Under field conditions, the cabbage butterfly, Pieris melete, displays a pupal summer diapause in response to relatively low daily temperatures and gradually increasing day-length during spring and a pupal winter diapause in response to the progressively shorter day-length. To determine whether photoperiod is ‘more’ important than temperature in the determination of summer and winter diapause, or vice versa, the effects of naturally changing day-length and temperature on the initiation of summer and winter diapause were systematically investigated under field conditions for five successive years. Field results showed that the incidence of summer diapause significantly declined with the naturally increasing temperature in spring and summer generations. Path coefficient analysis showed that the effect of temperature was much greater than photoperiod in the determination of summer diapause. In autumn, the incidence of diapause was extremely low when larvae developed under gradually shortening day-length and high temperatures. The incidence of winter diapause increased to 60–90% or higher with gradually shortening day-length combined with temperatures between 20.0°C and 22.0°C. Decreasing day-length played a more important role in the determination of winter diapause induction than temperature. The eco-adaptive significance of changing day-length and temperature in the determination of summer and winter diapause was discussed.

The Japanese pine sawyer, Monochamus alternatus Hope (Coleoptera: Cerambycidae), is a major pest of pines and it is also the key vector of the exotic pinewood nematode in China. In the present study, we cloned, expressed, and purified a chemosensory protein (CSP) in M. alternatus. We surveyed its expression in various developmental stages of male and female adult tissues and determined its binding affinities for different pine volatiles using a competitive binding fluorescence assay. A CSP known as CSP5 in M. alternatus was obtained from an antennal cDNA library and expressed in Escherichia coli. Quantitative reverse transcription polymerase chain reaction results indicated that the CSP5 gene was mainly expressed in male and female antennae. Competitive binding assays were performed to test the binding affinity of recombinant CSP5 to 13 odour molecules of pine volatiles. The results showed that CSP5 showed very strong binding abilities to myrcene, (+)-β-pinene, and (−)-isolongifolene, whereas the volatiles 2-methoxy-4-vinylphenol, p-cymene, and (+)-limonene oxide have relatively weak binding affinity at pH 5.0. Three volatiles myrcene, (+)-β-pinene, and (−)-isolongifolene may play crucial roles in CSP5 binding with ligands but this needs further study for confirmation. The sensitivity of insect to host plant volatiles can effectively be used to control and monitor the population through mass trapping as part of integrated pest management programs.

Among Anoplura, the family Echinophthiriidae includes species that infest pinnipeds and otters. Previous evidence obtained from pinnipeds infested by echinophthiriids, specifically from seals, indicates that flippers are the preferred infestation sites, while lice from fur seals select areas in the pelage. We studied habitat selection of Antarctophthirus microchir on South American sea lion pups (Otaria flavescens Shaw, 1800) from Patagonia, Argentina, during the austral summer of 2009. We found a clear pattern of habitat selection: eggs are laid on the dorsal surface; nymphs 1 hatch there and then migrate to the belly, where they develop into adults and copulate; and then ovigerous females return to the dorsal surface. On the one hand, nymphs 1 are characterised by their low locomotory ability; therefore, the fact that they migrate as soon as they hatch suggests a clear pressure leading to microhabitat restriction. On the other hand, the described pattern of microhabitat selection seems to respond to the physiological requirements of each stage, which vary according to the physiological process considered, e.g. oviposition, morphogenesis, hatching and development. Accordingly, it appears that A. microchir would prefer the host's ventral area for development and copulation and the dorsal area for oviposition. However, the causes of this pattern are not clear, and many factors could be involved. Considering that sea lion pups periodically soak at high tides, and that prolonged immersion and very high humidity are known to be lethal for lice eggs, selecting the dorsal area would be advantageous for oviposition because it dries much faster. Furthermore, because humidity should be retained for longer periods on the ventral surface of the pup, wetter conditions on the sea lion would prevent desiccation of the nymphs in the very arid environment where O. flavescens breeds.

