Parental care is important to offspring survival in many species. Because care benefits young and is often costly to parents, it can generate fitness trade-offs that influence the evolution of family life. In particular, interactions within families are predicted to generate variation in care, which in turn causes selection on traits used to give, receive, and influence care. My dissertation examines whether such socially dynamic processes have influenced the evolution of parental and embryo behavior in glassfrogs (Centrolenidae). These Neotropical frogs have terrestrial eggs, aquatic larvae, and multiple origins of male-only care. Embryos can plastically alter hatching age, which might allow them to adaptively respond to variation in egg care. I test for parent–embryo coevolution by combining field observations (40 species), experiments (8 species), and phylogenetic comparative analyses. First, I test historical and functional hypotheses of parental care evolution. I found that uniparental egg-care is ubiquitous in centrolenids, can be provided by either sex, and benefits young. Elaborate male-only care evolved repeatedly from simpler female-only care, a pattern consistent with constraints on female-care levels. Second, I examine the diversification of male-only care, testing whether maternal changes to egg-clutch traits influence embryo dependency and if such changes are associated with male-only care. Evidence indicates that reduced female expenditure on egg-jelly evolved with, and increases the importance of, elaborate male care. Next, I evaluate whether embryos respond to behavioral and evolutionary changes in parenting. Embryos behaviorally delay hatching when parents continue caring, and evidence indicates that evolutionary increases in hatching plasticity evolved with increases in care duration. I tested if male mating success causes variation in male care, and thereby influences embryo behavior. I found that increased mating success extends male care, making nests safer, and embryos delay hatching accordingly. Finally, I examine selective tradeoffs influencing hatching plasticity by measuring hatchling phenotypes and fitness correlates. Across species, delayed hatching provides performance benefits during the larval stage. Overall, my work reveals coevolutionary interactions among mothers, fathers, and embryos. It supports that embryos respond to parentally mediated changes in egg environments and elucidates how family life alters selection on parental and embryo traits.

Family-living has been recognized as a necessary prerequisite for the evolution of advanced cooperative societies, yet the evolutionary and ecological processes that drive the coupling of different forms of cooperation in family-based societies are still poorly understood. In my dissertation, I investigate the correlated evolution of parental care, monogamy, and cooperative breeding in a variety of family-based taxa. I explore the mating and social behavior of family-living beetles with incipient cooperation to better understand the factors driving these social traits. Specifically, I evaluate different causes of extra-pair mating in socially monogamous beetles, the potential benefits that young adult offspring may gain from remaining in the family group, and how these behaviors correspond to different ecological niches. These studies demonstrated that many of the factors predicted to favor family-living in cooperatively breeding animals fail to explain delayed dispersal and family cohesion in this beetle group. In a phylogenetic comparative study of birds, I further evaluate how ecological selective pressures drive the correlated evolution of monogamy, biparental cooperation, and cooperative breeding. Taken together, these studies have implications for our general understanding of the evolution of cooperation, and suggest the action of previously unrecognized processes in shaping and pairing social behaviors.

Male pregnancy is a complex and energetically costly form of male parental care found exclusively in the fish family Syngathidae, which includes pipefishes, seahorses, and seadragons. The novelty of the male brood pouch raises questions about how this trait evolved and what role it plays in sexual selection. One possibility is that brood pouch evolution was partially shaped by postcopulatory sexual selection. We used the sexually dimorphic Gulf pipefish, Syngnathus scovelli, to test for postcopulatory sexual selection within broods and tradeoffs between successive male pregnancies as a function of female attractiveness. Offspring survivorship within a pregnancy was affected by the size of a male's mate, the number of eggs transferred, and the male's mating history. These results indicate the males invest more resources into broods from large, attractive mates to the detriment of future broods. Next, we investigated the effects of food limitation on male parental care strategies. Our data suggests that male Gulf pipefish sacrifice investment in future reproduction, via somatic growth, in favor of current reproduction. A positive relationship between number of failed eggs and male growth rate in our low-food treatments suggests that males may derive an energetic benefit from unsuccessful eggs in the brood pouch. Finally, we used a paired design, to investigate the effect of perceived female attractiveness on offspring survivorship. We found that, in general, males prefer the largest female available. Within a replicate, we found that the male that preferred their mate more, regardless of stimulus female size, also had higher offspring survivorship in the resulting brood. This result is exciting because it shows not only that cryptic male choice affects offspring survivorship in Gulf pipefish but also that mate preference can have a prolonged effect on an individual’s reproductive success. Ultimately, our data suggests that the evolution of the brood pouch has produced a trait that not only nurtures the offspring but also exert cryptic male choice.

