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The reproductive strategies of the pill-box crab Halicarcinus innominatus Richardson, 1949Dunnington, Michael James January 1999 (has links)
This study examines the reproductive strategies of the Pill-box crab, Halicarcinus innominatus, at the Oaro Platform (24 km south of the Kaikoura Peninsula, New Zealand). As necessary components of reproductive strategies, the population dynamics, reproductive biology and mating behaviour of H. innominetus were examined from December 1997 through December 1998. There were obvious sexually dimorphic differences in secondary sexual traits in this species. Both males and females display a wide range of sizes over which individuals can moult to maturity. H. innominatus females displayed continuous breeding throughout the year, resulting in continuous recruitment. Females were found to outnumber males in each month. However, when comparisons were made between mature males and females with different brood stages (i.e. 0-5), males outnumbered each female type in each month. Investigations into the reproductive biology of H. innominatus females revealed that brood development and ovary development were in phase. This resulted in the ability of females to produce several broods in quick succession. Ovary development began before the moult to maturity, allowing for immediate production of a brood after the moult to maturity. Egg incubation periods were dependent on water temperature, being longest in the winter and shortest in the summer. Egg numbers were found to increase with female body size, but mortality of eggs through development was apparent. Sperm storage was found to occur in this species with possible layering of different ejaculates. Copulations were only observed between males and females in hard-shell conditions. Males mated more often with females carrying stage 5 broods, but also mated with all other female types, including pre-pubescent females. Postcopulatory mate guarding only occurred with stage 5 females. Males can detect females of different reproductive condition, which seems to be linked to the developmental stages of the females' ovaries. In conclusion, H. innominatus males seem to have two tactics to their reproductive strategies: mating with any receptive female, but only guarding stage 5 females.
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The reproductive strategies of the pill-box crab Halicarcinus innominatus Richardson, 1949Dunnington, Michael James January 1999 (has links)
This study examines the reproductive strategies of the Pill-box crab, Halicarcinus innominatus, at the Oaro Platform (24 km south of the Kaikoura Peninsula, New Zealand). As necessary components of reproductive strategies, the population dynamics, reproductive biology and mating behaviour of H. innominetus were examined from December 1997 through December 1998. There were obvious sexually dimorphic differences in secondary sexual traits in this species. Both males and females display a wide range of sizes over which individuals can moult to maturity. H. innominatus females displayed continuous breeding throughout the year, resulting in continuous recruitment. Females were found to outnumber males in each month. However, when comparisons were made between mature males and females with different brood stages (i.e. 0-5), males outnumbered each female type in each month. Investigations into the reproductive biology of H. innominatus females revealed that brood development and ovary development were in phase. This resulted in the ability of females to produce several broods in quick succession. Ovary development began before the moult to maturity, allowing for immediate production of a brood after the moult to maturity. Egg incubation periods were dependent on water temperature, being longest in the winter and shortest in the summer. Egg numbers were found to increase with female body size, but mortality of eggs through development was apparent. Sperm storage was found to occur in this species with possible layering of different ejaculates. Copulations were only observed between males and females in hard-shell conditions. Males mated more often with females carrying stage 5 broods, but also mated with all other female types, including pre-pubescent females. Postcopulatory mate guarding only occurred with stage 5 females. Males can detect females of different reproductive condition, which seems to be linked to the developmental stages of the females' ovaries. In conclusion, H. innominatus males seem to have two tactics to their reproductive strategies: mating with any receptive female, but only guarding stage 5 females.
