https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(09)60829-1.pdf

Human African trypanosomiasis

Miombo woodlands are the most extensive vegetation type in Africa south of the equator. These dry tropical woodlands cover some 2.5 million hectares and are home to over 40 million people. Miombo products are very important to the livelihoods and basic needs of an additional 15 million urban Africans. The book demonstrates how much livelihood strategies of rural communities depend on miombo goods and services, and indicates the strong differentiation of uses within communities and in space and time. The ecological constraints to human activity in the region are clearly articulated, ranging from nutrient-poor soils to the presence of the tsetse fly. The authors also trace the host of policies that have influenced miombo woodlands and their uses, from pre-colonial times to the present. The current importance of miombo products in markets, both locally and globally, is documented in a chapter on trade patterns. Options for management are outlined, including silvicultural treatment, fire management and grazing regimes. Institutional arrangements, both local and state, for the management of the woodlands are investigated, and the authors examine how local communities can be empowered to manage and benefit from the woodlands. The final chapter proposes a conceptual model of how all the diverse social, economic, political and ecological processes interact to shape how the household and woodland situations are changing. This conceptual framework is then used to identify key issues for research, which will reduce gaps in current understanding and facilitate formulation of new management strategies, policies and institutions. The Miombo in Transition is a resource for researchers, with over 250 pages reviewing and synthesising over 400 studies. There are numerous figures, tables and plates. The book contains contributions by a number of researchers, and yet has managed to ensure coherence, close linking of chapters and complete coverage of material through authors' workshops and tight editorial control. Each chapter was reviewed by international experts both in draft and final format, resulting in the high quality of the final produc

/pdf/the-miombo-in-transition-woodlands-and-welfare-in-africa-2zue88tnq3.pdf

The miombo in transition: Woodlands and welfare in Africa

During the 1930s and 1940s the idea of releasing insects of pest species to introduce sterility (sterile insect technique or SIT) into wild populations, and thus control them, was independently conceived in three extremely diverse intellectual environments. The key researchers were A. S. Serebrovskii at Moscow State University, F. L. Vanderplank at a tsetse field research station in rural Tanganyika (now Tanzania), and E. F. Knipling of the United States Department of Agriculture. Serebrovskii’s work on chromosomal translocations for pest population suppression could not succeed in the catastrophic conditions in the USSR during World War II, after which he died. Vanderplank used hybrid sterility to suppress a tsetse population in a large field experiment, but lacked the resources to develop this method further. Knipling and his team exploited H. J. Muller’s discovery that ionizing radiation can induce dominant lethal mutations, and after World War II this approach was applied on an area-wide basis to eradicate the New World screwworm Cochliomyia hominivorax (Coquerel) in the USA, Mexico, and Central America. Since then very effective programmes integrating the SIT have been mounted against tropical fruit flies, some species of tsetse flies Glossina spp., the pink bollworm Pectinophora gossypiella (Saunders), and the codling moth Cydia pomonella (L.). In non-isolated onion fields in the Netherlands, the onion maggot Delia antiqua (Meigen) has since 1981 been suppressed by the SIT. In the 1970s there was much research conducted on mosquito SIT, which then went into “eclipse”, but now appears to be reviving. Development of the SIT for use against the boll weevil Anthonomus grandis grandis Boheman and the gypsy moth Lymantria dispar (L.) has ended, but it is in progress for two sweetpotato weevil species, Cylas formicarius (F.) and Euscepes postfasciatus (Fairmaire), the false codling moth Cryptophlebia leucotreta (Meyrick), the carob moth Ectomyelois ceratoniae (Zeller), the cactus moth Cactoblastis cactorum (Berg), the Old World screwworm Chrysomya bezziana (Villeneuve), additional Glossina spp., other Anastrepha spp. and Bactrocera spp. fruit flies, and other pest insects.

History of the Sterile Insect Technique

UNDP/World Bank/WHO special programme for research and training in tropical diseases (TDR)

It is postulated that the sperm precedence characteristics of most insect populations have resulted primarily from selection on females (1) to optimize the genetic composition of their progeny; (2) to discourage or encourage multiple matings for reasons other than genetic considerations; (3) to optimize their sperm storage capacity and utilization. In addition, selection on males to maximize egg fertilization by reduced displacement of their sperm and increased displacement of other sperm to the extent that these can be achieved without sacrificing the optimal mating strategy (Parker 1970a) probably has been important in some species. Parker's (1970a) hypothesis that the amount of sperm displacement in a population should stabilize at the value which yields the optimal overall male fertilization rate is accepted as the optimal male strategy; however, it is suggested that females often largely determine, by their behavior and by the structure and functioning of their reproductive tract, the optimal male st...

