During 1972–74, 13 865 female mosquitoes of 25 species from eight genera were collected at the Kisumu heronry using light-traps, chicken-baited traps and battery-driven aspirators. A total of 3298 of these were engorged and 2169 were subjected to precipitin testing in order to determine their food sources. A high percentage of feeds on birds was recorded for Coquillettidia karandalaensis (Wolfs) (96%), Culex poicilipes (Theo.) (82%), and C. univittatus gp (65%); Mansonia uniformis (Theo.), M. africana (Theo.) and C. antennatus (Becker) were found to feed on birds occasionally. Results from catches in CDC light-traps set at various heights in trees with nesting birds indicated that C. univittatus gp, C. poicilipes and Aedomyia africana Nev.-Lem. were active in the upper levels of the canopy. Further analysis of blood-meals from birds indicated that C. univittatus gp mosquitoes were feeding principally on ciconiiform birds. Any mosquito which feeds regularly on birds and man must be considered as a potential vector of arboviruses; the results indicate that the most important vectors at Kisumu are probably C. univittatus gp mosquitoes.

Through the kindness of Mons. E. Séguy, of the Muséum d’Histoire Naturelle, Paris, I have recently been enabled to examine a considerable number of mosquitos from Madagascar and the neighbouring French islands, including the types or co-types of all the species described from Madagascar by Ventrillon. As the examination of this material has disclosedthe existence of several species hitherto unrecorded from these islands, aswell as some new synonymy, it has been thought desirable to record the results at once. In the following pages all the species of mosquitos hitherto known from this region are dealt with. The total number is only 28, as compared with about 180 in the African fauna, so that it is highly probable that further collecting would produce many others.

The garden chafer, Phyllopertha horticola (L.), has been recorded in most counties of England and Wales (43 out of 52) and is probably to be found in all. It is more abundant the warmer and wetter the region, i.e., it is more abundant in the west and south and most abundant in the south-west. It flourishes best in permanent pasture on light soil in hilly country, and occurs from sea-level to an altitude of at least 1,160 ft.

Patchiness in local distribution was investigated on the pastures of fell farms in the Lake District.

An infested fell pasture includes from one to five plant associations which are described as (1) Grass, (2) Sparse Bracken, (3) Bracken Bed, (4) Heath Rush and (5) Common Rush. Typically, all five are present in a pasture. The proportions of ground covered by grass turf (Agrostis-Festuca) in these associations are (1) 100 per cent., (2) 99 per cent., (3) 0 per cent., (4) 80 per cent, and (5) 50 per cent., the grass turf in the rush associations (4 & 5) filling the spaces between clumps of rushes. Soil stages of the garden chafer are found only in the grass turf and so the Bracken Bed association is never infested. In terms of density per unit area of ground, the other four associations exhibit the following relation between their infestations: Grass>Sparse Bracken>Heath Rush>Common Rush. This relation is only partly explained by the similar relation between proportions of ground covered by grass turf (see above). As to other factors that might be partly responsible, no correlation exists between botanical characteristics of grass turf and infestation but there are two negative correlations among physical characteristics which are suggestive: Grass and Sparse Bracken-<Heath Rush and Common Rush with respect to toughness of turf; and Grass<Sparse Bracken<Heath Rush<Common Rush with respect to wetness.

Grassland, an unbroken expanse of grass sward, is, in the Lake District, by far the most important habitat since it carries by far the greatest part of the garden chafer population.

In grassland no evidence was found of an association between density of soil stages and proximity to bracken.

The population of any soil stage, from egg to pupa, is always much greater in drier than in wetter parts of grassland.

Sampling at intervals within a generation indicated that the mortality rate is higher in the wetter parts of grassland. This is not due to any lack of food, or difficulty of utilising it, or to the presence of more enemies (competitors, predators, parasites and pathogens) in the wetter parts, but, as established by laboratory and field experiments, is attributable to a direct effect of moisture. Further experiments suggested that the egg stage is most and the feeding stages are least resistant to excessive moisture.

