1. G. pallidipes almost invariably attacks man on the leg from the knee downwards.

2. G. brevipalpis may attack man anywhere and not infrequently on the head.

3. Both species fill themselves readily with human blood once an attack has been made.

4. Neither sex of either species attacks man unless very hungry, as indicated by the very low mean fat content in the captures.

5. G. brevipalpis is apparently more reluctant even than pallidipes to attack man, and the fat contents in flies caught on man are proportionally lower than in the case of pallidipes.

The records and descriptions of Eriophyid mites hitherto described from tomato are discussed. A statistical examination was made of morphological measurements of the New Zealand tomato russet mite. The names of gall-mites occurring on tomato have been reduced to two: Acerialycopersici (Wolffenstein) 1879, the tomato erineum mite (causing the production of white, hairy patches on stems and leaf stalks); and Vasates lycopersici (Massee) 1937, the tomatorusset mite (causing stem and leaf bronzing). A key is given to the species of gall-mites occurring on solanaceous plants and several new combinations are recorded.

A single choice test was performed to examine developmental strategies in the uniparental endoparasitoid Meteorus pulchricornis and its host, the cotton bollworm Helicoverpa armigera. The results support the dome-shaped model in which the fitness functions are ‘dome-shaped’ relative to size (and age) of host at parasitism. Older and, hence, larger host larvae were simply not better hosts for the developing parasitoids. Although parasitoid size (measured as cocoon weight and adult hind tibia length) was positively correlated with host instars at parasitism, parasitoids developing in larger hosts (L5 and L6) suffered much higher mortality than conspecifics developing in smaller hosts (L2–L4). Furthermore, egg-to-adult development time in M. pulchricornis was significantly longer in older host larvae (L4–L6) than in the younger. Performance of M. pulchricornis, as indicated by fitness-related traits, strongly suggests that the L3 host is the most suitable for survival, growth and development of the parasitoid, followed by both L2 and L4 hosts; whereas, L1, L5 and L6 are the least favourable hosts. The oviposition tendency of M. pulchricornis, represented by parasitism level, was not perfectly consistent with the performance of the offspring; L2–L4 hosts, although with the same parasitism level, had offspring parasitoids with differences in fitness-related performance. Larval development in Helicoverpa armigera was usually suspended, but occasionally advanced, in the final instar.

β-Aminobutyric acid (BABA) is known to induce resistance to microbial pathogens, nematodes and insects in several host plant/pest systems. The present study was undertaken to determine whether a similar effect of BABA occurred against the Asian citrus psyllid, Diaphorina citri Kuwayama, in citrus. A 25 mM drench application of BABA significantly reduced the number of eggs/plant as compared with a water control, whereas 200 and 100 mM applications of BABA reduced the numbers of nymphs/plant and adults/plants, respectively. A 5 mM foliar application of BABA significantly reduced the number of adults but not eggs or nymphs when compared with a water control treatment. In addition, leaf-dip bioassays using various concentrations (25–500 mM) of BABA indicated no direct toxic effect on 2nd and 5th instar nymphs or adult D. citri. BABA-treated plants were characterized by significantly lower levels of iron, magnesium, phosphorus, sodium, sulfur and zinc as compared with control plants. The expression level of the PR-2 gene (β-1,3-glucanase) in BABA-treated plants that were also damaged by D. citri adult feeding was significantly higher than in plants exposed to BABA, D. citri feeding alone or control plants. Our results indicate the potential for using BABA as a systemic acquired resistance management tool for D. citri.

