Temperature is arguably the most important abiotic factor influencing the life history of ectotherms. It limits survival and affects all physiological and metabolic processes, including energy and nutrient procurement and processing, development and growth rates, locomotion ability and ultimately reproductive success. However, the influence of temperature on the energetic cost of development has not been thoroughly investigated. We show that in the diamondback moth [Plutella xylostella L. (Lepidoptera: Plutellidae)] rearing temperature (range10–30°C) affected growth and development rates, the energetic cost of development and fecundity. Rearing at lower temperatures increased development times and slowed growth rate, but resulted in larger adult mass. Fecundity was lowest at 10°C, highest at 15°C and intermediate at temperatures of 20°C and above. At a given rearing temperature fecundity was correlated with pupal mass and most eggs were laid on the first day of oviposition, there was no correlation between total eggs laid and adult longevity. The highest production cost was incurred at 10°C; this decreased with increasing temperature, was minimized in the range 20–25°C, and then increased again at 30°C. These minimized production costs occurred at temperatures close to the intrinsic optimum temperature for this species and may reflect the rearing temperature for optimal fitness. Thus at sub-optimal temperatures greater food resources are required during the development period. Predicted increased temperatures at the margins of the current core distribution of P. xylostella could ameliorate current seasonal effects on fecundity, thereby increasing the probability of winter survival leading to more resilient range expansion and an increased probability of pest outbreaks.

The distribution of phlebotomine sand flies is widely reported to be changing in Europe. This can be attributed to either the discovery of sand flies in areas where they were previously overlooked (generally following an outbreak of leishmaniasis or other sand fly-related disease) or to true expansion of their range as a result of climatic or environmental changes. Routine surveillance for phlebotomines in Europe is localized, and often one of the challenges for entomologists working in non-leishmaniasis endemic countries is the lack of knowledge on how to conduct, plan and execute sampling for phlebotomines, or how to adapt on-going sampling strategies for other haematophagous diptera. This review brings together published and unpublished expert knowledge on sampling strategies for European phlebotomines of public health concern in order to provide practical advice on: how to conduct surveys; the collection and interpretation of field data; suitable techniques for the preservation of specimens obtained by different sampling methods; molecular techniques used for species identification; and the pathogens associated with sand flies and their detection methods.

The life-cycle of five stocks of Cadra cautella (Wlk.) (Phycitidae) and the duration of the various developmental stages were studied at temperatures from 15 to 37·5°C. and relative humidities between 0 and 100 per cent, on a mixture of wheatfeed, wheat germ and yeast. At 70 per cent. R.H., the limiting temperatures for the completion of the life-cycle were about 15°C. and about 36°C. At 30°C., the limiting humidities were about 20 and above 90 per cent. R.H. Development was quickest at 30–32°C. and 70–80 per cent. R.H., taking 29–30 days from the laying of the egg to the formation of the adult moth. This period increased with lower temperature and humidity, reaching 145·0 days at 15·5°C. (70 per cent. R.H.) and 51 days at 20 per cent. R.H. (30°C.).

Near the optimal conditions for rapid development, the egg occupied about 10 per cent, of the developmental cycle, the larva about 70 per cent, and the pupa 20.

Temperature influenced the duration of all developmental stages, but humidity had a marked effect only on the larva. The pupation of some mature larvae was delayed: whether or not this delay is a diapause is discussed. Virgin adults lived 4·8 days at 35°C. to 18·9 days at 17·5°C. (70 per cent. R.H.). At 30°C., low humidity halved the length of adult life.

The mortality, even in favourable conditions, was often rather high, principally among eggs and young larvae.

There was poor survival of small numbers of larvae kept on maize and on cocoa beans, but survival on wheat was similar to that on the usual food mixture. The developmental period on wheatfeed alone was shortened by the addition of honey or glycerine or a combination of wheat germ and yeast.

The incidence of disease is discussed.

