Social parasitism, the exploitation of a society by other social organisms, has evolved independently numerous times within social animals. In this thesis, I integrate behavioral, evolutionary and chemical analyses to elucidate the evolution of social parasitism in Megalomyrmex ants. I examine host-parasite interactions in two Megalomyrmex species, identify venom alkaloids, and reconstruct the phylogenetic relationships between species. In Chapter 1, I analyze nest architecture and behavioral interactions between the ant host Cyphomyrmex cornutus and its parasite Megalomyrmex mondabora. This is the first detailed account of the natural history of this host and its social parasite. In Chapter 2, I report a one-year-long fitness experiment that tests whether Trachymyrmex cf. zeteki colonies suffer reduced fitness from an association with the social parasite Megalomyrmex symmetochus. I show that M. symmetochus parasites negatively impact host fitness though several mechanisms, including a) manipulation of the host worker grooming behavior; b) castration of host queens produced by the host colony, which then become workers; and c) reduction of garden size, host worker number, and host reproductive output. In Chapter 3, I determine that five venom alkaloids of Megalomyrmex are taxonomically informative to help differentiate cryptic species within the M. mondabora complex; new species in this complex need to be described in a future taxonomic revision. In Chapter 4, I reconstruct phylogenetic relationships of the genus Megalomyrmex with DNA sequence information. I conclude that the genus is monophyletic and corroborate two of the four species groups proposed by Brandão (1990) in a previous morphological revision. I also find evidence in support of Darwin’s Predation Hypothesis on the origin of social parasitism, which postulates that socialparasitic behaviors evolve from predatory behaviors. Lastly, I discuss promising future research directions on the evolution of social parasitism in the ant genus Megalomyrmex, which could serve as a model for the study of social parasitism in other lineages of social insects. / text

The general prevalence of sexual reproduction over asexual reproduction among metazoans testifies to the evolutionary, long-term benefits of genetic recombination. Despite the benefits of genetic recombination under sexual reproduction, asexual organisms sporadically occur throughout the tree of life, and a few asexual lineages persisted over significant evolutionary time without apparent recombination. The study of asexual organisms therefore may provide clues to answer why almost all eukaryotes reproduce via meiosis and syngamy and why asexual eukaryotes are almost always evolutionarily short-lived. Towards understanding the evolution of asexual lineages in the Hymenoptera, I first review the diversity of reproductive systems in the Hymenoptera, introduce the study organism, the fungus-gardening ant Mycocepurus smithii, and discuss my research objectives. Second, I integrate information from reproductive physiology, reproductive morphology, natural history and behavior, to document that that queens of M. smithii are capable of thelytokous parthenogenesis, workers are sterile, and males are absent from the surveyed population. These results suggest that M. smithii might be obligately asexual. To place the origin and maintenance of asexual reproduction in M. smithii in an evolutionary context, I use molecular phylogenetic and population-genetic methods to (i) test if M. smithii reproduces asexually throughout its distribution range; (ii) infer if asexuality evolved once or multiple times; (iii) date the origin of asexual reproduction in M. smithii; and (iv) elucidate the cytogenetic mechanism of thelytokous parthenogenesis. During field collecting for these studies throughout the Neotropics, I discovered a new species of obligate social parasite in the genus Mycocepurus. Social parasites are of great interest to evolutionary biology in order to elucidate mechanisms demonstrating how parasites gained reproductive isolation from their host species in sympatry. I describe this new parasite species, characterize its morphological and behavioral adaptations to the parasitic lifestyle, and discuss the parasite’s life history evolution in the context of social parasitism in fungus-growing ants. The dissertation research integrates population-genetic, phylogenetic, physiological and morphological approaches to advance our understanding of the evolution of reproductive systems and diversity of life-history traits in animals. / text

The proximate causes triggering nest abandonment are unclear for most species, including the Yellow Warbler (Dendroica petechia), which abandons nests parasitized by cowbirds (via burial or desertion). Cowbird parasitism and rejection of parasitism are costly to some hosts; therefore cues affecting their responses have important evolutionary implications. Manipulative experiments showed that experimentally adding a cowbird egg elicited similar rejection frequencies (2008: 31.8%; 2009: 26.1%) as naturally laid eggs (2008: 27.1%; 2009: 20.0%). In 2008, interaction with an egg-removing model increased the probability of abandonment and the most aggressive individuals were more likely to bury the model cowbird egg. In 2009, eggs added to nests before sunrise were rejected at a frequency (29.7%) similar to eggs added to nests after sunrise (22.9%). Warblers returning to nests after egg addition peered significantly longer at their clutch than at control nests, shuffled their bodies more frequently when on the eggs and spent more time probing eggs with their bill once settled on their parasitized clutch. Furthermore, although non-mimetic blue eggs were not abandoned significantly more frequently than cowbird eggs (blue 31.1% versus cowbird 21.4%), only blue eggs were ejected from some nests. Thus, warblers use both tactile and visual cues to detect the presence of a parasitic egg in their nest. Eggs added to nests were not rejected at a lower frequency than naturally parasitized nests, as was recorded in a previous study. It is difficult to know whether this increase in abandonment of experimental eggs is due to phenotypic plasticity, genetic changes, or other factors. Egg recognition abilities may have changed because I have shown that the warblers’ behaviour changes before versus after egg addition, whereas no changes were recorded in an earlier study. Finally, not all individuals that buried eggs for the first time in 2009 (21.4%) buried again after being re-parasitized (5.3%), when less time remained in the breeding season relative to the first parasitism event. This suggests that egg rejection and host responsiveness in warblers, and likely other avian hosts that use abandonment as a form of rejection, is affected by environmental cues which may act as genetic expressers.

