In pest management programmes that incorporate the sterile insect technique (SIT), the ability of mass-reared insects to tolerate dry conditions may influence their survival after release in the field. In the present study, desiccation resistance of adult mass-reared Queensland fruit flies, Bactrocera tryoni (Frogatt) (Diptera: Tephritidae), that are routinely released in SIT programmes was compared with that of wild flies at 1, 10 and 20 days after adult eclosion. Under dry conditions without access to food or water, longevity of mass-reared B. tryoni was significantly less than that of their wild counterparts. Desiccation resistance of mass-reared flies declined monotonically with age, but this was not the case for wild flies. The sharp decline in desiccation resistance of mass-reared flies as they aged was likely explained by decreased dehydration tolerance. As in an earlier study, desiccation resistance of females was significantly lower than that of males but this was particularly pronounced in mass-reared females. Female susceptibility to dry conditions corresponded with declining dehydration tolerance with age and associated patterns of reproductive development, which suggests that water content of their oocyte load is not available for survival during periods of water stress.

Field studies on the response of Anopheles gambiae s.l. Giles and Anopheles funestus Giles to tents baited with human odour or carbon dioxide were conducted in south-east Tanzania. Two exit traps and a CDC miniature light trap set beside a bed net were used to sample mosquitoes that entered the tent. Human odour, pumped from an underground pit into a bed net attracted a similar number of mosquitoes as a bed net occupied by a human male. Significantly fewer mosquitoes were caught in a tent into which carbon dioxide (300 ml min-1) was pumped than in a human-odour baited tent (9 and 27% for A. gambiae s.l. and A. funestus respectively). A five-fold increase of the carbon dioxide concentration (to 1500 ml min-1) did not increase the catches of A. gambiae s.l. whereas those of A. funestus were increased to 69% of the catches by human odour. Species identifications of A. gambiae s.l. catches showed that A. arabiensis Patton prevailed and that the proportions of A. arabiensis/A. gambiae s.s. did not differ between treatments. It is concluded that in the indoor situation described, human odour other than carbon dioxide is the principal cue to which these malaria vectors are attracted and that the physical presence of a host and carbon dioxide, when used as a kairomone on its own, accounts for only a minor part of the overall attractiveness of man, particularly for A. gambiae s.l.

A stimulus is necessary for the hatching of eggs of Aëdes mosquitos, but, while many different kinds of change in the external environment may be adequate as hatching-stimuli, there is variation in the response of the eggs to any given one of them.

Not only is there variation between species as regards behaviour of the eggs, but batches of eggs laid by different females in a single species may vary one from another and there is even variation of behaviour between the eggs laid in a single batch.

The response of the eggs of A. aegypti (L.) has been studied here and evidence produced that both parents contribute to their hatching-behaviour. Egg behaviour has also been studied in two populations of this species, one originating from West Africa and the other from East Africa. In the former, only a very low proportion of the mature eggs (0–9%) responded to the daily application of a suitable stimulus over a short period, whereas in the latter the proportion of responders in the same period with the same stimulus was very much higher (46–100%). The next generation reared from each of these gave very similar results (0–11 and 65–100%, respectively), while reciprocal crosses between them gave a wide range of scatter (16–100 and 4–99%, respectively).

Soil-dwelling tenebrionid larvae have developed in three evolutionary lines and are pests in all faunal regions. Description of and keys to most of the important species are available. However, revisional studies, on both adult and larval characters, are needed in many groups. The basic number of non-sex chromosomes appears to be 18, but the number and type of sex chromosomes are variable. Host ranges of both larvae and adults are usually extensive but usually only include plants. Development rates are related mainly to temperature, with life-cycles of one, two or three years. Larval development periods are rather long, and adults are long-lived. The number of instars is high, often above ten and frequently variable within a species. Sampling is best carried out by direct counts and pitfall trapping. In the species studied, mating follows a regular pattern and pheromones are involved. Species show definite temperature, moisture and soil-type preferences and these influence both spatial and temporal distribution. Recorded parasitoids include Diptera (mainly tachinids), Hymenoptera, mites, bacteria and fungi. Birds, carabids and a variety of other vertebrates are the main predators, but abdominal secretions and postural mechanisms provide some defence. Cultural control was formerly widely practised but has given way to chemical control.