Despite the fact that insect learning capacity has been broadly demonstrated, the role that this process plays during mate searching has been scarcely explored. We studied whether the sexual behaviour of a male parasitic wasp can be conditioned to the odours from two alternative host plant complexes (HPCs) present during its first copulation. The experimental subjects were newly emerged males of the aphid parasitoid, Aphidius ervi, and two alternative HPCs (alfalfa or wheat). In the training protocol, copulation experience corresponded to an unconditioning stimulus and HPC odours to the conditioning stimuli. The initial (just after eclosion) and trained responses were assessed in a glass Y-olfactometer. The results showed that neither alfalfa HPC nor wheat HPC stimuli elicited sexual-related behaviours in initial male responses. Conversely, both HPCs triggered strong attraction and wing fanning courtship behaviour in trained responses when the male was exposed to a female plus HPC during training. In males trained with females plus a given HPC but tested with the alternative HPC in the olfactometer, trained response showed a similar trend to the non-associative treatments. Hence, through learning, the olfactory stimulus context present during copulation could become a predictive cue for further mate searching. These results are discussed in terms of parasitic wasp ecology and host fidelity.

Atta sexdens rubropilosa is a leaf-cutting ant that is a significant agricultural and forestry pest in the Neotropical region. This ant is parasitized by flies from the genera Neodohrniphora spp., Apocephalus spp. and Myrmosicarius spp. This study was carried out to determine which species of Neodohrniphora spp. are found near foraging trails of Atta sexdens rubropilosa and to evaluate the specificity of attack behaviour of these parasitoids. From May 2002 to April 2004, we sampled Neodohrniphora spp. hovering over foraging trails of Atta sexdens rubropilosa between 8:00 and 11:00 h and between 15:00 and 18:00 h. To investigate the attacking behaviour against the ants, flies were released individually inside an observation chamber containing a single leaf-cutting ant worker. Each parasitoid was confronted successively with a worker ant of A. sexdens rubropilosa, Atta laevigata Smith, Acromyrmex crassispinus Forel and Acromyrmex subterraneus molestans Santschi. Phorids of three species were identified: Neodohrniphora elongata Brown, Neodohrniphora declinata Borgmeier and Neodohrniphora tonhascai Brown. The three phorid species were active throughout the year and often along the same foraging trails, but N. elongata was the most frequent species. In the laboratory assay, N. elongata, N. declinata and N. tonhascai attacked workers of A. sexdens rubropilosa, A. laevigata and A. crassispinus, but not of A. subterraneus molestans.

The effect of structurally related sesquiterpenoids (E,E)-farnesol and cis-nerolidol on the host-plant selection behaviour of the peach potato aphid Myzus persicae (Sulz.) was evaluated using electrical penetration graph (EPG) technique. No repellent effects of (E,E)-farnesol and (Z)-nerolidol to M. persicae were found but aphid probing activities on (E,E)-farnesol- and cis-nerolidol-treated plants were restrained. During non-phloem phases of probing, neither (E,E)-farnesol nor (Z)-nerolidol affected the cell puncture activity. On (E,E)-farnesol-treated plants, the total duration of phloem phase, the mean duration of individual sustained ingestion periods were significantly lower, and the proportion of phloem salivation was higher than on control plants. On (Z)-nerolidol-treated plants, the occurrence of the first phloem phase was delayed, and the frequency of the phloem phase was lower than on control plants. The freely moving aphids were reluctant to remain on (E,E)-farnesol- and (Z)-nerolidol-treated leaves for at least 24 h after exposure. (E,E)-Farnesol and (Z)-nerolidol show complementary deterrent properties, (E,E)-farnesol showing ingestive and post-ingestive activities and nerolidol showing pre-ingestive, ingestive, and post-ingestive deterrent activities.