Global warming and increasing atmospheric nitrogen deposition are ranked as second and third most important global drivers of biodiversity loss. Widespread species losses have deep implications for the functioning of ecosystems, the delivery of essential ecosystem services and their resilience to future environmental perturbations. There is growing recognition that interactions between species play a crucial role in determining the response of ecosystems to global environmental changes. Moreover, evidence of synergistic effects between global change drivers has prompted numerous calls to integrate multiple drivers in ecological research. Nevertheless, empirical studies assessing the impacts of temperature and nitrogen on communities at multiple trophic levels are largely absent. This thesis explores the effects of temperature and nitrogen on a tri-trophic system comprising plants, herbivores and natural enemies. The first chapter shows impacts of the drivers on the composition and phenology of an herbivore community. The second chapter highlights changes in biomass under the treatments at three trophic levels. The third chapter explores, for the first time, the impacts of temperature and nitrogen on quantitative food webs. Finally, the last data chapter uses body size as an important species trait to gain insights on the mechanisms causing shifts in food web structure. The key findings of this thesis were i) trophic interactions largely mediated the effects of both global change drivers ii) In particular, strong bottom-up effects determined the system response, with herbivores responding positively and consistently more so than plants and parasitoids in particular. However, iii) this contrasting response was not explained by a phenological mismatch. iv) Food-web structure responded to the changes in composition of herbivores and parasitoids, but shifts in interaction structure did not affect the resilience of the food. However, temperature and nitrogen impacted host-parasitoid food-web structure by altering the response of parasitoid species to host density and size structuring, which is likely to bear consequences on host-parasitoid co-evolution and future food-web architecture and stability. Finally, v) we found frequent, non-additive interactions between the global change drivers. We conclude that co-occurring temperature and nitrogen are likely to alter food-web structure and overall ecosystem balance, with increasing herbivore dominance likely to have important implications for ecosystem functioning and food-web persistence.

