Dentre os representantes de Campanulariidae, o gênero Orthopyxis é conhecido pela ampla plasticidade morfológica de suas espécies, bem como pela semelhança com o gênero Campanularia. Essas características levaram à descrição de muitas espécies nominais no Atlântico sul-ocidental e confusões com o gênero Campanularia, dificultando a identificação das espécies. Nesse contexto, este estudo teve os objetivos de (1) rever as ocorrências de Orthopyxis no Atlântico sul-ocidental, (2) compreender a variação morfológica intra-específica de Orthopyxis e delimitar suas espécies por meio de estudo morfométrico e molecular, e (3) compreender as relações entre os gêneros Orthopyxis e Campanularia no Atlântico sul-ocidental, levantando evidências morfológicas e moleculares que pudessem delimitá-los. A análise das sequências de DNA resultou no monofiletismo do gênero Orthopyxis e na delimitação das espécies O. sargassicola, O. integra e O. crenata, esta última um novo registro para o Atlântico sul-ocidental. As análises morfológicas permitiram identificar os caracteres informativos para a delimitação dessas linhagens, bem como a amplitude de variação dos caracteres morfológicos frequentemente utilizados para diagnose das espécies de Orthopyxis. Esse estudo aponta evidências morfológicas informativas para a delimitação dos gêneros, principalmente em relação ao cnidoma. O presente estudo do gênero Orthopyxis no Atlântico sul-ocidental poderá servir como modelo para o delineamento de outras pesquisas envolvendo a família Campanulariidae, ao mostrar que as espécies podem ser corretamente delimitadas a partir de análises morfológicas e moleculares. / Within the Campanulariidae, the genus Orthopyxis is known for its morphological plasticity and resemblance with the genus Campanularia. These characteristics have led to the description of numerous nominal species in the southwestern Atlantic, and also to considerable confusion with the genus Campanularia, making taxonomic identification very difficult. In this context, the goal of this study was to (1) review the occurrences of Orthopyxis in the southwestern Atlantic, (2) understand its intraspecific morphological variation and delimit species using morphological and molecular data, and (3) investigate the relationships between Orthopyxis and Campanularia to find morphological and molecular evidence for their delimitation. The molecular analyses resulted in a monophyletic Orthopyxis, and in the delimitation of O. sargassicola, O. integra, and O. crenata, the latter a new record for the southwestern Atlantic. The morphological analyses identified the characters that are most informative for the delimitation of these lineages, as well as the amplitude of morphological variation within the characters frequently used in the taxonomy of Orthopyxis.This study identified some morphological evidence for the delimitation of both genera, especially in relation to the cnidae. The present study of the genus Orthopyxis in the southwestern Atlantic can be used as a model for the delineation of future investigations of the family Campanulariidae, in the sense that species may be successfully delimited with an integrated morphological and molecular approach.

A seção Diabroticites Chapuis, 1875 (Chrysomelidae, Galerucinae, Luperini, Diabroticina), com 826 espécies descritas em 17 gêneros, registrada apenas para o continente americano, é uma das maiores assembleias taxonômicas de crisomelídeos. Composta essencialmente por espécies originalmente descritas no gênero Diabrotica Chevrolat, 1837 antes de 1947, é caracterizada pelas garras tarsais bífidas e machos com tíbias mesotorácicas simples, sem projeções. Os mais de 150 anos de história taxonômica da seção foram suportados primariamente por descrições morfológicas superficiais, baseadas em poucos exemplares (geralmente espécimes únicos) e a um número restrito de caracteres, relacionados apenas aos machos. Nunca houve uma revisão do grupo como um todo para investigar a posição sistemática dos Diabroticites como objetivo primário e ampliar o número de caracteres analisados nos dois sexos. O presente trabalho apresenta um estudo morfológico detalhado de vários representantes de Diabroticites visando testar a monofilia da seção, bem como elucidar o posicionamento filogenético dos gêneros que a compõem. Todos os gêneros e a maioria dos agrupamentos infragenéricos da seção foram amostrados no grupo-interno com, ao menos um terminal, num total de 49 terminais. O grupo-externo, incluiu sete terminais, representantes de Cerotomites (Luperini, Diabroticina), Phyllobroticites (Luperini, Luperina), Exosomites (Luperini, Luperina), além de uma espécie de Coelomerites (Galerucini), considerada a raiz. Uma análise de sensibilidade foi realizada, com buscas heurísticas com pesos iguais e pesagem diferencial. O resultado da análise demonstrou que a seção como definida, não forma um grupo monofilético, sendo necessária a inclusão de um ou mais terminais do grupo-externo para recuperar a sua monofilia. Os gêneros que incluíram mais de um terminal, em sua maioria não foram recuperados como clados e os caracteres diagnósticos tradicionalmente utilizados (incluindo diversos caracteres sexuais secundários), em grande parte não corresponderam a sinapomorfias. A única exceção foi Gynandrobrotica, encontrado como um subgrupo de Cerotoma. Caracteres relativos à genitália, utilizados pela primeira vez na elaboração de uma hipótese evolutiva para Diabroticites, tiveram valor significativo na definição das linhagens internas / Diabroticites Chapuis, 1875 (Chrysomelidae, Galerucinae, Luperini, Diabroticina) is one of the largest assemblies of chrysomelids, currently with 826 species in 17 genera, restricted to the American continent. It comprises essentially the species described in genus Diabrotica prior to 1947, characterized by the presence of bifid tarsal claws and males with simple mesothoracic tibiae. Despite having over 150 years of taxonomic history, the species in this group are mostly supported by superficial morphological treatment, frequently based in single specimens, and often relying on male characteristics. There is no general revisionary study for the section to this date, and the systematic position of Diabroticites has never been investigated as a primary objective. A cladistic analysis for the section is hereby presented, based on a detailed morphological study for several diabroticites, in order to test the group\'s monophyly and investigate the phylogenetic position of the genera that are comprised in it. All genera and most infrageneric groups were sampled in the ingroup with at least one terminal (in a total of 49 terminals). The outgroup comprises seven terminals representing section Cerotomites (Luperini, Diabroticina), Phyllobroticites (Luperini, Luperina), and Exosomites (Luperini, Luperina), plus one species of Coelomerites (Galerucini), regarded as the root. The sensitivity analysis included heuristic searches carried with equal and differential weighting. The results indicate that section Diabroticites as currently defined is not monophyletic. Its natural group status can be recovered with the addition of one or more members of the outgroup. Genera that included more than one terminal were, as a rule, not supported as clades, and the traditional diagnostic characters (along with secondary sexual characteristics) for the most part did not correspond to synapomorphies. The sole exception was Gynandrobrotica, found as a subgroup of Cerotoma. Genital characters, used for the first time to support an evolutionary hypothesis for section Diabroticites, were found to have significant value in the definition of internal lineages

Orientador: Marco Aurélio Zezzi Arruda / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-25T14:38:07Z (GMT). No. of bitstreams: 1 Maciel_BrunaCarolineMiranda_M.pdf: 2287580 bytes, checksum: 69534e40c093aed8660eb365cf0fa8f6 (MD5) Previous issue date: 2014 / Resumo: Tendo em vista que a prática da transgenia reflete uma realidade mundial no setor agrícola, o principal objetivo desse trabalho de Dissertação é avaliar algumas espécies de proteínas diferenciais entre folhas de Arabidopsis thaliana não transgênica (NT) e transgênica (T), ambas irrigadas com uma solução de Selênio (Se), frente a uma condição controle. De maneira a averiguar as diferenças entre as folhas NT e T, usando como parâmetros o efeito da transgenia e do estresse oxidativo induzido por Se, um estudo proteômico comparativo foi desenvolvido por meio da metodologia 2-D DIGE, uma variante da técnica de separação por 2-D PAGE, que oferece vantagens, tais como na detectabilidade das proteínas de baixa abundância e precisão para análise quantitativa entre as intensidades diferenciais dos spots proteicos, resultando, com efeito, um mapa proteômico mais representativo destas folhas. Quatro grupos de plantio foram combinados para análise comparativa, de tal forma que NT x T, NT x Se-NT, Se-NT x Se-T e T x Se-T. Embora não tenha sido detectadas espécies de proteínas diferencias no grupo T x Se-T, para os outros, 68 proteínas diferenciais foram detectadas, usando um fator de regulação 1,5 baseado no teste de t para p < 0,05. Dentre este total, 27 proteínas diferenciais foram precisamente identificadas por ESI-QTOF-MS/MS. Estas proteínas estão classificadas quanto às funções metabólicas, energéticas, de transdução de sinal, doenças/defensa vegetal, e algumas delas estão envolvidas nas vias da Glicólise, Fotossistema I e II, e combate à ERO (espécies reativas de oxigênio). Adicionalmente, um imageamento por ablação a laser foi feito para avaliar a distribuição de Se e Enxofre (S) em folhas dos grupos diferentes, corroborando com alguns resultados obtidos, principalmente àquelas proteínas envolvidas nas vias da Glicólise. A partir destes resultados é possível concluir que o vetor inserido também confere à planta a resistência ao estresse oxidativo, no qual o Selênio adicionado foi o efeito mais influente comparado com o efeito da transgenia / Abstract: In view of the techniques related to transgenesis show the global reality in the agricultural sector, the main goal of this Thesis work is to evaluate some differential protein species in non-transgenic (NT) and transgenic (T) Arabidopsis thaliana leaves, both they irrigated with Selenium (Se) solution in front of control condition. In order to estimate the differences between NT and T leaves, using as parameters the transgenesis effect and the oxidative stress induced by Se, a comparative proteomic study was performed using 2-D DIGE methodology, a variant technique of separation by 2-D PAGE that offers ideal advantages, such as detectability of low abundance proteins and accuracy to quantitative analysis among differential intensities of protein spots, resulting in a more representative proteomic map these leaves. Four plant groups were combined to comparative analysis, so that NT x T, NT x Se-NT, Se-NT x Se-T e T x Se-T. Although there differential protein species from T x Se-T group were not detected, for the others, 