Nocturnally active mosquitoes are attracted visually to large (1·5 × 2·4 m) unpainted plywood suction traps. Such traps, which discharge air horizontally in one direction only, were placed in an open field in Florida in various patterns to study the flight behaviour of mosquitoes. When four traps were placed 15 m apart in a column, the two end traps captured 83 or 53% more mosquitoes than the two inner traps, depending upon whether the air discharged from the traps was perpendicular to, or in line with, the trap column. When the traps were spaced 30 m apart, the end traps captured only 13% more than the inner traps, indicating that at this distance visual competition between traps was small. When 16 suction traps were spaced 15 m apart in a grid of four columns of four traps each, the traps at the four corners of the grid captured about 2·1 times, and traps between the corner traps along the edge of the grid 1·5 times, as many mosquitoes of most species as traps within the grid. Subsequently, four additional traps were placed 15 m beyond the corner traps, and these traps captured 3·3 times as many mosquitoes as traps inside the grid. Traps within the grid had four adjacent traps while traps at the edge, corner, and beyond the corner had three, two and one adjacent traps, respectively. The numbers captured by a trap at a particular location in the grid were inversely related to the number of adjacent traps, viz., suction-trap catches were decreased by about 33% as the number of adjacent traps were increased and thus each trap acted as a competing visual attractant on nearby traps. It was estimated that an isolated suction trap would capture approximately five times as many mosquitoes as a trap inside the grid. Assuming these differences between trap collections were caused by the distance at which mosquitoes respond to the traps and thus would be proportional to the visually unobstructed area about each trap, it was calculated that most adults responded visually to the traps from distances of approximately 15·5 to 19 m. Aedes vexans (Mg.) and Psorophora columbiae (D. & K.) were most responsive, followed by Culex nigripalpus Theo. and Culiseta melanura (Coq.) and then by Anopheles crucians Wied., P. ciliata (F.) and Uranotaenia lowii Theo. Only U. sapphirina (O.S.) and Culex quinquefasciatus Say appeared to possess visual ranges of 7.5 m or less. Visually conspicuous objects can serve as long-distance attractants. Low air velocities caused appreciable reductions in trap collections. At a distance of 15 m, the velocity of air discharged from the traps was only 0·6 m/s, but catches from a trap downstream of an adjacent trap were reduced by 17%. Catches from rows of traps downstream from one, two or three rows of traps were reduced by 15, 36, and 51%, respectively. Estimates of mosquito population densities in a natural environment will be affected by the differing visual attractiveness of objects of irregular distribution and sizes and their effect upon wind velocities.

Life table studies of Mussidia nigrivenella Ragonot, a pest of maize in Benin, showed that host plant species had a significant effect on larval survival and developmental time. The maximum percentage of larvae surviving was recorded on jackbean, Canavalia ensiformis (36%) and lowest on maize (18%). Mean developmental time for larvae was longest on maize (19.8 days) and shortest on jackbean (17.2 days). The number of eggs laid was highest for females from larvae fed on jackbean (x– = 176), followed by velvetbean, Mucuna pruriens(x– = 143), and lowest for females where larvae had fed on maize (x–= 127). Longevity of ovipositing females was higher on jackbean (5.4 days) than of those from any other host plants. According to the growth index and life table statistics, jackbean was the most suitable host plant, followed by velvetbean, and maize, the least suitable. Thus, jackbeans should be recommended for use in mass rearing programmes of M.nigrivenella, e.g. as a host for parasitoids in future biological control programmes. Because of the high suitability of jack- and velvetbeans for M.nigrivenella, planting of these increasingly important cover crops should be timed in such a manner that the emergence of female moths from mature pods does not coincide with maize plants in a suitable developmental stage for oviposition and development of young M. nigrivenella larvae.

The present world distribution of six species of Cryptolestes found in stored produce is delineated from the evidence of specimens collected from a small number of countries and from specimens collected from produce examined in ships at British ports.