Obligate brood parasites rely solely on other species, the hosts, to incubate their eggs and raise their offspring, which often reduces the host’s reproductive output. This reproductive cost has led to the evolution of anti-parasite adaptations among hosts, which in turn, has led to better trickery by parasites, a process termed an evolutionary arms race. The objective of this thesis was to investigate host-parasite coevolutionary arms races to address questions of host-use diversity. Host diversity varies dramatically among brood-parasitic species, but reasons for variations in host-use among brood parasites are not well understood. In Chapter 2, I address questions on host diversity specifically, whereas I address questions about coevolutionary interaction between hosts and parasites in Chapters 3, 4 and 5 using two host-parasite systems, one in New Zealand and one in North America. Chapter 2 investigates if host diversity is constrained by aggressive nest defence behaviour. I compared the nest defence behaviour of the exclusive host of the shining cuckoo Chrysococcyx lucidus lucidus on the main islands of New Zealand, the grey warbler Gerygone igata, to two other potentially suitable hosts that are not currently parasitised, the fantail Rhipidura fuliginosa and the silvereye Zosterops lateralis. The results suggest that grey warblers are as aggressive as fantails and silvereyes towards shining cuckoos at the nest and thus, host specialisation in shining cuckoos in New Zealand, at least, does not appear to be the result of nest-defence constraints imposed by potential but unused host species. Chapter 3 investigates if red-winged blackbirds Agelaius phoeniceus, a species that typically accepts the eggs of parasites, recognises, as indicated by changes in incubation behaviour, when they have been parasitised by brown-headed cowbirds Molothrus ater. Recognition without rejection suggests that rejection may be context-dependent but the results suggest that red-winged blackbirds do not recognise when their nests have been parasitised by brown-headed cowbirds, at least at the egg stage. This study was the first to investigate if hosts that almost invariably accept the eggs of parasites recognise when they have been parasitised. Chapter 4 investigated the possibility of coevolutionary arms races occurring through olfactory channels in contrast to earlier work that focussed only on visual and auditory cues. Recent research has revealed that olfactory abilities in birds are more common than previously thought. Uropygial gland secretions are posited to be a key source of avian body odour and its composition has been found to vary among species and individuals as well as between the sexes. I compared gas-chromatography (GC-FID) traces of shining cuckoo preen wax to the GC-FID traces of the grey warbler, the only host of the shining cuckoo in mainland New Zealand, as well as the preen wax of seven other species for evidence of mimicry. Preliminary results suggest there is evidence for mimicry and the potential for odour-based nestling discrimination in grey warblers. Further tests recording the response of grey warblers to odour-manipulated nestlings are necessary. Finally, in Chapter 5, I investigated the response of the song thrush Turdus philomelos, a species that rejects the eggs of the common cuckoo Cuculus canorus and conspecifics at intermediate and low frequencies, respectively, to nest-odour manipulations using the preen wax of conspecifics and heterospecifics. The results suggest song thrush do not use odour to assess the risk of parasitism at least as indicated in terms of changes in incubation behaviour. Investigations of the role of olfaction in avian brood parasite systems can provide a better understanding of brood-parasite coevolution. Only by considering all channels of communication can we be sure to completely understand the coevolutionary dynamics between brood parasites and their hosts.

The proximate causes triggering nest abandonment are unclear for most species, including the Yellow Warbler (Dendroica petechia), which abandons nests parasitized by cowbirds (via burial or desertion). Cowbird parasitism and rejection of parasitism are costly to some hosts; therefore cues affecting their responses have important evolutionary implications. Manipulative experiments showed that experimentally adding a cowbird egg elicited similar rejection frequencies (2008: 31.8%; 2009: 26.1%) as naturally laid eggs (2008: 27.1%; 2009: 20.0%). In 2008, interaction with an egg-removing model increased the probability of abandonment and the most aggressive individuals were more likely to bury the model cowbird egg. In 2009, eggs added to nests before sunrise were rejected at a frequency (29.7%) similar to eggs added to nests after sunrise (22.9%). Warblers returning to nests after egg addition peered significantly longer at their clutch than at control nests, shuffled their bodies more frequently when on the eggs and spent more time probing eggs with their bill once settled on their parasitized clutch. Furthermore, although non-mimetic blue eggs were not abandoned significantly more frequently than cowbird eggs (blue 31.1% versus cowbird 21.4%), only blue eggs were ejected from some nests. Thus, warblers use both tactile and visual cues to detect the presence of a parasitic egg in their nest. Eggs added to nests were not rejected at a lower frequency than naturally parasitized nests, as was recorded in a previous study. It is difficult to know whether this increase in abandonment of experimental eggs is due to phenotypic plasticity, genetic changes, or other factors. Egg recognition abilities may have changed because I have shown that the warblers’ behaviour changes before versus after egg addition, whereas no changes were recorded in an earlier study. Finally, not all individuals that buried eggs for the first time in 2009 (21.4%) buried again after being re-parasitized (5.3%), when less time remained in the breeding season relative to the first parasitism event. This suggests that egg rejection and host responsiveness in warblers, and likely other avian hosts that use abandonment as a form of rejection, is affected by environmental cues which may act as genetic expressers.

