This thesis was focused on monitoring the viability of eukaryotic and prokaryotic cells after exposure of termites-isolated chemicals. Recently, evidence of antibacterial and antifungal properties of these defense substances has grown, and they can find a wide range of uses not only in the pharmaceutical industry. In this work, three defensive substances from termites were studied: nerolidol, nitropentadecene and methylanthranilate. Their antibacterial effects, minimal inhibitory concentrations and minimal bactericidal concentrations against Escherichia coli STBL3 strain were monitored. Further, their cytotoxic effects on eukaryotic non-tumor (HEK293FT) and tumor cells (MCF7) as well as their effect on plasmid DNA were studied. Antibiotic ampicillin and cytostatic cisplatin were used as control substances for antibacterial and cytotoxic effects, respectively. In the case of the action of nerolidol, nitropentadecene and methylanthranilate on the STBL3 strain, antibacterial activity was not demonstrated. Cytotoxic effects were observed nerolidol and nitropentadecene. None of the examined substances modified the plasmid DNA.

Digestive proteolysis in termites has not been studied yet. In this diploma thesis, proteolytic enzymes of the digestive tract of two significant pest species Reticulitermes santonensis and Coptotermes formosanus (Rhinotermitidae) were analyzed. Proteases were identified and quantified in gut compartments using a panel of specific substrates and inhibitors. Major proteases were localized in the midgut and were classified as endogenous serine proteases of trypsin type. Minor cysteine proteases were detected in the paunch and were most likely produced by symbionts. The trypsin protease from R. santonensis was chromatographically isolated and its N-terminal sequence was identified. The physiological importance of the digestive trypsin proteases was demonstrated using selective inhibitors tested in vivo with C. formosanus. Based on the analysis of proteases from additional 12 termite species, a general scheme of digestive proteolysis in the order Isoptera was proposed. (In Czech)

The diet of an animal plays a fundamental role in its ecology, and the consequence of a specific diet may be more pronounced in mammals with a specialised diet that are more reliant on a specific food type. This can have a dramatic effect on its activity patterns, home range size and the interaction with heterospecifics. Investigating the diet of specialist mammals and the subsequent effects it will have on their ecology is thus vital to the management and subsequent conservation of the species, and crucial to our understanding of how the animal can survive and reproduce. In this thesis I investigate the effect that the diet of the aardwolf, a highly specialised myrmecophage, has on its ecology. Aardwolves feed predominantly on one genus of termite, Trinervoides spp., and are thus extremely dependent on the abundance and distribution of this arthropod. I firstly investigated the effect of temperature and rainfall on arthropod abundance and diversity, and further investigated the variation of arthropod abundance and diversity across the four habitat types at study site. This is one of a few studies that have been conducted on arthropod abundance and diversity in an arid environment and the findings show that in an arid environment arthropods are mainly influenced by temperature rather than rainfall. This is in contrast to studies in temperate and forest habitats where rainfall is the most important abiotic factor determining the abundance and diversity of arthropod assemblages. Habitat type still plays a major role in the abundance and diversity of arthropods, and habitat types that are more complex and diverse have both a higher diversity, and abundance of arthropods than other habitats. Due to the absence of prey items during the colder months of the year I investigated the diet of aardwolves to see if they display a switch in diet. This included an investigation into the seasonal variation of diet from a detailed scat analysis, using a newly developed method to assess scat content. The analysis of scats revealed that, contrary to previous studies, aardwolves showed no switch in diet and continued to feed on Trinervitermes. Using the data from the scat analyses and the information from the abundance and diversity of arthropods at the study site I expanded the study to investigate the functional responses of the aardwolf to change in prey abundance at the locality. Aardwolves demonstrate a Type I functional response to changes in prey abundance, a response that is normally found in plankton feeders. The expected functional response for specialist animals would be Type II response, and I propose that the Type I response seen in aardwolves is probably as a result of a limited handling time which reduces time spent foraging. The abundance of termites thus had a clear effect on the diet of aardwolves, showing that they feed on fewer when they are unavailable, and as such I investigated the effect of termite densities on home range sizes. The number of termite mounds in a home range influenced the size of the home range, and aardwolves with larger home ranges had a lower density of termite mounds. In contrast to previous studies, large overlaps between neighbouring individuals were recorded and indeed three male aardwolves shared a common den. I propose that the reason behind the overlap of home ranges is that a higher prey abundance during my study period occurred and as a consequence aardwolves did not need to defend an area to protect this resource. T. trinervoides has thus played a keystone role in driving the biology of the aardwolf and shaping many aspects of its ecology. / Thesis (PhD)--University of Pretoria, 2021. / South African Research Chair Initiative chair of Mammal Behavioural Ecology and Physiology / Zoology and Entomology / PhD / Unrestricted