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Sociosexual Development: Infusing the Belsky, Steinberg, and Draper Model with Sexual SelectionJackson, Jenee James January 2010 (has links)
Life history theory attempts to explain between- and within-species variation in maturational and reproductive patterns, whereas sexual selection attempts to explain between- and within-sex differences in intersexual mate choice and intrasexual competition for members of the opposite sex. These two expansive evolutionary theories have been used by developmental scientists and social/personality psychologists to explain the variation observed in human reproduction, including the timing of reproductive events and individual differences in orientation toward mating and parenting. In Part I of the following paper, I review research related to life history theory and sexual selection in humans. I then show how integrating the principles of sexual selection with life history models of human reproductive strategies can address existing limitations. In Part II, I empirically examine many of the unique propositions that emerge from theoretical integration using a longitudinal dataset on adolescent development. Under investigation is an expanded model of sociosexual development that incorporates key principles from Belsky, Steinberg, and Draper's (BSD) psychosocial theory and sexual selection theory. I specifically examine the role of early rearing conditions within the home, as specified by BSD, and self-perceived mate value, as highlighted by a sexual selection perspective, on timing of sexual debut and sexual risk taking. The current study combines variable-centered and person-centered methods to assess specialized developmental trajectories. In total, the study provides novel support for BSD theory, while also highlighting needed revisions to account for the role of self-perceived mate value on adolescent sexual behavior.
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Mammalian Community Recovery from Volcanic Eruptions in the Cenozoic of North AmericaFamoso, Nicholas 27 September 2017 (has links)
It is clear that ecosystems are devastated after a volcanic eruption coats the landscape with a layer of ash; however, the ecological recovery of mammalian communities after eruptions is poorly understood. Volcanic eruptions vary with magnitude and type and only a fraction of them have been analyzed for effects on mammalian communities. To better understand mammalian community recovery, I investigated three different lines of evidence. First, I created a new numeric metric for statistically analyzing reproductive strategies in mammals and tested the impact of diet and body size on reproductive strategies within a phylogenetic framework as proof of concept. The trend of lower reproductive rates and larger body size hold true for herbivores and omnivores, but different trajectories exist for carnivores. Second, I investigated how species richness, evenness, and similarity change across volcanic boundaries in the 1980 Mount St. Helens (MSH), Washington, and 1914-1917 Mount Lassen, California, eruptions. Richness and evenness remain unchanged in Lassen. MSH saw an immediate drop in richness followed by an increase over five years to pre-eruptive levels. Chord distance analysis suggests no long-term change in the Lassen fauna. The pre- and post-MSH fauna are different from one another. The post-eruptive fauna was more similar to neighboring regions. Lastly, I tested whether the Oligocene horse Miohippus demonstrated morphological changes across the volcanic Picture Gorge ignimbrite (PGI; 29.069 Ma) in the John Day Formation of Oregon. Variation in upper and lower teeth was first tested to define a single species in the assemblage. Length, width, and wear of teeth were compared across the PGI and there were no significant differences between pre- and post-PGI assemblages. It is clear from my results that larger eruptions tend to have a greater impact on mammalian community recovery than smaller eruptions, but ultimately, mammalian populations are robust and the presence of neighboring communities is important for recolonizing devastated areas.
There are two supplemental files associated with this dissertation, a CSV file of raw data downloaded for Chapter III and an excel file of raw data and coefficient of variation calculations for Chapter IV. This dissertation includes both unpublished and co-authored material.
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Evolutions des stratégies reproductrices au sein du genre Plagiolepis (Hymenoptera: Formicidae)Thurin, Nicolas 18 June 2010 (has links)
Selon la théorie de la sélection de la parentèle, les individus peuvent transmettre des copies de leurs gènes à la génération suivante sans accéder eux-mêmes à la reproduction, mais en aidant des apparentés à augmenter leur propre succès reproductif. Ce concept reste aujourd'hui l'explication la plus probable pour justifier l'évolution de l’altruisme de reproduction dans le règne animal. Les coefficients de corrélations génétiques entre les membres d’un groupe ont une importance capitale, puisqu'ils influencent directement les bénéfices génétiques indirects associés au comportement altruiste. Trois principaux facteurs sont cependant connus pour influencer profondément l'architecture des sociétés: (i) le nombre de reines présentes dans un nid (polygynie), (ii) le nombre d'accouplements des reines (polyandrie), et (iii) l’accouplement entre apparentés (consanguinité).