The success or not of ladybirds as biological control agents is dependent on both their foraging behaviour and their individual survival rates. The former is a function of the habitats they utilise; the latter, a consequence of their reproductive strategy. Egg clustering was investigated in two ladybird species, Aphidecta obliterata, a conifer specialist, and Adalia bipunctata, an arboreal woodland generalist. The effect of oviposition substrate (filter papers vs. spruce needles) on clutch size and oviposition preference was also tested. Adalia bipunctata laid significantly more eggs than A. obliterata. The size of egg clusters laid by the two coccinellids varied between species and substrate types. Adalia bipunctata laid larger egg clusters than A. obliterata, with batches reaching a maximum size of 32 eggs on spruce and 41 eggs on paper, while those of A. obliterata contained a maximum of 5 eggs on spruce and 9 eggs on paper. Of the clusters laid by A. obliterata, 18.6% of those on paper and 21.4% of those on spruce contained only a single egg, whereas a minimum of two eggs per cluster were laid by A. bipunctata. Smaller clusters were laid on the spruce cuttings by both species when compared with those laid on the filter paper, but A. obliterata laid significantly more eggs on spruce than on the filter paper (77% vs. 23%), whilst A. bipunctata laid significantly more eggs on the filter paper (91%). It is suggested that coccinellid eggs are more likely to be washed off spruce needles than broad leaves and that, by laying smaller egg clusters on spruce, A. obliterata reduces this risk. Adalia bipunctata usually lays its eggs on the underside of broad leaved trees and thus does not face this risk and thus can lay larger egg clusters. No differences in cannibalism rates were found between the two species. These findings have implications for the use of ladybirds as biological control agents in spruce forests.

Four Beauveria bassiana and three Metarhizium brunneum isolates were evaluated, as soil drenches, against Spodoptera littoralis prepupae. Treatment efficacy was determined by assessing total mortality during development from prepupae through to pupae and adults; mortality and sub-lethal effects on reproduction were also quantified for adults emerging from surviving prepupae/pupae. All isolates were pathogenic but overall mortality varied between 31.7 and 83.3% (0% for control); average survival time was 7.5–10.5 days (14.0 days for control). From 1.7–15.0% of adults emerging from surviving prepupae/pupae were deformed (0% in control). Contact with fungal suspensions as prepupae/pupae caused a significant reduction in fecundity of emerging adult females (15–58.9%), and a significant reduction in egg viability (6.8–28.4%) compared with controls. Two isolates were selected for virulence evaluation against S. littoralis prepupae. The LC50s were 1.7 × 107 and 1.8 × 107 conidia ml−1 and the median survival times were 7 and 6 days for isolates EAMa 01/58-Su and EAMb 09/01-Su, respectively. Destruxin A was present in pupae developing from prepupae treated with isolates EAMa 01/58-Su (0.010 ± 0.002 µg pupae−1) and EAMb 09/01-Su (0.015 ± 0.003 µg pupae−1). The use of entomopathogenic fungi as soil drenches could be a key component of S. littoralis IPM strategies due to direct reductions in the number of soil-dwelling life stages and, also, the significant reduction in reproductive potential of surviving adults.

The Acari dealt with in this paper were collected by Dr. G. F. Petrie during his plague investigations in Egypt. My best thanks are due to him and also to the authorities of the Lister Institute for their kindness in permitting me to examine this collection.

The foraging behaviour of the redlegged earth mite, Halotydeus destructor (Tucker), in annual pasture was documented and the relative numbers of individuals foraging on subterranean clover, Trifolium subterraneum (Leguminosae), capeweed, Arctotheca calendula (Compositae) and grasses (mainly Lolium rigidum (Gramineae)), estimated in winter and spring in south-western Australia. The main feature of H. destructor foraging behaviour was the presence of aggregations ranging in size from 3–36 individuals on the adaxial surfaces of the upper canopy of the pasture. Most aggregating individuals were feeding, while most solitary and paired individuals were searching. There was no evidence that individuals aggregated for reproductive behaviour; the adult sex ratio was similar to that of the population even though immatures were under-represented in aggregations. During winter the distribution of numbers of H. destructor on subclover, capeweed and grasses in the upper canopy of pasture was similar to the estimated ground cover of these plant species. However, individuals showed host-plant selection for subclover when feeding. During spring, when the pasture plants were flowering, there were more H. destructor in capeweed flowers than in aggregations on subclover foliage. The capeweed flowers were shown to enhance the rate of H. destructor reproduction in a laboratory experiment. Most H. destructor were on or near the soil surface, with 10% at any one time on the upper canopy of the pasture. H. destructor is polyphagous, and behaved in pasture as a selective opportunist feeder.

