Tribolium castaneum Herbst 1797 (Coleoptera: Tenebrionidae), an important pest of stored grains and byproducts, is naturally infected by Gregarina cuneata Stein 1848 (Apicomplexa: Gregarinidae). Changes in the life cycle of insects caused by the parasite development in the midgut were studied. Trophozoites, gamonts (solitary and associated), and gametocysts were present in the midgut of the insects. In young trophozoites, the apical region differentiated into an epimerite that firmly attached the parasite to the host epithelial cells. With maturation, trophozoites developed in gamonts that were associated with the initiation of sexual reproduction in the cell cycle, culminating in the formation of the spherical gametocyst. Morpho-functional analyses indicated that gregarines absorb nutrients from infected cells and can occlude the midgut as they develop. Consequently, nutritional depletion may interfere with the host's physiology, causing decreased growth, delayed development, and high mortality rates of the parasitized insects. These results suggest G. cuneata could be an important biological agent for controlling T. castaneum in integrated pest management programs.

Weekly catches of five species of mosquitoes over nearly two years at Belém, Brazil, were plotted against accumulated rainfall during the four weeks before catching. Rain-pool-breeding species (Aedes serratus (Theo.), A. scapularis (Rond.), Psorophora ferox (Humb.)) show a marked peak in catch size (population density) at 100–180 mm accumulated rainfall; one swamp-breeding species (Culex portesi Senevet & Abonnenc) shows no relation to rainfall while another (C. taeniopus D. & K.) reaches a plateau at 180 mm. A more detailed analysis of catches in relation to rainfall distribution showed that maximal populations of A. serratus appear 16 days after 39.7–87.9 mm of rainfall has accumulated over 14 consecutive days, which should include 3–7 dry days; P. ferox requires 55.2–99.4 mm rainfall in the same period; and A. scapularis requires 26.5–114.9 mm rainfall, with a marked alternation of wet and dry days.

A total of 167 blood-fed mosquitoes of the genera Ficalbia, Mimomyia and Uranotaenia was collected from the Kisumu area of Kenya using Monks Wood light-traps under the outside eaves of houses, CDC light-traps inside houses and sweep-net catches. Precipitin tests were used to obtain 72 positive identifications of the hosts, 89% of which were amphibia. M. mediolineata (Theo.) and M. splendens Theo. were shown to feed occasionally on man while U. balfouri Theo. and M. hispida (Theo.) were shown to feed on other mammals, including cattle. No identification was effected from a single F. uniformis (Theo.) specimen collected resting in vegetation. The medical importance of these mosquitoes is uncertain but, since there is evidence for several arboviruses in amphibia, further study of these potential vectors should be undertaken.

Hourly trap catches of Delia radicum (L.) from opposite sides of host-plant (cabbage) and non-host-plant (carrot) plots in eastern England were analysed with respect to local wind direction, wind speed, temperature and humidity. More females were caught around host- than non-host-plant plots. They predominantly approached host-plant plots by upwind movement, but equal upwind and downwind movement occurred to non-host-plant plots. A generalized linear model revealed that wind speed and humidity influenced the total trap catch of females, with wind speeds below 2 m/s and relative humidities above 65% being most favourable to fly activity, while wind speed was the only variable having a significant effect on the trap catches of flies moving upwind to host-plant plots.

Digestion in the larger black flour beetle, Cynaeus angustus (LeConte), was studied to identify new control methods for this pest of stored grains and grain products. The physiological pH of the larval gut, as measured with extracts in water, was approximately 6.1, and the pH for optimal hydrolysis of casein by gut extracts was 6.2 when buffers were reducing. However, under non-reducing conditions, hydrolysis of casein and synthetic serine proteinase substrates was optimal in alkaline buffer. Three major proteinase activities were observed in zymograms using casein or gelatin. Caseinolytic activity of C. angustus gut extracts was inhibited by inhibitors that target aspartic and serine proteinase classes, with minor inhibition by a cysteine proteinase inhibitor. In particular, soybean trypsin and trypsin/chymotrypsin inhibitors were most effective in reducing the in vitro caseinolytic activity of gut extracts. Based on these data, further studies are suggested on the effects of dietary soybean inhibitors of serine proteinases, singly and in combination with aspartic and cysteine proteinase inhibitors, on C. angustus larvae. Results from these studies can be used to develop new control strategies to prevent damage to grains and stored products by C. angustus and similar coleopteran pests.