Brown Planthopper (BPH, Nilaparvata lugens (Stål)) is one of the most serious pests of rice in both temperate and tropical regions of East and South Asia and has become especially problematic over the past few years. In order to analyze the effect of the change of rice cropping system on the population dynamics of BPH, field surveys of the occurrence and distribution of BPH were performed and other relevant data, including light trap data and ovary dissection data were collected in nearly 40 Chinese counties encompassing six provinces (or municipalities), including Hainan, Guangxi, Anhui, Shanghai, Fujian and Guangdong from April to October in 2007.

The mixed planting areas of single- and double-cropping rice in China include Hubei, South and Central Anhui, North Hunan, and North Jiangxi. In these areas, double-cropping rice has now been greatly reduced and single-cropping rice has been rapidly increasing since 1997. The surveys revealed that when the immigration peak of BPH occurred in June and July, the single-cropping rice was at the tillering to booting stage and fit for BPH, but early rice had already matured and most of late rice had not yet been transplanted. BPH immigrants from southern rice areas prefer to inhabit and breed in single-cropping rice paddies. Moreover, farming activities between early rice and late rice interrupted the continuous growth of BPH populations in double-cropping rice paddies. As a result, in comparison with data collected 30 years ago, the spatiotemporal dynamics and migration patterns of BPH have dramatically changed in the lower-middle reaches of the Yangtze River. In the mixed planting areas, due to their high suitability, the BPH population in single-cropping rice grew so quickly that it caused serious local damage and there was mass emigration of macropterous progeny to the Yangtze River Delta in late August and early September.

Global warming may also affect BPH populations, where results suggest steadily warmer autumns have occurred from the 1990s on, with such conditions gradually the norm. The combination of ‘cooler summer’ and ‘warmer autumn’ are conditions known to promote outbreaks of BPH in the lower-middle reaches of the Yangtze River. Immigrant BPH arrivals in late August and September now cause serious damage to late-maturing mid-season rice and late rice in the lower-middle reaches of the Yangtze River.

The north-western European species of the glomeratus-group of Apanteles are revised. Sixty-four species are dealt with, of which twentythree are described as new. Two species, A. pieridis (Bouché) and A. pilicornis Thomson, are lifted from synonymy. Host records are based mainly on reared specimens examined by the author.

1. The responses of adult mosquitos, consisting of several Canadian species of Aëdes, were investigated under field conditions by employing heated and clothed robots.

2. Moisture increased the attractiveness of a warm body two to four times when the air temperature exceeded 60°F. ; at cooler temperatures, surface moisture decreased the attractiveness.

3. Warmth increased the attractiveness of a body, so that a robot at 98°F. attracted three times as many mosquitos as one at 50–65°F.

4. It may therefore be concluded that moisture is the major attractant factor when the air temperature exceeds 60°F., and warmth when the temperature is less than 60°F.

5. Carbon dioxide vapour emitted from an artificial head almost doubles the attractiveness of a warm body.

6. The vapours of ether and gasoline were significantly attractive. A sweat-soaked jerkin was more attractive than a water-soaked one.

7. Light colours were less attractive than dark ones, and luminescent dyes decreased the attractiveness of cloths. Green is less attractive than red or blue.

8. Glossy satins were less attractive than matt broadcloths. Greenish-khaki nylon cloth was much less attractive than khaki drill or cotton.

9. There was no evidence of interspecific differences in the responses of the mosquitos investigated.

Rastrococcus invadens Williams was first noticed in Togo in 1981 and has since become a serious pest on many plants, especially mango and citrus. In June 1986, a programme for its biological control was begun, resulting in the introduction into Togo in October 1987 of an encyrtid parasitoid, Gyranusoidea tebygi Noyes. The parasitoid was reared under a simple system and releases were made from November 1987. The parasitoid established readily under a range of ecological conditions and produced significant control within the first year up to 100 km from each release point.

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.

