The nature, number, structure and behaviour of chromosomes during the meiotic and mitotic sequences in the armoured ground cricket, Acanthoplus speiseri Brancsik, were investigated from testicular and ovariole material. The karyotype of A. speiseri is 2n ♂=25 (24 autosomes + XO) and 2n ♀=26 (24 autosomes + XX). The species exhibits the primitive XO ♂ /XX ♀ type of sex determination mechanism. All chromosomes in the cell complement (including the X sex chromosome), in both sexes, are acrocentric in shape. The X sex chromosome is the largest element in the karyotype while the autosomes comprise three large, four medium and five small pairs. The behaviour of the chromosomes during the meiotic and mitotic processes is normal and typically orthopteran. The study discusses the important role that karyology and cytogenetics can play for species diagnostics in the subfamily Hetrodinae.

An integrated approach to the management of the sorghum shootfly (to keep its population below economic injury level) has been a major thrust of sorghum research workers during the last one and a half decades. The necessary foundation has been laid by detailed studies on the biology of the pest and a fairly thorough understanding of the effect of different ecological factors on the shootfly population. Based on seasonal incidence studies, sowing immediately after the onset of monsoon has proved to be effective for avoiding shootfly damage.

A large number of high yielding and shootfly-resistant derivatives have been developed by crossing agronomically desirable exotic lines with identified resistant sources. The new hybrids and varieties released recently possess low to moderate levels of resistance.

Parasites and predators affecting different stages of the shootfly have been identified but utilization of these natural enemies for the biological control of the pest is yet to be undertaken.

Carbofuran seed treatment has proved to be highly effective for protecting sorghum from shootfly damage. Some other insecticides have also been found to be promising.

Based on the control methods available at present, an integrated package has been recommended for implementation in traditional sorghum growing areas of the country.

The location of olfactory and gustatory sense organs in the larvae of the American bollworm, Heliothis armigera, have been studied using the scanning and transmission electron microscopy. The olfactory chemoreceptors of the larvae are located on the antennae, mostly on the top of the second antennal segment in the form of two trichoid sensilla, two basiconic sensilla, two styloconic sensilla, campaniform sensilla and a uniporous peg sensillum. The third antennal segment bears one basiconic sensillum and two styloconic sensilla. The gustatory sense organs are located on the mouthparts including the labrum, mandibles, hypopharynx, maxillary palps and labium. Trichoid sensilla have been located on the labrum. Epipharyngeal setae as well as long short spines are located in the epipharyngeal membrane. The basal segment of the maxillary palp bears three trichoid sensilla and one campaniform sensilla. The maxillary palp also bears four styloconic sensilla on the distal portion of the lateral protuberance and one styloconic sensillum at the apex of the medial protuberance. Close to the bases of the protuberances, there are three basiconic sensilla and one campaniform sensillum. The third apical segment of the maxillary palp carries three campaniform sensilla on its lateral side, while on its top, eight small basiconic sensilla are distributed.

A one-year survey was carried out in two brackish water pools to study the incidence of Amblyospora sp. in field populations of Culex sitiens larvae at the Kenya coast. Salinity of the pools, water temperature, and rainfall patterns were also recorded to check their possible effects on the infection rates. Levels of infection in both pools were low, and ranged between 2 and 15%. Infections occurred in a wide range of salinity. Statistical analysis (t-test) showed no significant correlation between infection rates and neither salinity, temperature nor rainfall in the field.

Whole body tick collections, carried out at 6-day intervals for 2 months at Nisheishiba, showed significant differences in tick counts between three breeds of cattle. Crossbred (Bos taurus × B. indicus) cows carried 4.5 times more ticks (mean tick count 70.5 ± 84.8) than the B. indicus Kenana (mean tick count 16.7 ± 24.4) and Butana cows (mean tick count 15.0 ± 18.4). In all cases, the SD's were larger than the means reflecting the usual wide variability in tick numbers between individuals. Significant differences also existed in the degree of engorgement achieved by female Hyalomma anatolicum anatolicum ticks on different breeds of cattle. The weight of detaching fully engorged females feeding on Kenana and crossbred cattle was 374.8 mg and 422.0 mg respectively. This was reflected in the amounts of eggs laid by the females which were 191.3 mg for the Kenana-fed ticks and 261.1 mg for those from the crossbreds. The resulting larval challenge from the crossbred-fed ticks was 36.5% greater than from the ticks fed on Kenana cattle.

