Studies on the effect of temperature on the development, longevity and population growth of Cotesia flavipes Cameron and Cotesia sesamiae (Cameron) indicated that the development of both Cotesia spp. from oviposition to cocoon formation and adult emergence was inversely to temperature. The longevity of the parasitoids was also inversely related to temperature. Both parasitoids lived longer when moisture and food (agar + honey/water) were provided. The mean number of females and total adult progeny produced by C. flavipes on two host were, in most cases, higher than C. sesamiae. The intrinsic rate of natural increase of C. flavipes was higher than that of C. sesamiae.

Paraleyrodes pseudonaranjaesp. n. is here described, from material collected from invasive colonies affecting agriculture in Hong Kong, Hawaii and the USA (Florida). This species had previously been identified as P. naranjaeDozier, based on puparial characteristics, but comparison of adult males with male syntypes of P. naranjae has indicated that identification to be mistaken. An adult male has been selected as lectotype of P. naranjae, but the identity of the puparia of the original sample remains uncertain.

Anopheles funestus Giles has been implicated as a major malaria vector in sub-Saharan Africa where pyrethroid insecticides are widely used in agriculture and public health. Samples of this species from northern Kwazulu/Natal in South Africa and the Beluluane region of southern Mozambique showed evidence of resistance to pyrethroid insecticides. Insecticide exposure, synergist and biochemical assays conducted on A. funestus suggested that elevated levels of mixed function oxidases were responsible for the detoxification of pyrethroids in resistant mosquitoes in these areas. The data suggested that this mechanism was also conferring cross-resistance to the carbamate insecticide propoxur.

A variety of host and non-host meals were tested for their potential in triggering oogenesis and oviposition in females of Cephalonomia stephanoderis Betrem, a synovigenic parasitoid of the coffee berry borer, Hypothenemus hampei (Ferrari). The consumption of non-host meals or meals composed of honey and crushed host eggs or pupae was insufficient to initiate oogenesis. The presence of suitable hosts for oviposition appeared essential for inducing oogenesis and oviposition in this parasitoid. Whereas females may host-feed on all developmental stages of H. hampei, these were not equally suitable in stimulating oogenesis and oviposition. In no-choice tests, oogenesis and oviposition were observed only in females supplied with fully-developed larvae, prepupae and pupae. Direct contact with hosts apparently stimulated egg maturation and egg-laying. Delaying the allocation of energy to egg production until suitable hosts are available for oviposition may be an adaptive attribute of a parasitoid of a concealed and patchily distributed host such as H. hampei.

The suitability of ten diets for the development and reproduction of Franklinothrips orizabensis Johansen, the key natural enemy of Scirtothrips perseae Nakahara, a pest of California grown avocados, was determined in the laboratory. The experimental diets evaluated were: (i) irradiated Ephestia kuehniella Zeller eggs; (ii) irradiated E. kuehniella eggs and avocado pollen; (iii) Tetranychus pacificusMcGregor eggs; (iv) T. pacificus eggs and avocado pollen; (v) irradiated E. kuehniella eggs and T. pacificus eggs; (vi) irradiated E. kuehniellaeggs, T. pacificus eggs and avocado pollen; (vii) Scirtothrips perseae; (viii) Heliothrips haemorrhoidalis (Bouchè); (ix) avocado pollen; and (x) a young avocado leaf. Franklinothrips orizabensis larvae were unable to develop to adulthood on diets 9 and 10. The remaining eight diets supported complete development of F. orizabensis, but only diets 1, 2, 5, 6, 7 and 8 produced fecund females. On diet 5, F. orizabensis exhibited high larval to adult survivorship (90%), mated females exhibited highest daily and lifetime fecundity, and the progeny of mated females were female biased (53%). Analysis of jackknife estimates of net reproduction (Ro), intrinsic rate of increase (rm), and finite rate of increase (λ) were all significantly greater for F. orizabensisreared on irradiated E. kuehniella eggs and T. pacificus eggs (i.e. diet 5) than corresponding values for other diets on which female F. orizabensiswere able to complete development and reproduce. Incorporation of avocado pollen into diets had an adverse effect on demographic statistics for F. orizabensis, and low quality diets resulted in male biased sex ratios for this predator.