Nous avons étudié les stratégies de reproduction de cinq espèces de fourmis du genre Plagiolepis. Nous avons d’abord déterminé l’origine endogène des signaux de reconnaissance responsables de la fermeture des sociétés (I). Nous avons également identifié les causes proximales de la forte consanguinité observée chez P. pygmaea : une éviction par les ouvrières des mâles étrangers tentant de s’introduire dans leur société et une préférence des femelles vierges à s’accoupler avec des mâles apparentés (II). A l’aide de marqueurs génétiques, nous avons estimé le degré de polygynie, le taux de polyandrie des reines, et le niveau de consanguinité pour quatre espèces libres : P. pygmaea, P. taurica, P. schmitzii et P. maura (III; IV). Enfin, nous avons testé l’hypothèse d’une réversion du nombre d’accouplements vers la monandrie chez les espèces parasites, au travers de P. xene. (V).
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Reproductive strategies of Weddell seals in McMurdo Sound, Antarctica: relationship among vocalizations, behaviors, and social interactionsRousseau, Ludivine Blandine 17 September 2007 (has links)
Phocid seals (true seals, Order Carnivora, Family Phocidae) use a diverse array
of breeding habitats and strategies, and produce many vocalizations. Therefore, phocids
are well suited as subjects for study of reproductive strategies and the role of
vocalizations in species mating at sea. However, the amount of information is still
limited for aquatically breeding pinnipeds. Using underwater audio and video recordings
of Weddell seals (Leptonychotes weddellii) interacting in McMurdo Sound, I compared
the frequencies of vocalizations and behaviors of males and females during the mating
season. I also investigated differences in these frequencies based on the social context.
Finally, I identified patterns of vocalizations and behaviors to help determine the
behavioral context of calls and used this information as a basis for considering the
degree of ritualization in Weddell seal displays. Mews, growls, knocks, and trills were
found to be almost exclusively male-specific. The territorial male produced chirps more
often when another male was present in its territory; whereas, mews and growls were
more frequent when one or more free-ranging females were present. Several vocal and
behavioral padeparture of the territorial male into or from the breathing hole. In the context of an
evolutionary-based model of communication, these findings suggest that low-frequency
vocalizations and stereotyped displays produced by territorial males may have been
favored by sexual selection: they may provide reliable information to females about the
fitness of the signaler and influence their choice of mate. They may also help in limiting
conflicts between the territorial male and females over access to the breathing hole.
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Effects of population size on the survival and reproduction of a rare carnivorous plant (Drosera rotundifolia)Williams, Jessica, Barker, Daniel, Arceo-Gomez, Gerardo 25 April 2023 (has links)
Approximately 40% of the world’s flowering plants are categorized as rare and of conservation priority. Carnivorous plants in particular are threatened and sensitive to environmental changes and hence can play a key ecological role in ecosystems, however, remain largely understudied. Drosera rotundifolia is classified as rare throughout North America, particularly in Southern Appalachia with only four known populations in Tennessee. Surprisingly, information on this species’ life history, survival and reproductive strategies is lacking, which limits conservation action. This project aims to fill these knowledge gaps by evaluating spatial variation, and in particular the effect of population size, in determining D. rotundifolia’s survival and reproductive strategies. This information is urgently needed to aid in the preservation of this species. I evaluated variation in germination rate, plant size, prey capture rate, flowering phenology, and mating strategies of D. rotundifolia across eight populations in Southern Appalachia and how this may be affected by population size and elevation. We recorded flower production, prey capture per individual, and plant size for all individuals in up to12 plots per population. We evaluated the degree of selfing, outcrossing and autonomous self-pollination for each population under greenhouse conditions.
Approximately 3050 individual plants were observed across all sites with an average size of 26.29 mm ± 9.71mm but with large differences across populations (6.2 mm – 45.84 mm). Average daily prey capture rate was 9.88 insects across all populations but range between 0 insects – 90 insects observed per visit. Elevation seems to have no effect on flowering phenology (time of peak flowering). We found a significant effect of population size on prey capture rate, but it did not affect peak flowering or plant size. Plant size did not affect prey capture rate. Evaluation of reproductive strategies is ongoing. It has been shown that population size plays a key role in mediating reproductive success and genetic diversity within plant populations. Our results however suggest that population size may also play a key role in nutrient acquisition in Carnivorous species, which is key for their survival. Population size and elevation however did not affect flowering phenology or plant size. Larger plants were also no more successful at obtaining prey compared to smaller plants suggesting other important mechanisms are at play. Our results, although preliminary, can have important practical applications for conservation and management efforts in this species.
