Single pair progenies (sibships) of three organochlorine resistant strains of Rhipicephalus appendiculatus Neum. from Kenya, Tanzania and Uganda showed similarity in dose-mortality response to γ-BHC. The homogeneous dose-mortality responses indicated such larvae have a similar high level of resistance, whereas the stepped nature of the dose-mortality curve for the heterogeneous sibships indicated that these sibships include both resistant and susceptible larvae. Crosses between the Uganda strain and the susceptible reference strain (Mwanza) indicated that a dominant gene exerts a major influence on resistance to γ-BHC and dieldrin. For some heterogeneous sibships the dose-mortality response indicated a significant departure from a 1:1 ratio of susceptible: resistant larvae. The deviation could be reduced by increasing the susceptible background genotype. The deviation differed in direction for different crosses, suggesting a genetic influence. The deviations occurred in all three resistant strains. Line selection of deviating sibships in either direction was unsuccessful.

Field experiments were conducted in the Gambia, West Africa, on the density of mosquitoes approaching animal baits (two goats). Using an array of ramp-suction traps arranged radially around baits, it was found that the density of Mansonia males was significantly greater at a distance 3 m from the bait than at distances of 7 and 15 m. By contrast, catches of Culex and Anopheles males were no higher at 3 m than at greater distances. It is concluded that Mansonia males, but not males of the other genera studied, are attracted to mammals from at least 3 m. Catches of Mansonia females were greater at 3 and 7 m than at 15 m, indicating that they are attracted to hosts from a greater distance than the males. This behaviour facilitates mate-finding by bringing the sexes together in the vicinity of the host.

Coptotermes acinaciformis (Frogg.) was collected from three different mound colonies and placed in holding jars in a matrix of mound material from an alien colony. After transportation and maintenance in a controlled insectary for 28 days, they were separated from the holding jars and pooled according to colony origin. They were then used in mixed groups of various combinations in a bioassay test of their feeding capacity and survival. Termites from a fourth colony were used to determine whether pooling of individuals originating from the same colony but maintained in different holding jars had any effect on their feeding and survival in the laboratory. It was shown that, although termites from the same original colony can be re-united without detriment after transportation and maintenance, those from different colonies cannot be mixed to form reproducible bioassay groups. Although chilling before mixing produced a slight improvement, the resulting groups were still unsuitable for use in bioassays. It is noteworthy that when brought together after maintenance in the holding jars under identical conditions in an identical matrix, the termites were able to recognise and accept fellows from their own colony and to detect and reject those from other sources.

Diflubenzuron was applied once at 2·5–20 g a.i. in 10 litres of water to coconut palms infested with larvae of Nephantis serinopa Meyr. in Tamil Nadu, India. The entire field population of larvae was eliminated within 14 to 18 days, depending on the dose. The mortality due to moulting inhibition in larvae treated in the field and then brought into the laboratory ranged from 77·4 to 88·8%. The higher the dosage, the higher was the inhibition of transformation to the pupal and adult stages. Diflubenzuron also apparently had an antifeedant effect on the larvae. The compound directly or indirectly affected the development of Parasierola nephantidis (Mues.), a parasite of N. serinopa. The preference of female parasites for parasitising host larvae and oviposition in and the number of progency produced from a single host larva that had been treated with diflubenzuron in the field were significantly reduced. The percentage of normal adults produced from treated parasite larvae ranged from 17·3 to 43·0% as against 99·1% from untreated larvae. Treatment of mature parasite larvae directly with diflubenzuron in the laboratory affected development and caused morphological deformities in the adults.

A key is provided to the ten genera of Anomaloninae occurring in sub-Saharan Africa. The numbers of African species in the various genera are discussed with particular reference to those having potential economic importance as parasites of Lepidoptera. Parania Morley is recorded for the first time from Africa, and two new species P. prima sp. n. and P. secunda sp. n. are described. A number of new host records are given.