https://www.jstor.org/stable/info/2460800

Sperm Utilization Strategies in Nonsocial Insects

Trypanosomiasis Control and African Rural Development

The literature published during 1964–72 concerned with the ecology and control of Glossina is reviewed and put into context with previously published information. Thirty species or subspecies of Glossina are recognised. Improved methods of sampling have been developed which catch many more females of the morsitans group than other methods and allow more accurate estimates of population density and structure to be made than has been possible hitherto. New concepts of the activity and behaviour patterns of G. morsitans Westwood have been developed from work carried out both in the field and in the laboratory. Detailed studies on resting sites have been followed by successful control campaigns based on the selective use of insecticides. Most large-scale control campaigns during the period under review were based on applications of insecticides from the ground; other control methods used were aerial applications of insecticides, mechanical clearing of vegetation, selective game destruction and a small-scale project using the sterile insect release method. Techniques for identifying and assessing trypanosome infections in Glossina are described and a Table is given of infection rates in various species of tsetse. Differences in observed infection rates can result according to the time and method of sampling but actual infection rates are affected by a variety of factors including the maintenance temperature of puparia and adults, the age of the fly at the time of the infective feed, the age structure of the tsetse population and the hosts on which it feeds. Genetic differences in infectibility may occur between different individuals of a single species and certainly occur between different species.

Recent developments in the ecology and methods of control of tsetse flies (Glossina spp.) (Dipt., Glossinidae)-a review.

The Glossinidae, or tsetse-flies, form a monogeneric family of the Diptera. The adults range in length from 6 to 14 mm and in all the 23 known species are various shades of brown — ranging from light yellowish brown to dark blackish brown. In some species the abdomen has alternate darker and lighter bands. Female flies give birth, at intervals of about nine days, to a single third-instar larva which rapidly burrows into the soil and transforms into a black puparium; according to the species, this varies in length from 3 to 8 mm.

Tsetse-flies (Glossinidae)

Male and female Glossina morsitans morsitans Westw. which emerged from puparia produced by animal-fed and in vitro-fed colonies in England were marked distinctively with non-toxic paint and released into a natural habitat of G. morsitans and G. pallidipes Aust. in Rhodesia. Concurrently, adults of both species which emerged from locally-collected puparia were marked and released. Recaptures from artificial refuges, odour attractants and mobile baits at periods up to 59 days after release and at distances up to 1800 m from the release site indicated no clear differences between native G. morsitans and the two laboratory-reared groups in respect of body size, amount of fat present at emergence, survival, dispersal, availability to a range of baits, diet, speed of taking a first meal, wing damage and insemination rate. Although the blood-meal identifications for marked female G. morsitans were similar to those for both sexes of unmarked flies, blood-meals from marked males showed a relatively high proportion of bovid identifications. Unmarked flies caught were generally older than marked catches. The ratio of females to males in unmarked samples (1:1 for G. morsitans, 2:1 for G. pallidipes) was roughly double that in marked catches.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0007485300010786

Survival and behaviour of tsetse flies (Diptera, Glossinidae) released in the field: a comparison between wild flies and animal-fed and in vitro -fed laboratory-reared flies

An examination is made of previously published data on the trypanosome infection rate and the natural hosts, as determined by serological tests, of 9 species of Glossina from various localities in Nigeria.

A relationship is demonstrated between a high total infection rate and a large proportion of meals derived from Bovidae (particularly bushbuck (Tragelaphus scriptus), with buffalo (Syncerus nanus) important in some localities). Infection rates and the natural hosts, as determined by the measurement of red blood cells found in the flies, of two species of Glossina in Northern Nigeria were recorded by Lloyd, Johnson, Young and Morrison (1924). An examination of their data shows that a similar relationship exists between feeds derived from Bovidae and total trypanosome infection rate.

Species of Glossina which had fed mainly on Suidae usually had fewer infections of T. vivax group of trypanosomes than those which had fed mainly on Bovidae; the numbers of T. congolense group infections were approximately the same in the two groups of species.

It is suggested that, at least in Nigeria, the source of food of the flies is the main factor involved in determining the level of infection with trypanosomes in Glossina. The importance of other factors, particularly temperature, is discussed.

A. M. Jordan

Papers

Trypanosomiasis Control and African Rural Development

Recent developments in the ecology and methods of control of tsetse flies (Glossina spp.) (Dipt., Glossinidae)-a review.

Tsetse-flies (Glossinidae)

Survival and behaviour of tsetse flies (Diptera, Glossinidae) released in the field: a comparison between wild flies and animal-fed and in vitro -fed laboratory-reared flies

The hosts of glossina as the main factor affecting trypanosome infection rates of tsetse flies in nigeria.