It is concluded that C. ferrugineus (Steph.) is worldwide, being found in temperate and tropical areas and in humid and dry zones. The range of C. minutus (Ol.) is limited by low temperature and low humidity but it is more abundant than C. ferrugineus in the wet tropics. C. pusilloides (Steel & Howe) is at present confined to the southern hemisphere but may be spreading slowly. It seems unlikely that this species entered stored products handled by the shipping trade much before 1944. C. turcicus (Grouv.) has been identified from Europe, North and tropical Africa, Turkey, North America, Uruguay and Argentina, and C. spartii (Curt.) only from Europe, North Africa and Turkey. C. ugandae Steel & Howe is rare, being found only from Uganda, Nigeria and Ghana.

A method for screening resistance of cowpea (Vigna unguiculata) to the legume pod-borer Maruca testulalis (Geyer) was developed. Several damage parameters were measured, including damage to stem, flowers, pods and seeds. Some of these parameters were assessed in more than one way. A decision was made at the end of the study as to which parameters were most appropriate for a field screening methodology. A plant resistance index, Ipr, was generated to aid in this decision. Based on this, it was concluded that flower, pod, and seed damage measurements provided the most important assessment of resistance to the borer. The larval population in the flowers showed marked differences in infestation levels between cultivars and is suggested as a means of comparing results in the future. Based on the methodology described, TVu 946 was the most resistant cowpea cultivar in every category of assessment. Five other cultivars were also selected for further evaluation as probable resistance donors: Kamboinse Local, TVu 1, VITA-5, TVx 3890–010F and VICAM-1/SP. The rationale behind the development of a field-screening methodology and some of its shortfalls are discussed.

Adult females of Panolis flammea (Denis & Schiffermüller) in the laboratory laid more eggs on some provenances of lodgepole pine (Pinus contorta) than on others, even when offered no choice. Their preoviposition period was inversely related to the suitability of the host for larval growth and development. The shorter the preoviposition period the greater the number of eggs that were laid. Delayed mating resulted in reduced fecundity and reduced egg fertility. Female moths lived longest on those hosts on which they oviposited most. Oviposition preferences were correlated with the ratio of the two monoterpenes α- and β-pinene within the host-plants. The effects of provenance, delayed mating and adult mortality were demonstrated through a simulation model; the effect of delayed mating was particularly marked when adult survival was poor. Egg production in the field in Scotland varied from 30 to 123 eggs per female, but this variation could largely be explained by spring temperature. It was concluded that this relationship was due to the influence of temperature on mating and egg laying. The relationship between temperature and egg production forms a basis for predicting damaging levels of Panolis flammea from either pupal or adult numbers. The effects of provenance and delayed mating demonstrate that the frequency of P. flammea outbreaks in the UK may be reduced by the planting of less preferred lodgepole pine provenances and by mating-disruption methods.

In eastern Africa between 1951 and 1955 and in south-western Morocco in 1960, orientations and densities of flying locusts in migrating swarms of Schistocerca gregaria Forsk. were recorded photographically, with supplementary visual observations. The densities ranged from 0·0006 to 1·23 locusts/m3 (mean spacing between nearest locusts 12 and 1 m, respectively) with a median value of 0·024 locusts/m3; in 50% of the samples mean spacing was 2–4 m, suggesting a preferred distance of that order. The orientations were affected by gregarious reactions to neighbouring fliers, and to locusts in a mass. In the swarms there was a preponderance of streaming groups in which locusts headed in the same general direction; in about half of these groups the angular deviation about the mean orientation was only ±20°. In comparatively dense swarms the orientations of the lower fliers in the interiors of swarms were diverse and random in relation to wind and to the swarm track. But at the leading, the trailing and the lateral edges they were predominantly into the swarm, as the result of observed changes of headings back towards the swarm in locusts flying out beyond the main mass. The orientations of locusts photographed at about 100 m and 200–400 m above the ground were found to be predominantly in the direction of the swarm track, i.e., with wind; it is suggested that they arose from compensatory optomotor responses to retinal velocities of substrate patterns, and are consistent with Kennedy's hypothesis of optomotor orientation to wind. Among lower-flying locusts such responses appeared to become important in diffuse formations and in strong winds. Thus flight on consistently into-wind courses was repeatedly seen in low-flying diffuse formations of sexually mature locusts migrating in light winds. In stronger winds the orientations of lower fliers in all types of swarms suggested responses to unacceptable retinal velocities, which interfered with the into-the-swarm orientations on the swarm edges; the continued cohesion of swarms may thus require a wind profile in which they are not evoked below a certain level. In persistent strong wind in excess of locusts' air speeds, flight activity was reduced, and swarms exhibited low into-wind flight by locusts in small numbers. It is suggested that the characteristic downwind tracks of discrete immature swarms are set primarily by the downwind orientations of their higherflying members. In sexually mature swarms the downwind displacements are probably performed mainly by the denser and the higher-rising swarms, while the into-wind flights of low diffuse formations would slow down movement, and could result in limited displacement up-wind.