Field experiments also indicated that the so-called ‘effective bee-liners’, females characterised by a direct and sustained flight from their roosting sites and that lay some eggs far afield, exercise some degree of discrimination in the choice of oviposition sites, the majority tending to choose the drier parts of grassland, the kind of site that does in fact, become more highly infested. Less than a quarter of all females become effective bee-liners and as such lay only about 15 per cent, of all eggs deposited by a population.

There is a dynamic aspect to the phenomenon that population is greater in drier than wetter parts of grassland. Although population is always greater in the drier parts, the magnitude of the population ratio between drier and wetter parts can change considerably from one year to the next as a result of either excessive rain or excessive drought during the larval feeding period. The mechanism of such change is indicated.

Spatial distribution on grassland was assessed statistically by employing Fisher's Coefficient of Dispersion. Eggs, and hence newly hatched larvae, are strongly aggregated. This strong degree of aggregation is gradually lessened, however, by the subsequent wanderings of the larvae in the course of feeding. Nevertheless, even in the final instar, larvae are still appreciably aggregated and hence so also are pupae. By the end of the feeding period, average dispersal from the hatching point is probably not more than 12 inches.

Apart from proper food, which is provided by grassland, the most important living condition for the garden chafer in the soil appears to be proper soil moisture. Although actual limits have not been specified, survival clearly depends on the soil containing neither too much nor too little water for too long.

As regards geographical distribution in England and Wales, the finding that the garden chafer is more abundant the warmer and wetter the climate is explained as follows. Females grow larger, and hence produce more eggs, where the larval feeding period is warmer, and more larvae survive where the climate is wetter, because the greater rainfall means less chance of too little water for an animal that has to live in freely draining soil to avoid too much water.

Fundamentally, the patchy local distribution of the garden chafer is mainly a matter of the patchiness of soil-moisture conditions. The patchiness determined by these conditions is maintained and intensified by the reproductive behaviour of the adults.

Accounts of other species in this and other countries suggest that, for pasture scarabs in general, soil moisture is the chief factor concerned in determining spatial distribution.

Male bushflies (Musca vetustissima Wlk.) are attracted to and feed on proteincontaining substances, although under laboratory conditions they ingested smaller quantities of blood and dung than did the females. Laboratory experiments showed that they are able to obtain water from fresh dung and blood, but no physiological requirement for the protein was found. Feeding on protein did not increase the life span or the total numbers of matings; it did not improve the mating success of males that had previously been multiple-mated; and it did not enhance sexual activity, contrary to the situation found in Lucilia cuprina (Wied.). It is concluded that protein feeding in male bushflies is casual, possibly a behaviour pattern that ensures their presence near females.

The habits and habitations of the natives in the Bwamba lowlands, Uganda, are briefly described.

A series of catches designed to assess the relative importance of the various species of biting insect and of various routes of transference in the transmission of yellow fever virus from the monkey population of the forest to the nearby human population is reported.

The microclimate in a native hut is discussed.

The species of biting insect encountered are listed, the results of the catches given, and the relative importance of the different species and routes assessed by means of indices.

It is concluded that yellow fever virus is most likely to be transferred to the native population by A. (S.) simpsoni in plantations, the infection in this insect being derived from forest monkeys which raid the plantations for food.

This paper reports the results of a field experiment on Florida beach, Falmouth, Jamaica, in which continuous observations were made on the biting rates of Culicoides furens (Poey) (7 707 specimens) and C. barbosai Wirth & Blanton (3 793 specimens) over two 48-h sessions in January 1960. Catches were standardised by the use of correction factors previously calculated. The standardisation experiments also provided additional information on parts of the 24-h cycle, particularly sunrise and sunset.

The population dynamics of three vectors of rice tungro viruses (RTV), Nephotettix virescens (Distant), N. nigropictus (Stål) and Recilia dorsalis (Motschulsky), were investigated in farmers' fields in the Philippines from 1979 to 1984. R. dorsalis was the most abundant vector species on the rice seedbeds and weed covered levees between rice-growing seasons, whereas N. virescens was the most abundant on the rice crop. Population curves for the three species were similar in the same season, suggesting common population-regulating processes. Adults and nymphs of all three species were present at the sampling site during a four-month fallow period between crops.

The main purpose of the investigation was to determine when larviposition occurs in these laboratories, under conditions of constant temperature, relative humidity and light cycle.