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Spawning habitat and reproductive strategies of lake trout (Salvelinus namaycush) in a northern boreal lakeCallaghan, David 29 July 2015 (has links)
Lake trout (Salvelinus namaycush) have a broad distribution across Canada’s north, yet most studies that describe reproductive habitat and behaviour have been conducted in the southern extent of their range. Northern regions are experiencing unprecedented changes from climate and industrial development, and thus there is a pressing need to understand the reproductive habitat and behaviour of this species. I examined a dozen sites around Alexie Lake, Northwest Territories, to test if physical habitat and wind exposure were important determinants of spawning site use and embryonic survival. Spawning was found to occur in ~2 m water depth, on 3–15 cm diameter clean substrate on the leading edge of shoals that ended in a rock crib rising abruptly in nearshore regions around the lake. Wind direction was predominantly from the west, although it was highly variable within and among spawning seasons. I found evidence of lake trout spawning at each site examined, which was not limited to shoals facing a predominant wind direction. High variation in embryonic survival (2–83%) from incubation trays was observed among spawning sites, demonstrating a large gradient in habitat quality exists within a given lake. However, modelled wind exposure did not predict embryonic survival, nor did physical characteristics - including shoal depth and slope, as well as cobble size and shape - that may influence interstitial water flow on spawning shoals.
Using an acoustic telemetry monitoring system and novel spatial temporal clustering analysis, I was able to quantify lake trout spawning movements and behaviours over the course of an entire spawning season. Lake trout formed clusters on spawning shoals around the entire nearshore region, as well as around several islands, confirming that suitable spawning habitat is abundant in Alexie Lake. Males arrived on spawning shoals earlier than females and remained longer for a maximum of 25 consecutive days; females occupied spawning shoals for a maximum of 8 consecutive days over the course of the spawning season. Males formed over four times as many spawning clusters and visited twice as many sites than females. Spawning clusters were predominantly formed at night but were also observed during daylight hours, especially during the peak spawning season (September 9–19). I found males had higher activity rates, and spent longer periods on spawning shoals, than females, in spite of similar daily travel distances between sexes. Overall, my findings challenge the conventional role of wind as a predominant predictor of lake trout spawning site quality. I propose that the unpredictable nature of wind and abundance of suitable habitat may favour lake-wide spawning by lake trout as a bet-hedging strategy in northern lakes with limited fetch. / May 2016
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Estratégias de história de vida de peixes neotropicais em diferentes tipos de habitatVogel, Carina January 2012 (has links)
A reprodução representa um dos aspectos mais importantes da biologia de uma espécie e a manutenção de populações viáveis dependem do seu sucesso. O sucesso alcançado pelos peixes em ambientes distintos deve-se à enorme gama de estratégias reprodutivas desenvolvidas pelo grupo. Nos ambientes aquáticos, a expressão da estratégia reprodutiva de uma espécie depende das interações entre fatores intrínsecos (fisiológicos, genéticos), e fatores extrínsecos como a qualidade do habitat, relações interespecíficas e também fatores físicos e regime de hidrológico. A teoria do “habitat template” propõe que a variabilidade temporal e espacial do habitat físico influencia na evolução da combinação do comportamento, fisiologia e características de história de vida das espécies. O habitat é o modelo contra o qual as pressões evolutivas dão forma à estratégia ecológica de uma espécie. Em contrapartida, as características históricas e filogenéticas limitariam algumas características específicas, independente do habitat. A teoria da história de vida lida com restrições entre variáveis demográficas e características associadas com reprodução e a maneira em que essas limitações, ou trade-offs, moldam as estratégias para lidar com diferentes tipos de ambiente. Sendo assim, o investimento em um atributo causaria a redução dos recursos disponíveis para investimento em outro. Trabalhos procurando vinculares os atributos biológicas de peixes as características ambientais do habitat em peixes propõem a existência de um gradiente entre três estratégias de história de vida em peixes de água doce: a oportunista, a de equilíbrio e a periódica. Contudo, é observado que espécies intimamente aparentadas podem exibir estratégias de história de vida diferentes ao passo que espécies distantes filogeneticamente