Although artificial feeding models for the poultry red mite (Dermanyssus gallinae) most frequently use biological membranes consisting of day-old chick skin, there are ethical considerations associated with the use of skin. The few studies reported in the literature that have investigated the use of synthetic membranes to feed D. gallinae in vitro have reported limited success. The current study describes an investigation into the use of synthetic membranes made from either Nescofilm® or rayon and silicone, used either alone or in combination with different feather or skin extracts, as well as the use of capillary tubes. In all, 12 different treatments were used, and the feeding rate of D. gallinae was compared to that of day-old chick skin. Allowing mites to feed on a membrane consisting of Nescofilm with a skin extract resulted in the highest proportion of mites feeding (32.3%), which was not significantly different to the feeding rate of mites on day-old chick skin (38.8%). This study confirms that synthetic membranes can be used to feed D. gallinae artificially. Further optimization of the membrane and mite storage conditions is still necessary, but the study demonstrates a proof of concept.

The larvae of certain flies belonging to the family Syrphidae have long been recognised as plant pests. Merodon equestris, Fab., was recorded in Great Britain as far back as 1869, having probably been imported in narcissus bulbs from Holland (Verrall). This fly is now universally known as the “ Large Narcissus Fly,” the larvae causing serious losses in nearly every locality where the narcissus is grown commercially. More recently flies of the genus Eumerus have been associated with a type of injury very similar to that caused by the larger fly, and the larvae have been recorded on a variety of host-plants in Europe and America. Chief among these hosts may be included narcissus, onion, hyacinth, parsnip, iris, and potato. The flies are commonly referred to as “ Lesser Bulb Flies ” or alternatively in some parts of North America, where they were first recorded as European introductions in 1904, as “ Lunate Onion Flies.”

Egg-batches of Spodoptera littoralis (Boisd.) collected in Crete showed an abnormal sex ratio; 24% yielded predominantly female adults. The field data and data from nine generations of a laboratory strain, which also produced predominantly female offspring, showed that this abnormal condition was transmitted between generations by the females. The mean percentage hatch of egg-batches collected from the field which produced females only was 59·6, and the mean percentage hatch of the eggs of the laboratory strain was 58·8. These results suggest that the production of females only is a result of the mortality of the male embryos. Occasionally, abnormal females from the laboratory strain reverted to producing offspring of both sexes. This recovery from the abnormal condition became more common as successive generations were bred in the laboratory. One female of a normal strain produced all-female offspring and descendants of this female were similarly affected. The females of the unisexual laboratory strain were similar in appearance to normal females but laid significantly smaller egg-batches.

Helicoverpa armigera (Hübner), H. assulta Guenée and Heliothis peltigera (Denis & Schiffermüller) were collected as mixed populations from safflower and the wild host Datura metel, from Patancheru, Andhra Pradesh, India, in 1992 and 1993, and their toxicological responses to insecticides determined. Both Helicoverpa armigera strains were highly resistant to cypermethrin, fenvalerate, endosulfan and quinalphos insecticides, based on resistance ratios relative to laboratory reared susceptible strains. There was no evidence of resistance development in H. assulta and Heliothis peltigera to the same chemicals. Light trap data collected from 1974 to 1987 showed that Helicoverpa armigera was at least 100 × more abundant than the other two species over most of the cropping season. Peak catches of H. assulta and Heliothis peltigera were confined to defined times in the season, corresponding with the flowering and fruiting periods of their respective host plants; August-October for Helicoverpa assulta and November-December for Heliothis peltigera. Helicoverpa armigera on the other hand, because of its high polyphagy on commercial and wild hosts, was abundant between August and April. Resistance has not developed in H. assulta and Heliothis peltigera in southern India, probably because of their restricted host range, limiting exposure to insecticides.