The louvre-trap hut was designed to be cheaper and simpler to use than the verandah-trap hut. The eaves are closed, and mosquitoes enter by way of a row of five louvre frames and leave by a window fitted with a window trap. In three trials at Magugu, Tanzania, window traps fitted over one or all louvre frames showed that the efficiency of the louvres in preventing egress was 66–79% for Anopheles gambiae Giles, 51–73% for Mansonia uniformis (Theo.) and 74–78% for Culex pipiens fatigans Wied. Egress through the louvres of A. gambiae is only slightly more, and of M. uniformis much less, than through the eaves of a verandah-trap hut.

Scaphoideus titanus is the invasive vector of the phytoplasma causing the Flavescence dorée in European vineyards. This epidemic is a serious threat to viticulture that has been increasing for more than 60 years in Europe. We studied the effect of synchrony with the plant phenology and the effect of plant-sap quality on the individual fitness. Thus, we conducted laboratory experiments to determine if insect hatchings were synchronized with grapevine bud break. We used two natural populations: one from a cold winter vineyard and one from a mild winter vineyard. In both cases, egg hatching was synchronized with bud break and leaf appearance. The phloem quality of the young and old leaves as a food source was analysed by high-performance liquid chromatography, and the effects on S. titanus growth were evaluated. Phloem composition varied with the grapevine cutting's age but also varied between leaves of different ages from the same plant. The older leaves were less nutritious because they had the highest carbon-to-nitrogen ratio and the lowest content of essential amino acids. Despite diverse phloem qualities, no fitness difference was observed. We found that the synchronization of egg hatchings with bud break is well regulated. However, the nymphs are not affected by the phloem-sap quality, suggesting that S. titanus may accept different food qualities and that egg hatching synchrony could contribute to population expansion in vineyards.

The Bemisia tabaci species complex is one of the most important pests of open field and protected cropping globally. Within this complex, one species (Middle East Asia Minor 1, B. tabaci MEAM1, formerly biotype B) has been especially problematic, invading widely and spreading a large variety of plant pathogens, and developing broad spectrum pesticide resistance. Here, we fit a CLIMEX model to the distribution records of B. tabaci MEAM1, using experimental observations to calibrate its temperature responses. In fitting the model, we consider the effects of irrigation and glasshouses in extending its potential range. The validated niche model estimates its potential distribution as being considerably broader than its present known distribution, especially in the Americas, Africa and Asia. The potential distribution of the fitted model encompasses the known distribution of B. tabaci sensu lato, highlighting the magnitude of the threat posed globally by this invasive pest species complex and the viruses it vectors to open field and protected agriculture.

Cytochrome P450 monooxygenases play a key role in pest resistance to insecticides by detoxification. Four new P450 genes, CYP6AS160, CYP6AS161, CYP4AB73 and CYP4G232 were identified from Solenopsis invicta. CYP6AS160 was highly expressed in the abdomen and its expression could be induced significantly with exposure to fipronil, whereas CYP4AB73 was not highly expressed in the abdomen and its expression could not be significantly induced following exposure to fipronil. Expression levels of CYP6AS160 and CYP4AB73 in workers were significantly higher than that in queens. RNA interference-mediated gene silencing by feeding on double-stranded RNA (dsRNA) found that the levels of this transcript decreased (by maximum to 64.6%) when they fed on CYP6AS160-specific dsRNA. Workers fed dsCYP6AS160 had significantly higher mortality after 24 h of exposure to fipronil compared to controls. Workers fed dsCYP6AS160 had reduced total P450 activity of microsomal preparations toward model substrates p-nitroanisole. However, the knockdown of a non-overexpressed P450 gene, CYP4AB73 did not lead to an increase of mortality or a decrease of total P450 activity. The knockdown effects of CYP6AS160 on worker susceptibility to fipronil, combined with our other findings, indicate that CYP6AS160 is responsible for detoxification of fipronil. Feeding insects dsRNA may be a general strategy to trigger RNA interference and may find applications in entomological research and in the control of insect pests in the field.