68 differential protein species were detected, using regulation factor of 1.5, which was based in t test to p < 0.05. Among them, 27 differential proteins were accurately identified by ESI-QTOF-MS/MS. These proteins are classified regarding functions as metabolism, energy, signal transduction, diseases/vegetal defense and some of these were involved in the Glycolysis pathway, Photosystem I and II, and combat the ROS (reactive oxygen species). Additionally an imaging by laser ablation was done to evaluate the Se and Sulfur (S) distribution in leaves of different groups corroborating with some obtained results, mainly those proteins involved in the Glycolysis pathway. From these results, it is possible to conclude that insert vector confers resistance to the T plant regarding oxidative stress where the added Se was the effect more influential than compared with transgenesis effect / Mestrado / Quimica Analitica / Mestra em Química

With the increase in the number of fast-moving vehicles and the simultaneous development of road building technology, roadside bird mortality has become an increasingly important environmental issue that has the potential to do serious damage to already vulnerable bird populations. This project was therefore initiated after an alarming number of owls were found dead along the N17 and R550 roads in the rural areas between Springs and Devon in the East Rand highveld of Gauteng Province. Five hundred and fifty four owls of four species, namely Marsh Owls, the Red Data listed Grass Owl, Barn Owl and the Spotted Eagle Owl were collected on the stretches of the R550 and N17 during the period between October 2001 and September 2003. They accounted for 53.6%, 27.4%, 17.5% and 1.3% of the mortalities respectively. Unidentified species of owls accounted for the remaining 0.2%. It was found that the monthly mortality rates of the birds varied throughout the year, with the greatest losses being suffered during July, as opposed to relatively lower mortalities occurring during the warmer months. All carcasses were collected, their GPS locations plotted on a map, and ‘hotspot areas’ identified as places of highest incidences of mortalities of the owls. Vehicle-induced mortalities are then discussed in relation to these hotspots, in terms of vegetation and habitat descriptions, daily vehicle counts along the route, as well as fixtures found along the route. It was found that traffic density was indirectly proportional to owl mortalities, with higher traffic speeds definitely having an increasingly detrimental effect on the owl mortalities. Weather conditions also play a role in mortality counts, with the mortalities being significantly negatively correlated to rainfall. Moon phases were also related to the times of highest mortalities, however, this factor did not play a significant role in influencing road mortalities. Another factor that was studied was the influence of differing tarmac road surface temperatures as opposed to gravel road verge surface temperatures, and how these temperatures differed from the ambient temperature. It was found that there was not a big enough difference in the temperatures that would warrant (the previously thought notion) that the owls were attracted to the roads at night to gain heat. Gravel roads had very low incidences of owl mortalities with the highest mortalities recorded along tarmac roads that are bordered by open grasslands or cattle grazing paddocks. It was shown that tarmac roads, bordered by croplands, had a lesser effect on the owl mortalities. Another factor influencing the road mortalities of the owls is grain that is spilled on the road during transport. This initially seemed to be the major factor in attracting granivorous rodents to the roads, and in turn, attracting the owls to prey on them. Rodents identified from recovered pellets and the stomach contents of dead owls confirmed the fact that the majority of rodent prey items were indeed granivorous species, namely Mastomys natalensis and Rhabdomys pumilio. This is in disagreement with previous studies that indicated that a large proportion of the prey species of the Grass Owl was Otomys irroratus, a grass-eating species, even though a rodent trapping study to determine prey abundance within the area indicated a healthy population of O. irroratus. Further studies into prey items of the owls that were dissected indicated that the majority of the prey items recovered were not caught directly on the road as it was already partially digested, suggesting that the prey was caught prior to the owl being killed. From the pellet analyses, other prey items were also found to form part of the owls’ diets. It was found that insects formed largely the diet of the Marsh Owl during the spring, summer and autumn months, with them resorting to smaller rodents during the winter months. Spotted Eagle Owls also preyed almost exclusively on insects. Grass Owls, on the other hand, preyed on small mammals exclusively, with the very rare exception of some insects also being taken. Of all of the dead owls recovered on the roads, post mortems were carried out on only 78 of the carcasses. All of the dead owls examined were in good health prior to death. Various morphometrics of the examined owls were noted. Comparisons of body mass showed that females were larger than males for most species. This was also found for most other measurements as well. It was also found that, according to body mass comparisons, Barn Owls and Marsh Owls were significantly similar. Conducting