The reproductive biology of three strains of Callosobruchus maculatus F. (Coleoptera: Bruchidae), the cowpea-seed beetle, was studied. This beetle is a serious pest of stored legume seeds in the semi-arid tropics. As females aged, energy reserves were depleted and aspects of this decline were related to the number of eggs laid in order to explain the observed daily egg laying pattern of C. macuiatus. Various factors affected the fecundity of females. The initial adult weight of females showed a strong positive relationship with the number of eggs laid. Substances, which could be extracted from cowpeas, were shown to be necessary to allow normal oviposition on an artificial substrate, glass beads. The male contribution to female fecundity was also investigated. Approximately half of the study was concerned with factors which govern a female's choice of oviposition site. The presence of a pheromone which enabled females to distribute their eggs more efficiently among cowpeas was demonstrated. This demonstration necessitated the development of a bioassay using a choice chamber which allowed beetles to choose between cowpeas marked with pheromone and control cowpeas. Using the bioassay, the solubility of the pheromone in different solvents was examined. The persistence of the pheromone over different periods of time was investigated and it was shown that the pheromone can remain active for at least thirty days. In addition to the marking pheromone, the role of physical characteristics of the oviposition substrates was also studied. The surface area and weight of such substrates were shown to affect the choice of oviposition site by females. The results obtained are discussed in the context of previous work on bruchids, particularly models of oviposition behaviour proposed by some workers.

The larvae of many Lepidoptera of the family Noctuidae have both green and brown forms. This trait had never been studied in depth. (Chapter 1) Larvae of Phlogophora meticulosa exhibit considerable colour variation. A method was developed to score larval colour. (Chapter 2) Eight colour types were defined, these being named "early green", "3rd instar green", and the main colour types "green, olive, brown, plain yellow, yellow-green and yellow-brown". Larval colour in the 1st, 2nd and sometimes 3rd instars is determined by foodplant colour. The seven colour types found in the late in stars, (3rd instar green is replaced by the green main colour type in subsequent instars), are controlled by five unlinked major genes which have a total of eleven alleles. The system involves a complex arrangement of dominance and epistatic effects. (Chapter 3) The change from foodplant to genetic control of larval colour is correlated with a change from a positive to a negative phototactic response. (Chapter 4) Study of allelic and phenotypic frequencies in wild populations has indicated that the genetic polymorphism is balanced from year to year, although the frequencies of some alleles show seasonal variation. (Chapter 5) Tests to determine the nature of the selective forces, which maintain the polymorphism, have indicated that choice of mate is random. Heterozygote advantage is implicated in the maintenance of at least two of the genes. (Chapter 6) Selection due to viral infection and parasitism both affect the maintenance of at least one gene, and beetle and small mammal predation may also do so. (Chapter 7) Experiments on the effects of bird predation have uncovered a complicated system of bird-larval morph relationships. (Chapter 8) Arguments are put forward to explain the switch from foodplant to genetic control of colour, and to explain the lack of linkage between the five major genes controlling larval colour. The relative importance of the selective agencies scrutinised is considered. It is suggested that bird predation is extremely important in the maintenance of the genetic system. The degree to which larval morphs are exposed to differential predation by birds is determined by the cryptic qualities of the larvae, and, because birds select apostatically to some extent, their abundance. Further lines of research are suggested (Chapter 9).

The interspecific aggressive behaviour of some British ants of the genera Myrmica. and Lasius was investigated. Since ants exhibit great variability in their behaviour the main part of the study was concerned with a comparative, numerical analysis of interactions between individuals in controlled laboratory conditions. Interactions were investigated between individuals and between entire colonies of M. scabrinodis and L. flavus under various experimental conditions. In this way it was possible to examine a number of factors that were believed to influence aggression such as age, hunger, number of combatants, place of interaction, relative colony size, etc. The experiments have shown how the behaviour of M. scabrinodis is adapted to living near to hostile L. flavus colonies, and the ecological relationship between the two species in terms of predation and competition in their common, naturally - occurring 'compound nests is discussed. The behaviour of individuals of M. scabrinodis was examined towards five different ant species that occur in the same habitat. A numerical analysis of the interactions has shown that the intensity of fighting is usually greater in intra- rather than intergeneric encounters. Intraspecific combats are of long duration but, however, lack severity. The individual behaviour patterns of six closely - related species' of the genus Myrmica were investigated in interactions with the same opponent species, L. flavus. The behavioural relationship of the species to one another was found to be similar to the taxonomic one. However, an exception to this general pattern stressed the need to consider the ecological position of the species in such comparisons. Finally, the study has shown that several types of responses shown by ants in interspecific interactions must be considered and more than one measurement of these responses may be necessary to gain a true assessment of the aggression present.

