The bedbugs Cimex lectularius and C. hemipterus (Hemiptera: Cimicidae) have been identified from a study area in northern Natal and KwaZulu. South Africa, between 26° 45' S and 28° 45' S, and 32° 00 ' E and 32° 52' E. Morphological behavioural data suggest that the pigeon bug, C. columbarius, which closely resembles C. lectularius, is not present in Zulu huts. Two characters are suggested to supplement Usinger's (1966) key for distinguishing the nymphal stages of C. lectularius, and a key is presented for the case of G. hemipterus. Distinguishing features between the nymphal stages of the two species are also given. The two species were found to be sympatric over most of the study area, with C. hemipterus the more plentiful species in the north and apparently still in the process of invading the study area. Evidence was found that C. hemipterus replaces C. lectularius in huts where initially both species were found, and this agrees with laboratory findings that interspecific mating tends to shorten the life span and reduce the egg production of female C. lectularius females. Interspecifically mated female C. lectularius can be recognised by an easily visible morphological change in the reproductive system (Walpole, 1988b) and this character was used to prove that interspecific mating takes place in the wild. The size and life-stage composition of bedbug infestations were investigated together with factors likely to affect their growth. Cimex hemipterus was found not to be at a disadvantage as regards rate of egg production despite low temperatures in the wild, which suggested that such interspecific differences apparent in the laboratory may be an artifact. The specific status of C. lectularius and C. hemipterus are discussed, with particular reference to their cross-mating in the wild and the production of a hybrid. The acceptability of the Recognition Concept of species (Paterson, 1985) is considered in detail. The susceptibilities of wild bedbugs of both species to DDT, dieldrin and fenitrothion were tested in comparison with a susceptible strain of C. lectularius. Field trials of bendiocarb, deltamethrin and fenitrothion were carried out involving monitoring by bioassay and insecticidal knockdown. Subsequent to successful bedbug control operations, reinfestation rates and rates of replastering of mud walls of huts (an indigenous method of attempted bedbug control inimicable to malaria control operations) are assessed. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1989.

Pest insects cause great financial losses in the forest and food industry every year. To fight these pests industries have used insecticides, which are sometimes harmful to nature and humans. One potential way of avoiding insecticides is the use of integrated pest management based on insect communication, which would offer species-specific methods for protecting forest and food resources. Insects use chemicals known as semiochemicals for both intra- and interspecies communication. By learning how insects use these semio-chemicals to talk to each other we can eavesdrop and mimic their communication for our benefit. One research area dealing with these questions is chemical ecology, which is an interdisciplinary area as knowledge in chemistry and biology is required. Collaborations between groups within and outside of Sweden are essential in order to make progress in this field of research. This thesis presents the identification and synthesis of semiochemicals from several insect species, most of which are considered to be pests. Synthesised compounds have been sent to collaboration partners around Sweden and Europe for biological evaluations. Studies of the African butterfly, Bicyclus anynana, have unravelled particular biological phenomena that may aid in the understanding of the Bicyclus genus, though recognizing individual species variation is crucial. In 2008 the putative male sex pheromone of B. anynana was determined to consist of three compounds: hexadecanal, (Z)-9-tetradecenol and 6,10,14-trimethylpentadecan-2-ol, and the specific stereoisomer for 6,10,14-trimethylpentadecan-2-ol has been determined in this thesis. The ratio of 6,10,14-trimethylpentadecan-2-ol and the corresponding ketone were investigated for seventeen Bicyclus species (including B. anynana) that live in overlapping regions in Africa. The stereochemistry was determined for most of the species and may provide a way to chemically distinguish them. The orchid bees, Euglossa spp, are important pollinators of many orchids in Central America. Insight about pollination and conservation of endangered orchid species may be possible by gathering more information about the Euglossa genus. Males of the Euglossa genus have pouch-like structures on their hind legs where they store compounds collected from their surroundings. 6,10,14-Trimethyl-pentadecan-2-one is a common component of leg extracts from Euglossa imperialis, E. crassipunctata and E. allosticta, the specific stereochemistry of which has been determined in this thesis. Another, different compound was found in high amounts in E. viridissima and its structure has been elucidated; several synthetic pathways are under investigation to obtain the target compound. Bed bugs (Cimex lectularius and C. hemipterus) are an ectoparasite that feed on human blood, and the number of reported infestations of these parasites has increased considerably during the last decade. Two 5th instar nymph-specific compounds, 4-oxo-hexenal and 4-oxo-octenal, were identified and synthesised. Utilizing domestic dogs (Canis lupus familiaris) in the identification of bed bug infestations has become popular during recent years. Their training is usually conducted using live bed bugs, however this thesis describes an alternative method of teaching dogs to find infestations. This alternative method is based on synthetic compounds and dogs trained in this manner have achieved a high positive indication rate. Two species of the tiny, Acacia leaf-eating insect pests in Australia known as thrips, Kladothrips nicolsoni and K. rugosus, have been investigated by means of larval extracts and have been shown to contain large amount of (Z)-3-dodecenoic acid which was synthesised and tested in bioassays. Fruit flies are common pests on fruit in almost every private household. Even though fruit flies has been investigated extensively, their chemical communication has not been completely elucidated. (Z)-4-undecenal was identified as a compound emitted by females, it was synthesised in high stereoisomeric purity and evaluated in biological assays. / FORE