Males of Helicoverpa punctigera (Wallengren) show considerable variation in the number of femoral scales on the prothoracic legs. Such intraspecific variation in adult morphology could indicate the presence of undetected sibling species, or it may be related to larval diet. Helicoverpa punctigera is polyphagous, and different host plant species are likely to represent diets of different quality. Femoral lengths and the numbers of femoral scales on the prothoracic legs were therefore determined from: (i) individuals that had been collected as larvae from various host in the field; and (ii) individuals that had been laboratory-reared, in split-family tests, on different diets, namely cotton, lucerne, sowthistle and artificial diet. Host plant species (and therefore presumably diet quality) influenced femoral length of H. punctigera males perhaps in conjunction with this, the number of femoral scales on the fore leg. The rearing experiment indicated, in addition, that the effect of host plant quality varies with larval stage, and that the pattern of this variation across the immature stages is dependent on host plant species. recorded variation in the morphology of field-collected H. punctigera males is therefore most readily explained as a consequence of different individuals developing (at least for most of their larval life) on different host plant species, with diet quality varying significantly species. The relevance of these results for insect developmental studies and evolutionary interpretations of host relationships is outlined.

A novel type of emergence trap capable of capturing and separating ‘live’insect catches is described. The trap was shown to be 96% efficient at capturing newly emergent adult Hylobius abietis Linnaeus on bare ground and at least 82% efficient over stumps on a weedy Sitka spruce clearfell. The trap was more than 80% efficient at capturing Bracon hylobii Ratzeburg, the most commonly found parasite of H. abietis. It was also shown to be effective at capturing adult H. abietis of unknown age (98%), indicating that it could also be used to trap out H. abietis from known areas to estimate on-site overwintering densities. Fifty-four percent of newly emergent weevils were captured within 12 h of release on bare mineral soils. Forty-two percent of unknown age weevils and 52% of parasites were captured within 1 h of their release within the trap. The rapid rates of capture mean that when traps are checked frequently they can be used to reflect accurately temporal patterns of emergence. Its potential for use in control programmes and ecological studies is discussed.

The ichneumonid Diadromus collaris (Gravenhorst) has been recorded in many parts of the world as an important parasitoid of the diamondback moth, Plutella xylostella (Linnaeus), a serious pest of brassica vegetable crops worldwide. Some aspects of its biology and its interactions with Oomyzus sokolowskii(Kurdjumov), another major parasitoid of the same pest, were studied in the laboratory. At 25°C, female wasps did not have mature eggs in their ovaries until about 12 h after emergence. Both males and females mated successfully 24–48 h after emergence, and females started to oviposit one to two days after emergence. Unmated females produced male progeny only; mated females produced progeny of both sexes. The development rate of the parasitoid increased linearly with temperature from 15 to 30°C, with an estimated low temperature threshold of 7.4°C and a thermal constant of 225.1 day-degrees for development from egg to adulthood. Rates of survival from larva to adulthood were about 90% between 20 and 28°C and decreased as temperature decreased or increased. No immatures survived to adulthood at 35°C. When provided with honey solution, the females lived on average 8.3, 11.5 and 7.0 days, and parasitized 26, 44 and 46 host pupae at 20, 25 and 30°C, respectively. Female wasps could be stored at 15°C for up to four weeks without detrimental effects on reproduction. Females of D. collaris attacked host pupae already parasitized by O. sokolowskii, inserting their ovipositor into the hosts at a similar frequency as into unparasitized host pupae, but they did not lay eggs inside the hosts.