Doctor of Philosophy / Department of Grain Science and Industry / Subramanyam Bhadriraju / Hulya Dogan / Heat treatment, a more than 100-year-old technology, involves raising the ambient temperature of a an empty bins/storage space or a clean gran-processing facility to 50-60°C for 24 h or less to kill stored-product insects. Heat treatment is an environmentally benign and a safer alternative to chemical insecticides. The studies reported here were conducted to determine the effect of short-term exposure to sub-lethal temperatures on adults of Tribolium castaneum (Herbst) and their subsequent susceptibility to temperatures of 50 and 55°C for 60 and 15 min, respectively; to determine the effect of rearing T. castaneum at select elevated temperatures for 10 generations on their subsequent susceptibility to temperatures of 50 and 55°C; to determine the effects of age and sex on susceptibility of T. castaneum adults to 50 and 55°C; and to determine the effectiveness of a diatomaceous earth (DE) formulation at several elevated temperatures below 50°C on the mortality of T. castaneum adults. Results of the studies showed that short-term exposure between 24 and 72 h, to sub-lethal temperatures (32, 36, and 40°C) only increased survival for insects acclimated to 32°C. Acclimation at 36 and 40°C resulted in higher mortality after exposure for 24, 48, and 72 h at 50 and 55°C. Rearing insects at 32 and 36°C for 10 generations resulted in the highest survival of adults at 50°C. However, when adults reared at 32°C were exposed during heat treatment of Hal Ross Flour Mill, the adults were least susceptible to dynamically changing temperatures over time. Female T. castaneum adults were more heat tolerant than males, and adults 1 d post-emergence were the most heat tolerant when exposed to 55°C for 15 minutes compared with adults aged 7-42 d. The efficacy of DE was enhanced at higher constant temperatures, which can lessen energy inputs in order to obtain a complete kill of insects when temperatures do not reach 50°C or greater. Given the changing climate, it is very useful for researchers to understand the implications of increasing temperatures on the heat tolerance of insects.

<p> Biodiversity has decreased due to anthropogenic activities, and extinction rates are currently one hundred to one thousand times greater than the background rate. While the connection between deforestation and biodiversity loss is well documented within tropical rainforest ecosystems, comparatively little is known about the effects of desertification on biodiversity in dryland ecosystems. Drylands, which cover nearly half the terrestrial surface and are highly vulnerable to desertification, are among the most endangered ecosystems. To understand how biodiversity responds to environmental degradation in these fragile ecosystems, I studied arthropod diversity within a human-modified landscape suffering from deforestation and desertification in the Sahel of western Senegal. My specific objective was to determine whether arthropod, beetle, spider and ant diversity differed between protected areas of tropical dry forest and surrounding communal lands suffering from desertification. I established 12 quadrats spaced homogenously throughout each protected area as well as adjacent communal land at three different locations (Beersheba, Bandia and Ngazobil). Within each quadrat, I measured canopy closure, characterized vegetation and collected arthropods using pitfall traps during the 2014 dry (May) and rainy (September) seasons.</p><p> I collected 123,705 arthropods representing 733 morphospecies, 10,849 beetles representing 216 morphospecies, 4,969 spiders representing 91 morphospecies and 59,183 ants representing 45 morphospecies. Results showed protected areas contained greater arthropod and spider diversity than communal lands, beetle diversity varied depending on location and season, and communal lands contained greater ant diversity than protected areas (<i>P</i> &le; 0.05). My results illustrate the importance of a multi-taxa approach in understanding biodiversity response to anthropogenic disturbances. Conserving arthropod diversity in the Sahel will require the creation and preservation of more protected areas of a variety of sizes and successional stages as well as the adoption and extension of land-restorative techniques such as Zai and farmer managed natural regeneration (FMNR).</p>

Forensic Entomology utilises arthropods in legal investigations that involve death, neglect and abuse of humans and animals and even civil cases like insurance claims. This study aimed to make general observations on the decomposition of a pig carcass (Sus scofa Linneaus) in relation to recorded temperatures of the carcass and the surrounding site during both summer and winter on the Gauteng Highveld. The study also aimed to identify the dominant blowfly species occurring in the region. Six species were identified: Calliphora vicina, Chrysomya marginalis, Ch. albiceps, Ch. chloropyga, Lucilia sericata and L. cuprina. The cephaloskeleton, anal spiracles and anterior spiracles were dissected from the first, second and third larval instars of the flies to isolate the key features currently used in morphological identifications. The ITS2 region was investigated for the development of a multiplex PCR method to identify these species. The multiplex PCR method did not include Chrysomya albiceps but does successfully differentiate between the other five commonly occurring blowflies.

