One–dimensional slab polyacrylamide gel electrophoretic techniques, staining systems and isoenzyme banding patterns for 14 soluble enzymes separated from crude homogenates of individuals of six species of cereal aphids (Sitobion avenae (F.), S. fragariae (Wlk.), Metopolophium dirhodum (Wlk.), M. festucae (Theo.), Rhopalosiphum padi (L.) and R. maidis (Fitch)) are described. The value of the techniques and banding patterns to taxonomic and population genetic studies of these and other aphid species are briefly discussed. With the six species, it was possible to separate the different genera as well as individual species within genera. The enzymes found to be most useful for inter–generic and/or -specific separations were adenylate kinase (AK), esterase (EST), glucose-6-phosphate dehydrogenase (G-6-PDH), hexokinase (HK), malate dehydrogenase (MDH), peptidase (PEP), phosphatase (PHOS), phosphoglucomutase (PMG), 6-phosphogluconate dehydrogenase (6-PGD) and sorbitol dehydrogenase (SORDH), whilst glutamate oxaloacetate transaminase (GOT), α-glycerophosphate dehydrogenase (α-GPD), malic enzyme (ME) and peroxidase (POD) were of relatively little taxonomic use. There were no banding pattern differences between the various morphs of S. avenae (first to fourth-instar nymphs, apterous and alate adults using the 14 enzymes.

There are certain smells remarkably attractive to male flies of the genus Dacus and by the employment of these smells the movements of the flies can to a great extent be controlled, in any given direction. The reaction is strictly confined to the male sex, and different species exhibit a variation as regards the smell which is most attractive to them. It is uncertain whether the females emit similar smells; on the whole improbable.

Three of the commoner species of the flies (D. diversus, ferrugineus and zonatus) normally breed respectively in (1) anthers of Cucurbitaceae, (2) fruits of Solanaceae and mango, and (3) peach, guava, mango and other fruits. D. diversus (1) is most strongly attracted by iso-eugenol, zonatus (3) by methyl-eugenol, and ferrugineus (2) by both methyl and iso-eugenol. The smells of these substances have not yet been identified with those of the plants which constitute the normal breeding-places, but male flies have been found attracted to mango, Papaya, a Cycad, and Colocasia. plants with a very characteristic smell similar to that of eugenol-derivatives. Females have never been seen to frequent these plants or to breed in them, but more extended observation is required on this point before it can be definitely said that they never do so. The males give the impression that they might visit these plants for food, for they suck the surface of the flowers, though they do not seem to exhibit any very particular avidity. One species (ferrugineus?) has been bred from a Eugenia at Bangalore.

Three explanations suggest themselves:.—

(a) The smell is a direct sexual guiding smell emitted by the female.

But young crushed females did not attract males.

(b) The smell is not emitted by the female, but may be termed an “indirect” sexual guide to the plants where the females are accustomed to congregate for breeding purposes.

Under these circumstances it is difficult to see why females should not also be attracted by the odoriferous chemicals.

(c) The smell is a food-smell.

It must then be a food attractive only to males.

Two other species of fruit-flies, D. caudatus (breeding in fruits of Cucurbitaceae) and an unidentified species, were captured by means of an amyl-vanillin solution and of eugenol respectively. The rarity of the flies and the small numbers caught (four and one) make it advisable, however, to postpone detailed comment on these two cases, and future work may give more definite information as to their chemical relations. No substance attractive to male cucurbitae has been found.

All the observations described were made at the Pusa Research Institute, India.

The life history of Frankliniella occidentalis (Pergande) was studied at six different temperatures on English cucumbers, cv. Pepinex. Life tables constructed indicate that the highest population growth rate (rm) and net reproduction rate (R0) occur at 30°C and the lowest at 15°C, where the population remains nearly stable. Generation time (T) was the shortest at 30°C and increased as temperature decreased. At 30°C oviposition increased, females matured and reproduced earlier and the time specific fecundity (mx) was higher than at lower temperatures. Adult longevity was shortest at 30°C and longest at 15°C. The threshold value for development was determined as 9.4°C. Average duration of each developmental stage and the sex ratio at six different temperatures are given.

