Mixed T. congolense and T. brucei appeared in mice when proboscis from 3 field collected G. pallidipes were individually inoculated into mice. One of these flies had earlier been shown by dissection, to have T. congolense and the other two had T. brucei infection. A comparison of the growth rates of T. congolense and T. brucei in mice revealed that T. brucei always overshadowed T. congolense. These observations highlight the significance of multiple trypanosome infections in the epidemiology of African trypanosomiasis.

Egg-masses of Simulium damnosum s.l. were investigated to explain the frequent presence of undeveloped eggs in the lower layers. Natural development within egg-masses depended on whether eggs were laid (a) all at once or (b) were added to on consecutive evenings. In the field where the development of eggs from situation (a) was followed, top layer (TL) eggs hatched in 2 days when unexposed bottom layer (BL) eggs were still white. BL eggs uncovered 12 hr after oviposition were undeveloped, then hatched in 3 days. BL (a) eggs uncovered after 5 days were still untanned and undeveloped but were not further investigated.

In the laboratory, portions of egg-masses—intact or with the BLs exposed—were incubated in Petri dishes with and without preceding KOH egg separation treatment, or in flowing water. Other samples of BL eggs were incubated at different O2 levels. In Petri dishes, most TL eggs hatched within 24 hr of setting up but exposed BL eggs hatched (if at all) after much delay in 6–14 days. No unexposed BL eggs hatched even after TLs above them had done so. Transfer to flowing water or KOH treatment increased hatching and reduced the delay. Hatch rates of exposed BL eggs rose from 2.7 to 63% with increased O2 levels.

Implications with regard to laboratory culture and control operations are discussed. Mortality of covered eggs could be a potent population regulating factor within and perhaps even between species of the S. damnosum complex.

Experiments were carried out to study the effect of sublethal doses of gamma radiation (10–100 krad) on fecundity, longevity and sterility of adults of Silotroga cerealella. The results indicate that fecundity of females decreased as the dosage increased from 10–90 krad. At 100 krad no eggs were deposited. Raising the dose to 100 krad resulted in shortening the longevity to about half the longevity of the untreated moths. When irradiated females mated with similarly irradiated males, a dosage of 20 krad caused 97.17% sterility. A dose of 28 krad induced 96.69% sterility when normal females were mated with irradiated males, while 94.14% sterility resulted when normal males were mated with irradiated females.

The formation of the International Advisory Council for Biosystematic Services in Entomology (IACBSE) in Hamburg at the XVIIth International Congress of Entomology in 1984 is described and its composition and long-term objectives are stated. These include fostering the development of biosystematic research and identification services on a world basis by co-ordinating and assisting interactions and exchange of information between organizations and individuals, and by establishing a series of Working Groups on major projects. The main user needs for biosystematic services are also summarized. The particularly important needs of medical, agricultural and forestry entomology are emphasized and other needs for the support of faunal surveys, conservation, ecology, physiology, biogeography, litigation, amateur and general public interest are noted.

Laboratory studies were carried out to determine factors which induce larval diapause in a Nigerian strain of Plodia interpunctella.

Larvae reared at constant temperatures of 20 or 30°C did not enter diapause. However, 13.3 and 37.7% respectively of larvae reared for 8 or 12 days (third or fourth instars) at 30°C and then transferred to 20°C entered diapause. Larvae transferred to 20°C immediately after hatch (first instar) and after 16 days (final instar) did not enter diapause. Developmental periods from egg-hatch to adult of diapausing individuals ranged from 136 to 151 days, while those of non-diapausing individuals reared at constant temperatures of 30 and 20°C ranged from 23 to 34 days and 60 to 72 days, respectively.

Different photoperiods did not induce diapause when reared at constant temperatures but exposure of larvae that experienced a drop in temperature from 30 to 20°C, at 4th instar stage to continuous light or to a long photoperiod (light 16 hr: dark 8 hr) caused a drop in the percentage larvae that diapaused.

Larvae reared at high larval density at 30°C did not enter diapause, and increased mortality was observed.

An ecological study was conducted in two pools, one temporary and one semi-permanent at the Kenya coast to determine the relationship between infection levels of Coelomomyces indicus Iyengar in larvae of Anopheles gambiae Giles, and the species and density of copepods found in these sites. Microcyclops minutus Claus, an intermediate host of Coelomomyces indicus, was the predominant species in both pools. Other species were, Mesocyclops leuckarti Claus, Mesocyclops leuckarti pilosa Kiefer, and Mesocyclops (Thermocyclops) decipiens Kiefer. Infections occurred during the periods when M. minutus densities were above 12 cyclops per 250 ml of water. A positive relationship was shown between M. minutus density and infection levels in An. gambiae with C. indicus. The r-value for this relationship in the temporary pool was 0.726, and in the semi-permanent pool, 0.639.