podem convergir independentemente para estratégias semelhantes. Dentro deste contexto, o objetivo dessa dissertação é a abordagem das relações das estratégias de história de vida em relação à diferentes tipos de habitat em algumas espécies de peixes neotropicais. O primeiro capítulo trata das estratégias reprodutivas de espécies de Characidae em escala local com diferentes distribuições dentro de uma sub-bacia. Seria esperado encontrar diferenças nas estratégias reprodutivas das espécies que habitam ambientes que contrastam na magnitude das flutuações, com espécies de estratégia oportunista presentes a montante na bacia e espécies com estratégia periódica a jusante na bacia. O segundo capítulo analisa, em maior escala, as relações entre as estratégias de história de vida de peixes neotropicais da América do Sul e quatro tipos de habitat e a influência da taxonomia baseada em atributos morfológicos e reprodutivos das espécies. Se as características funcionais (um conjunto de atributos) dos organismos são previsíveis a partir características ambientais então seria esperado encontrar uma convergência desses atributos em organismos habitando o mesmo ambiente. Esse tipo de estudo é importante na busca de padrões de distribuição e na compreensão de quais características fisiológicas permitem as espécies permanecerem em um determinado ambiente ou que colonizem um novo. Esse conhecimento também é importante no manejo da pesca e na conservação dos estoques de peixes e espécies ameaçadas. A utilização de atributos funcionais permite a comparação entre áreas distantes geograficamente e entre espécies filogeneticamente distantes e auxilia na busca de padrões evolutivos. Os resultados sugerem a conservação de alguns atributos dentro de grupos taxonômicos menores, sendo possível observar uma maior afinidade de algumas famílias com alguma das estratégias de história de vida. Também é possível perceber que existe um continuum de espécies entre as estratégias, mostrando que alguns atributos são mais versáteis que outros e podem sofrer maior variação entre populações do que entre espécies. Quando se leva em consideração a diversidade de espécies de peixes neotropicais, ainda são poucos os estudos sobre informações básicas da biologia desses organismos, sendo que maior a representatividade dos estudos concentra-se em alguns grupos taxonômicos. As descrições parciais e a caracterização de forma imprecisa das características reprodutivas entre os trabalhos dificultam a sua utilização em futuros estudos. / Reproduction represents one of the most important aspects of species biology, because the maintenance of viable populations depends on its success. The success achieved by fishes in different environments is partially related to the diverse reproductive strategies developed by this group. In aquatic environments, the expression of the reproductive strategy of a species depends upon the interactions between intrinsic factors (physiological) and extrinsic factors such as the habitat quality, interspecific relationships, physical factors and hydrological regime. The habitat template theory proposes that the temporal and spatial variability of the physical habitat influences evolution of the combination of behavior, physiology and life history characteristics of species. The habitat is the model against which the evolutionary pressures shape the ecological strategy of a species. In contrast, historical and phylogenetic traits limit some specific characteristics regardless of habitat type. Life-history theory deals with constraints among demographic variables and traits associated with reproduction and the way these constraints, or trade-offs, (i.e., investments in one trait leaving fewer resources available for investment in another), shape strategies for dealing with different kinds of environments. Studies seeking to link biological traits of fishes to environmental characteristics of habitat suggest the existence of a gradient between three primary strategies in freshwater fishes: opportunistic, equilibrium and periodic. However, it has been observed that closely related species exhibit different life-history strategies, while phylogenetically distant species converge independently to similar strategies. Within this context, the goal of this study is to address the relationship in life-history strategies of Neotropical freshwater fishes against different types of habitat. The first chapter deals with the reproductive strategies of Characidae species with different distributions within the basin at a local scale. The second chapter examines at a larger scale the relationships between life history strategies of neotropical fishes of South America and four habitat types and the influence of taxonomy based on morphological and reproductive traits of the species. If the functional characteristics (a set of traits) of organisms are predictable from environmental characteristics would be expected a convergence of these traits in organisms