<p>A long-held assumption in animal behavior is that females and males differ fundamentally in their mating strategies. Females are thought to be more choosy because female reproduction typically is limited by parental investment. Males, on the other hand, are expected to compete among themselves for access to females or resources, since male reproduction is limited primarily by mating access. This dichotomy is challenged by the increasing realization that males can be choosy and females also compete aggressively. It remains unclear, however, if and how selection acts on aggressive behavior in the context of intrasexual competition among females (reviewed in Chapter 1). In this thesis, I use a population of free-living tree swallows (<i>Tachycineta bicolor<i>) to test predictions about the selective pressures shaping aggressive behavior in females. First, using an experimental manipulation of nest site availability, I demonstrate that more aggressive females have a competitive edge in acquiring nestboxes, a critical limiting resource required for breeding (Chapter 2). This result shows that more aggressive females are more likely to breed and, thus, that females experience direct selection to be aggressive in the context of competition for mating opportunities. Next, I demonstrate a fitness cost of female aggression (Chapter 3): high levels of aggression in females are not associated with the quantity of offspring, but instead, more aggressive females had offspring of lower quality (i.e. reduced mass). Using a cross-fostering approach, I explore the causal link between female aggression and offspring mass, and I find that a trade-off between female aggression and maternal care best accounts for this cost of aggression. Site differences may create variation in how selection shapes female aggression, but the overall finding that more aggressive females have lower quality offspring indicates that this cost may work counter to selection favoring aggressive behavior in the context of competition over nestboxes. Understanding the evolution of female aggressiveness in a biparental system is incomplete without examining how males may alter the selective environment shaping female behavior. In Chapter 4, I explore the potential role of a female's mate in offsetting the costs of aggression. Males appear to mitigate these costs for their female partners, but not by compensating for poor parenting by aggressive females. Instead, females invest more heavily in reproduction, laying more and larger eggs, when mated to a male that is more different from her own phenotype. If this differential investment outweighs the cost of aggressiveness in terms of offspring quality, then male phenotype may play a key role in understanding the selective pressures shaping the evolution of aggressive behavior in females. Altogether, this dissertation explores the costs and benefits of female aggressive behavior. The focus on aggressiveness as a sexually selected trait in females provides a much needed parallel to the wealth of information already known about the selective pressures shaping sexually selected traits in males.</p> / Dissertation

This thesis concerns genomic variation within the Annelida, for which genome size studies are few and provide data for only a handful of groups. Genome size estimates were generated using Feulgen image analysis densitometry for 35 species of leeches and 61 polychaete species. Relationships were explored utilizing collection location and supplementary biological data from external sources. A novel, inverse correlation between genome size and maximum adult body size was found across all leeches. Leeches that provide parental care had significantly larger genome sizes than leeches that do not. Additionally, specimens identified as Nephelopsis obscura exhibited geographic genome size variation. Within the Polychaeta, Polar region polychaete genomes were significantly larger than those of Atlantic and Pacific polychaetes. These studies represent the first exploration of leech genome sizes, and provide base evidence for numerous future studies to examine relationships between genome size and life history traits across and within different annelid groups.