In West and Central Africa, panicle-feeding mirid bugs, particularly Eurystylus oldi Poppius (Hemiptera: Miridae), are major pests of improved sorghum cultivars. Population dynamics of panicle-feeding bugs were studied on the sorghum cultivar ICSV 197, sown on eight dates each year from 1992 to 1994 at Samanko, Mali. Relationships between weather factors and abundance of paniclefeeding bugs were examined for the three most commonly found mirids, E. oldi, Campylomma spp. and Creontiades pallidus Rambur (representing on average respectively 58, 39 and 2% of all mirid species). Although only one generation of E. oldi could develop between flowering and grain maturity on a particular panicle, there were three successive generations each year during the extended grainmaturing period in the experiment with eight sowing dates, with a major peak in abundance in early October, followed by a gradual decrease until late November. Abundance of Cr. pallidus peaked in late October, while that of Campylomma spp. showed no relationship with date of sowing.

An increase in abundance of E. oldi nymphs (y1) was favoured by high precipitation, reduced maximum temperature and high minimum relative humidity during and 2–3 weeks before the grainfilling period [a strong negative relationship was found with the number consecutive days without precipitation from 78–88 days after sowing (das) (x1): y1 = −11.7x1 + 149.3 (r2 = 0.67)]. The abundance of Cr. pallidus (y2) was correlated with wide temperature ranges and low precipitation during the same periods (notably precipitation frequency from 75–91 das: x2): y2 = −2.28x2 + 24.6 (r2 = 0.65). The abundance of Campylomma spp. (y3) was negatively correlated with amount of rainfall between 19–32 das (x3): y3 = −3.82x3 + 705.9 (r2 = 0.49). Reasons for these trends are suggested and their possible application for management of panicle-feeding bugs discussed.

The stemborers Busseola fusca (Fuller) and Chilo partellus (Swinhoe) cause the highest economic damage to maize and sorghum in Zimbabwe. A number of studies on stemborer bioecology and management in Zimbabwe have been conducted, but most are still incomplete. The more important of these are studies on life history, incidence and distribution patterns, host plants, yield losses, chemical control, cultural control, host plant resistance, the use of sex pheromones, and biological control. These are discussed here in detail, and areas where further research is needed are pointed out. As part of an integrated strategy for managing stemborers in Zimbabwe, an exotic braconid larval parasitoid, Cotesia flavipes Cameron, has been released in the lowveld area and prospects for its establishment appear to be good. However, this establishment might be curtailed mainly by the inability of Co. flavipes to adapt to the seasonal carryover mechanisms utilised by the indigenous Cotesia sesamiae (Cameron).

Sperm are transferred from male to female tsetse, as in most insect species, within a spermatophore. The spermatophore of the tsetse species, Glossina morsitans morsitans Westwood (Diptera: Glossinidae), is highly organized, and can be visualized as a sac deposited in the uterus of the female tsetse. The wall of the spermatophore comprises two layers, whose components are strikingly similar to those of the secretions made by the male accessory reproductive glands. Dense aggregates of material, matrix filaments, and clusters of granules predominate in both. An ultrastructural study of these components is reported in this paper.

Scirtothrips dorsalis Hood is a polyphagous species and an important sucking pest of tea (Camellia sinensis) (Theaceae). The fitness traits of S. dorsalis on two alternative host plants: Capsicum annuum L. (chilli) (Solanaceae) and Ricinus communis (castor oil plant) (Euphorbiaceae) and on C. sinensis and corresponding levels of defence enzymes was studied. The study revealed that C. sinensis is the more suitable host of S. dorsalis based on faster development (13.6 days) compared to the alternative hosts, C. annuum (15.5 days) and R. communis (16.7 days), a higher fecundity (C. sinensis: 11.4 eggs; C. annuum: 9.7 eggs; R. communis: 8.6 eggs), and superior egg hatchability (C. sinensis, 92.6%; C. annuum: 82.5%; and R. communis: 74.6%). The host-based variation in the fitness traits of S. dorsalis corroborated in light of differential activity of three major detoxifying enzymes, such as the general esterases (GEs), glutathione S-transferases (GSTs), and cytochrome P450 mediated monooxygenases (CYPs). Densitometric analysis of GEs showed five esterase isozymes (EST I–V) with retardation factor (Rf) values of 0.17, 0.22, 0.27, 0.35 and 0.52, respectively. The pixel density, and accordingly the profile height, varied in different host-specific S. dorsalis. A significant variation of the quantity of these enzymes was also apparent in the insect when reared on the three hosts. A 2.4 and 2.7, 1.6 and 2.0, and 2.0 and 2.3-fold higher GEs, GSTs and CYPs activity on the two non-tea hosts possibly signify a predisposition of the species for higher tolerance to insecticides, enabling the pest to switch to tea where synthetic insecticides are routinely used.