ANOVA analysis on other morphometrics to determine gender differences, it was found that Grass Owl males were significantly different to females in terms of body mass and length. Marsh Owl males were significantly different to females in terms of body mass and tail length; with Barn Owl males being significantly different in terms of tarsus length to females. Except for Spotted Eagle Owl tarsus lengths all other measurements were in favour of females being significantly larger. These findings were also confirmed when applying the Dimorphism Index to all morphometrics measurements, especially body mass. The degree of parasite infestation was also studied during post mortem examinations. Very few cestodes and nematodes were found, with too few to have an effect on the overall health of the birds prior to death. The vegetation type was studied at transects that coincided with hotspot and non-hotspot sites. Using the PRIMER statistical software package, hotspot sites were found to have highest plant cover and diversity, whereas nonhotspot sites showed lowest plant cover and diversity, generally dominated by Hyparrhenia hirta. During these studies, the degree of available nesting habitat was determined and nesting sites were identified, using the ropedragging technique to flush out roosting and nesting owls that would otherwise have been impossible to find in the thick cover. It was found that Grass Owls preferred a habitat rich in thick grass cover that was relatively high (0.75 m–1 m). It was found that the grass species preferred by these owls were Eragrostis curvula, Paspalum sp., Setaria sp., Sporobolis sp., with few other small herbaceous plants. Marsh Owls, on the other hand, seemed not to be too partial regarding roosting and nesting sites, with them roosting and breeding in more mixed vegetation grasslands that had sparser cover, not reaching the height of the grass cover typical of the habitat preferred by the Grass Owls. Opposed to this were the non-hotspot vegetation sites. These sites were found to have vegetation cover unsuited to both the Marsh and Grass owls, with mixed H. hirta grassland not forming the dense cover, or the height, needed by those two species of owls. Foraging owls were also observed, with the vegetation type in the immediate vicinity noted. Vegetation types similar to breeding areas were noted in these foraging areas. Habitat preferences as well as breeding performance were noted for both grassland species of owls, and found to be directly related to land usage in terms of varying agricultural practices and regimes. Fallow, undisturbed lands were found to be highly productive for the owls. Lands planted with Eragrostis sp. were also found to be very productive, but only if left undisturbed for a period of time sufficient to allow the grassland owls to colonise it. Maize-planted fields were found to be utilised only as foraging fields and no breeding of owls was found to take place close to these fields. After extensive nest searching, it was found that both Marsh and Grass owls were breeding from late March to early June, with the Barn Owls breeding in October and again in March. Grass Owls occur in the study area because of the presence of a natural corridor of suitable habitat that runs parallel with the Blesbokspruit. This favourable habitat of the study area is thus conducive to high population density of grassland owls utilising these uncultivated patches of dense and tall vegetation. The high incidence of mortalities on the road in the study area is due to the concomitant high population densities. This healthy population seems to be sustaining the losses occurring on roads. Owls also seem to be gathering in larger numbers in hotspot zones because of the easy available prey, which are attracted to these high productive areas. Agricultural practices in the area lead to the spillage of grain on the road during transportation. Potential prey species foraging on the roads expose themselves to the nocturnal hunters offering an easy dinner. This process leaves these owls vulnerable to vehicle collisions. The overall population size may be larger than previously thought, not with standing the high mortalities already recorded. The small patches of viable habitat in the study area remains suitable for the breeding of the two grassland owl species allowing for such high densities to occur in the area. The Grass Owl, nonetheless, remains severely threatened as it already occurs as a high priority species for conservation concern in the Gauteng Province. This study provides the first assessment of this owl species of this scale in South Africa and this will ultimately promote the long-term survival of these owls. / Dr. V. Wepener

A review of the species groups of the Neotropical myrmecophilous genus Homopterus Westwood is presented based on the first molecular phylogenetic analysis of the genus and morphological study of 260 specimens. Two new species groups, the H. subcordatus group and the H. filiko group are erected based on the results of the molecular phylogenetic analysis and morphological analysis. The genus consists of one species known only from Dominican amber, H. hispanolienses Nagel, and thirteen extant species, one of which is described as new: Homopterus filiko n.sp. from Peru. An illustrated dichotomous identification key to species, diagnoses of the species groups and updated distribution maps are provided. The potential of several of the species groups to harbor additional cryptic diversity is discussed.