The results of studies on the Ephemeroptera (mayflies) of Sri Lanka and southern India are reported. / The species of the genus Povilla are reviewed and a new subgenus, Lanquidipes, is established. Five new species, P. (P.) andamanensis, P. (P.) heardi, P (P.) junki, P. (P.) ulmeri, and P. (L.) taprobanes, are described from the Oriental Region. Keys to the adults and nymphs of Povilla are included. / Two new species of Ephemera (E. hasalakensis and E. lankensis) are described from Sri Lanka, Ephemera supposita Eaton is redescribed, and the only described member of the Potamanthidae in Sri Lanka, Rhoenanthus posticus Banks, is transferred to Ephemera and redescribed. A key to the imagos of Ephemera from Sri Lanka is included. Two new species of Ephemera, E. distincta and E. nathani, are described from South India. / The systematics of Kimminsula and related genera from Sri Lanka are reviewed. Three new genera, Wijesinhe, Belihuloya, and Lankaella, are established. Four new species, K. podi, K. indrakanthiae, L. eka, and L. deka, are described. Three other species, K. taprobanes (=K. annulata), K. fasciata, and W. femoralis are redescribed. The related new species Petersula nathani is described from South India. These genera belong to the Atalophlebioides phylogenetic lineage. / A systematic account of the Ephemeroptera of Sri Lanka is given, along with an account of their ecology, both in general and at the generic level. The biogeographic origins of the Sri Lankan mayfly fauna are discussed at the generic level. / A systematic catalog of the Ephemeroptera of the Indian Subregion is given. The species are listed, along with their synonyms and information on type-specimens. Literature citations to references to the species are given along with an indication of the stage described or illustrated. The type-specimens of mayflies in the collections of the Zoological Survey of India are discussed. / Source: Dissertation Abstracts International, Volume: 45-04, Section: B, page: 1108. / Thesis (Ph.D.)--The Florida State University, 1984.

The taxonomy and phylogeny of selected northern Neotropical Leptophlebiidae were investigated. Results are presented on two separate systematic problems. The first includes the description and phylogenetic analysis of a curious new genus and species of Atalophlebiinae from the southern coastal mountains of Brazil. Nymphs of this taxon display a large number of derived character states that appear to be correlated with a sprawling habit and use of the legs for collecting-gathering. The second concerns the systematics of Terpides Demoulin and closely related genera. The taxonomic treatment of Terpides and related genera includes revisions of two genera, establishment of two new genera and one new subgenus, recognition of two species-groups within Terpides, description of ten new species, redescription of six species including the transfer of three species previously described in Choroterpes Eaton to their respective Neotropical genera, keys to genera and species, distribution maps for genera and species, and illustrations of useful morphological characters. Phylogenetic analysis demonstrates that Terpides and related genera constitute a monophyletic lineage, the Terpides lineage. The Terpides lineage is an ancient lineage that stems from the base of the Atalophlebiinae very near the basal furcation within the Leptophlebiidae between the subfamilies Atalophlebiinae and Leptophlebiinae. Members of the Terpides lineage are placed in the subfamily Atalophlebiinae because they share the following derived states with other Atalophlebiinae: (1) square facets in upper portions of male imaginal eyes; (2) denticles on anteromedian emargination of labrum; (3) two rows of hair-like setae on dorsal anteromedian margin of labrum; and (4) absence of anterosubmedian, spine-like setae on labrum. The Terpides lineage appears to have been isolated on the ancient Guiana and / Brasilian Shields of South America during the Tertiary and dispersed northward when the isolation of South America ended with the development of the lower Central American isthmus in the Quaternary. The Terpides lineage is presently widely distributed in the Neotropics from Bolivia north to southern Mexico. The phylogenetic relationships among species of the Terpides lineage are represented by phylograms and data on character state distributions presented. / Source: Dissertation Abstracts International, Volume: 44-11, Section: B, page: 3297. / Thesis (Ph.D.)--The Florida State University, 1983.

Dolania oogenesis is unique in Ephemeroptera with the presence of only one oocyte per ovariole, low numbers of ovarioles, and complete resorption of 1/3-1/2 of the total number of ovarioles. This results in fecundity and egg length values which are respectively 1/20 and 2-4 times the values of most other mayflies. Approximately 70% of the linear growth of those oocytes which will mature takes place in a 2-3 week period during the late penultimate to early final larval stadia. Oocytes which will be resorbed remain small during this period until resorption occurs at about the time the other oocytes are mature. Resorbed oocytes probably do not offer a significant food reserve for the maturing oocytes or the female larva due to their small size, the timing of resorption and because the gut does not atrophy completely until the developing oocytes are nearly mature. Oocyte resorption is probably common and unimportant in most other mayfly species. / Dolania's large egg possesses a thick tough chorion and produces a well developed first instar 2.5-5 times the length of any other mayfly. It is probably soon capable of burrowing in the coarse sand substrate and of consuming a wide range of prey sizes. / The vitelline membrane possessed a globular ultrastructure. The chorion was composed of the endochorion and exochorion, which differed in paracrystalline ultrastructure and density. Chorionic channels traversed the entire width of the chorion and formed an interconnected meshwork in the inner endochorion. A suprachorionic layer was composed of an inner layer of long narrow fibers terminated by distal knobs approximately 46 nm in diameter, and an outer very thin granular layer. The follicle cells secreted the suprachorionic layer. Up to five funnelform micropyles were located at the equator of the egg. The inner portion of the micropyle canal was just large enough to permit the passage of sperm, and thus by its physical dimensions alone may limit polyspermy. / Source: Dissertation Abstracts International, Volume: 47-07, Section: B, page: 2745. / Thesis (Ph.D.)--The Florida State University, 1986.

Source: Dissertation Abstracts International, Volume: 35-02, Section: B, page: 0874. / Thesis (Ph.D.)--The Florida State University, 1973.