The shootfly, Atherigona soccata Rondani, is a major seedling pest of sorghum in many areas of tropical Asia, Africa and Mediterranean Europe. A chronological review of the progress made in various programmes on the screening techniques (natural and artificial) with artificial diets, sources, stability and mechanisms of resistance, bases (physico-morphological and biochemical factors) of resistance, inheritance and breeding for resistance is made. Many resistant varieties have been identified and sources of resistance utilized in breeding programmes to transfer resistance in high yielding background are listed. In addition, the glossy and trichome traits identified is sorghum cultivars are also reported. Glossy leaf surface and trichomes are frequently associated with shootfly resistance.

The effect of planting dates on beanfly infestation was investigated in successively planted bean plants during cropping seasons. The population tended to build up in the course of the season following the initial invasion by egg-laying females. Ophiomyia spencerella (Greathead) and Ophiomyia phaseoli (Tryon) were the species of beanflies infesting the bean plants in all seasons. The number of beanfly leaf punctures, eggs, larvae and puparia were more in late planted than early planted bean crop. The bean crop planted late in the season was severely damaged due to the generally higher population levels which had been building up in the course of the season.

Role of trichome density in cassava resistance to mealybug, Phenacoccus manihoti Matile-Ferrero was evaluated on the apex, the first expanded leaf and the stem in pubescent and glabrous cassava varieties. Pubescence significantly retarded the rate of settling and establishment of P. manihoti. The weight of the developing larvae was also affected becoming more pronounced at the pre-ovipositing adult stage. However, the relationship between pubescence and P. manihoti weight was not significant. Moreover, the significant differences in weight at the preovipositing adult stage was not reflected in the corresponding fecundity on the glabrous and pubescent varieties. Pubescence accounted for only 18% of the differences in observed fecundity. There was also no significant difference in the development period of the mealybug on glabrous and pubescent varieties. Pubescence appeared to be a mechanical irritant only.

The southwestern corn borer, Diatraea grandiosella, has expanded its range during this century so that it is now distributed between about 18 and 38°N latitude in Mexico and the United States. The species survives from year to year by entering a facultative larval diapause, and over most of its range it is bivoltine or trivoltine. Fully grown pre-diapausing larvae prepare an overwintering cell in the stalk crown of their host plant, typically maize, and then ecdyse from a spotted to a pigment-free morph at the onset of diapause. Southwestern corn borers originally obtained from southcentral Mexico (19°N latitude) and the United States (33–38°N latitude) were reared on an artificial diet under standardized conditions to compare several of their life history traits. Information is presented about voltinism, photoperiodic responses, growth and reproduction, larval behaviour and ecdyses, and the diapause-associated protein in an attempt to evaluate characteristics that have enabled the species to disperse from a tropical to a temperate region.

Stenogiffardia Evans, 1977 is considered the senior synonym of Pratura Theron, 1982 syn. nov. and Doraturella Emeljanov, 2002 syn. nov., resulting in four new combinations. Duraturopsis Melichar, 1908 syn. nov. is considered a junior synonym of Chiasmus Mulsant and Rey, 1855, resulting in one new combination. Figures of the ovipositor of Stenogiffardia parvula (Kirkaldy) are provided for the first time, and habitus images of S. parvula and Chiasmus katonae (Melichar) comb. nov. are provided.

When the compound eye of the adult of the planthopper, Myndus crudus, is light-adapted, pigments are condensed in a zone proximal to the crystalline cones. Viewed externally, the eye is straw-colored. When dark-adapted, pigments migrate distally into the region of the crystalline cones and thus are closer to the cuticle. Viewed externally, the dark-adapted eye is maroon-colored. The eyes of most adult M. crudus observed during daylight hours were light-adapted. Eyes of males and females changed from the light to the dark-adapted condition between sunset and ½hr after sunset. When planthoppers with light-adapted eyes were placed abruptly into darkness at a temperature of 25–27°C, the eyes became dark-adapted within 15–30 min. When planthoppers with dark-adapted eyes were placed abruptly into light, the eyes became light-adapted within 30–60 min. At 8°C the planthoppers were immobile, and light-adapted eyes had not changed to the dark-adapted condition within 45 min. Eyes of M. crudus nymphs, which live in the root zones of grasses, are dark red and do not change color in response to changes in light. Field samples showed that adult M. crudus were active in coconut palms during the day and night, but higher numbers were caught during the day (P < 0.01).

Stemborers in Africa are attacked by a complex of about 120 species of hymenopteran parasitoids, including about 15 species which are either facultative or obligatory hyperparasitoids. Several dipteran parasitoids also attack stemborers. An overview of hymenopteran stemborer parasitoids is here presented by superfamily and family, giving numbers of genera and species involved, their biologies (where known) and distributions.