Biological invasions threaten biodiversity globally, and degraded ecosystems increase the potential for invaders to compete with threatened native populations. In natural systems, niche partitioning minimizes interspecific competition, but introduced species may alter expected outcomes by competing with ecologically similar species for scarce resources. Where food production is highly variable, coexistence of native and invasive competitors may depend on dietary niche flexibility. Territorial species under invasion face additional challenges to maintain economically defendable territories. From 2011-2016, we conducted removal and behavior experiments to determine effects of non-territorial introduced Abert’s squirrels (Sciurus aberti) on diet, space use, and territoriality of endangered Mount Graham red squirrels (MGRS; Tamiasciurus fremonti grahamensis) in their declining habitat in the Pinaleño Mountains, Arizona. We collected comparative data from Arizona sites of natural syntopy between Abert’s and Fremont’s squirrels (T. fremonti). Stable isotope analysis revealed similar dietary partitioning among populations. Experimental removals did not appear to affect MGRS diet. Space use by MGRS responded inconsistently to removals; territory sizes increased after the first removal, but did not change following the second removal. Territory sizes and body mass of MGRS were sensitive to conspecific population density and food production. Behavioral experiments showed MGRS were more aggressive than other Fremont’s squirrels (hereafter, red squirrels). Dietary flexibility of Abert’s squirrels may have facilitated coexistence with MGRS, possibly due to coevolved resource partitioning with red squirrels. However, aggressive territoriality toward Abert’s squirrels may incur fitness costs for MGRS especially during poor food production years. Climate change may reduce the advantage of ecological specialist species globally, and where introduced species are better-adapted to novel environmental conditions, native species may ultimately be replaced.

Grasslands in the western United States face severe environmental threats including those brought about by climate change, such as changes in precipitation regimes and altered fire cycles; land-use conversion and development; and the introduction, establishment, and spread of non-native species. Lehmann’s lovegrass (Eragrostis lehmanniana) was introduced to the southwestern United States in the early 1900s. Since its introduction, it has become the dominant grass in the mid-elevation grasslands of southern Arizona, including the Santa Rita Experimental Range (SRER), where it has displaced native grasses including Arizona cottontop, three awns, and gramas. Like all plants in terrestrial ecosystems, this grass harbors fungal symbionts that can be important for its establishment and persistence. This thesis focuses on fungal symbionts of Lehmann’s lovegrass and has two components. First, the diversity and distributions of endophytes in Lehmann’s lovegrass are evaluated in the context of biotic and abiotic factors in the SRER. Culturing from roots and shoots of Lehmann’s lovegrass at points beneath and outside the canopy of native mesquites, which are encroaching on grasslands over time, provides insight into how a single plant species can exhibit local variation in the composition of its symbionts. Second, the thesis is used as the basis for engagement of students in science, technology, engineering, and mathematics (STEM) through the development and implementation of classroom- and field activities centered on endophytes, which help high school students address core learning aims while also gaining real research experience. Engaging students in important questions relevant to their local environment can catalyze interest in science and help students cross the threshold into research. The contributions of such approaches with respect to learning not only fulfills key next-generation science standards and common core objectives, but provides students with a meaningful introduction to the excitement, importance, and accessibility of science.

>Magister Scientiae - MSc / With a decrease in water availability and arable land, and the ever-increasing reports of toxic chemical pollutants, it is crucial to elucidate plants’ mechanisms of adaptability to these abiotic stressors. South Africa alone accounts for approximately 30% of global Zirconium (Zr) production. However, reports on Zr-induced stress in plants are sparse. Increased mining activity leads to soil contamination which subsequently has harmful effects on crop plants. Under normal conditions B. rapa crop plants flourish, they are rapid in their cycling and circumvent the seed dormancy stage which enables them to have high yields over relatively short periods. However, when unfavourable conditions arise, such as exposure to toxic chemicals and metal ions like Zirconium, the development and growth of B. rapa L., much like other crop plants is affected. More specifically, the damaging effects of Zr is not only attributed directly; as with substitutions of biometals [like Iron (Fe)] in various biomolecules rendering them inactive, but more as a consequence of the production of toxic molecules such as reactive oxygen species (ROS) and methylglyoxal (MG). ROS such as superoxide anion (O₂⁻) and hydrogen peroxide (H₂O₂ ) are known to have signalling roles in plants with reports on their involvement in alleviating seed dormancy and seedling development. However, the signalling roles of MG are not known with regards to plant cells and have been reported more so in animal cells; playing vital roles in fat signalling in diseases such as diabetes. Furthermore MG, in plant and animal cells, directly converts oxygen (O₂) to O₂⁻ and thus increases the cell’s oxidative imbalance, leading to cell damage if O₂⁻ is not rapidly dismutated to H₂O₂ and H₂O by superoxide dismutase (SOD). In turn, H₂O₂ is more stable than O₂⁻ and consequently is more toxic to cells over time. Therefore, H O must be removed as well by a collection of enzymes, such as ascorbate peroxidase (APX) and catalases (CAT). In this study, possible stress-signalling of MG in seedlings under normal conditions and Zr-stress were investigated to establish whether MG at a low dose (6 μM) would benefit seedling growth and development, via a proposed preinduction of the B. rapa L. antioxidant system. Therefore, it was proposed that ROS accumulation