Seasonal changes in two natural larval populations of Leptoconops becquaerti (Kieff.), a biting sandfly of economic importance in the Caribbean area, are described from studies in 1963–64 near Montego Bay. Aspects of the ecology arising from these observations are included. An attempt is made to relate the seasonal changes in the larval populations to the seasonal distribution of adults, and in addition, a separation is made between the autogenous and anautogenous forms of the insect.

Larvae of both autogenous and anautogenous forms lived together in the same breeding sites and did not appear to differ in their spatial distribution. The two populations studied consisted mainly of larvae associated with the small, autogenous form. Drastic reduction in both populations occurred following events such as wave action and heavy rain that had a mechanical action on the sand in which the larvae lived. The distribution of both forms of larvae was dependent upon the surface elevation with respect to the level of free soil water, since this to a large extent, owing to the upward capillary movement of water, governs moisture content of the surface sand. Elevations between about 9 and 17 in. appeared to be the most favourable. Permanent breeding probably does not occur in sand at elevations greater than about 21 in., though temporary breeding may occur at higher elevations if some other source of moisture (e.g., frequent rain) is available.

In the autogenous form, a prolonged period was spent in the third larval instar. This was probably induced by some factor associated with lack of moisture in the sand, and appears to be broken (causing completion of development) by an effect of increased moisture content after heavy rain. This phenomenon probably does not occur in the anautogenous form.

Species of the genus Hieroglyphus are well known in India as serious pests of rice, sugar-cane, Sorghum, and some other crops, but in nearly all economic entomological publications one species only, H. banian, F. (= furcifer, Serv.) is regarded as being noxious. It is obvious, however, from some of the earlier descriptions and figures that there is more than one injurious species, but the exact status of each one of them could not be established even in more recent economic publications owing to the very unsatisfactory state of the systematics of this group, which made correct identification of species uncertain even for a specialist and quite impossible for an economic entomologist. It is true that comparatively recently I. Bolivar (1912) and J. Carl (1916) published more or less comprehensive papers on the genus, but these papers are not revisions, as the authors did not include all the known species and hardly touched questions of synonymy; moreover, Carl's paper, though published four years after that of Bolivar, was written without any reference to the latter, which resulted in the same species being described twice under different names, thus increasing the confusion. Further, both these authors based their papers on insufficiently extensive material, so that they were unable to appreciate the range of variation in the species.

The citrus red mite, Panonychus citri McGregor, is a key pest of different citrus species in various parts of the world. Considering the key role of resistant host plants in integrated pest management strategies, we evaluated the effects of five citrus species including grapefruit (Citrus paradisi), lime (Citrus aurantifolia), tangerine (Citrus reticulata), orange (Citrus sinensis), and sour orange (Citrus aurantium) on life table parameters of P. citri under laboratory conditions (25 ± 1°C, 65 ± 5% RH, 16:8 L:D). In addition, biochemical traits of the citrus plant species were evaluated in order to understand any possible relationship between important life history parameters with biochemical metabolites of citrus plant leaves. Phytochemicals were determined in leaf extract of citrus plant species. Various citrus species had significant effects on life history and demographical parameters of P. citri. The longest pre-adult time was observed on grapefruit (16.52 ± 0.43 days). Higher fecundity rate was on orange (15.05 ± 2.41 eggs) and tangerine (14.60 ± 3.07 eggs) and the lowest was on grapefruit (7.21 ± 2.00 eggs). The highest intrinsic rate of increase (r) was recorded as 0.071 (day−1) on tangerine, and the lowest value of this parameter was obtained on grapefruit (0.016 day−1). Significant correlations were observed between life history parameters with biochemical metabolites (carbohydrate, phenolic compounds, anthocyanin, and flavonoid). The results revealed that grapefruit was a relatively resistant host plant and tangerine was the most suitable host plant for feeding of P. citri. Our findings could be helpful for sustainable management of P. citri in citrus orchards.