Life history parameters of the pea aphid, Acyrthosiphon pisum were studied at five constant temperatures on two cultivars of peas, Scout and Sancho. The development and mortality of juveniles and the life-span, age-specific fecundity and survivorship of adult aphids were recorded and used to construct life tables. The juvenile development period (from birth to adulthood) was longest at 11.9°C (16.8 days on cv. Scout and 16.2 days on cv. Sancho) and shortest at 26.7°C (8.5 days on cv. Scout and 8.8 days on cv. Sancho). At all temperatures, except 26.7°C, juveniles developed faster on cv. Sancho than on cv. Scout. On both pea varieties juvenile mortality was highest at temperatures above 19.6°C and lowest at 19.6°C. Highest cumulative juvenile mortality was recorded on cv. Scout at 26.7°C when only 9% of aphids survived from birth to reproductively mature adults. Fecundity rates were unaffected by temperature in the range tested on cv. Sancho but increased with increasing temperatures between 11.9 and 19.6°C on cv. Scout. These differences in life history parameters were reflected in the population growth (rm) of aphids on both pea cultivars which increased with increasing temperatures between 11.9 and 23.1°C on cv. Sancho and 11.9 and 19.6°C on cv. Scout, declining thereafter. Population growth was consistently greater at all temperatures for aphids reared on cv. Sancho than those reared on cv. Scout.

The effect of constant temperature on development, reproduction and population growth of Thrips hawaiiensis (Morgan) reared on a diet of pollen and honey solution was studied. Although hatchability and survival rates from egg hatch to adult were higher than 79% between 15 and 25°C, they were lower than 55% at 10 and 30°C. Developmental rates increased linearly as rearing temperature increased. It was estimated that 153.8 degree-days, above a lower threshold temperature of 10.4°C, were required to complete development from egg to adult oviposition. According to these figures, between 11 and 18 generations of T. hawaiiensis could have developed annually under outdoor conditions in western Japan, between 1990 and 1999. Mean adult longevity decreased with increasing temperature, from a maximum of 102.7 days at 15°C to a minimum of 27.8 days at 25°C. The mean fecundity on pollen and honey solution was highest at 20°C with 536.9 eggs per female. The highest intrinsic rate of natural increase (rm) 0.208 was observed at 25°C.

To monitor the quality of male tsetse for use in the sterile insect technique (SIT), a field cage test was developed and evaluated. Mating competitiveness was tested with male Glossina pallidipes Austen that emerged from pupae stored for different periods at 15°C. Control males emerged from pupae stored at 23–24°C and emerged at 26.5°C. Each sample of test males was divided into two groups with one group being irradiated at 120 Gy; the other group was not irradiated. More than 70% of the maximum possible number of mating pairs occurred in all tests. Males emerged from pupae kept at low temperature and then irradiated formed a greater proportion of mating pairs than the controls. Males emerged from pupae kept at 15°C generally started mating more quickly than the standard colony males although there was no significant difference. Insemination rates were above 99%. Pooled data indicated that mean spermathecal values for females mated with irradiated males were significantly lower than for control males. The duration of copulation varied significantly between treatment groups and was significantly longer for irradiated male flies; there was no correlation between duration of copulation and mean spermathecal value.

The parasitoid Anagyrus kamali Moursi was recently introduced into the Caribbean as a biological control agent against the hibiscus mealybug, Maconellicoccus hirsutus Green. In the laboratory, parasitoid size, as measured by left hind tibia length, was positively correlated several indicators of the parasitoid‘s fitness: longevity, mating preference, fecundity, reproductive longevity, progeny emergence and sex-ratio. When fed ad libidum with honey drops, large male parasitoids lived significantly longer (29.1 ± 6.5 days) than small ones ± 5.7 days). Large females also lived significantly longer (35.4 ± 10 days) than small females (27.9 ± 9.6 days). Females showed no significant mating preference between large and small males. Lifetime fecundity was positively correlated with the size of adult females ranged from 37 ± 21 eggs for small females to 96 ± 43 eggs for large ones. The reproductive longevity, daily oviposition rate, and number of progeny were also higher among large parasitoids. The sex ratio of progeny from small female parasitoids was higher (0.76 ± than that of large individuals (0.47 ± 0.18).