due to the exogenous application of MG, would incite the activation of antioxidants and thus mitigate the effects of Zr stress. Physiological tests to determine dry weights (figure 3.2.3) and germination percentage (figure 3.2.2) revealed that MG-treated seedlings yielded an improved biomass and early development compared to Zr-treated seedlings and the control. Membrane damage as assessed by lipid peroxidation viz. Malondialdehyde [MDA] (figure 3.2.4) and conjugated dienes [CD] (figure 3.2.5) also indicated less damage in MG-treated seedlings compared to the Zr-treated set. The chlorophyll content observed was prominent (table 3.1). MG-treated seedlings exhibited a 40% and 15.5% increase compared to Zr-treated seedlings and the control respectively. Moreover cell viability had improved in MG-treated seedlings compared to the control, and in MG+Zr-treated seedlings only a slight increase in cell death occurred despite Zr being present. O₂⁻, H₂O₂ and •OH (figure 4.2.1 – 4.2.3) were investigated in B. rapa L. seedlings in response to Zr and MG by spectrophotometric biochemical assays, as well as their scavenging enzymes, MG accumulation and Gly-I activity. Furthermore, BrGLY1 gene expression and Zr-uptake by ICP-OES were performed. Seedlings treated with MG and Zr respectively showed an increase in ROS. However, all of the ROS observed in MG+Zr-treated seedlings were markedly lower compared to Zr-treated seedlings. SOD and CAT activity observed in MG+Zr-treated seedlings had decreased compared to Zr-treated seedlings, whereas APX activity had increased. Gly-I activity and BrGlyI gene expression had increased across all treatments, showing an elicited response to oxidative stress, due to the observed upregulation, as a result of the accumulated MG. The observed Zr-uptake in MG+Zr-treated seedlings was inhibited by 5-fold compared to Zr-treated seedlings. Clear signs of stress were evident in seedlings treated with Zr compared to the control and MG- treated seedlings, the MG-supplemented (MG and MG+Zr) seedlings displayed a vast improvement comparatively. Modulation of antioxidant activity observed in this study is indicative of an incited response to oxidative stress (figure 4.2.4 – 4.2.6). MG revealed distinct involvement in stress-signalling, ROS levels had increased, although not as severely as with Zr-treated seedlings, but seemingly enough to activate antioxidants without eliciting damage. Furthermore, the proposed early-onset activation of antioxidants has been observed in B. rapa L. seedlings of this study, and as such has resulted in improved growth, development and seed germination. The results of this study has therefore negated the previous reports on MG-toxicity (at high concentrations), and has shed light on further properties of this ubiquitous and inevitably-occurring metabolite at low levels. / National Research Foundation (NRF)

The question of group-living in animals has attracted a lot of research attention. Today, we have a nuanced understanding of ultimate explanations and proximate mechanisms for group-living, as well as the genetic basis for seemingly puzzling aspects of sociality such as altruism. However, our current view of sociality has been obtained almost entirely in an intraspecific context, i.e. based on groups consisting of individuals of a single species. On the other hand, heterospecific sociality, i.e. groups formed by individuals of multiple species, has been largely ignored in group-living theory and empirical research. This is despite the fact that heterospecific sociality is widely prevalent in nature and is known to occur in many different contexts, in a variety of taxa and in both marine and terrestrial habitats. My dissertation focuses on one of the best-known examples of heterospecific sociality, namely heterospecific foraging associations of terrestrial insectivorous birds (commonly called mixed-species flocks; flocks hereon). Flocks are found all over the world, in a variety of habitats, and include a unique suite of species in each area. Although flocks are the best-studied among different types of heterospecific associations known, most of the research has been descriptive. In other words, while we have descriptions of the richness, size and composition of flocks from many areas, we know little about why and how flocks form. Therefore, one broad objective of this dissertation was to better understand the causes of flock formation. Birds are thought to join flocks either to obtain direct foraging benefits or better protection from predators. I used different approaches to understand which of these two reasons is likely to be more important. Additionally, to situate heterospecific sociality within sociality in general, I also examined whether the mechanisms underlying flocks are similar to single-species groups or unique to a mixed-species condition. In other words, are flocks a different route to obtain the same benefits as single-species groups, or a route to obtain benefits that conspecifics cannot provide? In the previous section, I described why understanding flocks is important from the point of view of sociality. Flocks are also important for the consequences they might have on community organization. While each flock is a collection of interacting individuals of different species, populations of species are linked in a network of interactions across multiple flocks in an area. The theoretical framework guiding our understanding of community organization is currently dominated by the idea of interspecific competition. Mutualisms or positive interactions, if any, are only expected to occur between members of different trophic levels. Only recently has the need to incorporate positive interactions between members of the same trophic level into ecological theory been emphasized. Flocks and other heterospecific associations present an important example of within-trophic level positive interactions. Therefore, the second broad objective of this dissertation was to examine the consequences of flock formation on community organization. The objectives described above were addressed using multiple approaches in this dissertation. “Why” questions in ecology and evolution are generally tackled using manipulative experiments. Given that experiments are neither feasible nor ethical in the case of multispecies flocks in the wild, I addressed the “why” question by focusing on “who” instead. To understand “why” flocks form, I examined