Triatomines are vectors that transmit the protozoan haemoflagellate Trypanosoma cruzi, the causative agent of Chagas disease. The aim of the current review is to provide a synthesis of the immune mechanisms of triatomines against bacteria, viruses, fungi and parasites to provide clues for areas of further research including biological control. Regarding bacteria, the triatomine immune response includes antimicrobial peptides (AMPs) such as defensins, lysozymes, attacins and cecropins, whose sites of synthesis are principally the fat body and haemocytes. These peptides are used against pathogenic bacteria (especially during ecdysis and feeding), and also attack symbiotic bacteria. In relation to viruses, Triatoma virus is the only one known to attack and kill triatomines. Although the immune response to this virus is unknown, we hypothesize that haemocytes, phenoloxidase (PO) and nitric oxide (NO) could be activated. Different fungal species have been described in a few triatomines and some immune components against these pathogens are PO and proPO. In relation to parasites, triatomines respond with AMPs, including PO, NO and lectin. In the case of T. cruzi this may be effective, but Trypanosoma rangeli seems to evade and suppress PO response. Although it is clear that three parasite-killing processes are used by triatomines – phagocytosis, nodule formation and encapsulation – the precise immune mechanisms of triatomines against invading agents, including trypanosomes, are as yet unknown. The signalling processes used in triatomine immune response are IMD, Toll and Jak-STAT. Based on the information compiled, we propose some lines of research that include strategic approaches of biological control.

A quick and developmental-stage non-limiting method of the identification of vectors of tospoviruses, such as Thrips tabaci and T. palmi, is important in the study of vector transmission, insecticide resistance, biological control, etc. Morphological identification of these thrips vectors is often a stumbling block in the absence of a specialist and limited by polymorphism, sex, stage of development, etc. Molecular identification, on the other hand, is not hampered by the above factors and can easily be followed by a non-specialist with a little training. The mitochondrial cytochrome oxidase I (mtCOI) exhibits reliable inter-species variations as compared to the other markers. In this communication, we present the differences in the mtCOI partial sequence of morphologically identified specimens of T. tabaci and T. palmi collected from onion and watermelon, respectively. Species-specific markers, identified in this study, could successfully determine T. tabaci and T. palmi, which corroborated the morphological identification. Phylogenetic analyses showed that both T. tabaci and T. palmi formed different clades as compared to the other NCBI accessions. The implication of these variations in vector efficiency has to be investigated further. The result of this investigation is useful in the quick identification of T. tabaci and T. palmi, a critical factor in understanding the epidemiology of the tospoviruses, their management and also in quarantine.

The reasons for adopting the name “ leaf-curl ” for the virus disease which is manifested by symptoms of “ leaf-crinkle ” on certain varieties of cotton, and by “ mosaic ” on certain others, are discussed.

A brief review is given of the very few references in previous literature which are relevant to leaf-curl.

Up to the end of February 1931, 168 straightforward attempts had been made to transmit crinkle from Sakel cotton to Sakel by means of white-flies (Bemisia gossypiperda, Misra & Lamba), of which no fewer than 157 were successful. No transmission was obtained with any other insects.

A single white-fly can transmit the disease to a healthy plant, though infection is less regularly obtained when one or only a few white-flies are used.

There is a large amount of negative evidence which indicates that the virus is not transmitted through the seed of Sakel cotton. There is also no evidence that it can be transmitted through the soil.

In nearly 200 controlled experiments, the incubation period of the virus in the plant varied from 8 to 34 days, but over two-thirds of the recorded periods were between 11 and 19 days. Possible causes of the variation in the incubation period are discussed.

Little is known with certainty about the factors which influence the severity of the disease.

At least one case of complete recovery from the disease appears to have been observed. Partial recovery is not infrequent.

The ability to resist or avoid natural enemy attack is a critically important insect life history trait, yet little is understood of how these traits may be affected by temperature. This study investigated how different genotypes of the pea aphid Acyrthosiphon pisum Harris, a pest of leguminous crops, varied in resistance to three different natural enemies (a fungal pathogen, two species of parasitoid wasp and a coccinellid beetle), and whether expression of resistance was influenced by temperature. Substantial clonal variation in resistance to the three natural enemies was found. Temperature influenced the number of aphids succumbing to the fungal pathogen Erynia neoaphidis Remaudière & Hennebert, with resistance increasing at higher temperatures (18 vs. 28°C). A temperature difference of 5°C (18 vs. 23°C) did not affect the ability of A. pisum to resist attack by the parasitoids Aphidius ervi Haliday and A. eadyi Starý, González & Hall. Escape behaviour from foraging coccinellid beetles (Hippodamia convergens Guerin-Meneville) was not directly influenced by aphid clone or temperature (16 vs. 21°C). However, there were significant interactions between clone and temperature (while most clones did not respond to temperature, one was less likely to escape at 16°C), and between aphid clone and ladybird presence (some clones showed greater changes in escape behaviour in response to the presence of foraging coccinellids than others). Therefore, while larger temperature differences may alter interactions between Acyrthosiphon pisum and an entomopathogen, there is little evidence to suggest that smaller changes in temperature will alter pea aphid–natural enemy interactions.