Significant differences in nymphal development period and fecundity were observed between five populations of Cicadulina mbila (Naudé) and C. triangula Ruppel from three climatic zones in Nigeria: rain forest (Ibadan), southern part of Sudan savanna (Kadawa, Kano) and the Jos Plateau. The C. triangula population that is used in mass rearing for resistance screening at the International Institute of Tropical Agriculture (IITA), Ibadan, developed much more rapidly than the wild C. triangula population from Ibadan. Similarly, the C. mbila population from the Kadawa Irrigation Scheme, Kano, developed more rapidly than the population from the Jos Plateau. All Cicadulina populations were 3–4 times as prolific on pearl millet as on maize, sorghum or the grass Digitaria exilis. The IITA colony of C. triangula was significantly more fecund than C. mbila. It is clear that Cicadulina species and populations with high reproductive potential would be most suitable for mass rearing for resistance screening to the maize streak virus disease.

The damage caused by the larvae of four Melolonthine and one Ruteline scarab species to four grasses and Trifolium repens grown in pots was examined for interactions between species with and without manure added to the soil. Only slight interactions between scarab species and plant species were detected in the damage to pastures, and these were caused by a differential insect response to Trifolium. Most scarabs damaged Trifolium as much as they damaged the grasses, but Anoplognathus sp. appeared to avoid Trifolium in the absence of manure. Sericesthis geminata Boisd. caused more damage to Trifolium than S. vigilans (Sharp) or Rhopaca magnicornis Blkb.

The addition of manure to soil reduced to negligible proportions the damage to all pasture species except Phalaris tuberos, which suffered significantly greater reduction of foliage than other plants in the presence of manure. The highly significant alleviation of damage by manure occured with all scarab species except S. vigilans, which did not cause damage even in the absence of manure.

In this short-term experiment survival and pupation were not influenced significantly by plant species or manure.

The emission and form of the spermatophores of Eriophyes sheldoni Ewing are described and illustrated. Glued to the substratum by a drop-like pad which varies in shape, they consist of a stalk with a basal stiff section and a distal flexible part ending in a strongly convex lens-like head, in which the sperm mass is kept. The fine structures of the adult integument, characteristic of this species, are described and illustrated.

Sexual behavioural isolation can result from sexual selection and represents a relevant factor associated with the speciation process. We analysed the pheromone emission pattern and the courtship of males of five different populations of the Anastrepha fraterculus cryptic complex: Brazil (Vacaria, Tucumán and Piracicaba), Colombia and Peru. The time of pheromone emission was recorded in each population every 30 min during the day. The behavioural sequences of courting were video recorded and analysed using EthoSeq software. Males from different populations have showed different period of pheromone emission – Vacaria, Piracicaba and Tucumán executed calling only during the morning, Colombia only in the afternoon and Peru during both periods. The general frequencies of the courtship units of the males were distinct among the populations. Three groups were formed in the classification from the function of 14 behavioural routines: Vacaria, Piracicaba and Tucumán formed a single group (Brazil-1), while Colombia and Peru formed two distinct groups. In the probabilistic trees generated, the behavioural units that most contributed to the occurrence of copulation were distinct among the three groups formed: Brazil-1 (Contact, Alignment and Arrowhead-1); Colombia (Flying, Mobile, Contact and Alignment); Peru (Flying, Arrowhead-1 and Calling). Our results indicated differences in sexual behaviour that may explain the behavioural isolation found between the distinct groups in addition with the temporal isolation found between the Brazil-1 and Colombia populations. The evolutionary implications for the A. fraterculus cryptic species complex are discussed.

Drosophila suzukii (Spotted Wing Drosophila) has recently become a serious invasive pest of fruit crops in the USA, Canada, and Europe, leading to substantial economic losses. D. suzukii is a direct pest, ovipositing directly into ripe or ripening fruits; in contrast, other Drosophilids utilize decaying or blemished fruits and are nuisance pests at worst. Immature stages of D. suzukii are difficult to differentiate from other Drosophilids, posing problems for research and for meeting quarantine restrictions designed to prevent the spread of this pest in fruit exports. Here we used a combined phylogenetic and bioinformatic approach to discover genetic markers suitable for a species diagnostic protocol of this agricultural pest. We describe a molecular diagnostic for rapid identification of single D. suzukii larva using multiplex polymerase chain reaction. Our molecular diagnostic was validated using nine different species of Drosophila for specificity and 19 populations of D. suzukii from different geographical regions to ensure utility within species.

