The conventional theology regarding the role of science in the social and economic development of the Third World is that its crucial function must be the transfer of technology from the science-based industrialized countries to the developing regions of the world. Indeed, ever since 1963, when the world took part in the “United Nations Conference for the Application of Science and Technology to Development” in Geneva, Switzerland, national planners in the Third World and economic planners attached to the donor community, have been consumed by the concept of transfer of technology as a short-cut to science-driven socio-economic development in the Third World. The 1979 United Nations Conference on Science and Technology for Development, on the same theme held in Vienna, Austria, reinforced this concept, and rather confirmed the policy of focussing human and financial resources on the technology facets of science rather than on the fundamental research aspects.

Integrated pest management (IPM) is nowadays considered the most appropriate approach to pest control. The introduction of IPM in developing countries is however not easy. Experience shows that it is a long-term process. Some experience of IPM programmes are briefly discussed (cotton in Latin America; rice in South East Asia and basic food crops in the Sahel). The attention of tropical entomology should not be focused on IPM only, but also be directed at problems not directly related to IPM. These include the need for better pesticide management, the avoidance of further spread of pests to previously infested area and the control of grasshopper outbreaks in Africa.

The recently developed “International Code of Conduct on the Distribution and Use of Pesticides” which was unanimously adopted by FAO Member Countries in 1985, can be an important instrument for better pesticide management. To make this code work is a challenge. The control of introduced pests absorbs resources which otherwise could have been used for the control of indigenous pests. Therefore quarantine measures should be strengthened to prevent such spread. Strengthening of Plant Protection Services represents another challenge as these services play a key role in pest control in general and also in implementing IPM. Training in biological control has to be strengthened with emphasis on practical methods which effectively lead to better field pest control. Biological control units have to be set up in countries where they do not exist. There is no fixed level of IPM which should be reached. IPM strategies should fit local conditions and be promoted in conjunction with improved agricultural practices. Priorities for intervention have to be set when developing IPM programmes.

The tropics abound with insect diversity; yet we hardly know about a tenth of them. Destruction of natural habitats due to deforestation, monoculture and urbanization results in their extermination or change of habits, often with devastating results. If the insects are to be properly managed for the benefit of mankind, an inventory of them should be taken before they are destroyed and their habits and habitats studied. A team of well trained taxonomists is required. Taxonomie centres are to be developed where taxonomists can be trained and insect collections can be housed and studied. Taxonomie manpower and resources should be developed in various countries of the tropics so that the rich and abundant insect diversity is studied and finally utilized for the benefit of mankind.

This Symposium was held on 1 September 1986 to assess available resources and current requirements for biosystematic research, identification and other services in support of entomological work in the tropics, especially in Africa, India and S.E. Asia. Particular attention was given to biosystematic services for agriculture and to the need for long-term financial support to maintain and develop reference collections; to train and employ taxonomists; to provide identification services and to undertake biosystematic research at local, national, regional and international levels.

The formation of the International Advisory Council for Biosystematic Services in Entomology (IACBSE) in Hamburg at the XVIIth International Congress of Entomology in 1984 is described and its composition and long-term objectives are stated. These include fostering the development of biosystematic research and identification services on a world basis by co-ordinating and assisting interactions and exchange of information between organizations and individuals, and by establishing a series of Working Groups on major projects. The main user needs for biosystematic services are also summarized. The particularly important needs of medical, agricultural and forestry entomology are emphasized and other needs for the support of faunal surveys, conservation, ecology, physiology, biogeography, litigation, amateur and general public interest are noted.

FAO recognizes the value of, and attaches a high importance to the continuance of existing taxonomie identification services. It considers it desirable that there should be an increase in the number of institutions qualified both to provide authoritative identification and to conduct taxonomie research on pests of agricultural significance. Regrettably, direct support to taxonomie identification services in general cannot be provided by FAO. As components of ongoing projects, identifications and relevant taxonomie research can be financed in certain instances. Preference is given to the development of a self-help capability through production of identification keys and pictorial guides, in-depth taxonomie studies and training, rather than simply paying for routine identifications.

Increasing interaction among specialists in the field of biosystematics so as to facilitate better identification services is suggested, taking into consideration the increasing intraspecific diversity resulting in recognizable “biotypes”. The need for a more comprehensive idea of intraspecific diversity in different insect groups is also indicated.

The recent history of initiatives in support of tropical insect taxonomy and the current status of the insect collection resources of Africa are reviewed with special emphasis on the development of the Department of Entomology, National Museums of Kenya as a regional centre for insect biosystematic services, training and research. Specific proposals are offered for the future development of such centres.

