Tibial campaniform sensilla of Glossina morsitans

On the basis of behavioural tests and light microscopy, a pair of dome shaped sensilla occuring on the outer and inner surfaces of Glossina morsitans morsitans tibiae were considered to be sex pheromone receptors. Recent observations using electrophysiological tests and ultrastructural methods have revealed that those receptors have no olfactory function; they are ampaniform sensilla sensitive to mechanical stimulation.     

Ultrastructural changes in salivary glands of tsetse, Glossina morsitans morsitans, infected with virus and rickettsia-like organisms

Electron microscope observations on enlarged hypertrophied salivary glands dissected from adult laboratory-reared male Glossina morsitans morsitans show a concurrent infection of the salivary gland tissue with rod-shaped virus particles and intracellular rickettsia-like organisms. The latter are found intracellular in the epithelium and in the gland lumen enclosed within lytic zones. The virus particles are found within the degenerating cytoplasm, nuclei, and lumen of the cell where they are especially numerous. Stratified epithelium and gland enlargement are a prominent feature of the infection. These observations suggest that biological associations between salivary gland tissue and diverse microbes may be more common than formerly recognized. The microbes appear to cause damage to salivary gland cells, causing hyperplasia which assumes pathologic proportions.     

Prevalence of enlarged salivary glands in wild populations of Glossina pallidipes in Kenya,with a note on the ultrastructure of the affected organ

Enlarged salivary gland was found to be widespread among wild populations of Glossina pallidipes in Kenya. The incidence of this abnormality varied from 0.9% in Meru National Park in Central Kenya to 5.4% in the Shimba hills area on the Kenya coast. Ultrastructurally, the enlarged glands were multinucleated with lumen reduced substantially in size. A large number of viruses filled both the lumen and the broken pieces of epithelial cytoplasm. In some cases Trypanosoma brucei trypanosomes were seen in the lumen of the enlarged glands. The epithelial cytoplasm was heavily vacuolated. Comment is made on the suitability of the diseased flies as transmitters of T. brucei.     

Early survival and growth of Allanblackia stuhlmannii (Clusiaceae): a threatened tropical rainforest tree of high economic value in Tanzania

Rural households living in tropical ecosystems depend heavily on forest trees for valuable nontimber forest products that are, however, undergoing unsustainable harvesting. This study assessed early survival and growth of Allanblackia stuhlmannii (Clusiaceae), a nontimber tree species endemic to Tanzania. A total of 400 seedlings sourced from twenty elite female trees were planted in two adjacent locations. Data were collected over 59 months for survival, height and root collar diameter. Seedling survival at 59 months was significantly different between Emau and Shebomeza, being on average ~11% higher in Shebomeza. However, survival of the progenies of each female tree at 59 months was not significantly different. Overall, mean RCD (range: 6.8–59.7 mm) and height (range: 17.1–274.4 cm) were positively correlated (r = 0.84, P < 0.001). The correlations in heights of individuals between 17 and 59, and 23 and 59 months were positive (r = 0.34 versus 0.53, respectively). Results also suggested that if growth rate is related to ontogeny from juvenile to adult, then the progenies of ten female trees that have shown consistently higher growth rates may flower and fruit earlier than other progenies. Future planting for conservation of this threatened, overharvested tree species can therefore be based on data gathered from these field genebanks.     

Body size and allometric variation in facial shape in children

Objectives

In group‐living primates, it has been reported that the alpha male exhibits high concentrations of cortisol and testosterone in the context of mating competition. We investigated how the presence of females affected salivary cortisol and testosterone levels in males from a small captive group of chimpanzees (Pan troglodytes). Specifically, we assessed whether the presence of females resulted in a rapid increase in salivary cortisol and testosterone levels in the alpha male.

Materials and methods

We compared the social behavior and salivary hormone concentrations of four males before and after the presentation of receptive females. Three times a day, we collected saliva samples, a useful matrix for investigating short‐term hormonal changes, and measured cortisol and testosterone concentration by liquid chromatography–tandem mass spectrometry (LC–MS/MS).

Results

The frequency of inter‐male aggression increased in the presence of females, indicating intense competition among males. Salivary cortisol levels increased in all males in the presence of females; however, the increase was significantly more pronounced in the alpha male. We found a complex three‐way interaction among the presence of females, sampling timings, and male dominance rank in the analysis of salivary testosterone. Contrary to our prediction, a post hoc analysis revealed that salivary testosterone levels decreased after female introduction and that the alpha male did not show a higher level of salivary testosterone.