The spectral sensitivity of gravid female Aedes aegypti (L.) was investigated in the laboratory using their responses to oviposition sites illuminated by light of defined intensity and spectral composition. An inverse relationship between the illumination of an oviposition site and its selection for egg-deposition enabled the sensitivity of the mosquitoes to narrow wavelength bands to be assessed. This species showed low sensitivity to long (red) wavelengths; a peak of maximum spectral sensitivity near 550 mμ (yellow-green) with a range of significant sensitivity about this maximum between 450 (violet) and 630 mμ (orange); and positive sensitivity at 366 mμ (ultraviolet) which, from the different order of effectiveness in deterring oviposition, may represent a second, independently functioning, light receptor system. This pattern of sensitivity is sufficient to explain all published observations on the responses of mosquitoes, in physiological conditions other than gravidity, to coloured stimuli. It may, therefore, represent the spectral sensitivity of mosquitoes in general.

The parasitoid complex and apparent parasitism of Choristoneura murinana Hübner were investigated in relation to the relative abundance of budworm larvae at several sites in Europe. A single outbreak population was sampled, while other sites supported varying but much lower host population abundance. Sampling at Sion in Switzerland from 1984–89, indicated that the species richness of the parasitoid complex was correlated with relative host abundance and in general more polyphagous parasitoids were represented in sites with greater budworm abundance. Of the specialized parasitoids, Apanteles murinanae Čapek & Zwölfer (Hymenoptera: Braconidae) was dominant in less abundant host populations and both Cephaloglypta murinanae (Bauer) and Dirophanes maculicornis (Stephens) (Hymenoptera: Ichneumonidae) were supported only at greater budworm abundance. These findings are discussed in relation to the use of Choristoneura murinana parasitoids in the biological control of native Choristoneura spp. pests in other continents.

Anthores leuconotus Pasc., indigenous in East, South-East, South and South-West Africa, is an important ring-barking and wood-boring pest of the main stem and root of arabica coffee. The duration of the life-cycle ranges from 12 to 25 months, with most individuals requiring 16–20 months. Thus beetles developed from eggs laid during the long rains (April–June) of one year will mostly emerge during the short rains (Nov.–Jan.) of the following year, with some appearing during the rains preceding and others during the ensuing rains.

If the mean life-cycle is taken to be 18 months, the approximate duration of each stage is as follows:— eggs require 21–23 days for eclosion; larvae in the first five instars ring-bark the tree for 4 months, and those in the final two instars bore into the wood for 12 months; the pupal period lasts about 4½ weeks, and the beetle remains in the tree for a further two weeks before emerging.

♀. Head shining green; face and front with purplish shine. Thorax orange-yellow, with a small black spot on each side of the pronotum; mesopleurae and propodeon slightly brownish. Abdomen aeneous-black, with dark green shine near the end; first segment (except two brown spots at the sides) and second segment (except hind border) whitish. Valvae of ovipositor white. Antennae brown, with scape and pedicel yellow. Wings dark brown, with the base and a bent stripe in the middle hyaline. Legs brownish yellow, with the trochanters and tip of tibiae and tarsi clearer yellow; base of hind coxae and a stripe on the inner side of middle and hind femora dark brown.

Changes in relative humidity had a very marked influence upon the biological activities of γ BHC, dieldrin and DDT sorbed on Uganda mud blocks. In agreement with field observations, kills of mosquitos increased as the humidity increased and this effect was rapidly reversible.

Disappearance of insecticide particles from the mud surface was inversely related to humidity, the rate increasing as humidity decreased. On the other hand, the rates of diffusion of sorbed insecticide away from the surface were greater at higher humidities.

It is suggested, therefore, that when the biological activity of a mud surface is increased by increasing the humidity, the insects acquire a greater dose of insecticide not because the concentration of insecticide in the surface layers is greater but because the insecticide that is already present acquires a greater mobility. This greater mobility results in a more rapid diffusion in the mud itself away from the treated surface and a greater potential for diffusion into insects resting on the mud surface.

Support for these conclusions was obtained by showing that on transferring dieldrin-treated mud blocks from low to high humidity the change in biological activity occurred at about the same rate as the increase in water content of the blocks.

The influence of humidity upon the sorption of DDT and dieldrin on a selection of soil samples of widely differing origin was observed. Both insecticides disappeared from the surface more rapidly at low than at high humidity on all the soils.