Bark beetles regulate forest succession by removing weakened or stressed trees and exposing understory species to light from canopy gaps. Subterranean termites are predominate decomposers of coarse woody debris in southern pine forests; however, little is known about their role in forest health and succession. Both groups of insects rely heavily on fungal symbioses to fill their respective ecological niches in southern pine forests. During recent inspections of southern pine timber, we observed that trees in the early stages of bark beetle attack often had subterranean termites in blue-stained portions of the trunk. The frequency of subterranean termite presence in blue-stained areas of trees increased proportionally to the stage of bark beetle attack. However, practically no research has undertaken the challenge of describing how woody resources created by bark beetles are identified and utilized by subterranean termites before any signs of stress are visible. Therefore, this study examined possible facilitative interactions between subterranean termites, bark beetles and their blue-stain fungal associates, and other invertebrates, and investigated the effect of blue-stain fungi on surface properties of wood. Both native (Reticulitermes spp.) and Formosan subterranean termites exhibited a higher feeding preference for blue-stained sapwood than for unstained sapwood in laboratory assays. Native subterranean termites also consumed blue-stained sapwood at a higher rate than decayed wood. This study was the first to demonstrate that wood containing a non-decay fungus could elicit a feeding response from subterranean termites greater than that observed for decayed wood. Additionally, the surface properties of bark beetle-attacked southern pine were initially reduced by blue-stain fungal infection; however, the process of kiln-drying reversed this effect, resulting in a surface that was more conducive to wood product manufacturing.

This dissertation defines electromagnetic properties that are responsible for directing subterranean termite foraging behavior. Research identified specific frequencies and intensities that can attract Coptotermes formosanus Shiraiki and Reticulitermes flavipes (Kollar) to the site where the electrical fields are generated and defined on repellant freuency and intensity for C. formosanus. US Patent Docket Number 2343-215 PCT and MSU disclosure 05-0606-163 were filed based on the results. Data showed that frequencies and intensities were different for attracting the two species. Future work will address new alternatives for addressing termite infestations that will reduce and change the amounts and use of current termiticides.

Currently, soil termiticides are the primary termite defense mechanism used under and around living spaces in the continental United States. While this form of treatment has been effective for many years, the creation of a new, more environmentally friendly termite management system could reduce the amount of termiticides introduced annually into the environment around structures. A natural barrier containing soil amendments and mulches amended with insect-repellent plant tissues discourages termite foraging and directs the termites away from the structure. The proposed integrated management system developed during this project, divides a structure into three zones. Each zone has particular responsibilities to the overall biological durability of the structure. This study concentrates on the inner-detritus zone, which extends 24” (0.61m) from the outer wall of the structure, an area that can harbor potential hazards such as moisture traps, conducive termite food, water and protection sources, and other factors that could put undue biological pressures on the structure. Altering this zone, more specifically the pH of the soil and the mixture of products used as mulch, creates an environment unsuitable for termite foraging. This integration of several termite repelling strategies should obviate or significantly reduce the need for termiticidal soil barriers under and around houses.