Functional diversities associated with structural polymorphism involving oedymery and gynaecoidy among males and major and minor forms in females, with or without alary polymorphs appear typical of many mycophagous Tubulifera. Notable is the occurrence of reproductive polymorphism resulting in oviparity, ovoviviparity, and viviparity among individuals of the same species reflecting both gross as well as histological profiles.

While alary polymorphism tends to result in ovarian diversities in some species, the combination of this feature with gynaecoidy and oedymery among Tubulifera results in a variety of mating combinations and variations in egg output. Information presented pertains to the mating patterns in mycophagous and sporophagous species in relation to the degree of polymorphism and reproductive efficiency in terms of oviposition rates. The considerably higher longevity of the oedymerous males as compared to gynaecoids adds further to the reproductive efficiency of the oedymeres. Size assortive mating is very evident, with females tending to reject males smaller than them, and with males competing for larger females in this intrasexual rivalry.

The main effects of gall midges in tropical agriculture are as primary pests of cultivated plants; as predators on pests, especially mealybugs, scale insects and mites; as potential biocontrol agents of weeds and as pollinators of cocoa. Published information is briefly reviewed under these main headings, with particular emphasis on the sorghum midge, Contarinia sorghicola (Coquillett), on the Asian and African rice gall midges, Orseolia oryzae (Wood-Mason) and O. oryzivora Harris & Gagné and on cecidomyiid predators on mealybugs and scale insects.

With perhaps a thousand species present in the endemic fauna, the Hawaiian Drosophilidae represents one of the most striking examples of explosive adaptive radiation known in the animal kingdom. However, there is mounting evidence that it is shifts within the sexual environment that are more important in the speciation process. Classical concepts of sexual selection theory are reviewed and some new ideas regarding the role of sexual selection in the origin of secondary sexual characters are presented. It is suggested that there is a range of mating types in both sexes and that differential selection between the two sexes, i.e. selection for males with superior mating ability and for less discriminant females, results in the maintenance of an optimum behavioural phenotype in the population. It is further suggested that the dynamics of the sexual selection process and the effects of pleiotropy play a significant role in levels of genetic variability in a single interbreeding population.

Biotypes refer to the infraspecific category of insect populations with similar genotypes for biological attributes. They have been encountered mostly in association with cultivation of resistant crop cultivars and in well-studied cases a gene-for-gene relationship between pest virulence and host plant resistance has been documented. To date, biotypes have been reported to occur in 36 crop pest species belonging to 17 arthropod families in six Orders. Almost 50% of these pest species with known biotypes are aphids. Knowledge of occurrence of insect biotypes is crucial to the success of crop improvement programmes aiming to incorporate pest resistance. Biotypes represent evolutionary transients in the process of speciation and develop through natural selection acting upon genetic variations within the pest populations. To slow down the process of biotype selection, crop cultivars with broad genetic bases are needed.

Insects have evolved a potpourri of mechanisms for manipulating the allelochemicals that fortify their preferred host plants. A concatenation of physiological and biochemical events frequently follows the ingestion of a toxic natural product and can eventuate in a variety of fates for the compound. A particular allelochemical may be absorbed, metabolized, and sequestered, whereas the fates of concomitant natural products may be very different. Some compounds may be directly excreted in the faeces and their concentration will thus mirror that in the plant. In other cases, selective absorption and sequestration combine to biomagnify minor constituents so that the concentration of these sequestered compounds in insect tissues diners drastically from their concentrations in the host plants.

The acridid Romalea guttata is utilized in this paper as a paradigmatic insect which eclectically processes ingested allelochemicals from a wide range of host plants. This generalist herbivore is eminently suitable as a model because it feeds on plants containing a veritable pharmacopoeia of toxic compounds. The proven sequestrative potential of its defensive glands further qualifies R. guttata as an excellent candidate for determining the fates of toxic phytochemicals. An analysis of this insect's processing strategies for the compounds ingested after feeding on catnip (Nepeta cataria) reveals that for R. guttata variety is the spice of herbivorous life. The results of this investigation persuasively demonstrate that each insect species—and the phytochemical mixture that it ingests—must be regarded as a unique evolutionary case that constitutes a distinctively idiosyncratic phenomenon.