Coptotermes acinaciformis (Frogg.) was collected from three different mound colonies and placed in holding jars in a matrix of mound material from an alien colony. After transportation and maintenance in a controlled insectary for 28 days, they were separated from the holding jars and pooled according to colony origin. They were then used in mixed groups of various combinations in a bioassay test of their feeding capacity and survival. Termites from a fourth colony were used to determine whether pooling of individuals originating from the same colony but maintained in different holding jars had any effect on their feeding and survival in the laboratory. It was shown that, although termites from the same original colony can be re-united without detriment after transportation and maintenance, those from different colonies cannot be mixed to form reproducible bioassay groups. Although chilling before mixing produced a slight improvement, the resulting groups were still unsuitable for use in bioassays. It is noteworthy that when brought together after maintenance in the holding jars under identical conditions in an identical matrix, the termites were able to recognise and accept fellows from their own colony and to detect and reject those from other sources.

Laboratory cultures of Cicadulina mbila (Naudé), C. storeyi China and C. parazeae Ghauri derived from field wheat at Salisbury, Rhodesia, during August 1967 were maintained on caged pots of dwarf wheat seedlings. At constant temperatures of 23, 25 and 30°C developmental periods for eggs and adults were similar for all three species. Cultures of C. mbila were reared at a wider range of temperatures (15–30°C) and developmental rates for eggs, and male and female adults were shown to be well expressed by logistic equations. Mean durations are given for the five nymphal stages reared at 26°C. In C. mbila males and females had a similar life span, fecundity was greatest at 28°C, and there was a predominance of males reared from eggs laid by females less than 15 days old.

The persistence of DDT deposits, derived from dilutions of an emulsion concentrate, Arkotine D.25, on the leaves of riverine vegetation in the Northern Guinea Savannah vegetation zone of Nigeria was studied in the laboratory by a bioassay method using teneral females of Glossina palpalis (R.-D.) as test insects. Irrespective of whether sprayed in the dry or wet season, deposits derived from sprays containing 5.0 per cent. DDT produced by the Warley knapsack sprayer were still reasonably toxic one year after spraying. Deposits derived from sprays having a concentration of DDT varying from 1·25 to 5·0 per cent. DDT were equally toxic when young, but those from the lower concentrations were weathered much more rapidly than those from the 5·0 per cent, sprays. Young deposits produced by Warley and Motoblo sprayers were equally toxic, but deposits from the Motoblo deteriorated more rapidly than those of the Warley.

The toxicity of the DDT deposits on leaves varied regularly with the seasons. The various climatic factors that it is thought influenced the variations in toxicity are discussed. Accumulations of wind-blown dust on the leaves during the late dry season and low evaporation rates at the height of the rains appear to be responsible for reduced toxicity at those times; in the early wet season, the occasional violent storm probably washes off the leaves the dust accumulated during the dry season and makes the insecticidal deposits once more available. Heavy rainfall is important in removing the insecticidal deposits from the vegetation, and leaf decay and refoliation are important in reducing the availability of the deposits. The implications of these variations in toxicity and factors that reduce the availability of the deposits are discussed in relation to the eradication of riverine tsetse.

Great differences in the rates of foliage decay and refoliation occur between different riverine plants, and it is suggested that a thorough study of this feature in riverine plants and of resting sites favoured by tsetse flies might reveal information that would enable tsetse to be eradicated by selective spraying of certain plant species only.

A short account of the life-cycle and symptoms of damage of the cotton Jassid, Empoasca lybica, de Berg., is given. In the initial cage experiments it is shown that DDT emulsion was superior to the copper compounds used. Experiments on the residual toxicity of DDT and “Gammexane” sprays are described. Tests with DDT emulsion showed that very young cotton is injured by emulsion containing as little as 0·025 per cent. DDT, but that emulsions containing up to 0·5 per cent. DDT can be used with safety on plants which are two months old. A coarse DDT suspension caused severe leaf distortion, but a fine suspension used later was quite safe at the concentration used.