Mononychellus tanajoa (Bondar), a spider mite new to Africa, was discovered on cassava in Uganda in 1971. This exotic mite of Neotropical origin has since spread to 27 countries, causing an estimated 13–80% reduction in cassava yield. The history of its introduction and spread in Africa is reported, and present knowledge on the taxonomy, biology, ecology and pest status of the mite, and the evolution of strategies to control it are reviewed. While attempts have been made to control M. tanajoa, it remains a serious pest in most areas. The prospects for classical biological control as an appropriate control strategy are discussed.

The preparation and use of a simple, durable silicone membrane for feeding females of Glossina morsitans Westw. are described. Mean fecundity and mean pupal weight were nearly as good on the silicone membrane as on agar/Parafilm or rabbit ears, and survival of females after 108 days was 46·7%, as against 4·4% and 24·7%, respectively.

The stabling of horses at night reportedly offers protection from African horse sickness and the most significant vector of the disease, Culicoides imicolaKieffer, has been shown to be exophilic. In certain high-lying regions of South Africa, however, C. bolitinos Meiswinkel, may be the major vector of the disease but its entry behaviour into stables is unknown. Accordingly, in the eastern Free State province of South Africa, light trap catches of C. bolitinos inside stables and outside, were compared. Two horse-baited stables, one traditional, and one modern, were used and combinations of stable (old/new), ceiling fans (on/off) and accessibility to Culicoides (stable doors open/closed or windows gauzed/ungauzed) were investigated as treatments. A total of 111,452 Culicoides of 26 species was collected on 60 trap nights; C. bolitinos was dominant (89.1% overall) with C. imicola second in abundance (2.9%). Outside catches were greater on warmer, drier, evenings but were suppressed by high wind speeds. Catches of C. imicola inside stables with doors open, or with windows ungauzed, were less than the numbers captured outside. In contrast, more C. bolitinos were caught in open stables than outside, i.e. open structures may protect horses from the exophilic C. imicola, but may increase attack rates from the endophilic C. bolitinos. The closing of doors and the gauzing of windows, however, led to a 14-fold reduction in numbers of C. bolitinos and C. imicola entering stables. A well-gauzed ‘traditional’ stable was as effective as a closed ‘modern’stable. Ceiling fans had no suppressant effect.

The susceptibility to several insecticides of 16 and 8 strains of Myzus persicae Sulzer and Aphis gossypii Glover, respectively, received from different European countries in 2001 was investigated. Most of the strains were derived from places known for their aphid resistance problems to conventional insecticides before imidacloprid was introduced. In many regions and agronomic cropping systems imidacloprid has been an essential part of aphid control strategies for a decade, and therefore the susceptibility of aphid populations to imidacloprid using FAO-dip tests and diagnostic concentrations in a leaf-dip bioassay was checked. Additional insecticides tested were cyfluthrin (chemical class: pyrethroid), pirimicarb (carbamate), methamidophos and oxydemeton-methyl (organophosphates). Diagnostic concentrations (LC99-values of reference strains) for each insecticide were established by dose response analysis using a new leaf-disc dip bioassay format in 6-well tissue culture plates. Virtually no resistance to imidacloprid in any of the field-derived populations of M. persicae and A. gossypii was detected. In contrast, strong resistance was found to pirimicarb and oxydemeton-methyl, and to a lesser extent also to cyfluthrin. Two strains of A. gossypii exhibited reduced susceptibility to imidacloprid when tested directly after collection. However, after maintaining them for six weeks in the laboratory, the aphids were as susceptible as the reference strain. The diagnostic concentration of methamidophos did not reveal any resistance in M. persicae, but did so in four strains of A. gossypii.

Insect activity was significantly reduced in dung from cattle treated with a recommended topical dose (500 μg/kg) of the endectocide, ivermectin. Reductions affected an ecologically and taxonomically diverse group of insects including coprophagous flies, parasitic wasps, and both predacious and coprophagous beetles. Whereas some species appeared unaffected by faecal residues, the emergence of other species was reduced in dung voided ≤ 12 weeks post-application. The species most affected were the flies, Sepsis sp. and Coproica mitchelli (Malloch). eucoilid wasps. and the beetles, Cercyon quisquilius (Linnaeus) and C. pygmaeus (Illiger). Results were consistent within and between years. Similar reductions have been reported previously, but typically for a much shorter post-application period. The greater duration of effect observed in the current study is attributed to a more accurate bioassay, species-level identifications, and the use of sample sizes generally larger than those used in previous studies. Reduced insect activity was associated with slower dung pat degradation. When ivermectin was added directly to dung, at levels previously reported to occur in dung from treated cattle, the treated dung had not appreciably degraded after 340 days in the field. In contrast, untreated dung pats deposited at the same time and place had largely degraded after 80 days in the field. The effect of ivermectin use on pasture quality is probably ‘moot’ in southern Alberta because of the current pattern of use. Should this pattern change, however, results of the present study validate the need for future studies to assess the off-target effects of ivermectin use on pasture quality.