Habitat fragmentation potentiates biodiversity loss worldwide. Species preservation requires an integrated understanding of wildlife-habitat relationships; however, responses to habitat fragmentation may vary considerably as a function of the species ecological flexibility and the unique attributes of each fragment habitat. In this dissertation, I explore the behavioural and health ecology of an ecologically flexible primate, the ringtailed lemur (Lemur catta), occupying forest fragments in south-central Madagascar that differ in isolation, degree of anthropogenic pressure, and L. catta food resource structure. Anja Special Reserve is a 34 ha rocky-outcrop forest fragment that is highly isolated from other forests containing L. catta. L. catta in this reserve have access to abundant food and water resources year-round due to the introduction of non-native fruit trees and the construction of an artificial lake adjacent the reserve, which support a population density of L. catta (6.6 lemurs/ha) that is higher than at any other site in which the species has been studied. In comparison, the Tsaranoro Valley forest is a 53 ha rocky-outcrop forest fragment that is surrounded by a matrix of grassy savannah and a few anthropogenic crops. While land clearing is pronounced in the valley, a few fragments remain within range for L. catta dispersal. L. catta in this fragment have limited access to introduced or anthropogenic resources and the population density (1.13 lemurs/ha) is one-sixth that at Anja. During the late dry season of 2010 and mid- to late-wet season of 2011, I collected continuous time focal animal data to examine behavioural patterns related to habitat use (ranging, matrix use, terrestriality), activity budgets, and feeding ecology of L. catta in each fragment. In addition, I examined two health parameters, stress and endoparasitism, through the collection of fecal samples from focal individuals. I compared these variables between and within populations to examine the potential impacts of habitat fragmentation on an ecologically adaptable primate. L. catta at Anja depended on smaller home range areas and a focused diet consisting largely of introduced food resources, and correspondingly exhibited lower energy expenditure, while spending more time engaging in rest and social acitivities when compared with the Tsaranoro lemurs. In comparison, L. catta at Tsaranoro occupied large home ranges, traveled greater distances to forage in the matrix habitat surrounding the fragment, and exhibited a more broad-based dietary strategy that contained few introduced or anthropogenic resources. From a health perspective, L. catta at Anja exhibited higher stress levels throughout the study period, while L. catta at Tsaranoro exhibited a greater prevalence of endoparasites, which may be reflective of differences in the social pressures and ranging patterns of L. catta between the two fragments, respectively. These results illustrate differences in the quality of the habitats and the potential fitness consequences that the L. catta populations must cope with, with important implications regarding the long-term suitability of these fragments for sustaining these populations. Such information is integral when assessing the viability of wildlife populations in degraded landscapes and should be a primary consideration for wildlife managers in biodiversity conservation. / Graduate / 0327 / 0329 / denisegabrie@gmail.com

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

?rea de concentra??o: Silvicultura e manejo florestal. / Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-08-09T23:04:22Z No. of bitstreams: 2 daniel_junior_martins.pdf: 1407857 bytes, checksum: 35837ffe0a3033cb340c421e657b405d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-08-14T16:36:33Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) daniel_junior_martins.pdf: 1407857 bytes, checksum: 35837ffe0a3033cb340c421e657b405d (MD5) / Made available in DSpace on 2017-08-14T16:36:33Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) daniel_junior_martins.pdf: 1407857 bytes, checksum: 35837ffe0a3033cb340c421e657b405d (MD5) Previous issue date: 2016 / Funda??o de Amparo ? Pesquisa do estado de Minas Gerais (FAPEMIG) / A incid?ncia de lepid?pteros desfolhadores ? um dos fatores ambientais que podem regular a produtividade dos maci?os florestais. O parasitoide Palmistichus elaeisis Delvare & LaSalle (Hymenoptera: Eulophidae) se destaca pela efici?ncia no parasitismo de pupas desses lepid?pteros e auxiliam na manuten??o do equil?brio biol?gico. Esses podem ser criado em diferentes hospedeiros alternativos. Com isso, uma pesquisa foi conduzida no laborat?rio de Controle Biol?gico de Insetos do Departamento de Engenharia Florestal da Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM) em Diamantina, Minas Gerais. Objetivou-se neste trabalho, avaliar a efici?ncia de diferentes hospedeiros para a cria??o de Palmistichus elaeisis e estudar