Das Tierreich zeichnet sich durch eine große Diversität an Sozialsystemen aus, die von einer einzelgängerischen Lebensweise bis hin zum Leben in komplexen sozialen Gruppen reicht. Diese Variation in Sozialsystemen liefert den perfekten Rahmen um die evolutionäre Entwicklung von sozialen Merkmalen zu untersuchen. Ein besonders erfolgsversprechender Ansatz besteht darin, eng verwandte Arten, die sich durch einen unterschiedlichen Grad der Vergesellschaftung auszeichnen, miteinander zu vergleichen. Die Charaktersierung von Sozialsystemen wird für verschiedene taxonomische Gruppen unterschiedlich gehandhabt. Bei Vögeln wird das Sozialsystem normalerweise durch das Brut- und das soziale Paarungssystem charakterisiert. Die meisten Vogelarten sind paarlebend, aber man findet auch komplexere Gruppen welche im Allgemeinen durch das Verbleiben der Jungen am Aufwuchsort und kooperatives Brüten charakterisiert sind. Bisher wurden verschiedene Hypothesen im Zusammenhang mit Demographie, Ökologie, Lebensgeschichte und Verwandtschaftsverhältnissen vorgeschlagen um den Übergang von Paarbrütern zu kooperativen Brutsystemen in Vögeln erklären. Kurzfuß-Stelzenrallen (Mesitornis variegata) sind mittelgroße, am Boden lebende Vögel, die zur Familie der Mesitornithidae gehören. Diese Vogelfamilie ist endemisch in Madagaskar und beinhaltet zwei weitere allopatrische Arten, welche sich hinsichtlich des Grades der Vergesellschaftung unterscheiden: Die Einfarb-Stelzenralle (Mesitornis unicolor) des östlichen Regenwaldes welche in Paaren brütet und die Monias-Stelzenralle (Monias benschi) des südlichen Dornenwaldes welche in Gruppen lebt und kooperativ brütet. Die Kurzfuß-Stelzenralle hingegen kommt im westlichen Trockenwald vor und lebt für gewöhnlich in Paaren oder kleinen Gruppen von denen angenommen wird, dass es sich um Familiengruppen handelt, wobei allerdings nur wenig Informationen über das Brutsystem vorhanden ist und bisher keine Studie die genetischen Verwandtschaftsverhältnisse innerhalb der kleinen sozialen Einheiten untersucht hat. Das Hauptziel dieser Arbeit war es erstens die verschiedenen Komponenten des Sozialsystems der Kurzfuß-Stelzenrallen zu beschreiben, ein Art für welche bisher angenommen wurde das sie kooperativ brütet, deren Jungen jedoch Nestflüchter sind und prinzipiell nur wenig elterliche Fürsorge benötigen. Zweitens sollten die proximaten und ultimativen Ursachen untersucht werden, die dieses Sozialsystem geformt haben könnten. Um dieses Ziel zu erreichen habe ich genetische, morphologische, räumliche sowie Verhaltensdaten von 10 bis 15 sozialen Einheiten von M. Variegate während fünf Feldsaisonen (Oktober 2009 bis April 2012) im Kirindy-Wald im Westen von Madagaskar gesammelt. Das Ergebnis dieser Studie zeigt, dass die Kurzfuß-Stelzenralle in sehr kohäsiven stabilen Paaren oder kleinen Familien lebt, die durch eine verspätete Abwanderung der Jungtiere entstehen, und dass nur die Elterntiere sich um die Aufzucht der Brut kümmern. Außerdem versorgen die Eltern ihre Jungen entgegen bisherigen Vermutungen in den ersten zwei Lebensmonaten intensiv mit Nahrung, und auch darüber hinaus bis zum 12. Lebensmonat obwohl mit viel geringerer Häufigkeit. Diese lange Periode der elterlichen Fürsorge hängt wahrscheinlich mit der langsamen Entwicklung der Jungtiere hinsichtlich der für die Nahrungssuche erforderlichen Fertigkeiten zusammen. Die hohe Kohäsion sozialer Einheiten mit inter-individuellen Abständen von selten mehr als drei Metern steht eher mit einer Strategie der Raubfeindvermeidung als einer