Thesis (Ph. D.)--University of Queensland. / Includes bibliographical references.

Many small, numerically abundant animals of low trophic position exhibit polymorphisms for colour and pattern. This variation is assumed to be adaptive and maintained by frequency-dependent selection, the fitness of phenotypes being negatively correlated with their frequency in the population. Noctua pronuba is an abundant moth species of the western Palaearctic and is now established in north eastern America. When the moth is at rest it is apparently cryptically coloured with the visible surfaces polymorphic in colour and pattern. The limitation of this variation to the exposed surfaces of the moth suggests that the variation may be maintained by visual selection by predators. The forewing polymorphism in N.pronuba can be split into three distinct phenotypes: rufous, ochre and silver, with the variation probably controlled by a single locus, with three alleles in a dominance hierarchy. The expression of these alleles is influenced by sex with females lighter in colour than males. The aim of this work was to establish whether natural selection maintains variation in forewing colour and pattern to give a balanced polymorphism, using the null hypothesis that the variation was neutral to selection and non-adaptive. This has been approached by experiment and the analysis of temporal and geographic variation in forewing phenotype frequencies. Background resting experiments failed to show different phenotypes adopting different backgrounds on which to rest but experimental conditions did affect the behaviour of individuals. Selection acting in opposite directions on males and females has been suggested as a mechanism maintaining the forewing polymorphism. Little evidence has been found to substantiate this claim with phenotype frequencies in light trap samples similar in males and females. No systematic changes in phenotype frequencies were observed in an analysis of temporal variation over a twenty-five year period. Only the ochre allele varied significantly but the variation is minimal suggesting that the polymorphism is temporally stable. Geographically there was remarkably little variation in phenotype frequencies with only samples from Finland, Scotland and N.lreland having significantly differentiated phenotype frequencies. A study of polymorphic allozymes suggested that large amounts of gene flow occur in the species. The consequence of this gene flow will be to unite geographically separate populations into one panmictic unit. High levels of gene flow, in conjunction with the local abundance of the species, mean that the effective population size will be large. Previous authors have considered that as crypsis is an adaptive trait, variation in the colour and pattern of a cryptic species must also be adaptive, and maintained by selection. This is not necessarily true, and there may be a number of colour patterns that are equally cryptic in the same habitat. It is hypothesised that the large population size and magnitude of gene flow in N.pronuba gives the forewing polymorphism inherent stability both temporally and geographically, without the need to invoke balancing selection.

1. The patterns of projection of some of the perpendicular neurones between the retina and medulla of the optic lobes of various insects have been studied. Axon paths have been studied from consecutive semi-thin plastic sections cut transversely and stained with toluidine blue. The termination positions and the paths of axons are both highly ordered and predictable. 2. In all insects with fused-rhabdomere eyes the axons of one ommatidium project to one cartridge of the lamina and the array of cartridges duplicates the array of ommatidia. In insects with open-rhabdomere eyes visual information is distributed amongst a number of lamina cartridges so that each cartridge receives information originating from one visual axis. 3. In both open- and fused-rhabdomere types the cartridge, array of the lamina is exactly duplicated in the medulla but by the intervention of the chiasma is reversed about a dorso-ventral plane. The axons of one lamina cartridge contribute to one medulla cartridge. Thus, in all insects studied, the visual field is projected exactly from retina to medulla. 4. Most of the retinula axons from one ommatidium terminate in the lamina but usually one pair passes directly to the medulla. These are from the central retinula cells (open-rhabdomere eyes) or from the small retinula cells (apposition type fused-rhabdomere eyes). Retinal responses are known mainly only for the short retinula axons so that visual information delivered to the medulla cartridge is still largely unresolved. 5. The lamina neuropile probably contains the elements responsible for the lateral correlation between parallel receptor inputs which is necessary for movement perception, but units with long lasting responses which could act as the delay circuit of movement perception are unknown. 6. The occurrence of errors in termination of the first projection of the optic lobe of the fly, which are reported for the first time in this work, provide no direct clues to the developmental processes by which such a morphologically complex system arises. Nevertheless errors may arise within a sequence of growth processes which are fundamentally quite simple and not obvious from knowledge of the generalized perfect pattern of connections.

As a population in a world rises, and as conventional breeding seems to be as terrible as the worst nightmare, there appears necessity to find some of alternative sources of "meat". Yes, it's also good opportunity for vegetarians to add every essential amino acid to their diet. Entomophagy can be helpful with improving and ensuring food safety and food security, which is related with new world conception One Health and food -- borne diseases. Potential of insects can be well utilized, but only if they are farming properly, with right biosecurity plans and keeping sufficient hygiene and correct storage. Deeper we go in exploring insects and its good side, perfect nutritional value (FAO, 2010) we also strike on potentional hazards of its consumption. This work will be focused on microbiology (mainly fungi) and parasitology (nematodes) of given specimen in Indonesia, compared with Czech studies.