Surveys of parasites of Sylepta derogata (F.) on cotton at Ibadan, Nigeria, in 1979–80 showed that there were three larval parasites: Apanteles syleptae Ferrière, A. sagax Wlkn. and Charops sp. An average of 17·7% parasitism was recorded, and A. syleptae accounted for 98·6% of this. There were three pupal parasites: the chalcidid Brachymeria feae Masi, the ichneumonid Xanthopimpla sp. and the tachinid Cadurcia auratocauda (Curr.). Together, they caused an average of 31·7% parasitism. Xanthopimpla was the most abundant, while B. feae was of secondary importance.

The response of F1 larvae from reciprocal crosses of susceptible × organophosphorus-resistant strains of Lucilia cuprina (Wied.) to diazinon was intermediate in relation to that for larvae from the parental lines to the chemical. Exposure to a concentration of 0·4 p.p.m. diazinon for 24 h was lethal to susceptible larvae. Close agreement with 1:1 ratios of susceptible: hybrid resistant larvae was obtained when larvae from a repeat backcross series were exposed to 0.4 p.p.m diazinon in each generation. Additionally, there was correspondence between response lines for larvae of backcrosses 1 and 3. This information, plus the recovery of a homozygous-resistant sub-strain by exposure of F2 larvae to a level of the chemical that discriminated against susceptible and hybrid genotypes, suggest that diazinon resistance in the larvae is due to a major allele.

Turfgrass applications of imidacloprid were previously shown to suppress the abundance of certain soil arthropods. To ascertain whether those impacts harbor functional consequences, the effect of neonicotinoids on Japanese beetle (Popillia japonica Newman) predation was examined in three experiments that measured removal of eggs implanted into non-irrigated field plots. A first experiment confirmed that a single imidacloprid application reduced the abundance of nontarget fauna and the rate of egg removal. A second experiment compared the impacts of imidacloprid with those of three other neonicotinoids, while a third measured the impact of imidacloprid when applied in July, August or September. Egg removal declined 28.3–76.1% in imidacloprid-treated plots across all studies. Effects were detected as early as one week after treatment (WAT) and persisted as long as four WAT. The extent of suppression did not vary across month of application. Clothianidin, dinotefuran and thiamethoxam also suppressed egg removal, and the effects were similar among them and with imidacloprid. There was no discernible association between variation in rainfall and treatment effects, but this was not explicitly tested. Results support the hypotheses that a single neonicotinoid application can suppress predation on pest populations and that the effect does not vary with respect to active ingredient or season of application. Neonicotinoid application at the time of beetle oviposition puts intended effects (mortality of neonates) in conflict with unintended effects (disruption of egg predation). The conservation of predation on early life stages might buffer the reduced efficacy of late season applications that target more advanced instars. As application timing and post-application irrigation affect insecticide performance, they might also be manipulated to reduce nontarget effects.

Several months' constant traveling in the “proclaimed area” has led the writer to conclude that it contains at least four “primary centres” which harbour tsetse-flies, situated as shown on the map as follows:

No. 1, opposite Rifu, near Patsanjoka Marsh ;

No. 2, W. & S.W. of Kuti Marsh ;

No. 3, at Nyansato near the Chitawa Marsh ; and

No. 4, along and on each side of the Lingadsi River, between Long. 38° 8′ and 34° 13′ E.

The formulation and weathering properties of toxic bait developed for the control of Anoplolepis longipes (Jerd.) in the Seychelles is described. The bait, based on a carrier of sieved coir waste (available locally), was designed to simulate the protein requirements of the ant colony and incorporated yeast extract as a major attractant. It was easy to produce and remained attractive to ants in the field for at least a week under normal weather conditions. The bait could be stored for more than two weeks under ambient conditions in the Seychelles at 23–35°C and 60–95% RH or for about 10 weeks under air-conditioning at 22–29°C and about 60% RH.

In previous papers (1917,1921) accounts have been given of four species of the genus Bibio, and the present paper deals with two species of the genus Dilophus, viz., D. febrilis, L., and D. albipennis, Mg. They are the commonest species of Dilophus in Britain, and both frequently occur in great numbers.