1. An account is given of two organised grass fires carried out in the Lomagundi fly-belt of Southern Rhodesia in the years 1927 and 1928, as a method of controlling G. morsitans.

2. The effect of these fires on the flora and game is described, and details given of the immediate effect of these fires on both the adult fly and the puparia. The effect on the adult fly was to concentrate it along the shady watercourses and other parts of the forest where the fires were less fierce and the requisite shade was to be found.

3. On the puparia, no immediate effect was noticeable. The number of dead puparia collected increased during October and November, and this is considered to be attributable to the lethal effects of the sun, not of the fire.

4. The pupal period of the fly decreases from eighty-two days for puparia collected in June, to twenty-one days for puparia collected in November. The period of greatest activity of the fly, as indicated by emerging flies, density and collected puparia, is in September.

5. A short account is given of the trypansome infection and food of the fly. On the average 11 per cent. of the flies are infected with pathological trypansomes in the proportion of ten congolense group to seven vivax group. Only one infection of the gland was found out of 1,523 dissections. There is a tendency for the percentage of infected flies to increase during the late dry season. This rise coincides with the increased visibility of the game. Examination of the fat content failed to indicate any degree of starvation amongst the flies.

The food of the fly consists almost entirely of mammalian blood, only one case of avian blood being found.

6. A final decision has not yet been pronounced upon the efficacy of grass fires as a means of controlling G. morsitans in Southern Rhodesia.

Blood smears from 378 examples of Glossina morsitans Westw. from the Daga-Iloi fly-round were tested by serological methods, including a new test involving the inhibition of agglutination of tanned red blood cells.

About half the feeds were derived from wart-hog or bushpig, though these apparently formed only some ten per cent, of the ungulate mammals present.

A procedure for rearing Clavigralla tomentosicollis Stål on dry seeds of cowpea (Vigna unguiculata) is described. Dry seeds produced results for nymphal development and adult oviposition similar to those from fresh pods and fresh seeds, which are more frequently fed on by the insect in nature. The rearing method described here is much more efficient in terms of time and manpower requirements than the widely used method using fresh pods. Furthermore, the dry-seed procedure may be adapted for rearing other hemipteran pod pests of legumes.

Gamma BHC, aldrin, dieldrin, endrin, DDT and parathion have been tested as seed dressings in field experiments for the control of wheat bulb fly, Leptohylemyia coarctata (Fall.), in eastern England. The concentrations ranged from 20 to 70 per cent, and the dressings were applied at 2–3 oz./bushel.

At concentrations of 40 per cent, or over, the first three materials appreciably reduced attack and at high infestations increased yield; within the period October to January their effectiveness increased the later the wheat was sown. There was evidence that they were less effective on highly organic soils. The other materials were either less effective or had other disadvantages.

Seed dressings of γ BHC usually reduced the number of larvae entering the plant but had little effect on larvae which succeeded in entering. Aldrin and dieldrin and probably most other materials usually had less effect on the entry of larvae but were very effective in killing larvae after entry so that the plant could subsequently recover.

Combine-drilling of aldrin or dieldrin affected the larvae in the same way as seed dressings; in one season on a peaty soil seed dressings were more effective than combine-drilling, but in another season on a mineral soil seed dressings were slightly less effective than combine-drilling. However, it was clear that with combine-drilling very much higher quantities of insecticide per acre were needed to achieve a comparable result. Both aldrin and dieldrin gave similar results.