Molecular detection systems used to analyse the gut contents of invertebrate predators have enhanced our understanding of trophic interactions, but do not distinguish between the methods of consumption. Many predators regularly scavenge, which could have profound implications for quantitative analyses of the dynamics of predation. We report the first quantified assessment of the potential error caused by scavenging in post-mortem measurements of predation in a slug = carabid system. An anti-slug monoclonal antibody was able to detect antigens from decayed slugs after surprisingly long periods, significantly longer on relatively sterile peat than on natural soil. On soil the half-life of antibody-detectable slug proteins was 8.2 days while on peat it was 11.5 days. When slugs that had decayed on soil for 100 h were fed to the carabid predator Pterostichus melanarius, slug proteins could still be identified after 6 h (but not 12 h) digestion. Fresh and decayed slug was eaten in equal quantities by the beetles suggesting no aversion to the latter. The results suggest that significant errors may be caused by scavenging leading to inaccurate interpretation of predation rates in the field.

1. In Canada, European holly (Ilex aquifolium) can only be grown successfully in the mild, humid climate of western British Columbia. The sales of cut holly for decorative purposes amount to several hundred thousand dollars annually, and the tree is also in good demand for ornamental planting in public parks and private estates.

2. The most serious pest of holly in this part of the world is the Agromyzid fly, Phytomyza ilicis, or the Holly Leaf-miner, which was accidentally introduced from Europe without its attendant natural enemies. The larvae of this insect produce large unsightly blotches on the leaves which greatly lower the value of the cut foliage. As a rule 75 to 80 per cent. of the leaves are attacked in this manner.

3. Since chemical forms of restraint offered little hope of success, it was decided that the biological method of control should be given a trial. Accordingly, the writer undertook a general survey of the fly and its parasites in England, the results of which are described in the preceding pages. An account of the biological control of P. ilicis will be published in a separate paper at a later date.

4. A general account of the systematics, synonymy, distribution, host relationship, and biology of the holly fly itself precedes the parasite section.

The parasites and predators found attacking the Aphids, Myzus persicae, Macrosiphum solanifolii and Aulacorthum solani, during field survey work of potato Aphids in the Northern Agricultural Advisory Province during 1944 and 1945, are treated individually, receiving the proportionate attention which their occurrence merits.

Aphidius avenae was the most important primary parasite, and in potato seed growing areas, the only one; while Asaphes vulgaris in particular, augmented by Lygocerus testaceimanus composed the majority of hyperparasites. The effect and relative importance of both types of parasite upon the Aphid populations of the survey are discussed with their percentage figures.

Predacious Syrphids included Platychirus manicatus and P. immarginatus whose life-histories were previously unknown; feeding records are also given for these two, and the former species accompanied invariably by P. scufatus occurred regularly on potatoes. More unusually, but often more effectively, Syrphus balteatus appeared. Other species were found.

Catches of Culicoides spp. in a Surrey copse in 1967–69 showed the univoltine C. impunctatus Goetgh. to be dominant. This species reached peak numbers from late May to early June, when nulliparous females were commonly seen at rest on tree trunks. Proterandry was marked in catches from light-traps but not apparent in those from emergence traps or taken at rest. Biting was most frequent 1–2 h before sunset; many bites did not result in a blood-meal. Females taken at rest and from emergence traps could complete their ovarian cycle without a blood-meal, most eggs being matured by the former; midges taken biting matured the fewest eggs but could not do so without a blood-meal. Large full fat-bodies were an indication of nulliparity. It was concluded that C. impunctatus can develop the first egg-batch autogenously, and that the resting habits and responses of females to light and human bait change subsequent to the laying of the first batch of eggs.