In the British Solomon Islands Protectorate Agricultural Gazette (1 no. 3, pp. 2–3, pl. i, July 1933) Mr. R. J. A. W. Lever has described and illustrated the life-history of a Coreid which is injurious to the inflorescence of the coconut palm. This species which had previously been provisionally referred to the genus Dasynus now proves on further investigation to be referable to the closely allied genus Amblypelta, and is herewith described.

Observations in the laboratory on the larva of Glossina tachinoides and G. submorsitans show that in both species it is slow in crawling and burrowing and often cannot burrow at all. It penetrates coarse sand more readily than fine, and fine sand than wood ash, and burrows easily in fine sand with pebbles. In nature it probably always burrows eventually, unless it is attacked by predators or parasites to which its behaviour renders it vulnerable.

Previous field work indicates that the depth to which the larvae burrow influences the effect of predators and parasites and sometimes of solar radiation on the puparia. Records of breeding-places suggest that larvae often crawl over hard soil to reach suitable places in which to burrow, and that unless the female fly, before depositing a larva, carefully selects such a place, the mortality due to other insects is probably high.

A vehicle-mounted net was used to study the circadian flight activity of several species of Simulium in a northern Guinea savanna area in Nigeria during the dry season. The sampling method yielded large numbers of both sexes of Simulium squamosum (Endertein) of the, S. damnosum Theobald complex, S. hargreavesi Gibbins, S. vorax Pomeroy, S. adersi Pomeroy, S. hirsutum Pomeroy and other species. The main peak of activity of all species recorded occurred just after sunset and there was a smaller peak just before sunrise. Flies continued to be caught at a low level 2·5 h after sunset when sampling ceased. Differences in the activity patterns of S. squamosum males and females and of the other species were analysed. Of the S. squamosum females caught, 12% were blood-fed; these and gravid females were mainly active in the evening, while the blood-thirsty flies had a high level of activity throughout the day. Differences between species in the relative activity of blood-thirsty and gravid flies, and nulliparous and parous flies are noted.

Three suitable sex pheromone trap designs for trapping the red bofiworm of cotton, Diparopsis castanea Hmps., including a simple omnidirectional monitoring trap, are described. In trials in Malawi, Diparopsis was more readily trapped on open horizontal trapping surfaces (water or adhesive) than in enclosed types of traps. The presence of a roof above the trapping surface, at spacings of up to 20 cm, significantly reduced catches. White traps, or unpainted traps in the case of vane traps constructed from galvanised metal, caught more moths than traps of other colours. Catches were greatest when monitoring traps in cotton were placed at ground level or at a height of 0·5 m and, when dicastalure was released from polyethylene vials, by employing a trap 60 cm in diameter. Evidence was obtained that competition may exist between female-baited traps spaced up to 73 m apart, although catches in traps baited with dicastalure were not significantly different when traps were 40–60 m apart. The greatest catches of moths in cotton were in traps located in insecticide-sprayed fields, but moths were also trapped in considerable numbers in other crops and to a reduced extent in open areas 4·8 km from the nearest cotton. From about the end of February, catches in maize, groundnut and fallow areas frequently exceeded the catches recorded within cotton fields, which may indicate an increased dispersal flight from cotton by adult moths later in the season. Weekly replacement in monitoring traps of polyethylene vials containing dicastalure produced maximum moth catches, but there was no significant difference in catch between traps in which pheromone was replaced at intervals of 2, 3, 4 or 6 weeks.

Records are given of the localities (with altitudes) of approximately 900 specimens representing 21 species of Diatraea Guild, and four species of Zeadiatraea Box, from Mexico, Central and South America. Most of the moths were reared from known food-plants (all Gramineae) and the larvae of several of them are important agricultural pests as stalk-borers in sugar-cane and maize.

Three species of Diatraea are described as new to science and their genitalia are figured, viz., colombiana, sp.n. (Colombia), balboana, sp.n. (Panama) and veracruzana, sp.n. (Mexico). The previously unknown male of D. instructella Dyar (Mexico) is described and its genitalia figured. These moths (except colombiana) are illustrated in the Plate. An attempt is made to clarify the confusion which has existed concerning D. magnifactella Dyar and the closely related D. considerata Heinrich, both of which are endemic in Mexico, but each with its own area of distribution without overlapping. The paper includes additional records and observations on the polytypic D. busckella Dyar & Heinrich and certain of its subspecies in Panama and Venezuela, previously discussed by the writer in this journal in 1951.