The flight periods of eight species of Adelgids were deduced from suction trap catches in a mixed woodland site at Alice Holt, Hampshire from 1965 to 1970. Nine species from other natural forest areas in the northern hemisphere occurred on trees in the study area, but some immigration may have contributed to the numbers trapped. Large catches (often >200 individuals per day) of three pest species, Adelges laricis Vall., A. cooleyi (Gill.) and Pineus pini (L.), occurred during late May and June. Only small catches (<10 individuals per day) were obtained during July–September. The sexuparae from the non-Picea hosts occurred mainly in May and June whereas the gallicolae from Picea hosts flew during certain periods from June to September. Analysis showed that the threshold temperature for flight was 16°C and that 64% or more of the total monthly catch occurred in the afternoon (13·00–19·00 h). The variation in length of the early summer flight period by ± one week was related to air temperature maxima, but the fluctuation ( ± one week) in the mean date for flight of each species in the early summer period is probably connected with the phenological condition of the host-plant.

Spodoptera littoralis is a highly polyphagous pest that attacks numerous important crops in the world and causes substantial economic losses to agricultural production. In the present study, the effects of different leafy vegetables, including Purslane, Chives, Parsley, Basil, Dill, Coriander, and Mint, were investigated on feeding responses and enzymatic activities of S. littoralis under laboratory conditions. Furthermore, the total contents of the three major secondary metabolites (phenolics, anthocyanins, and flavonoids) in the studied vegetables were determined. Our findings showed that the lowest and the highest approximate digestibility were on Basil and Purslane, respectively. The highest values of efficiency of conversion of ingested and digested food were achieved in larvae fed on Chives and Coriander, respectively, whereas the lowest values were recorded after feeding on Purslane. The highest and lowest relative growth rates were in larvae reared on Dill and Purslane, respectively. Furthermore, the highest amylolytic and proteolytic activities were in larvae fed with Coriander and Dill, respectively, while the lowest activities of these enzymes were on Purslane. In addition, correlation analysis revealed significant correlations between feeding characteristics and enzymatic activity of S. littoralis with biochemical compounds of the studied leafy vegetables. Our results suggest that Coriander is a suitable host, while Purslane displayed tolerance traits against S. littoralis, which can be used in sustainable management programs aiming to reduce chemical inputs.

Platypus cylindrus is an important wood borer of cork oak trees (Quercus suber) in the Mediterranean region, namely Portugal, Morocco and Algeria where its presence has drastically increased in the past few decades. On the contrary, the insect is not a relevant pest in Tunisia. The aim of this work is to analyze morphological and genetic differences among Tunisian and Portuguese populations in order to understand their role in the diverse population dynamics (e.g., aggressiveness) of the insect. The information could be used as a novel tool to implement protective measures. Insects were collected from cork oak stands in Tunisia (Ain Beya, Babouch and Mzara) and Portugal (Chamusca and Crato). Morphological traits of female and male mycangial pits were determined, using scanning electron microscopy but no significant differences were found. Genetic differences were analyzed using nuclear (internal simple sequence repeat polymerase chain reaction) and mitochondrial (cytochrome oxidase I (COI)) molecular markers. The results showed a very low level of intraspecific polymorphism and genetic diversity. The alignment of COI sequences showed high percentage of identical sites (99%) indicating a very low variation in nucleotide composition. Other variables related with the ecology of the insect and its associated fungi must be studied for a better understanding of the differences in the insect population's dynamic in Mediterranean countries.

Currently, dengue control relies largely on reactive vector control programmes. Proactive vector-control using a rational, well-balanced integrated vector management approach may prove more successful for dengue control. As part of the development of a cluster randomized controlled epidemiological trial, a study was conducted in Johor Bahru, Malaysia. The study included one control site (three buildings) and three intervention sites which were treated as follows: targeted outdoor residual spraying only (TORS site, two buildings); deployment of autodissemination devices only (ADD site, four buildings); and the previous two treatments combined (TORS + ADD site, three buildings). The primary entomological measurement was per cent of positive ovitraps—ovitrap index (OI). The effect of each intervention on OI was analyzed by a modified ordinary least squares regression model. Relative to the control site, the TORS and ADD sites showed a reduction in the Aedes OI (−6.5%, P = 0.04 and −8.3%, P = 0.10, respectively). Analysis by species showed that, relative to control, the Ae. aegypti OI was lower in ADD (−8.9%, P = 0.03) and in TORS (−10.4%, P = 0.02). No such effect was evident in the TORS + ADD site. The present study provides insights into the methods to be used for the main trial. The combination of multiple insecticides with different modes of action in one package is innovative, although we could not demonstrate the additive effect of TORS + ADD. Further work is required to strengthen our understanding of how these interventions impact dengue vector populations and dengue transmission.