Conclusions

Our study provides experimental evidence suggesting that the presence of females plays a significant role in the rank‐related variation in the cortisol levels in male chimpanzees. Furthermore, our findings demonstrate the usefulness of salivary hormones for detecting short‐term physiological changes in studies of socioendocrinology.

     

Sexual dimorphism of antennal,tarsal and ovipositor chemosensilla in the African stemborer,Busseola fusca (Fuller) (Lepidoptera: Noctuidae)

The number and distribution of chemosensilla located on different organs of Busseola fusca (Fuller) (Lepidoptera: Noctuidae) males and females are described based on observations using scanning electron microscopy, selective staining with silver nitrate, and gustatory electrophysiological recording. The antennae and the fifth tarsomere of the prothoracic legs of both sexes bear chemosensilla: uniporous chaetica and multiporous trichoidea sensilla. However, there is a sexual dimorphism in the number and size of sensilla on these organs. The distal part of the ovipositor has uniporous gustatory chemosensilla of the chaetica type. The involvement of these sensilla in oviposition site selection by B. fusca is discussed.     

Sensilla on antennae,ovipositor and tarsi of the larval parasitoids,Cotesia sesamiae (Cameron 1906) and Cotesia flavipes Cameron 1891 (Hymenoptera: Braconidae): a comparative scanning electron microscopy study

Two braconid parasitoids of cereal stemborers in eastern Africa, Cotesia sesamiae and Cotesia flavipes, have been shown to display a similar hierarchy of behavioural events during host recognition and acceptance. In order to understand the mechanisms underlying host recognition and acceptance, the morphology of antennal sensilla on the last antennomeres, on the ovipositor, and on the fifth tarsomere and pretarsus of the prothoracic legs tarsi were studied using scanning electron microscopy followed by selective silver nitrate staining. It appeared that female C. sesamiae and C. flavipes shared the same types and distribution of sensory receptors, which enable them to detect volatiles and contact chemical stimuli from their hosts. In both parasitoids, four types of sensilla were identified on the three terminal antennomeres: (i) non-porous sensilla trichodea likely to be involved in mechanoreception, (ii) uniporous sensilla chaetica with porous tips that have gustatory functions, (iii) multiporous sensilla placodea, which are likely to have olfactory function, and (iv) sensilla coeloconica known to have thermo-hygroreceptive function. The tarsi of both parasitoids possessed a few uniporous sensilla chaetica with porous tips, which may have gustatory functions. The distal end of the ovipositor bore numerous dome-shaped sensilla. However, there were no sensilla coeloconica or styloconica, known to have gustatory function in other parasitoid species, on the ovipositors of the two braconid wasps.     

Distribution of chemo- and mechanoreceptors on the antennae and maxillae of Busseola fusca larvae

The stem borer Busseola fusca (Fuller) (Lepidoptera: Noctuidae) is a major pest of maize, Zea mays L., and sorghum, Sorghum bicolor (L.) Moench (both Poaceae), in sub-Saharan Africa. Like in many other lepidopteran insects, the success of B. fusca in recognizing and colonizing a limited variety of plants is based on the interaction between its sensory systems and the physicochemical characteristics of its immediate environment. The sensilla on the maxillary galeae of B. fusca larvae are typical of Lepidoptera and comprise two uniporous styloconic sensilla, which are contact chemoreceptors, three basiconic sensilla, and two aporous sensilla chaetica. The maxillary palp is two-segmented and has eight small basiconic sensilla at the tip, which were also found to be gustatory. The antennae of B. fusca larvae are short and simple. The sensilla of the antenna are composed of two aporous sensilla chaetica, three multiporous cone-shaped basiconic sensilla, three small basiconic sensilla, and one aporous styloconic sensillum. The basiconic sensillum located on the third antennal segment displayed a contact chemoreception response. The other basiconic sensilla did not show any action potential activity in tip-recording tests. The significant and positive dose–response curve obtained for the antennal basiconic sensillum with sucrose indicated for the first time the presence of gustatory chemoreceptors on the antennae of a lepidopteran larva.     

Ultrastructural evidence for trans-ovum transmission of the DNA virus of tsetse,Glossina pallidipes (Diptera: Glossinidae)

The occurrence of vertical transmission of the DNA virus of tsetse was studied in virus-infected, femaleGlossina pallidipes with hypertrophied salivary glands (HSG). Ultrastructural examination of tissue components of ovaries of these females revealed virus particles within both germ cell cystocyte clusters and in the follicles, sparsely distributed within nurse cells and in the oocyte cytoplasm. The presence of the virus particles within the ooplasm demonstrates the ovum as a vehicle through which theG. pallidipes virus is disseminated in nature.