Female Musca vetustissima Wlk. may be allocated to one of seventeen classes of development between emergence and the start of the fourth ovarian cycle, the criteria being the amount of pupal fat body, but chiefly the presence and size of the follicular relics (yellow bodies and beads in the ovaries) during successive ovarian cycles. The duration of these cycles was estimated under standard and differing environmental conditions. Withholding protein for up to two weeks merely delayed the first ovarian cycle, but longer deprivation caused reduced fertility. The initial phase of the first ovarian cycle was independent of protein feeding, but a protein feed was necessary to complete the cycle, and a further protein feed was needed to complete the second ovarian cycle. No development in the first cycle took place below 57°F, but between 58 and 78°F development was progressively faster. Unfertilised females developed and laid the first batch of eggs, but were unable to complete a second batch. Oviposition was delayed by lack of favourable sites, and after one week fertility was progressively reduced. It is shown that, because of these variables, valid estimates can be made only of the minimum age of female bushflies.

Larvae of Aphidoletes Kieffer and Monobremia Kieffer feed exclusively as predators on aphids. The taxonomic status of these genera and their included species is reviewed and new generic and specific synonymies are given. A. aphidimyza (Rondani), A. urticariae (Kieffer), A. abietis (Kieffer), A. thompsoni Möhn and M. subterranea (Kieffer) are accepted as good species and a neotype is designated for A. urticariae. Diagnostic characters of these species are indicated and characters of the male genitalia, female wings and larval skins are illustrated. Published information on their biology, particularly of the commonest species A. aphidimyza, is summarized and includes details of host ranges and geographical distribution. Lestodiplosis grassator (Fyles), L. pini Barnes, Trilobia aphidisuga Del Guercio, Uncinulella eriosomiperda Del Guercio, Trilobiella siphae Del Guercio and Adelgimyza strobilobii Del Guercio probably prey on aphids but have not been recognized since they were originally described. Comparative assessments of field populations of Aphidoletes by examination of aphid colonies in the field, by incubation of samples in polythene bags and by laboratory examination of samples fixed in 70% ethyl alcohol showed that only the last gives accurate counts of eggs and larvae. Counts of aphids, Aphidoletes, Syrphids, Coccinellids and Anthocorids in 35 samples taken from aphid colonies occurring at Wisley in 1970–72 are tabulated, together with seven samples from other localities. Aphidoletes (mainly A. aphidimyza) was numerically the dominant predator in all three years at Wisley and was about ten times more numerous on wild plants than on cultivated plants.

(1) Three insects, Tribolium confusum, Ephestia kuehniella and Dermestes vulpinus, have been grown at several humidities and the following factors have been determined: length of larval period; water content of food and of the freshly formed pupae; wet and dry weight of pupae and wet and dry weight of food consumed during larval development. The “net utilisation” of the food has been calculated as the ratio of dry weight of food eaten per larva to dry weight of pupa.

(2) At lower humidities more food is eaten to produce a given unit of body weight. The length of the larval period increases and the weight of the pupae decreases.

(3) More food is eaten at low humidities, because part of the food is utilised as water. As a consequence of this, the larva grows more slowly and its final size is smaller. It is shown for Dermestes at 30 per cent. and Ephestia at 1 per cent. R.H. that less than 32·9 and 7·6 per cent. of the water in the pupae can be derived from water ingested with the food.

The numbers of insects colonizing the dung of cattle injected with the anthelmintics ivermectin or moxidectin were compared with the colonization of the dung from control animals given no treatment, in a blind field trial. Dung was collected 2, 7, 14, and 21 days after dosing and set out in a randomized grid of standard 2 kg pats. Pats were retrieved from each of the three groups group after 7, 14, 21 and 42 days in the field for analysis of insect fauna. There were no significant differences in the number of adult Aphodius spp. (Coleoptera: Scarabaeidae) found in the dung from the three treatment groups with either time of exposure in the field or time after treatment, showing that adult beetles were attracted to all pats equally. However, dung from animals treated with ivermectin prevented the development of larval Aphodius spp. for at least 7 days after treatment. In contrast, the dung from animals treated with moxidectin supported the development of Aphodius spp. at all stages after dosing, as did dung from control animals. There were no significant differences in the number of cyclorrhaphous Diptera larvae in dung from control or moxidectin-treated animals. In contrast, such larvae were largely absent from the dung collected from ivermectin-treated cattle for up to 14 days after dosing. The results show that moxidectin is less toxic to dung-inhabiting insects than ivermectin following standard injection treatment. The results are discussed in relation to the effects of anthelmintics on non-target pastureland insects.