Eleven artificial diets with principal base-ingredients as pulses and beans, viz. winged bean, Psophocarpus tetragonolobus; green gram, Vigna radiata (L.) Wilczek; dew gram, Vigna aconitifolia (Jacq.) Marichat; broad bean, Vicia fabia (L.); soybean, Glycine max Merr.; and cluster bean, Cyamopsis tetragonoloba Taub., were formulated either alone or in combination, for the mass rearing of Chilo partellus (Swinhoe). On the basis of important biological parameters having direct bearing on the selection of media for rearing, seven diets were unsuitable. These diets were compounded with either winged bean, soybean grains (dry and water soaked), or broad bean or with different quantities of cluster bean blended with green gram and dew gram as principal base-ingredients. The superiority of the remaining four diets based on (i) kidney bean, (ii) kidney bean + sorghum leaf powder, (iii) green gram + dew gram, and (iv) green gram + dew gram + sorghum leaf powder, was established. The modified green gram + dew gram + sorghum leaf powder-based diet has an added advantage over its original version due to low cost of production of moths and eggs in both the generations. This highlights the formulation of a new modified diet which can be utilized not only as an alternative to the original green gram + dew gram based diet but also can replace it to overcome the phenomenon of inbreeding depression due to continued rearing in the same diet.

FAO recognizes the value of, and attaches a high importance to the continuance of existing taxonomie identification services. It considers it desirable that there should be an increase in the number of institutions qualified both to provide authoritative identification and to conduct taxonomie research on pests of agricultural significance. Regrettably, direct support to taxonomie identification services in general cannot be provided by FAO. As components of ongoing projects, identifications and relevant taxonomie research can be financed in certain instances. Preference is given to the development of a self-help capability through production of identification keys and pictorial guides, in-depth taxonomie studies and training, rather than simply paying for routine identifications.

Increasing interaction among specialists in the field of biosystematics so as to facilitate better identification services is suggested, taking into consideration the increasing intraspecific diversity resulting in recognizable “biotypes”. The need for a more comprehensive idea of intraspecific diversity in different insect groups is also indicated.

Twelve models are presented to examine the feasibility of using pheromone baited traps containing chemosterilant for pest control, and to compare the efficiency of this method with the use of (i) pheromone baited traps containing insecticide, and (ii) sterile releases. It was found that the number of matings per individual has little effect on the efficiency of population control, whereas immigration of even a relatively small number of the pest species severely limits this method in its ability to control the population. The existence of density-dependent regulation on the other hand greatly enhances the effectiveness of this control method. If the birth rate greatly exceeds one young per adult per day, then the method using chemosterilants is approximately twice as efficient as either insecticides in the pheromone traps or the release of sterile males. However, if the birth rate is much less than one per day, as in tsetse, then chemosterilants are very much more efficient than either method. These differences in relative efficiency appear to depend on the frequency of mating relative to the birth and mortality rates.

Fly catching experiments using the biconical trap and a vector collector (under mosquito net) were performed in different biotopes of the forest zone in Côte d'Ivoire (Daloa region).

Of the three species of tsetse usually caught, Glossina palpalis, and to a very minor degree Glossina pallicera, was attracted to man. G. palpalis showed vis-a-vis man a clear difference in attractiveness according to the point of capture. In those habitats where hosts were rare and dispersed (gallery forest, coffee and cocoa plantations) this species frequently attacked man who came into contact with it during the accomplishment of his usual activities, whereas in the village it voluntarily abandoned him in preference for pigs. Whatever the type of biotope, the trap had the same attractiveness. Its use, in contrast to captures on man, enabled a simultaneous study of diverse species that co-existed anthropophilically or zoophilically.

Although almost all the tsetse taken in the trap or on vector collector were hungry, it was noticed that the number of females in the trap samples was always higher than that of males.

The effect of fly age, sex, and period of starvation on the uptake and development of Trypanosoma congolense infection was examined in Glossina morsitans morsitans. In a study consisting of 1739 specimens of various ages, young unfed 16-hr-old flies and 2-day-old starved flies developed significantly higher mature infections than 2-day-old and 7-day-old flies which had been fed previously on a clean blood meal. Females displayed significantly higher immature infections, while mature infections were recorded more frequently in males, suggesting that females possess a stronger barrier to trypanosome development. The possible factors involved are discussed.