Electrophoretic studies of Guatemalan blackflies, Simulium ochraceum, the main vector of Central American onchocerciasis, were performed using isozyme patterns. A total of six larval and adult populations originating from four localities (a non-endemic area, Finca La Ruda, a low-endemic area, Finca Rincon, and two high-endemic areas, Finca Brote and Finca Recreo) were analyzed. The enzymes examined were adenylate kinase (AK), alkaline phosphatase (ALP), glucose phosphate isomerase (GPI), hexokinase (HK), isocitrate dehydrogenase (IDH), leucine aminopeptidase (LAP), malic enzyme (ME), and phosphoglucomutase (PGM). Of these, six enzymes, AK, ALP, HK, IDH, LAP, and ME showed no variation either within or among populations. GPI and PGM were found to be highly polymorphic in all of the six populations. χ2-test for fit to Hardy-Weinberg equilibrium (HWE) revealed that the distribution of the phenotypes of the two polymorphic enzymes was not significantly out of the HWE. A verages of values of proportion of polymorphic loci (P) and heterozygosity per individual (H) of the six populations were 0.234 and 0.084, respectively, each of which was similar to the values reported for different groups of organisms (Nei, 1975). Genetic diversity among populations was measured by FST and GST and both parameters showed that the non-endemic population from the Finca La Ruda (Dl) was greatly differentiated genetically from the other five populations. Estimates of genetic distance (Nei, 1975) showed that the Dl population was furthest from the other populations.

The study of life history traits in tropical insects is still in its infancy. We are just beginning to appreciate that tropical insects do not all develop and reproduce continuously throughout the year. Developmental and reproductive events may be as highly seasonal in tropical species as they are in insects from the temperate zone. Yet, little is known about the evolutionary forces that shape the life history traits of tropical species. What are the developmental options and what dictates which option is expressed? What are the ultimate factors determining whether a species will diapause or develop without interruption? What other life history traits are linked to the decision to diapause or not to diapause? What environmental cues are utilized by tropical insects to regulate seasonal cycles, and how are these cues translated into meaningful hormonal signals that direct the insect's development fate?

The band-legged ground cricket group comprises a pair of very closely related species; Dianemobius fascipes occurs widely over tropical and subtropical regions of Southeast Asia, while D. nigrofasciatus is restricted to temperate regions. A similar situation is found in the lawn ground cricket group; the tropical/subtropical species D. taprobanensis is replaced by D. mikado in temperate regions. In both southern species, tropical strains were almost homodynamic, but they produced a few delayed eggs independently of photoperiod and a variable proportion of macropters in response to photoperiod; subtropical strains showed clearer responses. Both northern species controlled egg diapause, nymphal development and wing form by various photoperiodic responses. The two species groups showed parallel geographical profiles of size variation, and the adults and eggs were smaller in the southern than in the northern species. In the absence of strong climatic selection for larger growth rate, size increase in tropical regions would be counteracted by predation pressure. The optimal adult size thus seems to be smaller in tropical than in temperate regions, being determined by the geographically variable balance between counteracting selecting forces.

Samples of ground beetles (Carabidae) were collected throughout the year-long 1985 Joint Indonesian–Royal Entomological Society expedition, Project Wallace, in an area of rain forest in N. Sulawesi. The beetles were collected by a range of collecting techniques including insecticide fogging, malaise, flight interception, pitfall and light trapping as well as hand collecting. The state of ovary maturation was determined by dissecting the females. A high number of species of Carabidae show a distinct seasonal reproductive rhythm in the form of gonad dormancy, avoiding reproduction in the slightly cooler months in the middle of the year. In contrast, most species of tiger beetles (subfamily Cicindelinae) are reproductively active at this time of year. The study area appears to have an unusually variable monthly rainfall for this region, and we suggest that the seasonality in the ground and tiger beetles is a response to the strict annual rainfall patterns of the coastal areas 10–20 km to the north and south.

The dry and largely deciduous forests in Santa Rosa National Park in northwestern lowland Guanacaste Province, Costa Rica, Central America, have a moth fauna of about 2800 species. These moths pass the six month rain-free dry season, and some other portions of the year, by: (a) remaining dormant in the egg stage (1 species only), (b) remaining dormant in the pupal or prepupal stage (many species), (c) undergoing larval development (a few species of particular life forms) (d) remaining in the Park as a potentially active but non-reproductive adult (many species), and (e) migrating out of the Park after one to two generations and then returning at the beginning of the following rainy season (a few species of particular life forms). The migrating moths constitute a strong link between the dry forest and the rainforests to the east of the dry forest. The seasonal patterns of dormancy of immatures, reproductively dormant adults, and migration are not well correlated with the simple presence or absence of foliage on host plants, or with climate changes (except that the temperature drop that occurs at the beginning of the rainy season appears to be a widely used cue for pupal eclosion). The pattern of habitat use by leaf-eating caterpillars is probably determined more by the seasonal abundance of carnivores (parasitoids and predators) than by the mere presence of leaves; this process is very strongly evident in the failure of many moths to have more than one generation per year, even when their host plants are leafy throughout the six month rainy season or are even evergreen.

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.