inhabiting the same environment. The second chapter analyses the relationships among life-history strategies of Neotropical fish at different types of habitat and the taxonomic influence using a trait-based approach across large spatial scale. This type of study is important in the search for patterns in distribution and understanding which characteristics allows species to remain in a particular environment or in the colonization of a new one. This knowledge is also important in fisheries management and stocks conservation and endangered species. The trait-based approach allows comparison among geographically distant areas and phylogenetically distant species and support research in evolutionary patterns. The results suggest conservation of some attributes within lower taxonomic groups and it is possible to observe a greater affinity with some families and life-history strategies. It is possible to notice that there is a continuum of species among the strategies showing that some attributes are more versatile than others and may experience greater variation between populations than between species. Taking into account the diversity of neotropical fish species, there are few studies on basic information about the biology of these organisms and the representativeness of the studies focus on a few taxonomic groups. The partial descriptions and imprecisely characterization of reproductive characteristics among studies difficult their use in future studies.
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Estratégias de história de vida de peixes neotropicais em diferentes tipos de habitatVogel, Carina January 2012 (has links)
A reprodução representa um dos aspectos mais importantes da biologia de uma espécie e a manutenção de populações viáveis dependem do seu sucesso. O sucesso alcançado pelos peixes em ambientes distintos deve-se à enorme gama de estratégias reprodutivas desenvolvidas pelo grupo. Nos ambientes aquáticos, a expressão da estratégia reprodutiva de uma espécie depende das interações entre fatores intrínsecos (fisiológicos, genéticos), e fatores extrínsecos como a qualidade do habitat, relações interespecíficas e também fatores físicos e regime de hidrológico. A teoria do “habitat template” propõe que a variabilidade temporal e espacial do habitat físico influencia na evolução da combinação do comportamento, fisiologia e características de história de vida das espécies. O habitat é o modelo contra o qual as pressões evolutivas dão forma à estratégia ecológica de uma espécie. Em contrapartida, as características históricas e filogenéticas limitariam algumas características específicas, independente do habitat. A teoria da história de vida lida com restrições entre variáveis demográficas e características associadas com reprodução e a maneira em que essas limitações, ou trade-offs, moldam as estratégias para lidar com diferentes tipos de ambiente. Sendo assim, o investimento em um atributo causaria a redução dos recursos disponíveis para investimento em outro. Trabalhos procurando vinculares os atributos biológicas de peixes as características ambientais do habitat em peixes propõem a existência de um gradiente entre três estratégias de história de vida em peixes de água doce: a oportunista, a de equilíbrio e a periódica. Contudo, é observado que espécies intimamente aparentadas podem exibir estratégias de história de vida diferentes ao passo que espécies distantes filogeneticamente podem convergir independentemente para estratégias semelhantes. Dentro deste contexto, o objetivo dessa dissertação é a abordagem das relações das estratégias de história de vida em relação à diferentes tipos de habitat em algumas espécies de peixes neotropicais. O primeiro capítulo trata das estratégias reprodutivas de espécies de Characidae em escala local com diferentes distribuições dentro de uma sub-bacia. Seria esperado encontrar diferenças nas estratégias reprodutivas das espécies que habitam ambientes que contrastam na magnitude das flutuações, com espécies de estratégia oportunista presentes a montante na bacia e espécies com estratégia periódica a jusante na bacia. O segundo capítulo analisa, em maior escala, as relações entre as estratégias de história de vida de peixes neotropicais da América do Sul e quatro tipos de habitat e a influência da taxonomia baseada em atributos morfológicos e reprodutivos das espécies. Se as características funcionais (um conjunto de atributos) dos organismos são previsíveis a partir características ambientais então seria esperado encontrar uma convergência desses atributos em organismos habitando o mesmo ambiente. Esse tipo de estudo é importante na busca de padrões de distribuição e na compreensão de quais características fisiológicas permitem as espécies permanecerem em um determinado ambiente ou que colonizem um novo. Esse conhecimento também é importante no manejo da pesca e na conservação dos estoques de peixes e espécies ameaçadas. A utilização de atributos funcionais