The arthropod community associated with irrigated rice grown in five sites in Luzon Island, Philippines, was analysed using guild categories. Phytophages and predators were predominant in all sites. The phytophage species were mainly Homoptera and dominated by Nephotettix virescens (Distant), N. nigropictus (Stål) (Cicadellidae), and Nilaparvata lugens (Stål) and Sogatella furcifera (Horváth) (Delphacidae). Predators were mainly Heteroptera with Microvelia douglasi atrolineata Bergoth (Veliidae), Mesovelia vittigera (Horváth) (Mesoveliidae), and Cyrtorhinus lividipennis Reuter (Miridae) as the most abundant species. Spiders were the next dominant group with Pardosa pseudoannulata (Böesenberg & Strand) and three species of Tetragnatha the most common. Differences in species diversity between the sites were easily differentiated using diversity indices. The relative differences in arthropod abundance, species richness and diversity may be attributed to the median temperatures, cropping patterns, and diversity in crop stages and germplasm in the sites. Predator-Homoptera correlations were significant in all cases. High positive correlations were obtained for veliids, spiders and Cyrtorhinus lividipennis, in most sites.

New Zealand is currently the only major fruit producing country in the world that is free of economically important fruit flies. As part of the effort to maintain this status, there is a need to supplement quarantine decision-making procedures with a means of rapidly identifying immature life stage infestations to the species level. Here we describe a molecular method that achieves this, using simple restriction patterns of ribosomal DNA (rDNA) as diagnostic markers. The 18S and 18S plus internal transcribed spacer (ITS) regions were amplified from larval DNA by the polymerase chain reaction (PCR). Nineteen species, spanning four genera (including five subgenera of Bactrocera) were analysed. Restriction analysis of the 18S PCR product provided poor resolution, even at the generic level. Digestion of the 18S + ITS PCR product, however, generated thirteen diagnostic haplotypes as defined by the composite restriction patterns from RsaI, Sau3a HaeIII and AluI. No variation was detected at these restriction sites within or between populations. Twenty two restriction enzymes have been screened, but diagnostic RFLPs have yet to been found for six out of the ten Bactrocera (Bactrocera) species; B. passiflorae (Froggatt) cannot be distinguished from B. facialis (Coquillet), nor B. kirki (Froggatt) from B. trilineola (Froggatt) or B. neohumeralis (Hardy) from B. tryoni (Froggatt). Geographic origin could assist in distinguishing the first four species, but the latter pair are very closely related with overlapping origins, hosts and adult morphology. All six species, however, are considered high risk with respect to their likely establishment in New Zealand. Therefore diagnosis based on this molecular technique would support the same quarantine decision. We consider this method could be useful as a diagnostic technique and discuss directions for further development.

For insect herbivores, the quality of the larval host plant is a key determinant of fitness. Therefore, insect populations are supposed to be positively correlated with the nutritional quality of their host plant. This study aimed to determine if and how different varieties of grapes (including the wild grape Lambrusque) affect both larval and adult performance of the polyphagous European grapevine moth Lobesia botrana (Denis & Schiffermüller). Significant differences were found in larval development time, but not in pupal mass, adult emergence rate, or sex ratio. Although the fecundity of females is not different among varieties, females fed on some varieties produced eggs of different sizes which are correlated to their fertility. Thus, females adapt resource allocation to eggs depending on their diet as larvae. Using a fitness index, the average reproductive output was found to be highest for females reared on cv. Chardonnay. Females reared on wild grape produced a fitness index identical to the cultivated grapes. However, Lambrusque and Gewurztraminer separate themselves from the cultivated varieties according to our discriminant analyses. It is emphasized, through this study, that cultivars fed on by larvae should be considered in the population dynamics of L. botrana and that egg number is insufficient to determine host plant quality.