Genetic sexing systems based on a conditional lethal require good discrimination between the different phenotypes. DDT resistance in the early instars of Anopheles stephensi Liston is not a good candidate when based on mortality, but this study shows that the knockdown response gives exceptional discrimination between heterozygous resistant and homozygous susceptible individuals. One- and two-day-old larvae of the DlDDT strain showed high (417-fold) resistance to knockdown by DDT, but very low resistance to mortality (3.3-fold). This changes with the onset of the third instar, so that by the fourth instar, mortality resistance is high (108-fold) and knockdown resistance is low (6.5-fold). Susceptibility to DDT decreases from first to fourth instar in the susceptible strain by 443-fold for knockdown and 15-fold for mortality and in the resistant strain by 8.5-fold for knockdown and 491-fold for mortality. The DDT knockdown response in young larvae was successfully used to identify two Y-autosome translocations linked to the resistance gene, DDT. T(Y-3)69 and T(Y-3)72 gave recombination values between the translocation breakpoint and the DDT locus of 4.1 and 10.1 crossover units, respectively. T(Y-3)69 proved to be an adequate genetic sexing system for laboratory studies.

The functional response of the predatory mite Phytoseiulus persimilis Athias-Henriot to eggs of its prey, the spider mite Tetranychus urticae Koch was examined on three plant species. Experiments were done to determine whether differences in the functional response on the three plant species were due to the morphological features of the crop directly on the predator or through an effect of the plant species on the prey. The results show that crop morphology is the only factor influencing the predatory ability of P. persimilis on the three plant species. Fewer eggs were eaten on Ceanothus thyrsiflorus var. ‘Autumnal Blue’, the plant species with hairy leaves, and greater numbers of prey consumed on Choisya ternata, a species with smooth leaves. However, similarly few eggs were eaten on the smooth, but waxy leaved Euonymus japonicus as on Ceanothus thyrsiflorus, demonstrating that morphological characters of leaves other than the possession of hairs and trichomes may affect the rates of predation. The implications of these results for the tritrophic interactions between plant, predator and prey, and the development of suitable biological control strategies are discussed.

Amplification of the second internal transcribed spacer (ITS2) of ribosomal DNA was used to compare seven samples of the Tetranychus kanzawai Kishida–T. hydrangeae Pritchard & Baker mite complex from five different countries: Australia, the Congo, Indonesia, Japan and the USA. No morphological differences were detected between these mites and their ITS2 sequences displayed strong similarity except for a small nucleotide divergence of 0.2% in specimens from Australia and Indonesia. Reciprocal crosses and backcrosses between mites assumed to be T. kanzawai and T. hydrangeae respectively showed reproductive compatibility. Fertile hybrid females were obtained in all cases, indicating conspecificity of the mites tested. It is concluded that T. hydrangeae is a synonym of T. kanzawai. The evidence suggests that T. kanzawai originated in South-east Asia and probably spread throughout the world on Hydrangea spp. cuttings.

Three sites in south west Scotland, each having one deciduous and one coniferous woodland with populations of roe deer, were sampled over three years for Ixodes ricinus Linnaeus ticks using cloth drags. Nymphs and adult ticks were age graded by dissection of gut and Malpighian tubules and staining for lipid with Sudan red. Temperature and relative humidity were recorded in developmental and questing microclimates. Two annual cohorts of both nymphs and adults were found. For both instars one cohort became apparent in early spring and the other in autumn. The timing of the cohorts of nymphs corresponded to peaks of numbers questing, but neither females nor males had any clear seasonal pattern of questing. The maximum life of questing nymphs and adults was three to four months. Nymphs and adults were found questing at all months of the year and at temperatures ranging from 3.5°C to 29.3°C. Questing of larvae in summer peaks of numbers was positively correlated with temperature and negatively correlated with relative humidity. These results are explained by a descriptive model which invokes behavioural and morphogenetic diapause. Tests of the model are discussed and it is proposed that the main adaptive advantage of the complex life cycle is to permit moulting and oviposition to occur at favourable summer temperatures in ticks that have engorged at any time of the year.

