abundance of A. simpsoni in the axils.

The resistance of two melon lines (CHI-7 and BUS-7) selected for resistance to the carmine spider mite, Tetranychus cinnabarinus (Boisduval), and of the susceptible line (NY), was studied under field and laboratory conditions. Significant differences among lines were observed at different growth stages. Throughout the season, the resistant lines had reduced populations of mites, 35–100% lower on CHI-7 and 25–100% lower on BUS-7, compared with the susceptible line NY. Laboratory evaluation of antibiosis to the mite at different plant growth stages showed that on CHI-7 and BUS-7 mite fecundity was reduced by 29–60% and 43–83%, respectively.

Genetic variability in four polymorphic loci and variation in phenotypic plasticity in relation to the relative size of wings, were compared and contrasted among eight local populations of Sitonasulcifrons Thunberg from the Czech and Slovak republics. The distances between localities from which samples were taken were between 49 and 492 kilometres. The results demonstrated that: 1. The variability between populations was 5.5% and the other 94.5% of the total variability was realized within populations. 2. Significant differences in allozyme frequencies among populations existed when distances were more than 100 km. A similar trend was also found in variability of relative wing size in males among populations when distances were more than 200 km. 3. Overall, a significant deficiency of heterozygotes in relation to Hardy-Weinberg predictions existed from all samples. The results support the idea that, at least inagricultural areas, gene flow in S. sulcifrons does not seem to be strong enough to stabilize one large interbreeding population in distances over 100 kilometres.

Reports of the African armyworm, Spodoptera exempta (Walker), in eastern Africa for sixteen seasons (1972–73 to 1987–88) were analysed together with weather records to identify the most frequent locations of outbreaks and their relationships with weather. Outbreaks were classified into ‘primary’ outbreaks (derived from low density parent populations), ‘secondary’ outbreaks (derived from previous out breaks) and ‘critical’ outbreaks (leading to many subsequent outbreaks). Differences in seasonal severity of armyworm infestations in relation to the timing and location of primary outbreaks and early season rainfall were also examined. Trajectory analysis was used to estimate migrations of windborne moths, and the distribution of rainstorms was used to help estimate the timing of moth concentration leading to outbreaks of S. exempta. First reported armyworrn outbreaks from October to December in Kenya and Tanzania were usually primary. Critical primary outbreaks mostly occurred in east-central Tanzania, north-east Tanzania and the adjacent Taveta district of Kenya, and east-central Kenya. Strategic control (to prevent subsequent, downwind outbreaks) is best carried out in these areas. Migration direction was largely determined by seasonally dominant winds, although windfield disturbances were occasionally important. Three seasons in which very low numbers of S. exempta were reported, had heavy, persistent October to December rainfall leading to high larval mortality. Seasons with many outbreaks often had rainstorms separated by dry periods, during the rainy seasons.