For some years after the intensive study of mosquitos began in tropical countries, surprisingly little interest was taken in the European species, particularly those of Northern Europe. Ficalbi had published his monographic revision in 1896–99, but from then until 1914 very little further had been done; the adults were assumed to be more or less known, though very few of the larvae had been described. Since 1914, however, a great deal of work has been done all over Europe, bionomic as well as systematic, and considerable advances have been made in every branch of our knowledge of these insects.

The differences between the eggs of A. gambiae and A. melas form an absolutely reliable diagnostic character for distinguishing the two species in the Lagos area.

Identification of eggs laid by wild-caught females has formed the basis of work on the seasonal incidence of gambiae and melas adults in houses in different localities in and around Lagos.

In the area as a whole both melas and gambiae are abundant in most localities, but the greater part of Lagos town on Lagos Island is an almost pure gambiae area.

The sporozoite rate of gambiae—10·0 per cent.—is consistently much higher than that of melas—3·5 per cent.—in all catching stations. Fluctuations in sporozoite rate in relation to population density have been studied in both species.

The composition of the mosquito population in houses, and in outside resting places has been studied in relation to the movements of mosquitos into and out of houses. Melas makes use of outside resting places to about ten times the extent of gambiae.

In African village houses about 90 per cent. of the blood feeding by these two species takes place after midnight, the peak of activity being the hour or two before dawn.

An improved design of experimental hut and window trap is described. It has been used in studying the exodus of mosquitos from houses after feeding, and on experiments on host selection by Anopheles.

Swarms of male “gambiae” in nature have been described. In captivity both melas and gambiae have been persuaded to mate by using artificial light.

By cross fertilisation between melas and gambiae a generation of healthy hybrid adults can be obtained. Of these the females are evidently normal sexually, while most if not all of the males are sterile.

The breeding places of melas and gambiae in and around Lagos have been studied in relation to control. In this lagoon area, where conditions are very different from those of Freetown Estuary, melas breeds under a variety of conditions, and Avicennia mangrove is only of limited value in indicating major breeding grounds.

Studies have been made of the bionomics and ecology of Aëdes aegypti (L.) entirely under natural conditions and in its natural habitats on the Kenya coast.

Development from egg to adult under conditions approximating as nearly as possible to those in nature took a minimum of eight days and a maximum of twenty-five.

Males were in excess of females, in the proportion seventeen to ten, from eggs hatched in natural breeding places.

Although the mosquito may be able to propagate in houses, adults from outside habitually enter premises. If this entry is for egg-laying, then eradication by domestic larval control alone, although reputedly achieved elsewhere, is not possible under conditions obtaining in the coastal belt of Kenya. Windowtrap captures, however, indicate that the entry may not be for the purpose of egg-laying.

The seasonal reduction of both larvae and adults in houses during the hot, dry months of February and March is attributed to a combination of the absence of breeding places outside and the shorter life span of the mosquito at this time.

It is shown that both sexes enter and leave native huts throughout the 24-hour period, but the movement is confined almost wholly to the hours of daylight. The flight from houses is much reduced in the cool months (July and August). This corresponds with the season when most enter.

The percentage infection of secondary symbionts (SS) (Wolbachia, Arsenophonus, Rickettsia, Hamiltonella, Fritschea and Cardinium) in the exotic Bemisia tabaci (Genn.) invaders, commonly known as biotypes B and Q from China, were determined by PCR. In total, 373 biotype B and 1830 biotype Q individuals were screened for the presence of SS. Biotype B was more abundant than biotype Q from 2005 to 2006, and biotype Q was more abundant from 2007 to 2009. Each of the SS, with the exception of Fritschea, was detected in both biotypes B and Q; Fritschea was found in none of the samples examined. For biotype B, the percentage infection of Hamiltonella was the highest (92.0%) followed by Rickettsia (70.2%). For biotype Q, the percentage infection of Hamiltonella was again the highest (73.3%). Arsenophonus was the least common of the SS observed in both biotypes B and Q. The percentage infection of Wolbachia, Rickettsia and Hamiltonella in biotype B was each significantly higher than in biotype Q, whereas the percentage infection of Cardinium in biotype B was significantly lower than in biotype Q. The percentage infection of SS in biotypes B and Q varied from year to year over the period 2005–2009. Furthermore, within biotype Q, two distinct subgroups were identified which differ from each other in terms of their SS complement. We discuss these results in the light of the potentially influential factors and roles of the SS.