Spodoptera exigua Hübner and Sesamia cretica Led. (Lep., Noctuidae) are two important pests of corn. In this study, the effect of weed bands in the corn field, as weedy culture, on population density and damages of the pests were evaluated during two growing seasons (2016/2017). Cumulative insect days (CID) of each lepidopteran pest in weedy culture were compared with non-weedy culture. Results showed that CIDs of S. exigua and S. cretica in the non-weedy corn culture were significantly higher than the weedy corn culture. There was no significant difference between the total yield in the weedy and non-weedy cultures. Also, determinations of spatial distributions of the pests in the weedy and no-weedy treatments using Taylor's power law (TPL) and Iwao's patchiness (IP) showed that TPL provides a better fit for the data than IP and spatial distributions of both pests on both cultures were aggregative. Moreover, minor differences were observed between spatial distribution parameters of the pests in the weedy and non-weedy cultures. Green's model was used for developing a fixed-precision sequential sampling plan of the pests on the weedy and no-weedy treatments. Optimum sample sizes of S. exigua ranged from 532 to 5370 and 428 to 5296 plants and S. cretica varied from 297 to 2040 and 43 to 186 plants in the non-weedy and weedy cultures based on the desired precision level (0.25–0.1). Estimated stop lines of non-weedy and weedy cultures for S. exigua ranged from 0.000057 to 52.59 and 0.00029 to 58.87 and for S. cretica ranged from 1.59 to 111.5 and 2.09 to 98.03 larval cumulative numbers, respectively (0.25–0.1). The performance of the sampling plan was validated by resampling analysis using RVSP software. Results of the study can be used in the integrated pest management program of corn fields.

We tested the hypothesis that host tree age may act as a selective factor and lead to local adaptation of the hemlock looper (Lambdina fiscellaria), a geometrid Lepidoptera that has a wide geographical distribution and has evolved in different eco-zones characterized by different levels of floristic composition, age structure and fragmentation level. Considering that hemlock looper outbreaks mainly occurred in old forests, we compared the biological performances of two populations. The first population was collected in the northern virgin boreal forest, which is dominated by mature and overmature coniferous stands that have not suffered from human disturbance. The other population was collected in the southern mixed-wood forest, which is more diversified and has been modified by forest harvesting. Larvae were reared under controlled conditions on foliage from three age classes of balsam fir trees: juvenile, mature and overmature. Although we measured significant variations of biological performances between the two populations, no significant effect of the age of the balsam fir trees could be detected for males from both populations or for females from the southern population. However, northern females were strongly affected by the age of balsam fir trees on which they fed, as their pupal weight was 12% higher and their fecundity increased by 27% on overmature trees compared with juvenile ones. These results indicate that under the same selective pressure, females adapt their strategy to maximize their fitness, and thus they appear as the driving force of evolution through the local adaptation concept. Furthermore, the two populations evolved in distinct habitats and their adaptation reflects selective pressures occurring inside their original environment. This is the first report on local adaptation of an herbivore that is mediated by host tree age. Changes in forest age structure may have a considerable impact on insect local adaptation and presumably on their population dynamics.

The potential role of oviposition deterrents in the egglaying behaviour of Neodiprion sertifer (Geoffroy) females was studied by investigation of natural egg distribution, and by a laboratory study of potential oviposition deterrents. Pine shoots were sampled from different whorls on the sun-exposed and the shaded side of trees. More shoots with eggs from two or more females were found than would be expected if each female laid eggs on a randomly chosen shoot. The anti-predatory larval oral secretion of N. sertifer had no effect on N. sertifer egglaying but acted as an oviposition deterrent to Diprion pini in laboratory experiments. The different responses may be due to differences in the species' life-cycles. In other experiments, the effect of the presence of N. sertifer eggs, extracts obtained from eggs or from needles with eggs, were all tested on N. sertifer egg laying. None of the treatments had any inhibitory effect on egglaying. Thus, neither the natural pattern of egg distribution nor the results of the laboratory experiments indicated that an oviposition deterring pheromone is used by N. sertifer. Results from earlier studies, showing a deterrent effect of larval oral secretion in D. pini, were confirmed.