Combined effects of constant temperature (15–35°C) and relative humidity (50–90%) on longevity and total duration of life cycle of Tetrastichus pyrillae Crawford, one of the most common egg parasitoids of the sugar-cane leaf hopper, Pyrilla perpusilla Walker were determined and are discussed. Influence of the temperature both on the longevity and the developmental duration of this egg parasitoid was highly significant while the relative humidity did not produce any marked change. Average longevity of males decreased from 5.89 to 1.06 days and that of females from 9.60 to 1.04 days in response to corresponding rise in test temperature from 15 to 35 ± 1.5°C. Mean duration of its life cycle also declined from 40.5 to 9.8 days as the rearing temperature was raised from 15 to 30 ± 1.5°C. Developing parasitoid died, without attaining adulthood within its host eggs, at or above 32.5°C.

The recent history of initiatives in support of tropical insect taxonomy and the current status of the insect collection resources of Africa are reviewed with special emphasis on the development of the Department of Entomology, National Museums of Kenya as a regional centre for insect biosystematic services, training and research. Specific proposals are offered for the future development of such centres.

This bibliography on diseases of insect pests of rice contains 287 references. Major groups of insect pathogens are briefly discussed. Available records on diseases, insect hosts and locations of collections are tabulated. Additionally, references are grouped by subject.

The susceptibility of the different stages of Sitotroga cerealella (Olivier) to gamma radiation was studied. The stages arranged in a descending order according to the values of gamma radiation LD50 are: adults (190.100 krad) for females and 183.200 krad for males, pupae (6.039 krad), 3 days old eggs (5.570 krad), one week old larvae (4.800 krad), 1-day-old eggs (4.181 krad) and 2 weeks old larvae (3.056 krad).

The fat body protein content of silkworms increased with 0.5 μg of thyroxine (T4) per gram of body weight and more so with 1 μg/g on days 4 and 8 after injection. Thyroxine with 1 μg/g dose, however, caused an earlier increase in protein content on day 2. The higher doses of T4 (2 and 5 μg/g) decreased the protein content. All T4 treated groups (except with an ineffective dose of 0.25 μg/g) showed reduced protein level in the adult stage in comparison to the control. Thyroxine with a dose of 0.25, 0.5 and 1 μg/g increased the fat body RNA content over the control level which was observed on days 2, 4 and 8. But on day 13, the RNA content in these groups returned to the control level. Higher doses of T4 (2 and 5 μg/g) decreased the RNA content during the developmental period. DNA content was not altered by lower doses of T4 (0.25,0.5 and 1 μg/g), while the higher doses (2 and 5 μg/g) surprisingly caused a reduction in DNA content during the larval, pupal and adult stages.

The increase in protein and RNA contents with lower doses of T4 and decrease with higher doses, indicates a biphasic nature of thyroid hormone action in silkworm fat body.

Most fifth instar Argina cribraria female larvae reared in paired groups on fresh sunnhemp leaves practised cannibalism on the male. A potential cannibal pounced on the victim and severed its dorsal vessel, causing profuse bleeding of haemolymph, immobility and contraction. The cannibal fed on victim's carcass and might consume 1–2 larvae and 1–3 pupae. More females emerged from an experiment having larval cannibalism. The cannibals were lighter, but the relative titres of sugars, proteins and phenols were higher in cannibals than those in control female caterpillars.

The plant factors that contribute to the abundance of beetles in coffee fields were studied and analysed relative to shoot and canopy features of the host plant. During infestation Dirphya nigricornis Olivier constructed niches within specific heights (145.0–210.0 cm) of the canopies such that there was a highly significant (r = 0.99, P = 0.001) availability of adequate habitat for larval development. The adaptation of the pest to the host plant was good, irrespective of varieties and culture systems of the coffee plant. It was concluded that the alignment of eggs to tip internodes synchronised the newly hatched larvae with the coffee tissues, usually between 0.5 to 30 cm off the shoots, of extremely low dry matter, and high moisture content, such factors favouring early larval development.

Functional diversities associated with structural polymorphism involving oedymery and gynaecoidy among males and major and minor forms in females, with or without alary polymorphs appear typical of many mycophagous Tubulifera. Notable is the occurrence of reproductive polymorphism resulting in oviparity, ovoviviparity, and viviparity among individuals of the same species reflecting both gross as well as histological profiles.

While alary polymorphism tends to result in ovarian diversities in some species, the combination of this feature with gynaecoidy and oedymery among Tubulifera results in a variety of mating combinations and variations in egg output. Information presented pertains to the mating patterns in mycophagous and sporophagous species in relation to the degree of polymorphism and reproductive efficiency in terms of oviposition rates. The considerably higher longevity of the oedymerous males as compared to gynaecoids adds further to the reproductive efficiency of the oedymeres. Size assortive mating is very evident, with females tending to reject males smaller than them, and with males competing for larger females in this intrasexual rivalry.