La coopération et les conflits sont les deux facettes de l’évolution sociale. L’objectif principal de cette thèse a été d’étudier chez les fourmis du complexe d’espèces Neoponera apicalis les mécanismes de régulation permettant de maintenir la coopération dans les groupes sociaux face aux risques d’exploitation internes et externes au groupe, à travers une approche comparative et intégrative. Nous montrons que la structure génétique des colonies entraine des conflits d’intérêts liés à la reproduction, notamment en ce qui concerne la production des mâles. L’étude de la régulation du partage de la reproduction révèle que les décisions reproductives des individus sont principalement basées sur la détection de signaux associés à la fertilité grâce à des capacités fines de discrimination de statut. Ces informations permettent aux ouvrières d’ajuster leur comportement reproducteur selon le contexte social et en fonction de leurs intérêts en termes d’inclusive fitness. En effet, alors qu’une auto-restriction reproductive des ouvrières est observée en présence d’une reine fertile, un conflit ouvert se déclare quand celle-ci disparait, régulé par la mise en place d’une hiérarchie reproductive linéaire dans laquelle les ouvrières de haut rang accèdent à la reproduction. Le signalement du statut reproducteur parait jouer un rôle capital dans la régulation des interactions de dominance/subordination, et donc dans la détermination des rangs hiérarchiques. Les signaux associés à la fertilité sont par ailleurs fortement conservés entre les différentes espèces de ce complexe, ce qui souligne leur honnêteté et donc leur stabilité évolutive. Nous montrons enfin l’existence d’une reconnaissance coloniale chez ces espèces, basée sur les mêmes indices de reconnaissance, et permettant de moduler la réponse territoriale selon le niveau de familiarité des colonies étrangères. Cette étude démontre donc l’importance des mécanismes de reconnaissance dans la régulation de la vie sociale. / ASocial evolution implies both cooperation and conflicts. The main objective of this thesis was to study the regulatory mechanisms allowing to maintain cooperation in social groups against exploitation from within and outside. We choose a comparative and integrative approach using ants of the Neoponera apicalis species complex. We show that the colony genetic structure gives rise to reproductive conflicts, particularly over male production. The study of the regulation of the partitioning of reproduction reveals that the individuals’ reproductive decisions are mainly based on the detection of fertility-associated signals through fine-scale status discrimination abilities. This information allows the workers to adjust their reproductive behaviour according to the social context and following their inclusive fitness interests. Whereas worker reproductive self-restraint is observed with a fertile queen, an overt conflict arises in queenless conditions, which is regulated through the formation of a linear reproductive hierarchy where high-ranking workers reproduce. Reproductive status signalling seems to play a crucial role in the regulation of the dominance/subordination relationships, and thus in the determination of hierarchical ranks. Furthermore, fertility-associated signals are highly conserved among the species of the complex, which highlights their honesty and thus their evolutionary stability. We finally show that the nestmate recognition processes in these species are based on the same recognition cues and allow to modulate the territorial response depending on the familiarity with non-nestmates. This study demonstrates the importance of recognition mechanisms in the regulation of social life.

Black beetle virus (BBV) is a bipartite single-stranded RNA virus belonging to the family Nodaviridae. Its host range has been found to be limited to insects. RNA 1, the larger of the two RNA molecules, with a MW of 1,15 x 10⁶ and the smaller RNA 2 with a MW of 0,46 x 10⁶, are both packaged in the same virus particle. The two RNA molecules are translated separately, with RNA 1 coding for protein A of MW 105 x 10³ and RNA 2 coding for protein α of MW 47 x 10³. Protein α is the major capsid protein precursor, which during in vivo maturation is cleaved to form the coat protein β of MW 43 x 10³, and protein γ of MW 5 x 10³. Cell-free translation of BBV (strain W17) mRNA was carried out in rabbit reticulocyte lysates. Protein α was detectable between 0 and 30 minutes after RNA addition. A protein 'β', which was found to co-electrophorese on polyacrylamide gels with authentic β and which was immunoprecipitated by anti-BBV antiserum, was detectable after 30 minutes. Results of this work show that the formation of 'β' could be prevented by the addition of RNase to the lysate, indicating that intact RNA is necessary for α to β cleavage. Arresting protein synthesis by the addition of cycloheximide to the lysate mix did not inhibit the cleavage. The formation of β could also be prevented by cooling the lysate mix to 1°C. Cleavage of α to β still occurred when RNA 2, without the presence of RNA 1, was translated. Therefore the cleavage is not dependent on a translation product of RNA 1. Sedimentation of lysate on sucrose density gradients showed that α to β cleavage was not accompanied by assembly of BBV RNA and protein lnto a viral substructure as has been shown to occur with some viruses, for example certain picornaviruses. Serial dilution of lysate containing α showed that the level of β decreased with increasing dilution, indicating that the cleavage is not mediated by autocatalysis, but by some other unknown factor. Although much work has been carried out on black beetle virus, no work has been published to date concerning α to β cleavage as an indication of assembly in rabbit reticulocyte lysates. Results of these cell-free translation experiments thus indicate that BBV coat protein precursor α, in association with its messenger RNA 2, undergoes a maturation cleavage in the lysate to produce BBV coat protein β. In addition, this cleavage seems to occur without assembly into any intermediate viral structure