This research focuses on the evaluation of many aspects of the American Wood Protection Association (AWPA) Standard E1-97, “Standard Method for Laboratory Evaluation to Determine Resistance to Subterranean Termites.” This standard is used extensively for testing the efficacy of new products and preservative systems against subterranean termite species. Research was done to determine what changes, if any, are needed for testing against subterranean termite species such as Coptotermes formosanus (Shiraki) and species of native termite genus Reticulitermes (Holmgren), primarily R. flavipes (Kollar). Variables from the current standard were tested to determine effects of parameters such as moisture of sand substrate; size, type, and location of test material within a test bottle; and termite number and ratios of workers to soldiers per test bottle. Research also improved comprehension of termite biology in a laboratory setting, enabling researchers to develop new and safer control methods.

La diversité fongique des meules de plusieurs espèces de Macrotermitinae a été analysée au niveau taxinomique, fonctionnel et génétique à l’aide d’une approche polyphasique associant plusieurs techniques complémentaires. L’objectif étant d’évaluer la spécificité des taxons fongiques associés aux meules ainsi que les relations qu’ils entretiennent avec les termites champignonnistes. Une grande variété de phylotypes cultivables appartenant majoritairement au phylum des Ascomycètes a été obtenue par isolement et séquençage des ITS fongiques, et peu de séquences se sont révélées être spécifiques à un genre de Macrotermitinae particulier. Les profils physiologiques obtenus ont mis en évidence la nature saprophytique de la majorité des phylotypes et confirmé l’absence de taxons spécifiques. Par PCR-DGGE de l’ADN total de meules, 100% des phylotypes ITS et 28S fongiques identifiés étaient affiliés au genre Termitomyces. La technique Suicide Polymerase Endonuclease Restriction (SuPER) a été adaptée à la mycoflore des meules pour limiter l’impact de l’ADN majoritaire du Termitomyces symbiotique. Celle-ci a permis la détection de plusieurs autres populations fongiques. Les analyses phylogénétiques ont montré d’une part la spécificité des Xylaria associés aux meules de Macrotermitinae bien qu’aucune co-évolution n’ait été observée avec les termites hôtes et d’autre part leur affiliation dans un sous-genre spécifique. Une analyse préliminaire des facteurs d’inhibition a également révélé l’implication des termites dans la régulation des communautés fongiques des meules. Dans leur ensemble, nos résultats illustrent clairement l’influence des Macrotermitinae sur les communautés fongiques telluriques pendant leurs différentes activités. / Fungal diversity of several Macrotermitinae fungus combs was analyzed at taxonomic, functional and genetic levels using a polyphasic approach. The aim of this thesis was to evaluate the specificity of fungal strains from combs and to elucidate their relationship with fungus-growing termites. A large variety of culturable phylotypes mainly belonging to Ascomycota phylum was retrieved using conventional isolation techniques followed by sequencing of ITS1-5.8S-ITS2 region. Based on the obtained results, there is evidence for any speciesspecificity between these taxa and a given genus of Macrotermitinae. This finding was supported by the physiological profile of some representative phylotypes which revealed the saprophytic nature of most of the isolates. By PCR-DGGE analysis of fungal ITS and LSU, all of the sequences were belonged to Termitomyces genus. The Suicide Polymerase Endonuclease Restriction method was adapted to the analysis of comb mycoflora for restricting the impact of the dominant Termitomyces DNA. As expected, this latter technique revealed non-Termitomyces fungal populations. Phylogenetic analysis also showed the specificity of termiteassociated Xylaria although they do not evolved with termite hosts, and also their affiliation to a new genus or at least a specific sub-genus. Preliminary investigation revealed the implication of termite workers in fungal regulation in fungus combs. All in one, our results clearly underline the great impact of fungus-growing termite species on soil fungal community during their activities.