what kinds of species participate in flocks, who associates with whom, and who provides and who receives the benefits. This dissertation uses a combination of methods and data, including questions addressed at a global scale using descriptive information on flocks available from across the world. For other questions that were based on entirely new approaches developed in this dissertation, data were collected in a field site in the Western Ghats. In general, given the two broad objectives of this dissertation, the approaches I used were drawn from both behavioural and community ecology. The dissertation is organized in the following way: Chapter 1: General Introduction The first chapter provides the background to the two broad objectives of this thesis, namely understanding the causes and consequences of heterospecific foraging associations in terrestrial bird communities. Chapter 2 (published in The American Naturalist) Based on a global dataset (55 presence-absence matrices from 24 locations in multiple continents) on the composition of flocks, I asked if flocks largely consist of ecologically similar or dissimilar species. Using null models and randomization tests followed by meta-analysis, I found that the association strength of species in flocks was strongly related to similarity in body size and foraging behaviour, and higher for congeneric compared with non-congeneric species pairs. In other words, flocks seem to consist largely of similar species. Extending group-living and social information use theory to a heterospecific context, I discuss potential behavioral mechanisms leading to positive interactions among similar species in flocks as well as ways in which competition costs are reduced. These findings highlight the need to consider positive interactions along with competition when seeking to explain community organisation. Chapter 3 (published in Animal Behaviour) Two kinds of participants are recognized in flocks: those that join other species (‘followers’) and are therefore likely to be the recipients of the benefits of flock participation and those that are joined (‘leaders’). Through comparative analyses, using a large sample of flocks from around the world, I found (1) ‘followers’ tend to be smaller, more insectivorous, and feed in higher strata than matched species that participate in flocks to a lesser extent and (2) ‘leaders’ tend to be cooperative breeders (which are known to have well-developed anti-predatory systems) more often than matched species that are not known to lead flocks. Furthermore, meta-analyses of published results from across the world showed that bird species in terrestrial mixed-species flocks increased foraging rates and reduced vigilance compared to when they were solitary or in conspecific groups. Moreover, the increase in foraging rates was seen only in the case of flock followers and not flock leaders. These findings suggest a role for predation in the evolution of mixed-species flocking. Species that are vulnerable to predation follow species whose vigilance they can exploit. By doing so, they are able to reduce their own vigilance and forage at higher rates. Chapter 4 (to be submitted to Behavioural Ecology and Sociobiology) In this study, conducted in a tropical evergreen forest in the Western Ghats of India, I used intraflock association patterns to generate a community-wide assessment of benefits of flock participation for different species. I assumed that individuals needed to be physically proximate to particular heterospecific individuals within flocks to obtain any direct foraging benefit (flushed prey, kleptoparasitism, copying foraging locations). Alternatively, for all anti-predation benefits, physical proximity to particular heterospecifics is not required, i.e. just being in the flock vicinity will suffice. Therefore, I used the choice of locations within flocks to infer whether individual species are obtaining direct foraging or antipredation benefits. A small subset of the bird community (5/29 species), composed of all members of the sallying guild, showed non-random physical proximity to heterospecifics within flocks. All preferred associates were from non-sallying guilds, suggesting that the sallying species were likely obtaining direct foraging benefits, either in the form of flushed or snatched prey. The majority of species (24/29) chose locations randomly with respect to heterospecifics within flocks, and thus were likely obtaining anti-predation benefits. In summary, my study indicates that direct foraging benefits are important for only a small proportion of species in flocks and therefore that predation is likely to be the main driver of flocking. Chapter 5 (to be submitted to Oecologia) Two types of species – intraspecifically gregarious and sallying species – are thought to play important roles in flocks because studies have shown they attract other flock participants. However, it is not clear why these types of species are attractive, i.e. are they cues for flocks or do they directly provide benefits to other species? It is also not known whether these types are essential for flock formation. In this study, in a tropical evergreen forest in the Western Ghats of India, I used a novel approach to address these questions. Flocks contain anywhere between two and tens of species. My approach focused on the simplest, i.e. two-species, flocks. In two-species flocks, attraction between species must be based on direct benefit to at least one of the species. Therefore, only species combinations that result in benefit to at least one species will occur as two species flocks. Further, by examining leading and following behaviour in these combinations, I could also determine the direction of benefit-flow. Finally, given that all flocks pass through a two-species step, examining which two-species combinations are joined by other species helped understand species roles in flock formation. I found that intraspecifically gregarious species, but not sallying species, were disproportionately represented in two-species flocks, always provided the benefits when present, and that flocks containing them were joined significantly more often. Therefore, intraspecifically gregarious species, but not sallying species, play a role in providing flock benefits and flock formation. Moreover, given that most (7/8) intraspecifically gregarious species in my study site played these roles, the intraspecifically gregarious species