Nilaparvata lugens Stål, the Brown Planthopper (BPH), is a major pest in rice. The lycosid Pardosa pseudoannulata (Bösenberg & Strand) and the linyphiid Atypena formosana (Oi) are the early dominant predators in irrigated rice. Later, predatory bugs, including the mirid Cyrtorhinus lividipennis Reuter, become dominant. In unsprayed rice, BPH numbers normally remain low. While P. pseudoannulata is known to be a key natural enemy of BPH, the contribution to BPH reduction by the smaller A. formosana is less well known. Due to the size difference, A. formosana may also be an intraguild prey of P. pseudoannulata. To investigate predation on BPH by the two spider species alone, together and in combination with C. lividipennis, two cage experiments were conducted, the first with adult spiders, the second with immature/unmated spiders. In the latter, spiders were introduced with a delay to allow a better establishment of C. lividipennis. In both experiments, BPH numbers were lowest in treatments with more than one predator species present. Intermediate BPH reduction was obtained with P. pseudoannulata followed by A. formosana and C. lividipennis. While P. pseudoannulata can prey upon large nymphs and adult BPH, A. formosana favour early instar BPH, leading to a more even control across instars in treatments with both spider species. Pardosa pseudoannulata numbers increased more with A. formosana or A. formosana and C. lividipennis present. In contrast, P. pseudoannulata reduced A. formosana and C. lividipennis numbers. The presence of C. lividipennis apparently lessened intraguild predation on A. formosana and may be an intraguild prey of A. formosana. Competition for prey may have added to the antagonistic interactions found. From a biological control perspective, the presence of both spiders in early rice is an advantage for the biological control of BPH in rice. In early rice, results show that A. formosana is an important predator of BPH and, like C. lividipennis, can complement control by P. pseudoannulata and serve as intraguild prey for the latter species.

An incomplete ring of electrified nets was placed round a trap or round an electrified net and visual target in woodland infested with Glossina morsitans morsitans Westw. and G. pallidipes Aust. in Rhodesia. The distribution of catches in these systems was used to estimate the minimum efficiencies with which the trap or net and target captured flies that were initially attracted by odours derived from a herd of cattle hidden below ground. With mature tsetse, the estimates for the trap were 23 and 21% for male and female G. morsitans, respectively, and 70 and 49% for male and female G. pallidipes. For the net and target, the corresponding figures were 29, 30, 53 and 43. The coefficient of variation of such estimates (about 10%) was low enough to suggest that the technique affords a quick and reliable means of screening the efficiency of many trap designs. Factors responsible for the efficiency of the trap were elucidated. Data for other insects were obtained.

A methodology is presented to facilitate a declaration that an area is ‘pest-free’ following an eradication campaign against an insect pest. This involves probability models to assess null trapping results and also growth models to help verify, following a waiting period, that pests were not present when control was stopped. Two probability models are developed to calculate the probability of negative trapping results if in fact insects were present. If this probability is sufficiently low, then the hypothesis that insects are present is rejected. The models depend on knowledge of the efficiency and the area of attractiveness of the traps. To verify the results of the probability model, a waiting period is required to see if a rebound occurs. If an incipient but non-detectable population remains after control measures are discontinued, then a rebound should occur. Using a growth model, the rate of increase of an insect population is examined starting from one gravid female or one male and a female. An example is given for tsetse in which both means and confidence limits are calculated for a period of 24 reproductive periods after control is terminated. If no rebound is detected, then a declaration of eradication can be made.