D-glucoascorbic acid in 0·05–0·30% aqueous solution fed to adult males of Spodoptera littoralis (Boisd.) caused the production of deformed spermatophores. During mating the spermatophore corpus did not become inflated and permanent copulations were often observed. The inadequate moulding of the spermatophore was caused exclusively by oral uptake of D-glucoascorbic acid in male moths. This ascorbic acid analogue did not affect adult longevity, number of spermatophores or egg fecundity. Moths feeding on an aqueous diet of 0·3 % of this chemical were completely sterile. Bait-stations containing this material might possibly be used to induce sterility in the natural insect population.

Schizonycha larvae, of a species that cannot yet be named with certainty, are a serious pest of “lubia” (Dolichos lablab) and “dura” (Sorghum vulgare) in the Sudan Gezira. Damage from these grubs has seriously reduced lubia yields at the Gezira Research Farm during the 1946–52 seasons. Soil application of BHC, at rates between 10 and 40 gm. γ isomer per feddan (1·038 acre) give excellent control of this pest on lubia. Application with the seed at the time of sowing (in effect, by drilling) is, in general, more effective than broadcasting or applying the insecticide along the ridges. Seed dressings appear to be ineffective for control, with lubia.

Population estimates show that γ BHC does not kill Schizonycha larvae but repels them or prevents feeding. The larvae occur in the soil to a maximum depth of 60 cm., and are concentrated around the plant roots. The mean depth varies with time of year, and probably with type of plant, between 15 and 30 cm. The mean depth of the pupa is 15 cm.; this does not appear to be influenced by BHC.

Larvae are widely distributed in the Gezira but are most abundant in the South and Centre Groups of the Scheme. There is evidence that, where chafer larvae and termites are associated with groundnuts, the chafer larvae are responsible for initiating damage while the termites are secondary invaders. The beneficial effect of a good lubia crop (resulting from BHC application) is reflected in the cotton crop two years later.

The leucaena psyllid, Heteropsylla cubana Crawford, can devastate plantings of Leucaena leucocephala (Leguminosae), an economically important tree species in the Pacific Islands, Southeast Asia, Australia, India, Africa, and elsewhere. The predatory beetle, Curinus coeruleus Mulsant (Coleoptera: Coccinellidae), has been introduced into many of these areas from Hawaii for biological control of the psyllid. In this study, collections of C. coeruleus were made from 11 populations on four islands in the Hawaiian archipelago to determine population structure and estimate levels of gene flow. Over all populations, a measure of population subdivision, θ was 0.095, and the estimate of Nem, the average migration rate, was 2.4. θ values for the individual islands were 0.02, 0.12, 0.24 and 0.05 for Kauai, Hawaii, Maui, and Oahu, respectively. Estimated levels of gene flow between populations were not correlated with geographic distance, therefore isolation by distance does not appear to be an important process structuring C. coeruleus populations. Gene flow estimates can be used to characterize dispersal capabilities in insects or other organisms released for biological control. In this case, the inferior dispersal ability of C. coeruleus likely limits its rapid widespread establishment during release programmes.

A successful colony of Glossina morsitans orientalis Vanderplank was initiated at Langford in early 1967 with 94 females imported as pupae from Rhodesia. In September 1969, further pupae were received from Rhodesia. Experiments were undertaken in which the four possible combinations of crosses were made between males and females from the Langford colony and from the 1969 importation from Rhodesia. Females of Langford origin performed equally well irrespective of the origin of their mates and it is concluded that there is no evidence that the Langford colony of G. morsitans is either performing abnormally well, because of adaptation to the laboratory, or abnormally badly, because of adverse effects of inbreeding. The poorer performance of females of Rhodesian origin was manifested in poorer survival rather than a lower fecundity; it is attributed to adverse effects on these flies caused by handling of the pupae in the field and/or the stress of the journey from Rhodesia to Langford. It would seem that to avoid any risk of inbreeding in laboratory colonies, wild males only should be introduced periodically.