Strategie zur Verhinderung des Fremdgehens in Verbindung. Dennoch kann die hohe Kohäsion zwischen Paarpartnern das streng monogame Paarungssystem erklären. Die Untersuchung des Abwanderungsverhaltens hat ergeben, dass männliche Nachkommen länger in ihren Familien bleiben als weibliche, was mit der beobachteten langsameren Fluktuation der erwachsenen männlichen Population und dem Vorhandensein von „Stiefmüttern“ in einigen Familien übereinstimmt. Darüber hinaus konnte ich durch den Vergleich von Paaren mit und ohne Nachwuchs zeigen, dass Familienleben für die Eltern hinsichtlich der Effizienz der Nahrungsbeschaffung und hinsichtlich der Investitionen in zukünftige Reproduktion kostspielig ist. Dies könnte die Intoleranz der Eltern gegenüber älteren Nachwuchs erklären, welche ich beobachten habe. Zusammenfassend kann gesagt werden, dass die Einschränkungen bezüglich unabhängigen Brütens und einzelgängerischen Umherstreifens in Kombination mit der langsamen Entwicklung der Fähigkeiten die im Zusammenhange mit der Nahrungsbeschaffung stehen und elterliche Kosten wichtige Faktoren sind, welche das Abwanderungsverhalten der Jungtiere, die Bildung von Familien und die Familienstabilität in dieser Art erklären. Zusätzlich beeinflusst die Gefahr von Raubfeinden, die mit der starken Kohäsion innerhalb sozialer Einheiten einhergeht, das Paarungssystem bei Kurzfuß-Stelzenrallen und legt eine Verbindung zwischen genetischer Monogamie und Raubfeindruck bei sozial monogam lebenden Arten nahe. Basierend auf einem Vergleich mit den anderen Arten der Familie der Mesitornithidae könnte das Brutsystem der Kurzfuß-Stelzenralle als Übergansstadium zwischen einem allein auf den beiden Elternteilen basierenden und einem kooperativen Brutsystem erachtet werden in dem einige Jungen fähig wären Hilfe zu stellen, aber von den Eltern daran gehindert werden.

In this thesis, I describe the behavioural ecology of an Australian passerine, the Southern Emuwren Stipiturus malachurus (Maluridae). The southern emu-wren is threatened in several parts of its range, and yet information on the species’ breeding biology, habitat use and mating system is lacking. These data are fundamental to effective conservation management. My research investigated the breeding behaviour and habitat ecology of a population of southern emu-wrens in Portland, Victoria, Australia, over three breeding seasons (2000/01, 2001/02 and 2002/03). also collected data pertaining to habitat use from populations located in Anglesea and Lower Glenelg National Park (Victoria, Australia). Southern emu-wrens commonly formed socially monogamous pair bonds, although cooperative breeding was observed for the first time in this species, where male offspring within several families delayed breeding to help raise younger siblings. Successful nests produced 1.8 fledglings on average, however, a nest had only a 56% chance of success during incubation and nestling phases. Nest failure was mainly attributed to depredation and snakes were identified as major nest predators. The slow breeding rate of the southern emu-wren is typical of a small passerine in the Southern Hemisphere. Nevertheless, adult mortality was unusually high. In one breeding season the adult population was reduced by 50%. The population recovered when individuals dispersed from the adjacent coastal heathland to fill territory vacancies. This highlights the vulnerability of populations to local catastrophe, and potential extinction if spatial separation of populations exceeds the species’ dispersal capacity.