The red palm weevil, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Dryophthoridae), native to tropical Asian regions, has become a serious threat to palm trees all over the world. Knowledge of its flight potential is vital to improving the preventive and curative measures currently used to manage this pest. As R. ferrugineus is a quarantine pest, it is difficult to study its flight potential in the field. A computer-monitored flight mill was adapted to analyse the flying ability of R. ferrugineus through the study of different flight parameters (number of flights, total distance flown, longest single flight, flight duration, and average and maximum speed) and the influence of the weevil's sex, age, and body size on these flight parameters. Despite significant differences in the adult body size (body weight and length) of males and females, the sex of R. ferrugineus adults did not have an influence on their flight potential. Neither adult body size nor age was found to affect the weevil's flying abilities, although there was a significantly higher percentage of individuals flying that were 8–23 days old than 1–7 days old. Compared to the longest single flight, 54% of the insects were classified as short-distance flyers (covering <100 m) and 36 and 10% were classified as medium- (100–5000 m) and long-distance (>5000 m), respectively. The results are compared with similar studies on different insect species under laboratory and field conditions.

For parasitoids, the host represents the sole source of nutrients for the developing immature. Subsequently, host quality is an important factor affecting immature development and the resulting fitness of the emerging parasitoid, with impacts on fecundity, longevity and offspring sex ratio. Host age is an integral component of host quality and a key factor in host selection by the female parasitoid. The current study aimed to investigate the effect of decreasing host quality (determined by increasing host age) on adult life history traits (size, wing loading, longevity, and fecundity) and nutritional reserves (protein, lipid and glycogen concentrations) of the parasitoid Trichogramma brassicae. Higher quality hosts resulted in the production of larger offspring with increased resource reserves and enhanced mobility. One-day-old eggs contained significantly more protein and triglyceride than 25- and 45–day-old eggs. Quality of host and fitness of reared wasps decreased due to host aging. Parasitoids reared on 1-day-old hosts were larger, with greater fecundity and longevity, a reduced wind loading index, and produced a higher proportion of female offspring when compared with those reared on 25- and 45-day-old hosts. In addition, wasps reared on 1-day-old hosts contained higher energy resources, as determined by triglyceride, glycogen and protein reserves, which are essential to successful offspring production. One-day-old hosts can therefore be considered as the best age for producing wasps with greater fitness, since they contain the highest amount of protein, glycogen, and triglyceride. This has implications for the mass rearing of T. brassicae and enhancing the efficacy of this biological control agent.

Needle defoliation by diprionid sawflies decreases the increment and timber yield of Scots pine Pinus sylvestris L. The aim of this study was to provide approximate estimates of this decrease and preliminary estimates of the economic value of growth losses and tree mortality. Growth loss after needle damage by Diprion pini(Linnaeus) was studied in western Finland. Increment cores were sampled for radial growth measurements from trees subjected to slight, moderate and heavy defoliation. A literature survey was carried out to estimate radial growth losses after defoliation by Neodiprion sertifer (Geoffroy). Calculations for economic consequences were based on previous estimates and on the ongoing 9th Finnish National Forest Inventory. Moderate defoliation by N. sertifer and D. pini reduced volume growth by 21% and 86% and heavy defoliation by 38% and 94%, respectively. Tree mortality in defoliated stands was recorded as approximately 4%after an outbreak of N. sertifer and 30% after an outbreak of D. pini. The estimated average economic value of the losses due to reduced growth and tree mortality reached $40 ha−1 after a single-year outbreak of N. sertifer and $310 ha−1 in the case of D. pini. These preliminary estimates of economic losses indicate a much higher impact of pine sawflies than those revealed by the few earlier studies in Europe.