Les interactions interindividuelles permettent la transmission de l’information, la dispersion des pathogènes et la mise en place des comportements dans une population. Cette thèse a permis d’évaluer l’influence des interactions sociales sur le succès de fondation colonial des différents reproducteurs de deux termites européens, l’invasif Reticulitermes flavipes et le natif R. grassei. Les résultats révèlent (i) un meilleur succès de fondation des reproducteurs primaires de R. flavipes, (ii) une organisation biparentale des soins aux jeunes toutes espèces confondues et (iii) une communication et des soins aux oeufs propres aux caractères invasif et natif des espèces d’étude. Pour finir, (iv) une meilleure survie et communication a été observée dans les colonies fondées avec reproducteurs secondaires tandis (v) qu’une communication supérieure et une survie moindre sont observées pour R. flavipes. Les origines évolutives de l’organisation biparentale et des variations de succès de fondations sont discutées. / Individual interactions permit information transmission, pathogen dispersion and shape behavioral strategies in a population. This thesis has permit to explore the influence of social interactions on the colonial foundation success of two European termites, the invasive Reticulitermes flavipes and the native R. grassei. The overall results revealed (i) a better foundation success of primary reproductives of R. flavipes, (ii) a biparental organisation of parental care in both species (iii) a level of communication and egg care reflecting native and invasive status of the two species studied. To finish, (iv) better survival and communication rates were observed in colonies founded with secondary reproductives than in colonies without any and (v) a better communication rate and a weaker survival rate for R. flavipes foundations with or without secondary reproductives. Evolutive origins of biparental care and of the variations of foundation success observed are discussed.

Les biomatériaux de type hydrogel ou organogel obtenus à partir de molécules de faible masse molaire suscitent de plus en plus un vif intérêt autant sur le plan fondamental que sur le plan applicatif. Le travail, exposé ici, a pour objectif de synthétiser des composés amphiphiles présentant des variations de structure afin de pouvoir établir des relations entre la structure de ces composés et leurs propriétés gélifiantes. Nous avons été amenés à synthétiser des composés (bimodulaires et trimodulaires) avec et sans motif de jonction de type polyoxyéthylénique entre la partie peptidique et le module hydrophobe. Dans un deuxième temps, d?autres molécules amphiphiles gélifiantes ont été préparées, en substituant le motif polyoxyéthylénique par une entité dérivée du glycérol, pour permettre d'obtenir des composés d'origine renouvelable mais également pour diversifier la source de matières premières. Les composés visés ont été obtenus et leur comportement en solution a été étudié par différentes techniques (tensiométrie, conductimétrie, infrarouge,...). Certains d'entre eux, présentant des propriétés gélifiantes, associés aux sels de bore, ont été utilisés pour préserver le matériau bois (Pin Sylvestre). Les essais effectués se sont révélés concluant en termes de réduction du lessivage du bore car les tests avec Poria Placenta (champignon) cultivé sur un milieu gélosé ou avec les Réticulitermes Flavipès (termites) ont montré qu'un bois traité par l'association « borax-hydrogel » reste protégé même après lessivage / Biomaterials hydrogel or organogel obtained from low molecular weight molecules give rise to an increasing interest both in terms on the fundamental and application domain. The work outlined here, aims to synthesize amphiphilic compounds with structural changes in order to establish relationships between the structure of these compounds and their gelling properties. We were asked to synthesize compounds (bimodular and trimodular) with and without cause polyoxyethylene type junction between the peptide and the hydrophobic unit. In a second step, other gelling amphiphilic molecules were prepared by substituting the polyoxyethylene pattern derived by an entity glycerol, allowing to obtain compounds from renewable sources but also to diversify the source of raw materials. The target compounds were obtained and their behavior in solution has been studied by different techniques (tensiometry, conductivity, infrared,...). Some of them, with gelling properties, associated with boron salts have been used to preserve the wood material (Scots pine). The tests proved conclusive in terms of reducing the leaching of boron as tests with Poria placenta (mushroom) grown on an agar medium or with Reticulitermes flavipes (termite) showed that wood treated with the association "borax-hydrogel" is protected even after leaching