Cotesia flavipes Cameron has been released several times in Africa for biological control of gramineous stem borers. Establishment has been reported on the Indian Ocean islands of Mauritius, Réunion and Madagascar, however, several attempts to introduce C. flavipes into continental Africa are reported to have failed. Recently, several cocoon masses of C. flavipes were recovered from south-western Kenya where the parasitoid was never released. Identifications of the parasitoids from south-western Kenya were based on morphological characters, allozyme frequencies, and mating experiments with laboratory populations of C. flavipes. It is hypothesized that C. flavipes became established from individuals escaping from a laboratory colony maintained in south-western Kenya in 1991.

Known components of the female sex pheromone of Spodoptera littoralis (Boisd.), tetradecyl acetate (I), (Z)-9-tetradecenyl acetate (IIA), (Z,E)-9, 11-tetradecadienyl acetate (III) and (Z,E)-9, 12-tetradecadienyl acetate (IV), and related compounds dispensed from polyethylene vials were used to bait water traps and funnel traps in lucerne fields in Crete. In comparison with the catches of males in traps baited with the primary component (III) alone, catches were increased by the addition of 1–100% of I in relation to the amounts of III, decreased by the addition of 5% or more of IIA and decreased by the addition of more than 5% of IV. The diene III was more attractive than any of the other three geometric isomers, although combining the Z,Z isomer (V) or the E,E isomer (VI) with III increased catches while the addition of the E,Z isomer (VII) decreased catches. The alcohols VIII and IX corresponding to the acetates III and IIA were not attractive but caused a marked reduction in trap catch when combined with III. The homologue of III (Z,E)-11-methyl–9, 11-tetradecadienyl acetate (X), was unattractive to males but increased trap catches when combined with III. 9-Tetradecynyl acetate (XI) exhibited neither attractant nor inhibitory activity, and similar results were obtained with ethyl cyclohexane carboxylate (XII) and 2-nonynal dimethyl acetal (XIII), compounds which have similar far-infrared spectra to that of diene III. The distributions of males landing on sticky board traps 70 cm in diameter baited with III or mixtures of III with I, IIA or IV showed that a greater percentage of the moths landed at the periphery of the traps baited with certain combinations of III with I and IV than on traps baited with III alone. Collection and analysis of the volatiles emitted by virgin females of different origins indicated that those from Crete produced I and III only, those from Israel produced I, III and IV, while those from Egypt produced I, III, IV and IIA and/or (E)-11-tetradecenyl acetate (IIB). The results are discussed in relation to previous work on S. littoralis and current theories on insect communication, and also in terms of their relevance to the practical field usage of pheromones in control of this pest.

In Lucilia cuprina (Wied.), cuticular bands are deposited most clearly on the mesothoracic post-phragmata, and up to ten such layers can be counted. The bands are deposited clearly only in response to fluctuating temperatures where the minimum temperature in a cycle falls below about 15·5°C. Growth bands are deposited whenever such a change in ambient temperature occurs and the deposition appears to show no inherent rhythmicity. The maximum width of the phragmata is more or less constant and the number of bands which can be distinguished depends upon how quickly the maximum width of the phragmata is reached. The rate of growth of the growth bands and their consequent width depends upon the maximum temperature experienced and the length of time the insect is maintained at that temperature in any cycle. Trials showed that the count of growth bands was an acceptable estimate of the actual age in days when temperatures rose 3·5°C or more above the threshold value of 15·5°C. With a greater temperature range, greater accuracy was achieved. The availability of protein food was shown to have little effect on the deposition of growth bands. A mean age in days was calculated for samples of field-caught flies of a uniformly young ovarian ‘age’ using the counts of growth bands and by working back in the temperature records from their sites of capture using the day-degrees method. Significant differences between the two estimates of age were taken to indicate the occurrence of developmental delays. These were attributable to shortages of protein food in the field and were associated with periods of drought. The method allows the demonstration that developmental delays have occurred but does not provide an accurate estimate of the duration of these delays. It does not permit the confident identification of delays imposed by shortages of oviposition sites.