While seeking food sources and routes back to their hive, bees make use of their advanced nervous and sensory capacities, which underlie a diverse behavioral repertoire. One of several honeybee senses that is both exceptional and intriguing is magnetoreception – the ability to perceive the omnipresent magnetic field (MF) of the Earth. The mechanism by which animals sense MFs has remained fascinating as well as elusive because of the intricacies involved, which makes it one of the grand challenges for neural and sensory biology. However, investigations in recent years have brought substantial progress to our understanding of how such magneto-receptor(s) may work. Some terrestrial animals (birds) are reported to be equipped even with a dual perception system: one based on diminutive magnetic particles – in line with the original model which has also always been hypothesized for bees – and the other one, as the more recent model describes, based on a sensitivity of some photochemical reactions to MF (radical-pair or chemical mechanism). The latter model postulates a close link to vision and supposes that the animals can see the position of the geomagnetic North as a visible pattern superimposed on the picture of the environment. In recent years, a growing body of evidence has shown that radical-pair magnetoreception might also be used by insects. It is realistic to expect that such evidence will inspire a re-examination and extension or confirmation of established views on the honeybee magnetic-compass mechanism. However, the problem of bee magnetoreception will not be solved at the moment that a receptor is discovered. On the contrary, the meaning of magnetoreception in insect life and its involvement in the orchestration of other senses is yet to be fully understood. The crucial question to be addressed in the near future is whether the compass abilities of the honeybee could suffer from radio frequency (RF) smog accompanying modern civilization and whether the fitness of this dominant pollinator might be affected by RF fields. The goal of this review is to provide an overview of the path that the behavioral research on honeybee magnetoreception has taken and to discuss it in the context of contemporary data obtained on other insects.

Some eggs of Ephestia cautella (Wlk.) and E. kuehniella Zell. hatched after exposure to near 100% atmospheres of nitrogen (N2) or carbon dioxide (CO2) for up to 5 days at 15°C, 3 days at 20°C and 1 day at 25°C. The most tolerant age at the start of treatment at 25°C in E. cautella was 7–24 h after oviposition for CO2 and 7–30 h for N2. Generally, hatch was lower in CO2 than in N2 whatever the exposure, and lower for E. kuehniella than for E. cautella. Considerably more eggs of E. cautella aged 30 and 42 h hatched after exposure to N2 than to CO2, showing a toxic effect of CO2 in the absence of oxygen. Eggs of both species treated with either CO2 or N2 hatched 1–2 days later than controls, regardless of age or percentage survival.

The diamondback moth (DBM, Plutella xylostella L. (Lepidoptera: Plutellidae)) consumes a wide variety of brassicaceous host plants and is a common pest of crucifer crops worldwide. A highly unusual infestation of a sugar pea crop was recorded in Kenya in 1999, which persisted for two consecutive years. A strain (DBM-P) from this population was established in the laboratory and is the only one of several strains tested that can complete larval development on sugar peas. The oviposition acceptance and preference of the DBM-P strain was assessed in the presence of cabbage plants, sugar pea plants or both, in comparison to another strain (DBM-Cj) that was collected from cabbage and is unable to grow on pea plants. As expected, DBM-Cj females preferred to oviposit on cabbage plants. Surprisingly, DBM-P females also laid most eggs on cabbage and very few on peas. However, they laid significantly more eggs on the cabbage plant when pea plants were present. Our findings suggest that DBM-P manifested the initial stages of an evolutionary host range expansion, which is incomplete due to lack of oviposition fidelity on pea plants.

Pyrethroid and carbamate resistance was evaluated in Helicoverpa armigera from 2008 to 2015. Insects were collected as eggs primarily from cultivated hosts in the major cropping areas of New South Wales and Queensland, Australia. Larvae reared from eggs were tested for resistance to fenvalerate, bifenthrin or methomyl in the F0 generation using a topical application of a discriminating dose of insecticide. In 2008–2009, resistance to fenvalerate was 71% and no resistance to bifenthrin was recorded. In the following two seasons, resistance to pyrethroids was relatively stable with fenvalerate resistance ranging from 63% to 67% and bifenthrin resistance ranging from 5.6% and 6.4% in 2009–2010 and 2010–2011, respectively. However, in 2011–2012, pyrethroid resistance had increased to 91% and 36% for fenvalerate and bifenthrin, respectively. Resistance remained above 90% for fenvalerate and above 35% for bifenthrin in the following three seasons from 2012 to 2015. In 2008–2009, methomyl resistance was 33% and declined to 22% and 15% in 2009–2010 and 2010–2011, respectively. Methomyl resistance remained at moderate levels from 2011–12 to 2014–15, ranging from 21% to 40%. Factors that influenced selection pressure of pyrethroid and carbamate insecticides and impacted resistance frequency in H. armigera may have been associated with changes in the composition of the cropping landscape. The rapid expansion of the pulse industry and the commensurate increased use of insecticide may have played a role in reselection of high-level pyrethroid resistance, and highlights the need for an urgent and strategic response to insecticide resistance management in the Australian grains industry.

