JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. British Ecological Society is collaborating with JSTOR to digitize, preserve and extend access to Journal of Animal Ecology. Summary 1. Satellite imagery, geographic information systems (GIS) and spatial statistics provide tools for studies of population dynamics of disease vectors in association with habitat features on multiple spatial scales. 2. Tsetse flies were collected during 1988-90 in biconical traps located along transects in Ruma National Park in the Lambwe Valley, western Kenya. Fine spatial resolution data collected by Landsat Thematic Mapper (TM) satellite and reference ground environmental data were integrated in a GIS to identify factors associated with local variations of fly density.3. Statistical methods of spatial autocorrelation and spatial filtering were applied to determine spatial components of these associations. Strong positive spatial associations among traps occurred within transects and within the two ends of the park. 4. From satellite data, TM band 7, which is associated with moisture content of soil and vegetation, emerged as being consistently highly correlated with fly density. Using several spectral bands in a multiple regression, as much as 87% of the variance in fly catch values could be explained. 5. When spatial filtering was applied, a large component of the association between fly density and spectral data was shown to be the result of other determinants underlying the spatial distributions of both fly density and spectral values. Further field studies are needed to identify these determinants. 6. The incorporation of remotely sensed data imagery into a GIS with ground data on fly density and environnmental conditions can be used to predict favourable fly habitats in inaccessible sites, and to determine number and location of fly suppression traps in a local control programme.

No abstract

The prospects of the fungus Metarhizium anisopliae (Metsch.) Sorok. applied in contamination devices (Cds) to control tsetse fly Glossina fuscipes fuscipes Newstead was tested in a field experiment in Lake Victoria from 2 March 1999 to 31 August 2000. One hundred and sixty pyramidal traps mounted with Cds were deployed along the lakeshore and rivers on Mfangano Island. Contamination devices were loaded with 1.5 Á/2.0 g of dry conidia/Cd. On the second island, Nzenze Island, four pyramidal traps fitted with plastic bags were deployed and served as the conventional 'trap and kill' population suppression method. A third island, Ngodhe Island, remained untreated and served as a control. Cds were recharged monthly with fresh conidia; plastic bags were also changed monthly. The apparent changes in population density were monitored weekly using biconical traps set at random on the three islands. To assess the incidence of M. anisopliae in tsetse flies on Mfangano Island, flies captured during monitoring were maintained in the laboratory and their mortality recorded. Fly population was reduced to 82.4 and 95.8% relative to untreated control on Mfangano and Nzenze islands, respectively, during the experimental period. Compared to the fungus-treated island, the number of flies caught in monitoring traps increased considerably in 'trap kill' treatment at 5 months after the treatments were removed. The incidence of M. anisopliae in fly populations was low during the 12 weeks following the initiation of the experiment but increased afterward until termination of the treatment. M. anisopliae could still be recovered from fly populations at 3 months after termination of the treatment, although the incidence was low. The results of this study have shown that application of M. anisopliae in a contamination device can suppress the population of G. fuscipes fuscipes comparable to the 'trap and kill' technology.

Diurnal activity patterns and host preference of Glossina fuscipes fuscipes Newstead were studied in forest and linear habitats along Lake Victoria shore, Kenya. The objective was to identify the preferred hosts of G. /. fuscipes, the emanations of which may be attractive to this species. Hourly catches of flies in biconical traps were related to changes in the weather and the prevalence of hosts in the vicinity of traps. Flies were mainly active between 0800 and 1600 h, with males peaking around 1100 h and females around 1300 h. Activity of flies correlated directly with light intensity and temperature, but indirectly with relative humidity. Humans, livestock and the monitor lizard, Varanus niloticus, were the predominant hosts, although a significant positive correlation with fly catches could only be established with the prevalence of lizards. Blood meal identification by microscopic and serological methods showed that 73-98% of G. /. fuscipes fed on monitor lizards irrespective of host prevalence, season or location. The significance and possible epidemiological importance of the relationship between G. /. fuscipes and monitor lizards are discussed.

Species richness, diversity and composition of butter£ies intwo Kenya coastal forest remnants, Muhaka andMrima hill, were investigated. Sixty-three species were recorded from each forest remnant from a total of1329 individuals. Species accumulation curves for both forests did not reach an asymptote. High species similarity was recorded between the forest interior and the surrounding matrix, primarily due to invasion of the forest interior clearings by the savanna species. Despite their small sizes, these forest remnants were found to maintain viable populations of true forest butter£ies. However, the number of species was less than half that recorded from the larger forest reserve of Arabuko-Sokoke, located in the same geographical area. Records from Muhaka forest show species unique to it, not found in the larger forest reserves, underscoring the importance of small remnants in the preservation of forest biodiversity. The high species similarity between the forest remnants implied that if habitat corridors were created, gene £ow between these remnants and other larger forest reserves would be possible. This would reduce the isolation of true forest butter£y populations within the remnants and potential local extinction.Re¨sumeÖ n a e¨tudie¨la richesse, la diversite¨et la composition des espe© ces de papillons dans deux re¨sidus de foreª ts coª tie© res au Kenya, Muhaka et Mrima Hill. On a releve¨s oixante-trois espe© ces dans chaque foreª t, sur un total de 1329 individus. Les courbes d'accumulation des espe© ces pour les deux foreª ts n'atteignaient pas une asymptote. On a releve¨une forte similarite¨des espe© ces entre l'inte¨rieur de la foreª t et la matrice exte¨rieure, due en priorite¨a© l'invasion des clairie© res forme¨es a© l'inte¨rieur des foreª ts par les espe© ces de savane. Malgre¨leur petite taille, on a trouve¨que ces deux re¨sidus forestiers abritaient des populations viables de vrais papillons de foreª t. Cependant, le nombre d'espe© ces e¨tait infe¨rieur a© la moitie¨de celui qui est rapporte¨de la re¨serve forestie© re, plus grande, d' Arabuko-Sokoke, situe¨e dans la meª me zone ge¨ographique. Les rapports de la foreª t de Muhaka signalent une espe© ce unique, qui ne se trouve pas dans les plus grandes re¨serves forestie© res, ce qui met en e¨vidence l'importance des petits | ³ lots pour la pre¨servation de la biodiversite¨forestie© re. La grande similitude des espe© ces entre les re¨sidus forestiers implique que, si l'on cre¨ait des corridors entre ces habitats, il pourrait y avoir un £ux ge¨ne¨tique entre ces |ª lots et les plus vastes re¨serves forestie© res. Ceci re¨duirait l'isolement des populations de vrais papillons de foreª t au sein des |ª lots et peut-eª tre leur extinction locale. 266