permite a comparação entre áreas distantes geograficamente e entre espécies filogeneticamente distantes e auxilia na busca de padrões evolutivos. Os resultados sugerem a conservação de alguns atributos dentro de grupos taxonômicos menores, sendo possível observar uma maior afinidade de algumas famílias com alguma das estratégias de história de vida. Também é possível perceber que existe um continuum de espécies entre as estratégias, mostrando que alguns atributos são mais versáteis que outros e podem sofrer maior variação entre populações do que entre espécies. Quando se leva em consideração a diversidade de espécies de peixes neotropicais, ainda são poucos os estudos sobre informações básicas da biologia desses organismos, sendo que maior a representatividade dos estudos concentra-se em alguns grupos taxonômicos. As descrições parciais e a caracterização de forma imprecisa das características reprodutivas entre os trabalhos dificultam a sua utilização em futuros estudos. / Reproduction represents one of the most important aspects of species biology, because the maintenance of viable populations depends on its success. The success achieved by fishes in different environments is partially related to the diverse reproductive strategies developed by this group. In aquatic environments, the expression of the reproductive strategy of a species depends upon the interactions between intrinsic factors (physiological) and extrinsic factors such as the habitat quality, interspecific relationships, physical factors and hydrological regime. The habitat template theory proposes that the temporal and spatial variability of the physical habitat influences evolution of the combination of behavior, physiology and life history characteristics of species. The habitat is the model against which the evolutionary pressures shape the ecological strategy of a species. In contrast, historical and phylogenetic traits limit some specific characteristics regardless of habitat type. Life-history theory deals with constraints among demographic variables and traits associated with reproduction and the way these constraints, or trade-offs, (i.e., investments in one trait leaving fewer resources available for investment in another), shape strategies for dealing with different kinds of environments. Studies seeking to link biological traits of fishes to environmental characteristics of habitat suggest the existence of a gradient between three primary strategies in freshwater fishes: opportunistic, equilibrium and periodic. However, it has been observed that closely related species exhibit different life-history strategies, while phylogenetically distant species converge independently to similar strategies. Within this context, the goal of this study is to address the relationship in life-history strategies of Neotropical freshwater fishes against different types of habitat. The first chapter deals with the reproductive strategies of Characidae species with different distributions within the basin at a local scale. The second chapter examines at a larger scale the relationships between life history strategies of neotropical fishes of South America and four habitat types and the influence of taxonomy based on morphological and reproductive traits of the species. If the functional characteristics (a set of traits) of organisms are predictable from environmental characteristics would be expected a convergence of these traits in organisms inhabiting the same environment. The second chapter analyses the relationships among life-history strategies of Neotropical fish at different types of habitat and the taxonomic influence using a trait-based approach across large spatial scale. This type of study is important in the search for patterns in distribution and understanding which characteristics allows species to remain in a particular environment or in the colonization of a new one. This knowledge is also important in fisheries management and stocks conservation and endangered species. The trait-based approach allows comparison among geographically distant areas and phylogenetically distant species and support research in evolutionary patterns. The results suggest conservation of some attributes within lower taxonomic groups and it is possible to observe a greater affinity with some families and life-history strategies. It is possible to notice that there is a continuum of species among the strategies showing that some attributes are more versatile than others and may experience greater variation between populations than between species. Taking into account the diversity of neotropical fish species, there are few studies on basic information about the biology of these organisms and the representativeness of the studies focus on a few taxonomic groups. The partial descriptions and imprecisely characterization of reproductive characteristics among studies difficult their use in future studies.
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