An account is given of the life-history of Auchmeromyia luteola in a laboratory culture maintained in London for two-and-a-half years. Attention was centred on the bloodsucking larva, known as the Congo Floor Maggot, which is an intermittent ectoparasite specific to man. It was reared chiefly on the natural host, but a strain has been maintained on shorn guinea-pigs through several generations. It was also found possible to rear the larva on free blood.

The known distribution of A. luteola is reviewed on the basis of published records, museum collections and information from scientists in Africa. The species is highly successful in both the wettest and the driest parts of the Ethiopian region, but does not seem to extend south of Durban. It can flourish only where man occupies permanent settlements and makes his bed on the floor within reach of the maggot. Strains originating in Nyasaland, in the western part of the Belgian Congo, and in the Anglo-Egyptian Sudan were successfully cross-mated and produced fertile eggs. The second generation from these crosses, however, was not always fully fertile.

The method of cultivation of the material is described.

Batches of eggs hatched 36–60 hours after oviposition when kept at 26–28°C. and 50–50 per cent. R.H. In drier atmosphere development was delayed and took from 3 to 7 days at 23°C. and 10 per cent. R.H.

The habits of the larvae are discussed and it is shown that larvae took 20 minutes to gorge (although newly hatched specimens often stopped feeding after 10 minutes). Given the opportunity, a meal was taken daily except for a day missed before each moult. No larva could be induced to bite twice in one day unless the first feed had been interrupted.

The rate of growth of the larvae was found to be strongly influenced by the feeding schedule, those receiving. 4 meals a week having a much higher rate than those receiving only 2. There was also a correlation between rate of growth and temperature but the correlation with relative humidity was less well marked. After fasts of several days, meals of the order of two and a half times their own weight were taken by larvae of all three instars.

Larvae which were fed four times a week and kept at 23°C., besides growing faster than others fed at less frequent intervals, reached higher maximum and pupal weights and started to pupate on the 26th day. Larvae fed at less frequent intervals took larger meals but lighter pupae and flies were produced.

The time of moulting appeared to be directly related to weight and only through this to the environment. The first moult occurred after the larva had gorged to a weight of 1·5–2·1 mg. (usually at the 2nd or 3rd meal), the second moult after it had reached 12–19 mg. (at the 4th to 7th meal).

There are wide limits of weight between which the onset of pupation can occur, the upper limit being higher for female than male larvae. If the feeding schedule (in relation to climate) is favourable, the larvae reach a maximum weight which induces the onset of pupation regardless of other factors. If the meals are scarce, growth is retarded more than metabolism and time becomes the limiting factor; then, the scarcer the meals, the smaller, not the later, the pupae. If the meal schedule is so adverse that the larvae cannot reach the minimum weight for pupation (about 97·5 mg.) in the time set by their metabolic rate in the given climate, death ensues without pupation.

No larva has been known to complete an instar on a single meal. The minimum for complete development in any climate is probably six meals, two in each stage. Larvae reared at 28·5°C. in 60 per cent. R.H. on five meals a week, moulted after the rd and 7th meals and pupated after the 16th or 17th.

Failure to moult, followed by death, occurred in all strains in the laboratory. It is believed that this is sometimes due to overcrowding and sometimes to the larva being disturbed when ready to moult. Inability to moult was commonest in the dry atmospheres and among larvae fed only twice a week.

Saturated air was fatal to the larva but not to the pupa. The species tolerates a wider range of atmospheric humidity than most insects, and was even reared successfully in an atmosphere of 10 per cent. R.H.

Female larvae in the third instar take more blood than males and lose more by excretion ; they also grow larger and produce heavier pupae and adults.

The temperature lethal in one hour to larvae having completed the second moult is denned within about one degree (42·5–43·5°C.) and does not appear to vary according to atmospheric humidity.