After the recent introduction of the pest whitefly Bemisia tabaci (Gennadius) biotype B into Australia, research was undertaken to study the parasitoids of the long established native B. tabaci and Trialeurodes vaporariorum (Westwood). The genus Encarsia species which are important biological control agents of whiteflies and hard scales. The taxonomy of the Encarsia species attacking B. tabaci and T. vaporariorum in Australia and the Pacific Islands is revised. DNA sequencing of the 28S D2 ribosomal DNA was used characterize species. Sixteen species are recognized, with 12 occurring in Australia, eight in the Pacific region, and four in both regions. All except one species (E. formosa Gahan) are new records for Australia. Four species are described as new from Australia: E. accenta & Naumann sp. n., E. adusta Schmidt & Naumann sp. n., E. oakeyensis Schmidt & Naumann sp. n., and E. ustulata Schmidt & Naumann sp. n. Diagnostic descriptions are given for all species and each species is illustrated. pictorial key is provided to allow the identification of species by non-specialists.

The importance, geographical and temporal distributions of parasitoids of lepidopterous borers on maize and elephant grass, Pennisetum purpureum, were assessed during surveys in farmers’ fields in six villages and two on-station trials in the forest zone of Cameroon between 1995 and 1996. The borer species encountered were Busseola fusca (Fuller), Sesamia calamistis Hampson, Eldana saccharina Walker on both host plants, and Mussidia nigrivenella Ragonot on maize only. Busseola fusca was the predominant host accounting for 44–57% and 96% on maize and elephant grass, respectively, followed by E. saccharina on maize with 27–39%. Fifteen hymenopterous, two dipterous and one fungal species were found on these stem and cob-borers. Among those were six pupal, six larval, four egg, one larval–pupal parasitoid and four hyperparasitoids. The scelionid parasitoids Telenomus busseolae Gahan and T. isis Polaszek were found on B. fusca eggs in all locations. During the first season, mean egg parasitism was low and ranged between 3.1% and 27% versus 54–87% during the second season. Species belonging to the Tetrastichus atriclavus Waterston complex were recovered from all four borer species. The majority and most common larval and pupal parasitoid species belonged to the ingress-and-sting guild.Larval and pupal parasitism were very erratic and on more than 50% of the sampling occasions no parasitoids were recovered. Parasitoid diversity was higher on elephant grass than maize.

The development, survival, and reproduction of the black citrus aphid Toxoptera aurantii (Boyer de Fonscolombe) were evaluated at ten constant temperatures (4, 7, 10, 15, 20, 25, 28, 30, 32 and 35°C). Development was limited at 4 and 35°C. Between 7 and 32°C, developmental periods of immature stages varied from 44.2 days at 7°C to 5.3 days at 28°C. Overall immature development required 129.9 degree-days above 3.8°C. The upper temperature thresholds of 32.3, 28.6, 29.3, 27.2, and 28.6°C were determined from a non-linear biophysical model for the development of instars 1–4 and overall immature stages, respectively. Immature survivorship varied from 82.1 to 97.7% within the temperature range of 10–30°C. However, immature survivorship was reduced to 26.3%at 7°C and 33.1% at 32°C. Mean adult longevity was the longest (44.2 days) at 15°C and the shortest (6.2 days) at 32°C. The predicted upper temperature limit for adult survivorship was at 32.3°C. Total nymph production increased from 16.3 nymphs per female at 10°C to 58.7 nymphs per female at 20°C, declining to 6.1 nymphs per female at 32°C. The estimation of lower and upper temperature limits for reproduction was at 8.2 and 32.5°C, respectively. The population reared at 28°C had the highest intrinsic rate of increase (0.394), the shortest population doubling time (1.8 days), and shortest mean generation time (9.5 days) compared with the populations reared at six other temperatures. The population reared at 20°C had the highest net reproductive rate (54.6). The theoretical lower and upper temperature limits for population development, survival and reproduction were estimated at 9.4 and 30.4°C, respectively. The biology of T. aurantiiwas also compared with three other citrus aphid species.