abstract: Though it is a widespread adaptation in humans and many other animals, parental care comes in a variety of forms and its subtle physiological costs, benefits, and tradeoffs related to offspring are often unknown. Thus, I studied the hydric, respiratory, thermal, and fitness dynamics of maternal egg-brooding behavior in Children's pythons (Antaresia childreni). I demonstrated that tight coiling detrimentally creates a hypoxic developmental environment that is alleviated by periodic postural adjustments. Alternatively, maternal postural adjustments detrimentally elevate rates of egg water loss relative to tight coiling. Despite ventilating postural adjustments, the developmental environment becomes increasingly hypoxic near the end of incubation, which reduces embryonic metabolism. I further demonstrated that brooding-induced hypoxia detrimentally affects offspring size, performance, locomotion, and behavior. Thus, parental care in A. childreni comes at a cost to offspring due to intra-offspring tradeoffs (i.e., those that reflect competing offspring needs, such as water balance and respiration). Next, I showed that, despite being unable to intrinsically produce body heat, A. childreni adjust egg-brooding behavior in response to shifts in nest temperature, which enhances egg temperature (e.g., reduced tight coiling during nest warming facilitated beneficial heat transfer to eggs). Last, I demonstrated that A. childreni adaptively adjust their egg-brooding behaviors due to an interaction between nest temperature and humidity. Specifically, females' behavioral response to nest warming was eliminated during low nest humidity. In combination with other studies, these results show that female pythons sense environmental temperature and humidity and utilize this information at multiple time points (i.e., during gravidity [egg bearing], at oviposition [egg laying], and during egg brooding) to enhance the developmental environment of their offspring. This research demonstrates that maternal behaviors that are simple and subtle, yet easily quantifiable, can balance several critical developmental variables (i.e., thermoregulation, water balance, and respiration). / Dissertation/Thesis / Ph.D. Biology 2011

abstract: Parental care provides many benefits to offspring. One widely realized benefit is enhanced regulation of offspring's thermal environment. The developmental thermal environment during development can be optimized behaviorally through nest site selection and brooding, and it can be further enhanced by physiological heat production. In fact, enhancement of the developmental thermal environment has been proposed as the initial driving force for the evolution of endothermy in bird and mammals. I used pythons (Squamata: Pythonidae) to expand existing knowledge of behavioral and physiological parental tactics used to regulate offspring thermal environment. I first demonstrated that brooding behavior in the Children's python (Antaresia childreni) is largely driven by internal mechanisms, similar to solitary birds, suggesting that the early evolution of the parent-offspring association was probably hormonally driven. Two species of python are known to be facultatively thermogenic (i.e., are endothermic during reproduction). I expand current knowledge of thermogenesis in Burmese pythons (Python molurus) by demonstrating that females use their own body temperature to modulate thermogenesis. Although pythons are commonly cited as thermogenic, the actual extent of thermogenesis within the family Pythonidae is unknown. Thus, I assessed the thermogenic capability of five previously unstudied species of python to aid in understanding phylogenetic, morphological, and distributional influences on thermogenesis in pythons. Results suggest that facultative thermogenesis is likely rare among pythons. To understand why it is rare, I used an artificial model to demonstrate that energetic costs to the female likely outweigh thermal benefits to the clutch in species that do not inhabit cooler latitudes or lack large energy reserves. In combination with other studies, these results show that facultative thermogenesis during brooding in pythons likely requires particular ecological and physiological factors for its evolution. / Dissertation/Thesis / Ph.D. Biology 2012