The Floor Maggot can survive fasts perhaps longer than any other Dipterous larva. At 28·5°C. and 90 per cent. R.H. survival of first-instar larvae, unfed, after one meal and after two meals, was 9–20, 8–21 and 4–21 days respectively ; third-instar larvae after moult (i.e. at 12·19 mg.), and at about 90 mg. survived 17–18 and 28–47 days respectively. At the same temperature but 10 per cent. R.H. much more weight was lost and the survival time was much less. At 23°C. newly hatched unfed larvae survived 5–37 days at 60 per cent. R.H. and 9–22 days at 10 per cent. R.H., while third-stage larvae survived 25–48 days at 90 per cent R.H. and 9–19 days at 30 per cent. R.H. Newly hatched larvae lived for 3–8 days at 35°C. in 60 per cent. R.H.

The pupal stage lasts about 9 days at 34°C., 11 days at 28·5°C. and 15–16 days at 23°C. and is unrelated to atmospheric humidity. Losses in weight at different atmospheric humidities were studied; the proportion lost was about 16 per cent, at 90 per cent. R.H. and about 25 per cent, at 10 per cent. R.H.

The habits of the adult flies are discussed ; human faeces appear to be the staple diet. The male seeks the female persistently and mating is protracted and occurs repeatedly. One male can fertilise several females. Oviposition and development continue all the year round without diapause. In the laboratory at 22–23°C. a female normally laid about 54 eggs at her first oviposition, and in one case a female laid as many as 6 batches of fertile eggs. In warm weather, the first batch was laid about 16 days after emergence (or after 20–23 days at 23°C), smaller batches being laid subsequently at intervals of 5–8 days. The female lived in the laboratory up to 93 days and the male up to 85 days.

The life-cycle under natural conditions is roughly estimated as 10 weeks, so that five generations a year might be expected.

Anopheles stephensi – Liston (Culicidae: Diptera) is an important urban malarial vector in the Indian sub-continent, accounting for about 15% of the total annual malaria incidence. Chemical control represents a key strategy in the management of this insect vector. However, owing to erratic and continuous application of insecticides, resistance has become a common phenomenon among them and their control has become an uphill task. The genetics of alphamethrin, a synthetic pyrethroid resistance was studied to determine its mode of inheritance. The late third instar larvae were selectively inbred for 27 and ten generations to synthesize homozygous resistant (R) and susceptible (S) stocks, respectively, to the diagnostic dose of 0.12 mg l−1. The log-dosage probit mortality relationships and degree of dominance (D) were calculated. Resistance was observed in both sexes, the dosage-mortality (d-m) line of F1 was towards the resistant parent and the ‘D’ value was found to be 0.8 indicating alphamethrin resistant (amr) gene to be autosomal and incompletely dominant. The d-m lines of F2/backcross exhibited a clear plateau of mortality across a range of doses indicating monogenic resistance. The null hypothesis for monogenic resistance was tested from mortality data of backcross progeny compared with theoretical expectations using the χ2 test and was found to be non-significant. Understanding genetics of insecticide resistance is significant in prediction and management of resistant insects. The amr genes can be used as genetic marker in A. stephensi, which can be used in several applications in conducting basic and applied genetic research.

Following increased yields of cotton in the Sudan Gezira by DDT spraying, during the 1952/53 season 22,300 and 6,700 feddans of X1730A cotton were sprayed once and twice, respectively, in the Gash Delta of eastern Sudan, where nearly 60,000 feddans were grown under controlled flush irrigation. Each spray consisted of 1 lb. technical DDT per feddan and was applied by aircraft in 2 gals, of spray per feddan.

Systematic observations were made on the incidence of cotton pests in 30 observation stations scattered throughout the Gash Delta, such stations being selected more or less at random from cotton sprayed once and twice and unsprayed, ten amongst each of these three treatments.

A single DDT spray applied 50–70 days after sowing gave entirely satisfactory control of the Jassid, Empoasca lybica (de Berg.), and the thrips, Hercothrips fumipennis Bagn. & Cam. and H. sudanensis Bagn. & Cam., throughout the growth of the crop. There was little lasting control of the flea-beetle, Podagrica puncticollis Weise. The second spray, applied 70–90 days later, had little effect on any of these pests which were then present in low numbers.