This work provides a phylogenetic classification of the insect order PSOCOPTERA. Some of the problems involved, mainly arising from lack of adequate published data, are pointed out and work carried out to overcome them is indicated in a short introductory chapter (Chapter I). This consisted of accummulating data on the genera from published texts and illustrations, adding data from the study of fresh material or material held in collections and compiling generic definitions in adequate detail where possible. Chapter II gives a general description of the Psocoptera together with brief background information on their biology. As considerable changes are proposed in the classification of the order (in Chapter VII) the classification in use at present is set out for comparison to generic level and a brief history of systematic work on the order is given {Chapter III). The data necessary for a discussion of the phylogeny is presented in the series of definitions of genera and suprageneric groups in Chapter IV. Data on fossil forms is given in Chapter V. The principles of phylogenetic study are briefly discussed in Chapter VI and the important question of the relatively primitive or advanced condition of characters in the order is discussed. The monophyly of the order and the relationships between genera are established using Hennig's system and the results are set out in discussion and dendrogram. On the basis of the relationships so established a classification of the order is proposed which is considered to be practical and to reflect evolutionary history of the group. (Chapter. VII.) Comments on the distribution of the Psocoptera are made in Chapter VIII and it is suggested that, despite inadequacy of data, a consideration of the distributions supports the proposed classification in general terms. A general discussion follows and references and figures are included. An appendix provides a practical up-to-date key to the genera of the order.

Providence virus (PrV) is a member of the Tetraviridae, a family of small, positive sense, single-stranded RNA viruses, which characteristically infect the midgut tissue of heliothine larvae. PrV is the only known tetravirus that replicates in cultured insect cells. The virus comprises a monopartite genome resembling members of the genus Betatetravirus with the capsid precursor protein undergoing autoproteolytic cleavage at its C-terminus consistent with other tetravirus capsid precursor proteins. Analysis of viral cDNA predicted the presence of three potential overlapping gene products (from 5` to 3`): (1) p130, a protein of unrecognized nucleotide or amino acid homology with a 2A-like processing site at its N-terminus; (2) p104, the replicase ORF, which was found to be phylogenetically related to tombus-and umbraviruses replicases. The presence of a read-through stop signal in the p104 ORF was proposed to produce and amino terminal product with a predicted MW of 40 kDa (p40) and (3) the capsid protein precursor (81 kDa) which has two 2A-like processing sites at its N-terminus. Metabolic radiolabelling of viral translation products in persistently infected MG8 cells and in vitro translation of the individual ORFs were performed in order to analyse the expression of PrV gene products. p130 was translated with no evidence of 2A-like processing. Two products of 40 kDa and 104 kDa were translated from the p104 ORF, indicating that the read-through stop signal was likely to be functional. Finally, the capsid protein precursor ORF produced a major translation product of 68 kDa corresponding to the capsid protein precursor as well a peptide of 15 kDa that was attributed to the activity of the second 2A-like site at the N-terminus of the p81 ORF. The subcellular distribution of viral RNA (vRNA) and p40 in MG8 cells was investigated using immunofluorescence and biochemical fractionation. The results showed that p40/p104 and vRNA accumulated in polarized, punctate structures in some but not all MG8 cells and in some cases, co-localization was observed. This thesis concludes that PrV is a novel tetravirus with significant similarities plant carmolike viruses that should be re-classified at the family level.

Please read the abstract in the section 00front of this document / Thesis (DPhil (Entomology))--University of Pretoria, 2006. / Zoology and Entomology / unrestricted

Regulation of hemolymph and whole-body Mg ++ concentration was studied in the larvae of Aedes campestris Dyar and Knab from a salt-lake containing 190 m Eq Mg++/litre. Hemolymph Mg++ concentration of the larvae responded quickly to a change in external Mg++ concentration and reached a new level after one day. Over a wide range (0.02 to 200 m Eq/litre) of external Mg++ concentrations the blood Mg++ concentration changed only from 4 to 8 m Eq/litre. The rate of entry of Mg++ into the larvae by drinking was 19 to 57 n Eq/mg x hr. Drinking rate was found to be independent of temperature (10C- 22C), Mg++ concentration (100- 300 m Eq/litre), and presence of particles in the medium. More than 95% of the ingested Mg++ was absorbed from the midgut. Whole-body Mg++ content of larvae remained low, indicating that excess Mg++ was not stored in tissue. Measurement of urine Mg++ concentrations of animals in different media showed that excretion via urine could account for all of the ingested Mg++. Anal papillae need not therefore be implicated in Mg++ excretion in Aedes campestris larvae. / Science, Faculty of / Zoology, Department of / Graduate