The relative attractiveness of coloured sticky board traps to the carrot fly (Psila rosae (Fabricius)) is described by a model in which fly catch is related positively to the amount of light reflected from the trap in the green-yellow (550–570 nm) band of the spectrum and negatively to the amount reflected in the violet-green (390–550 nm) band. The model allows the performance of new coloured traps to be predicted solely from spectral reflectivity measurements. Similar numbers of carrot flies were caught/unit area on traps varying in size from 150 cm2 to 4800 cm2. Most flies were caught on traps resting on the ground. The number of flies caught was reduced by 0.84% for each cm the trap was raised above 10 cm from the ground. One-sided sticky traps angled at 45° to the vertical doubled the numbers of carrot flies caught/unit trapping area and reduced by 90% the numbers of non-target species caught.

Trypanosome infections were monitored in three species of tsetse fly (Glossina pallidipes Austen, G. morsitans centralis Machado, and G. brevipalpis News-tead) at four locations in the Kagera River region of Rwanda from May 1989 to September 1990. Two of the four areas (Mpanga Ranch and Bukora Ranch) were subjected to tsetse fly suppression operations with odour-baited traps. Proboscis infections of the Trypanosoma congolense and T. vivax types accounted for roughly equal numbers of the 207 mature infections detected (3.8%). Variation in infection rates was area-specific rather than tsetse species-specific. Order of magnitude differences in tsetse fly densities among areas were not correlated with differences in infection rates at the start of tsetse fly suppression operations. Similarly, declines in population density on both control and experimental areas were not associated with significant changes in infection rates. The prevalence of trypanosomiasis in cattle at Bukora Ranch was not affected by a roughly 90% reduction in Glossina densities. T. congolense accounted for 79% of the infections at an overall prevalence rate of 5.5%. Trypanosomiasis in cattle persisted at extremely low densities of about 0.1 fly/trap/day. Treatment of cattle with diminazene aceturate (BereniR) suggested that many T. congolense parasites were drug resistant, and hence, were cycling among cattle due to the few Glossina present.

Of the many insects which we now know to be dangerous menaces to the health of man, the house-fly, Musca domestica, has few (if any) equals, but the facts relating to its germ-transmitting capacity are unfortunately still very incomplete. In the case of those Anopheline mosquitos which transmit the parasites of malaria, and the tsetse-flies, which infect man and other animals with trypanosomes, we are in a position to estimate the inefficiency and loss of life directly attributable to them, for in each case we know most of the species directly responsible for the dissemination of these parasites. But in the case of the house-fly we have no conclusive proof that Bacillus typhosus, for instance, is carried by one, or more than one, species of Musca. Further, by the time the cases are diagnosed, the infected flies have either died or disappeared, and it is rarely possible to trace the infection to them. It is true, however, that many observers have recorded the finding of pathogenic bacteria in, and on, species of Musca, but the final proof of the identity of these bacteria has invariably been faulty. Yet in spite of these discrepancies there is no doubt, from everyday practical observation the world over, that one, and more than one, species of Musca regularly carry the bacilli of the enteric fever, cholera and dysentery groups, as well as many other pathogenic organisms, especially the virus of trachoma, from infected material and deposit them on food and the human body. In investigating outbreaks of infectious diseases the house-fly should always be considered as a possible vector of the causal organisms.

The ecology of earwigs in natural forest ecosystems is poorly understood. We used sweeping to determine the population densities of adult earwigs, by sex and species, on ten tree species in a temperate floodplain forest in southern Moravia (Czech Republic). We also determined the relationships between the properties of tree species and earwig density and diet as indicated by digestive tract contents. The densities and diet composition of earwigs differed between the three detected earwig species [Apterygida media (Hagenbach, 1822), Chelidurella acanthopygia (Genè, 1832) and Forficula auricularia Linnaeus, 1758] and among tree species. Earwig densities were related to lichen coverage and fungal coverage on the trees. The diet of earwigs was associated with specific leaf area, herbivore damage to the leaves, and light exposure of the trees. A. media was the most abundant of the three earwig species. Although the contents of its digestive tract changed depending on available food resources, A. media appeared to preferentially consume soft-bodied insect herbivores and fungi associated with wounds caused by herbivores rather than plant material. Therefore, this species has the potential to help reduce the population densities of soft-bodied pests of forest trees.