desempenho deste parasitoide em pupas de Tenebrio molitor criado em diferentes dietas. O delineamento experimental foi inteiramente casualizado (DIC), em sala climatizada temperatura variando ente 23 e 27?C, umidade relativa entre 60 e 80% e fotoper?odo de 12 horas. O primeiro estudo ensaio constituiu-se seis tratamentos e nove repeti??es. Pupas de Tenebrio molitor, Alphitobius diaperinus, Thyrinteina arnobia, Spodoptera frugiperda, Helicoverpa zea e Diatraea saccharalis foram individualizadas em potes pl?sticos e expostas ao parasitismo por seis f?meas durante 72h. Foi observado a porcentagem de parasitismo e emerg?ncia, n?mero de indiv?duos emergidos, raz?o sexual, longevidade e morfometria de P. elaeisis. Os dados foram submetidos a ANOVA e quando significativos as m?dias foram comparadas pelo teste de Tukey (p?0,05), ou teste kruskal Wallis (p?0,05) quando n?o-param?trico. A porcentagem de parasitismo variou de 88,8 a 100%. O n?mero da prole e tamanho do parasitoide foi influenciado pela biomassa do hospedeiro. A raz?o sexual variou de 0,76?0,04 a 0,94?0,01, e os maiores ciclos de desenvolvimento do parasitoide produziram prole mais longeva. Pupas de A. diaperinus n?o permitiram um bom desempenho de P. elaeisis na densidade testada. O segundo ensaio constituiu-se seis tratamentos e 10 repeti??es. Pupas de T. molitor geradas em seis dietas (farelo de trigo, fub? de milho, ra??o peletizada para coelhos, ra??o para aves poedeiras: farelada, peletizada e triturada) foram individualizadas em potes pl?sticos e expostas ao parasitismo por seis f?meas de P. elaeisis durante 72h. Foram observados os mesmos par?metros do primeiro estudo para o parasitoide. Al?m disso, foi realizada uma an?lise bromatol?gica das pupas de T. molitor e das dietas. A porcentagem de parasitismo e emerg?ncia foi de 100% em todos os tratamentos. N?o houve diferen?a no ciclo de vida, n?mero da prole e longevidade do parasitoide. Pupas alimentadas com fub? de milho geraram prole com menor raz?o sexual e menor comprimento da t?bia. A dieta a base de fub? de milho n?o foi adequada para o desenvolvimento de P. elaeisis. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Ci?ncia Florestal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016. / The incidence of defoliating lepidoptera is one of the factors that can regulate the production of forest stands. The parasitoid Palmistichus elaeisis Delvare & LaSalle (Hymenoptera: Eulophidae) stands out for the efficiency in the parasitism of pupae of these lepidoptera and helps in maintaining the biological balance. These can be created in different alternative hosts. With this, a research was developed in the laboratory of Biological Control of Insects of the Department of Forestry Department of the Federal University of the Jequitinhonha and Mucuri Valleys in Diamantina, Minas Gerais. The objective of this work was to evaluate the efficiency of different hosts for the creation of Palmistichus elaeisis and to study the performance of this parasitoid in pupae of Tenebrio molitor grown on different diets. The experimental design was completely randomized (CRD), in a heated room with temperature ranging from 23and 27?C, relative humidity between 60 and 80 % and photoperiod of 12 hours. The first assay consisted if six treatments and nine replications. Pupae of Tenebrio molitor, Alphitobius diaperinus Thyrinteina arnobia, Spodoptera frugiperda, Helicoverpa zea e Diatraea saccharalis they were individually placed in plastic pots and exposed to parasitism by six females during 72h. It was observed percentage of parasitism and emergence, number of emerged individuals, sexual ratio, longevity and morphometry P. elaeisis. Data were analyzed by ANOVA and when significant means were compared by Tukey test (p?0,05) or Kruskal Wallis test (p?0,05) when nonparametric. The percentage of parasitism ranged from 88,8 to 100 %. The number of offspring and parasitoid size was influenced by the biomass of the host, the sex ratio varied from 0,76?0,04 a 0,94?0,01, and the more parasitoid development cycles produced more offspring longeva. Pupae of A. diaperinus did not allow a good performance P. elaeisis tested in density. The second assay consisted if six treatments and 10 repetitions. Pupae of T. molitor generated in six different diets (wheat bran, cornmeal, pelleted feed for rabbits, for laying birds: farewell pelleted and crushed) they were individually placed in plastic pots and exposed to parasitism by six females during 72h. Were observed the same parameters of the first study for parasitoid furthermore, we carried out a bromatological analysis of T. molitor pupae and diets. The percentage of parasitism and emergency was 100 % in both treatments there was no difference the life cycle of the offspring number and longevity of the parasitoid. Pupae formed with corn meal generated offspring less sex reason and shorter length of the tibia. A diet based on corn meal was not suitable for development P. elaeisis.