Regression analyses of a long series of light-trap catches at Narrabri, Australia, were used to describe the seasonal dynamics of Helicoverpa armigera (Hübner). The size of the second generation was significantly related to the size of the first generation, to winter rainfall, which had a positive effect, and to spring rainfall which had a negative effect. These variables accounted for up to 96% of the variation in size of the second generation from year to year. Rainfall and crop hosts were also important for the size of the third generation. The area and tonnage of many potential host crops were significantly correlated with winter rain. When winter rain was omitted from the analysis, the sizes of both the second and third generations could be expressed as a function of the size of the previous generation and of the areas planted to lucerne, sorghum and maize. Lucerne and maize always had positive coefficients and sorghum a negative one. We extended our analysis to catches of H. punctigera (Wallengren), which declines in abundance after the second generation. Winter rain had a positive effect on the sizes of the second and third generations, and rain in spring or early summer had a negative effect. Only the area grown to lucerne had a positive effect on abundance. Forecasts of pest levels from a few months to a few weeks in advance are discussed, along with the improved understanding of the seasonal dynamics of both species and the significance of crops in the management of insecticide resistance for H. armigera.

The species of Diadegma that attack Plutella xylostella(Linnaeus) are revised. Following a morphometric study involving principal components and discriminant analyses, seven distinct morphospecies are recognized. One species is described as new: D. novaezealandiae from New Zealand. Diadegma mollipla(Holmgren) is the name for the species from sub-Saharan Africa and some Indian Ocean and South Atlantic islands. Diadegma varuna Gupta syn. nov. and D. niponicaKusigemati syn. nov. are both synonymized with D. fenestrale(Holmgren). Diadegma xylostellae Kusigemati is strongly presumed to be a synonym of D. semiclausum (Hellén). An illustrated identification key is provided and each species is described in a standard way.

The effects of two natural aphid enemies, adult Coccinella septempunctataLinneaus, a predator, and Aphidius rhopalosiphi de Stefani Perez, a parasitoid, on spread of barley yellow dwarf virus (BYDV) transmitted by the bird cherry–oat aphid, Rhopalosiphum padi (Linnaeus) were studied under laboratory conditions. Predators or parasitoids were introduced to trays of durum wheat seedlings and the patterns of virus infection were observed after two, seven and 14 days of exposure. More plants were infected with BYDV in control trays without A. rhopalosiphithan in trays with the parasitoid present, both seven and 14 days after the introduction of parasitoids. Patterns of virus infection were found to be similar over time in trays with a parasitoid present and in control trays. More plants were infected in trays with C. septempunctata present than in control trays, both two and seven days after the introduction of the coccinellid. The spread of virus infections progressed differently over time for the two treatments (predator and parasitoid), differences between treatments being most marked after two days and seven days, when more plants exposed to predators but fewer exposed to parasitoids were infected with BYDV compared to their respective controls. However, by the 14th day 88% of all plants were infected and there was no significant difference between the two treatments. The role of natural enemies in spread of BYDV is discussed.

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.

A convenient and accurate measure of size is necessary for studies on the physiology of tsetse flies (Glossina). Residual dry weight (i.e., dry weight minus fat) is adequate as regards the larva, pupa and teneral fly, but cannot be used for flies that have taken their first blood-meals. A linear measurement provides an index of size that remains constant throughout the life of the fly, but the use of the length of the middle part of the fourth longitudinal vein in the wing has certain disadvantages, and a measure of surface was thought preferable. That finally adopted was a function of the dorsal thoracic surface; details of it are given and a close correlation was demonstrated between it and residual dry weight for females of G. morsitans Westw. bred in the laboratory from puparia maintained at 28°C.

The relation between this measure and the weight of the newly emerged fly is affected by the temperature at which the pupal stage is passed; above approximately 25°C. the surface area of flies of any given residual dry weight decreases quite sharply, so that puparia of a given weight produce smaller but relatively heavier flies at 30 than at 25°C. This holds good also for G. pallidipes Aust. and G. swynnertoni Aust. The dependence of surface area on the temperature at which development has taken place unavoidably complicates the use of this measurement in work on transpiration; it also limits the application of the theory that stresses acting on the pregnant fly may be gauged from the size of flies two months later, and suggests that where the mean temperature of pupal sites is likely to exceed 26°C, any inference should be based on puparial rather than adult size.