Temelucha minuta (Morl.), a common parasite of Phthorimaea operculella (Zell.), is redescribed with emphasis on features enabling it to be separated from other species of Temelucha. T. clausa Kerrich is placed as a junior synonym of T. minuta. The known geographical range of the parasite is expanded to include Cyprus, Australia and India. A provisional key is given to the Australian species of Temelucha, and notes are given on their distribution and hosts. T. verimaculata (Cam.) is placed as a junior synonym of T. australiensis (Szépl.).

The mating behaviour of females of Glossina pallidipes Aust. from Kibwezi Forest, Kenya, was investigated in the field and in the laboratory. Field studies showed that very few tenerals were inseminated, that most nulliparous females become inseminated after the first blood-meal and that of females caught on a moving vehicle the majority of recently fed nulliparae were not inseminated while most non-teneral nulliparae with little or no residual blood-meal were inseminated. This suggested a mate-seeking behaviour by uninseminated, non-teneral nulliparae. Field data indicated that multiple insemination occurs in some nulliparae. In the laboratory, few females were receptive until 4–5 days old, which conforms to the field data. Peak receptivity in virgins was reached about nine days after eclosion, when more than 90% copulated. Receptivity in virgins decreased from about two weeks after eclosion. Females permitted one copulation a day between days 0 and 13 copulated, on average, 1·4 times; 38% copulated twice and 2% three times. Receptivity in virgins was higher than in non-virgins, suggesting that one or more components of the copulation affect receptivity.

A gracillariid moth belonging to the subfamily Lithocolletinae that was reared from larvae mining the leaves of Lonicera quinquelocularis (Caprifoliaceae), a weed in northern Pakistan, is described and named Phyllonorycter montanella sp. n. The larvae make blotch mines on the underside of the leaves and were discovered in the Murree Hills at about 2600 m.

Adults of Cnaphalocrocis medinalis (Gn.), a widely distributed pest of rice, were found to require an exogenous source of sugar, life-span and fecundity being greatly increased in the laboratory when sugar was available. Their sources of sugar in the field are not known, but evidence is presented which shows that in the laboratory they can utilise the honeydew produced by Nilaparvata lugens (Stål), a common pest of rice.

The chalcidoid wasps of the genus Monacon develop as parasites of the larvae of ambrosia beetles (mainly Platypodidae) in the tropical forests of the Old World. Their known hosts are reviewed. A key is given to species, which are treated in two groups, according to geographical region: first the Indo-Australian species, then the African ones. The previously known Indo-Australian species come from India and Bangladesh (two), North Borneo (one) and the Philippines (one), and another 14 are here described as new: two from Sri Lanka, two from Burma, two from West Malaysia, one from both West Malaysia and the Philippines, two from the Philippines only, four from Papua New Guinea only and one from both Papua New Guinea and the Philippines. Three African species were previously known from Zaire; one of them has now been found also in Uganda. Three species are described as new: one from Uganda, one from both Uganda and Nigeria and one from Kenya.

Sitona humeralis Steph. was successfully reared from egg to adult on potted lucerne plants. Soil pH was adjusted to 6·9, and soil additives were mixed with a ‘standard potting mix’ to produce a potting mix suitable for lucerne growth and S. humeralis development. Development was faster at 20 than at 15°C, but higher mortalities occurred at 20 than at 15°C.

A translocation homozygous strain (TT) of Delia antiqua (Mg) was released into a field cage in Wageningen, The Netherlands, together with a standard laboratory strain (++). During the course of the season, the fecundity and fertility of the adults were measured together with the karyotype frequencies (TT+; T+; ++) of the F1 progeny. No selective disadvantage of the translocation karyotypes was observed. However, only four F1 adults emerged in the field cage; therefore a sample of pupae was removed from the cage, and it was shown that nearly 100% of the surviving pupae had entered diapause. This figure was confirmed from the remainder of the pupae. The fertility of eggs from the emerging adults was reduced to 54%, compared with the standard fertility of nearly 90%, but because of the diapause response of the strains used, the effect of this reduced fertility in the field-cage population could not be followed. The reasons for the change in diapause response of the laboratory strains are discussed and suggestions made as to how this could be prevented. The report highlights the importance of quality in control techniques involving translocations.