Made available in DSpace on 2014-12-17T15:37:01Z (GMT). No. of bitstreams: 1 AlvaroCBG_DISSERT.pdf: 3916375 bytes, checksum: 808b5d48fcc610be37f32fdfdc7f716a (MD5) Previous issue date: 2010-08-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The new Evolutionary Psychology (E. P.) paradigm has been trying to understand how the human beings make their decisions over time regarding the most diverse variables, always bearing in mind that such a cognitive process is due to a complex natural selection process that occurred millions of years ago. One of the main topics discussed by this new paradigm is the issue of parental investment, i.e., the care the parents provide to an offspring at the expense of the investment into a new one. The present work sought to integrate these two topics, trying to understand how some variables modulate the process of decision making in a sample of the city of Natal, Rio Grande do Norte state. It was investigated the hypothesis that the presence of both parents, along the individual development, could signal a more favorable environment, providing clues to the individual that he could assume a competitive position at the socio-biological market. His decisions, therefore, could be guided by long-term investments with aims to obtain more robust rewards. On the contrary, those who has suffered for some moment the absence of one the parents could develop theirselves in a not so competitive way, starting to choose immediate benefits - but lesser ones -, since the future would be less predictable due to their worse development conditions. This study involved 152 individuals from three higher education institutions, one of them being public and the others being private ones. In the results found, there was no difference between children of coupled parents and children of deceased or divorced parents concerning discount rates. The levels of hopelessness did not affect the discount rates of children of single parents when compared to children of coupled parents. Not having one of the parents because of divorce made the child to tend to present lower scores in the domain of social relations of WHOQOL - Bref, whilst the absence of the father by death made the scores lower in the domain of environment. The results indicate that loosing one of the parents along the development influences the individual's quality of life perception, but the measurement method of future discounting rates by means of financial choices is not sensitive to this variation / O novo paradigma da Psicologia Evolucionista (P.E.) vem tentando compreender como os seres humanos tomam suas decis?es ao longo do tempo levando em conta as mais diversas vari?veis, tendo sempre em mente que tal processo cognitivo ? tribut?rio de um complexo processo de sele??o natural ocorrido nos milh?es de anos que se passaram. Um dos principais temas discutidos por este novo paradigma ? a quest?o do investimento parental, ou seja, o cuidado fornecido pelos pais a uma prole ?s custas do investimento em outra. O presente trabalho buscou integrar esses dois temas, tentando compreender como algumas vari?veis modulam o processo de tomada de decis?es de uma amostra do munic?pio de Natal, Estado do Rio Grande do Norte. Investigou-se a hip?tese de que a presen?a de ambos os pais, ao longo de desenvolvimento individual, poderia sinalizar um ambiente mais favor?vel, fornecendo ao sujeito pistas de que ele pode assumir uma posi??o competitiva no mercado s?cio-biol?gico. Suas decis?es, portanto, poderiam ser pautadas pelo investimento de longo prazo com vistas ? obten??o de recompensas mais robustas. Ao contr?rio, aquele que em algum momento sofreu a aus?ncia de um dos pais poderia se desenvolver de modo n?o t?o competitivo, passando a escolher benef?cios imediatos, por?m menores, uma vez que o futuro lhe seria menos previs?vel devido ?s suas piores condi??es de desenvolvimento. Neste estudo participaram 152 sujeitos oriundos de tr?s Institui??es de Ensino Superior, sendo uma p?blica e duas privadas. Pelos resultados encontrados n?o houve diferen?a entre filhos de pais unidos e filhos de pais separados ou falecidos no que concerne ?s taxas de desconto. Os n?veis de desesperan?a tamb?m n?o influenciaram as taxas de desconto dos filhos de pais separados nem dos filhos de pais falecidos, quando comparados aos filhos de pais unidos. N?o ter um dos pais por motivo de separa??o fez com que o filho tendesse a apresentar escores mais baixos no dom?nio das rela??es sociais do WHOQOL Bref e quando o pai estava ausente por motivo de falecimento os escores foram mais baixos no dom?nio de meio ambiente. Os resultados indicam que perder um dos pais ao longo do desenvolvimento influencia a percep??o de qualidade de vida do sujeito, mas o m?todo de mensura??o de taxa de desconto de futuro por meio de escolhas financeiras n?o ? sens?vel a essa varia??o