Calmodulin is a ubiquitous endogenous calcium receptor in eukaryotic cells and is involved in many different physiological functions. The presence of calmodulins in protozoa has been reported for Tetrahymena and Paramecium. Calmodulin purified from T. pyriformis is composed of 147 amino acids and the amino-terminal is acetylated.Compared to bovine brain calmodulin, there are 11 substitutions and 1 deletion of amino acid residue(s). Besides such structural specificity, Tetrahymena calmodulin (T-CaM) is highly unique in that it has a potential ability to activate the pellicle-bound guanylate cyclase in a calcium-dependent manner. This stimulatory effect is also observed in Paramecium calmodulin (P-CaM). Bovine brain calmodulin represses the T-CaM-dependent activation of guanylate cyclase, indicating that bovine brain CaM exerts its inhibitory influence by interfering with the calmodulin-binding site of this enzyme. The 14S and 30S dyneins extracted from demembranated cilia with EDTA contai ATPase activities which are potentiated by addition of calmodulin. Taken together with its location in cilia, T-CaM appears to regulate the ciliary movement. Moreover, evidence has been provided that calmodulin may be implicated in the glycoprotein biosynthesis. The phosphorylated derivatives of the long chain polyisoprenoid alcohols (dolichol phosphates) are known to act as coenzymes, and the microsomal enzyme involving dolichol phosphorylation is calcium-requiring CTP-dependent and activated by calmodulin. A role for calmodulin in the control of cell growth is postulated by the concerted fluctuations of calmodulin contentand guanylate cyclase activity during the cell cycle in synchronized Tetrahymena cells. In addition, some other possible functions for calmodulin can be considered in protozoa.

The insect fauna of rain-fed rice, Oryza sativa, was assessed using the sweep net and direct count methods. The objective of the study was to provide basic information on the insect pest complex of rice in the area and their natural enemies. One hundred and five insect species belonging to nine orders and 57 families were found. The insect orders in order of abundance were Diptera (45.67%), Coleoptera (12.77%), Lepidoptera (12.23%), Orthoptera (8.44%), Heteroptera (8.23%), Homoptera (7.03%), Hymenoptera (3.25%), Dermaptera (1.95%) and Dictyoptera (0.43%). Diopsis thoracica Westwood (Diopsidae) (69.43%) was the most abundant dipteran followed by the sarcophagids (14.93%) and calliphorids (7.11%). Members of the family Chrysomelidae represented 50% of the coleopterans followed by the coccinellids (17.46%). While 31% of the lepidopterans were noctuids, 60% were pyralids. The pentatomids (50.57%) were the most abundant heteropterans while the acridids (43%) were the most prevalent orthopterans. The homopterans were mainly Cofanaunimaculata Signoret (which represented 79%). The insects were clustered into three groups with D. thoracica alone in group 1, C. unimaculata and Sarcophaga species in group 2 and the rest in group 3. We therefore conclude that D. thoracica is the most important pest of rice in Ekpoma while C. unimaculata may also be very important, but Sarcophaga species appears to be the most important natural enemy in the system.

This note reports an unusual case of a high number of oocysts found by dissecting the midgut of Anopheles dirus Peyton & Harrison from Laos, where dissections have not been carried out for many decades. In dissected samples, the number of oocysts ranged from 1 to 250 and tests carried out on the heads and thoraces of A. dirus using the ELISA method were positive for Plasmodium falciparum.

The paper reviews advances in our understanding of the vectorial capacity and vector–parasite relationship in Kenyan sandflies since the early 1900s (when sandflies were first reported in Kenya). Of the 38 species of sandflies known to occur in Kenya to date, three (Phlebotomus pedifer, P. martini and P. duboscqi) can naturally carry biochemically and serologically confirmed Leishmania (aethiopica, donovani and major, respectively) and 12 (Phlebotomus rhodhaini, Sergentomyia garnhami, S. squamipleuris, S. africanus, S. kirki, S. ingrami, S. antennatus, S. bedfordi, S. schwetzi, S. affinis, S. graingeri and S. clydei) carry various flagellates of biochemically or serologically unknown character.

Current research on naturally infected wild-caught sandflies indicates that L. aethiopica promastigotes have close association with structures resembling a peritrophic membrane and invade P. pedifer gut cells. Promastigotes invade the malpighian tubules of S. garnhami and S. antennatus.

Studies on laboratory-reared sandflies show that P. martini is susceptible to L. donovani amastigotes and that cultured promastigotes of L. donovani can survive in the guts of S. schwetzi, S. ingrami and S. adleri.

Experimental infection of sandflies with Leishmania is discussed and priorities for laboratory work set.