Four years of light-trap and crop survey data from the Namoi Valley of New South Wales are presented for Heliothis armigera (Hb.) and H. punctigera Wllgr. These suggest there are four generations a year. The associated seasonal sequence of major host-plants supporting successive generations, appeared to be: H. armigera—wheat; pre-flowering cotton; flowering cotton and sorghum; sorghum, flowering cotton and sunflowers; and H. punctigera—lucerne, linseed and medics; pre-flowering cotton; flowering cotton, sunflowers and soyabeans; lucerne, linseed and medics; pre-flowering cotton. On host-plants common to both species, a change in dominance from H. punctigera to H. armigera occured as each summer progressed. Suggested causes are: seasonal changes in the availability of host-plants, favouring H. armigera over H. punctigera; insecticide resistance in H. armigera; and the competitive superiority of H. armigera. Large numbers of H. armigera in cotton appeared to be related to: warm springs, which favoured moth emergence during the period of wheat anthesis; the incomplete control of infestations within cotton itself, leading to the development of resident populations; and the influx of moths from other host-plants, especially sorghum, during the latter half of the season.

Attention has recently been focussed on the problem of why mosquitoes feed on some people more than others. In this paper, investigations of selective feeding by mosquitoes of the Anopheles gambiae Giles complex conducted in two villages in the Gambia are reported. Fed mosquitoes were collected from the bed nets of 35 groups of people who normally sleep together, for example mothers and infants or two children or two adults. A total of 2339 meals was analysed using haptoglobin or ABO typing to determine from which individual each meal had been obtained. The results showed that the proportion of feeds upon an individual in a group can be associated with the proportion of the total surface area or weight of the group contributed by that individual. The incidence of multiple feeding was between 3 and 6%. The results are discussed in relation to host selection by mosquitoes and their significance for models of malaria epidemiology.

Amongst 20 tea clones tested in Sri Lanka for susceptibility to Glyptotermes dilatatus (Bugnion & Popoff), five of the high-yielding soft-wooded clones, including the currently recommended and popular TRI 2023 and TRI 2026, were found very susceptible and to suffer a severe net loss in yield. A highly significant negative linear correlation was observed between the mean infestation percentage of clone with an infestation of over 30% and the mean percentage change in yield. In general, the high-yielding clones with soft-wooded sappy frames were particularly susceptible to termite attack. Since yield is one of the important criteria for selection, it is suggested that in areas prone to termite infestation, replanting should be limited to the high-yielding resistant clones such as GMT 9, KEN 16/3 and DG 39. The provision of shade with Gliricidia sepium may have prevented a steep increase in the incidence of infestation in the susceptible clones.

Severe defoliation of cassava by Zonocerus variegatus (L.) can occur every year during the dry season in southern Nigeria, but the effect of such defoliation on tuber yield was not known. Experiments simulating different forms of damage and direct observation on damage by Z. variegatus indicated that tuber yield is reduced significantly by defoliation only towards the end of the dry season after natural leaf regeneration has begun, when its effect is to delay regeneration so that damaged plants lag behind those which are undamaged. Continuous defoliation over six weeks at the end of the dry season caused a mean crop loss of 63%, and simulated debarking a mean loss of 49%. Z. variegatus confined in plots until the end of the dry season caused a mean loss of 36%, losses being less than those caused by simulated defoliation because cropping took place sooner after the end of defoliation. Defoliation during the dry season caused no significant crop loss when damage occurred before leaf regeneration at the beginning of the following wet season. Monitoring of natural defoliation by Zonocerus in successive years showed there were considerable differences in amount and timing. It is concluded that crop loss due to Zonocerus damage is significant only occasionally despite defoliation occuring every year.