The incidence of bollworms was observed between December and March, covering the important fruiting period. During these months, over 70 per cent, more larvae of Diparopsis watersi (Roths.) and 40 per cent, more larvae of Earias insulana (Boisd.) were observed on sprayed than on unsprayed cotton. Significantly more larvae of D. watersi were recorded on cotton sprayed twice than sprayed once; conversely, significantly fewer larvae of E. insulana were recorded on twice- than on once-sprayed cotton. Moreover the estimated total number of fruits damaged by or shed in association with bollworm attack between January and March was over 30 per cent, greater, and nearly 30 per cent, more bollworm damage to nearly mature bolls was recorded between December and March, on sprayed than on unsprayed cotton.

Yields of seed cotton were significantly less from twice-sprayed than from the other treatments. Once-sprayed cotton yielded less but not significantly so, than unsprayed cotton. Yield was negatively correlated with the number of sprays but the correlation coefficient just failed to reach significance.

Further analysis of the data from stations where yield differences were most marked indicated that D. watersi lowered the yield potential of the crop as expressed by fruit production and retention, as a result of continuous shedding of the damaged fruit. Attack, however, was concentrated on cotton with the best yield potential. The effect of spraying was to increase the numbers of D. watersi and thus to give rise to excessive shedding, increased production of fruit primordia, an increased number of damaged bolls, and finally reduced yield.

It is concluded that any benefits which the crop enjoyed, as a result of elimination of leaf-feeding insects by DDT spray, were completely lost through increased bollworm attack, which moreover reduced the yield below that of unsprayed cotton.

The following are preliminary diagnoses of new species of Culicidae from Kuching, Sarawak. The specimens were received from Mr. J. C. Moulton, and either were collected by the donor, or formed part of the old collection of mosquitos in the Sarawak Museum, which was for the most part obtained in the neighbourhood of Kuching by Messrs. J. Hewitt and J. E. A. Lewis. The types are all in the British Museum.

The mosquito fauna of Egypt appears to have received very little attention hitherto, and very few species have been recorded from this country up to the present.

The following list of species is based chiefly on the collection of the Ministry of Agriculture, and is supplemented by references to species recorded by other observers but not taken by us. The synonymy used is that proposed by Mr. F. W. Edwards in his papers:—“ The African Species of Culex and allied Genera ” (Bull. Ent. Res., ii, p. 241, 1911); “ Further Notes on African Culicidae ” (Bull. Ent. Res., iv, p. 47, 1913); “ Key for determining the African Species of Anopheles ” (Bull. Ent. Res., iii, p. 241, 1912), excepting where the contrary is stated.

Detailed data from a preselected release site in Tanzania were collected preparatory to testing the insect sterility concept against Glossina morsitans morsitans Westw. The site was at Mkwaja Ranch, a north-eastern coastal cattle-ranching enterprise, in which about 195 km2 was encompassed by a 1-km-wide fly barrier constructed at an average cost of $37/ha. Weekly surveys of flyround transects spaced 1 km apart were conducted over a 14-month period. The estimated male density of G. m. morsitans in the release site was about 630/km2 and for G. pallidipes Aust., 255/km2. The only other species of tsetse found was G. brevipalpis Newst., which was restricted to drainage areas during periods of low rainfall.

Anastatus umae sp. n., a parasite in the oothecae of two Indian species of cockroaches, mainly of Neostylopyga rhombifolia (Stoll), is described. It is assigned to Cladanastatus subgen. n. of Anastatus, based mainly on the branched antennae in the male and on some less conspicuous characters of the female. Eupelmus leithi Wlk., another Indian species, is transferred to Anastatus. In addition, two other parasites of Indian cockroaches, Tetrastichus hagenowii (Ratz.) and T. asthenogmus (Wtstn.), which were confused as a single species, T. hagenowii, in the synopsis of the cockroaches and their parasites by Roth & willis in 1960, are separated.

Details are given of the construction of an all-metal form of locust rearing cage which possesses several advantages over the more usual wooden type.

Age composition of the filarial vector mosquito Culex quinquefasciatus (Say) was determined by examining the number of ovariolar dilatations of 1200 adult females from Calcutta. Average duration of the gonotrophic cycle was 4.5 days. The proportion parous, the daily survival rate and daily mortality rates of the natural population were 0.53, 0.87 and 13%, respectively. The oldest mosquito sampled in the study area passed eight gonotrophic cycles in its lifetime.