In biological control programmes introduced natural enemies compete with indigenous enemies for hosts and may also engage in intraguild predation when two species competing for the same prey attack and consume one another. The large pine weevil, Hylobius abietis L. (Coleoptera: Curculionidae), is an important pest of coniferous reforestation in Europe. Among its natural enemies, the parasitoid Bracon hylobii Ratz. (Hymenoptera: Braconidae) and entomopathogenic nematodes have potential as biological control agents. Both parasitoid and nematodes target the weevil larvae and, hence, there is potential for competition or intraguild predation.

In this study, we examine the interaction of B. hylobii with the nematode Heterorhabditis downesi Stock, Griffin and Burnell (Nematode: Heterorhabditidae), testing the susceptibility of larvae, pupae and adults of B. hylobii to H. downesi and whether female parasitoids discriminate between nematode-infected and uninfected weevils for oviposition. In choice tests, when weevils were exposed to nematodes 1–7 days previously, no B. hylobii oviposited on nematode-infected weevil larvae. Up to 24 h, healthy weevils were twice as likely as nematode-infected ones to be used for oviposition. Bracon hylobii females did not adjust clutch size; nematode-infected hosts were either rejected or the parasitoid laid a full clutch of eggs on them.

When nematodes were applied to the parasitoid feeding on weevil larvae, the nematodes parasitized the parasitoid larvae, there was a reduction in cocoon formation and fewer cocoons eclosed. Eclosion rate was not reduced when nematodes were applied to fully formed cocoons, but nearly all of the emerging adults were killed by nematodes.

Extreme climate events such as heat waves are predicted to become more frequent with climate change, representing a challenge for many organisms. The pine processionary moth Thaumetopoea pityocampa is a Mediterranean pine defoliator, which typically lays eggs during the summer. We evaluated the effects of heat waves on egg mortality of three populations with different phenologies: a Portuguese population with a classical life cycle (eggs laid in summer), an allochronic Portuguese population reproducing in spring, and a Tunisian population from the extreme southern limit of T. pityocampa distribution range, in which eggs are laid in fall. We tested the influence of three consecutive hot days on egg survival and development time, using either constant (CT) or daily cycling temperatures (DT) with equivalent mean temperatures. Maximum temperatures (Tmax) used in the experiment ranged from 36 to 48°C for DT and from 30 to 42°C for CT. Heat waves had a severe negative effect on egg survival when Tmax reached 42°C for all populations. No embryo survived above this threshold. At high mean temperatures (40°C), significant differences were observed between populations and between DT and CT regimes. Heat waves further increased embryo development time. The knowledge we gained about the upper lethal temperature to embryos of this species will permit better prediction of the potential expansion of this insect under different climate warming scenarios.

In this paper we describe acoustically the wing-fanning behaviour showed by the male of the braconid Psyttalia concolor towards females and other conspecific males. Psyttalia concolor is a synovigenic koinobiont larval–pupal endoparasitoid of many Tephritidae, used in olive crops to control the olive fruit fly, Bactrocera oleae. In this braconid male wing fanning produces a courtship song characterised by sequences of homogenous pulses with harmonic structure and a fundamental frequency of about 180 Hz. Song parameters can vary according to the behavioural context. Statistically significant differences, both in terms of pulse frequency and duration, characterise fanning towards females in comparison with male–male approaches. Moreover, the pulse duration is associated with the fanning song displayed before a successful courtship. Our observations allowed us to define the airborne component of the sound and to definitely confirm the exclusive role of the wings in signal production within sexual communication in P. concolor.

Three cryptic species, Aphis gossypii, Aphis glycines, and Aphis rhamnicola sp. nov., are recognized as sharing buckthorn plant, Rhamnus spp. as primary hosts. These aphid species have morphological similarities; however, there are significant genetic differences between the three cryptic species. Based on the high level of genetic divergence and the different secondary host association, we described a new species, Aphis rhamnicola sp. nov., for apterous and alate vivipara, fundatrix, ovipara, and gynopara, including diagnostic key for the host sharing species in the genus Aphis.