The predacious mite, Pachylaelaps aegyptiacus Hafez & Nasr completed life cycle when fed on eggs of housefly, Musca domestica (L.) at 25 ± 2°C and 70–80% r.h. in the laboratory. The durations of the immature stages and of the adult stage were determined. Immature stages of P. aegyptiacus consumed in total an average of 16 eggs of housefly, whereas each day throughout her life, the adult female consumed an average of 7.6 eggs of housefly. Daily rate of single and multiple mating was 0.93 and 1.0 eggs/female respectively. Description of immature stages of the predatory mite was given.

At present there are nine species of tephritid fruit flies in Mauritius and together they plague a wide range of hosts, from wild guavas to cultivated fruits and vegetables. The most destructive among them are: the natal fruit fly, Pterandrus rosa Karsh; the medfly Ceratìtis capitata Wiedemann and the melon fruit fly Dacus cucurbitae Coquillet. Studies with parapheromones indicate that trap colour has little if any effect on the efficiency of fly capture, the olfactory component completely dominating any visual effect. The efficiency of the traps with respect to height varies from species to species and with the vegetation. A height of 120 to 180 cm from the ground was found to be optimal for the natal fruit fly in wild guava zones. Traps placed at ground level on creeping plants were found to capture the highest number of the melon fruit fly. The response of the medfly in fruit tree orchards with height of traps was erratic, showing inconsistent trends with more than one peak.

The effects of established phenomena of plant resistance on the levels of tolerance to malathion of an organophosphate resistant strain of Myzus persicae were investigated using topical application insecticide bioassay. Tolerance was significantly decreased when aphids were reared on the moderately aphid-resistant Brussels sprout variety Early Half Tall or on sprout plants given reduced nitrogen fertilization. Differences in insecticide tolerance were found to occur only at older plant ages. It is argued that the differences (less than 50% in LC50 terms) reported are of practical importance, and attention is drawn to much greater differences (5-fold) obtained in experiments at different times of the year.

Oviposition behaviour of the cotton bollworm, Heliothis armigera, and its relation to day-night cycle was examined under laboratory conditions. Eggs were laid both in large quantities of clumped eggs at one place, and singly distributed in the oviposition cage, always glued on the substrate. The maximum individual life time fecundity recorded was 3080, and the highest number of eggs delivered in 1 day was 949. The mean pre-oviposition period was 2.9 days. Peak fecundity occurred between days 5–9 and the highest mating frequency from days 4–6 after emergence. Maximum age for egg laying was 29 days, average life expectancy was 22 days, with longest individual survival of 32 days. Male longevity did not vary from that of females. There was a significant difference in the longevity of mated and virgin females; the mated females lived for a shorter time but produced a significantly higher number of eggs. Also, mating induced a sudden surge in oviposition. Almost 90% of the total eggs were laid in the darkness. Out of them, 60% were from the first and 30% from the second half of the dark period.

Laboratory evaluation of food consumption, food utilization, weight gain, development, fecundity and egg-hatchability were made from the beginning of the first instar to sixth instar on castor, groundnut, Indian bean, jute, sesame and sunflower. Total food consumption was highest on castor and lowest on jute. Development was fastest on castor, and castor was most efficiently digested followed by sunflower, sesame, groundnut, Indian bean and jute. Consumption index and digestive efficiency on all host plants declined with larval age. Digested portion of jute was most efficiently converted into body matter. Variations in fecundity and egg-hatchability for different host plants were statistically significant at P = 0.01. The differences in these parameters may be due to the variations in the nutritional quality of the hosts.

During investigations on the malaria parasites of lizards in the West Pokot district of Kenya, haemoproteids, haemogregarines, pirhemocyton-like and anaplasma-like organisms were found in the blood. Microscopic examination showed that some of these are new species and they are described in this paper. The new described species are Haemoproteus mungutii (haemoproteid), Karyolysus poleensis, Schellakia mabuyai (haemogregarines), Pirhemocyton kongelai, Haematractidium omogoi, Sauroplasma kachelibaensis (Pirhemocyton-like organisms), Eperythrozoon ngokai and Aegyptianella elgonensis (anaplasma-like organisms). K. poleensis and S. mabuyai are regarded as the first report of the genera in lizards in Africa while A. elgonensis is regarded as the first report of the genus Aegyptianella in lizards.

Observation on the distribution and seasonal variation of riverine tsetse population at Egbe in the Derived Savanna Zone of Nigeria was made and compared with variation in other vegetation types of the country. Egbe, in a sub-humid location, was observed to have a low rainy/high dry season population density similar to what occurs in part of the Southern Guinea Savanna Zone. To the north of these areas, the less humid vegetation zones show a definite reverse pattern (high rainy/low dry season) of seasonal population density. The Rain Forest Belt, a humid zone has, surprisingly, more similarity with the less humid zones to its far north than with the sub-humid zones nearer to it Irrespective of zone and season, a favourable temperature of between 26.1 and 26.7°C appeared important towards having a high population density. Reasons were given for the low rainy season tsetse density at Egbe. Unlike zones in the less humid north where rainy season dispersal is well marked, tsetse distribution in the Derived Savanna Zone remained by the riverine vegetation almost throughout the year. The advantage of this study to a proposed ranch for the area was highlighted.

During investigations into the epidemiology of malaria of lizards in Kenya, Giemsa-stained smears made from the peripheral blood, liver and spleen of hand-caught lizards from West Pokot district were examined for the presence of Plasmodium species. Ten new species were found and described. These are Plasmodium sapaaensis, P. kyaii, P. kachelibaensis, P. icipeensis, P. gloriai, P. odhiamboi, P. bowiei, P. kaninii, P. kadogoi and P. adunyinkai.

P. sapaaensis was found to be related to P. mabuiae, P. kadogoi to P. rhadinurum, P. kaninii to P. minasense (s. Telford) and P. adunyinkai to P. maculilabre. P. kyaii and P. kachelibaensis have distinct characteristics which distinguish them from the Plasmodium species in the tropiduri group reported so far.

Four species i.e. P. icipeensis, P. odhiamboi, P. gloriai and P. bowiei, exhibited peculiar characteristics most especially their effect on the white cells. They were therefore constituted into the “Kenyan” group.

The presence of larvae in cowpea seeds affects the number of eggs laid and seed choice for oviposition by females of Callosobruchus maculatus (F.). Gravid females can discriminate between seeds with differing number of larvae before oviposition. Seeds bearing no larva or few larvae were preferred for oviposition to those bearing greater number of larvae. In addition, seeds bearing younger larvae were preferred for oviposition to those bearing older larvae. The results are discussed in relation to observations on oviposition behaviour of C. maculatus reported by earlier workers.