guild can be considered an example of a within-trophic level “keystone”. Chapter 6 (“in press” in Oikos) There is a growing recognition of the need to integrate non-trophic interactions into ecological networks for a better understanding of whole-community organization. To achieve this, the first step is to build networks of individual non-trophic interactions. In this study, I analyzed the network of interdependencies among bird species that participated in flocks in an evergreen forest site in the Western Ghats, India. I found that flock networks contain a small core of highly important species that other species are strongly dependent on, a pattern seen in many other biological networks. Further, I found that structural importance of species in the network was strongly correlated to functional importance of species at the individual flock level. Finally, comparisons with flock networks from other Asian forests showed that the same taxonomic groups were important in general, suggesting that species importance was an intrinsic trait and not dependent on local ecological conditions. Hence, given a list of species in an area, it may be possible to predict which ones are likely to be important. Chapter 7: Conclusions In this section, I provide a summary of the main findings of this dissertation, discuss the main conclusions with regard to each of the two broad objectives and finally suggest future lines of investigation to further understand the causes and consequences of flock formation and heterospecific sociality in general. In summary, the work presented in this dissertation provides a picture of how and why flocks form and their likely consequences for community organization. The main driver of flock formation seems to be protection from predators, although a few species do obtain direct foraging benefits. Additionally, given that I found flocks to largely be groupings of similar species, the mechanisms through which benefits are obtained are likely to be similar to those in single-species groups. In other words, flocks are possibly a way for species that are unable to group with conspecifics, to obtain group-living benefits. My finding, that flocks largely consisted of similar species, also questions the stereotyping of interactions between similar species in communities as competitive. Other results from this study demonstrate the importance of intraspecifically gregarious species in flocks. Such species are the main providers of benefits to other flock participants and seem essential for flock formation. Finally, network analysis showed that a small core of species, mainly including species known to provide benefits at the individual flock level, are disproportionately important in the emergent community-level network of interdependencies. Such species are possibly one of the first examples of within-trophic level “keystones” discovered. Apart from the findings, this study also provides a set of new approaches and analytical frameworks that can be used to examine other multispecies foraging groups and heterospecific foraging associations in other contexts.

Landscape change and biodiversity decline is a global problem and has sparked world-wide initiatives promoting biological conservation techniques such as reintroductions, protected area networks, and both preservation and restoration of landscape connectivity. Despite the increasing abundance of such working landscapes (i.e. “human-modified” landscapes), we know relatively little about their ecological mechanics; these landscapes can be vast, encompassing areas too large to obtain high resolution ecological data to test ecological process. To investigate the ecological mechanics of working landscapes, I use a small, tractable, landscape mesocosm situated in east-central Alberta, Canada, The Cooking Lake Moraine (a.k.a. the Beaver Hills Biosphere). The chapters within this dissertation quantify biodiversity across a hierarchy of measurements (from genes to communities) and investigate consistencies in ecological processes generating patterns in these biodiversity measurements across spatial scales. As a result, I investigate both a depth, and breadth, of spatial ecological processes underlying the efficacy of biodiversity conservation techniques in heterogeneous working landscapes. In Chapter I, I explore between-landscape functional connectivity by investigating the genetic contribution of reintroduced individuals to an ostensibly successfully reintroduced population within the mesocosm. I find that contemporary animals are the result of recolonization from adjacent sources rather than putative reintroduction founding individuals, indicating greater mesocosm functional connectivity to adjacent landscapes than previously thought. In Chapter II, I probe within-landscape functional connectivity by quantifying the contribution of protected areas, natural, and anthropogenic landscape features to animal movement across the mesocosm. I find that natural features had the largest effect on animal movements, despite the presence of protected areas. Chapter III investigates protected area network efficacy on biodiversity conservation by quantifying the contribution of protected areas, natural, and anthropogenic landscape features to mammalian functional diversity across multiple spatial scales within the mesocosm. I find that protected areas rarely predict functional diversity across spatial scales; instead natural features positively predict functional diversity at small spatial scales while anthropogenic features are negatively associated with biodiversity at large spatial scales. Finally, Chapter IV ties the previous three chapters together by testing implicit assumptions of the species occurrence data collected in each. I compare GPS collar data (Chapter II) to species occurrence data collected on wildlife cameras (Chapter III) to demonstrate that the magnitude of animal movements better predict species occurrence than the commonly assumed proximity of animal space use. Across chapters, two central themes emerge from this dissertation. First, the importance of natural features at small spatial scales, and anthropogenic features at large spatial scales, within the landscape matrix is predominant in predicting multiple measures of biodiversity. And second, we cannot assume predictable efficacy of conservation strategies or even the ecological process inferred from the data collected to test these strategies. / Graduate