The evolutionary ecology of interactive synchronism: The illusion of the optimal phenotype

In this article, we discuss some ecological-evolutionary strategies that allow synchronization of organisms, resources, and conditions. Survival and reproduction require synchronization of life cycles of organisms with favourable environmental and ecological features and conditions. This interactive synchronization can occur directly, through pairwise or diffuse co-evolution, or indirectly, for example, as a result of actions of ecosystem engineers and facilitator species. Observations of specific interactions, especially those which have coevolved, may give the false impression that evolution results in optimal genotypes or phenotypes. However, some phenotypes may arise under evolutionary constraints, such as simultaneous evolution of multiple traits, lack of a chain of fit transitional forms leading to an optimal phenotype, or by limits inherent in the process of selection, set by the number of selective deaths and by interference between linked variants. Although there are no optimal phenotypes, optimization models applied to particular species may be useful for a better understanding of the nature of adaptations. The evolution of adaptive strategies results in variable life histories. These strategies can minimize adverse impacts on the fitness of extreme or severe environmental conditions on survival and reproduction, and may include reproductive strategies such as semelparity and iteroparity, or morphological, physiological, or behavioural traits such as diapause, seasonal polyphenism, migration, or bet-hedging. However, natural selection cannot indefinitely maintain intra-population variation, and lack of variation can ultimately extinguish populations

Sistemas de Herança: As Múltiplas Dimensões da Evolução

Evolutionary theory unifies Biological Sciences and hasalso been applied in several areas of Exact and Human Sciences.Originally proposed by Darwin as "descent with modification,"itpresupposes the existence of inheritable variation that is transmittedunequally to the next generation. In the twentieth century, however,this theory took on a strongly genetic bias: biological evolution cameto be understood as a process that modifies the composition of a population’sgenetic pool throughout successive generations. Here arisesthe genetic determinism, which inspired ideas about sociobiology andselfish genes, among others. In the last decades, several evolutionistshave emphasized that, in addition to the genetic dimension, thereare other systems of inheritance that can also promote evolutionarychange. Here I present the biological and cultural heritage systemscurrently recognized by evolutionary biologists, which have beenexplored and disseminated by Paulo Abrantes as essential sources ofvariation associated with human evolution.A teoria evolutiva unifica as Ciências Biológicas e tem sido também aplicada em diversos setores das Ciências Exatas e Humanas. Originalmente proposta por Darwin como “descendência com modificação”, ela pressupõe a existência de variação herdável que é transmitida de forma desigual para a geração seguinte. No século XX, entretanto, essa teoria adquiriu um viés fortemente genético: a evolução biológica passou a ser compreendida como um processo que modifica a composição dos genes de uma população no decorrer de gerações. Nasce aqui o determinismo genético, o qual inspirou ideias sobre sociobiologia e genes egoístas, dentre outras.  Nas últimas décadas, diversos evolucionistas têm enfatizado que, além da dimensão genética, há outros sistemas de herança que também podem promover a descendência com modificação. Neste artigo serão apresentados os sistemas de herança biológica e cultural, atualmente reconhecidos pelos biólogos evolucionistas, e que têm sido explorados e divulgados pelo Prof. Paulo Abrantes como importantes fontes de variação associadas à evolução humana

Measuring the variability of the drosophilid assemblages associated with forests of the Brazilian savanna across temporal and spatial scales

AbstractThe relevant scales over which specific communities vary must be identified to address fundamental ecological questions and to advance the conservation of biological diversity. In this study, the variation among drosophilid assemblages associated with forests was quantified at a large temporal–spatial scale. Our results are based on data collected in four conservation units (CUs) in the Brazilian savanna across four seasons and two years. The primary component of variation occurred at the temporal scale: it was three times greater than that of the spatial scale. Significant variability was also found in the interaction between seasons and CUs. Measuring the temporal and spatial variability of drosophilid diversity in forests contributed to the improvement of the methodological framework supporting such assemblages as bioindicators and provided important insights into the mechanisms behind the dynamic patterns in time and space that ultimately can improve our understanding of Cerrado biodiversity

Temporal dynamics and resource availability for drosophilid fruit flies (Insecta, Diptera) in a gallery forest in the Brazilian Savanna

Seasonality can cause severe bottlenecks in natural populations, even leading to local extinction. Large variation in resource availability may explain the bottlenecks, but the role of these variations is still poorly understood. The goal of this study was to analyze if temporal variations in the guild of drosophilids breeding in fruits of Mauritia flexuosa (Arecaceae) can be explained by the shortage of this resource during the dry season. Fruits of M. flexuosa were collected over one year in a gallery forest located in the Central Brazilian Savanna. The drosophilid assemblage varied over time, with a lower density of species and of individuals in the dry season, when the percentage of colonized fruits was also smaller. These findings suggest that although the fruits were available during the dry season, they were underused. This way, the resource availability does not seem to regulate the community in the dry season

Temporal Dynamics and Resource Availability for Drosophilid Fruit Flies (Insecta, Diptera) in a Gallery Forest in the Brazilian Savanna

Seasonality can cause severe bottlenecks in natural populations, even leading to local extinction. Large variation in resource availability may explain the bottlenecks, but the role of these variations is still poorly understood. The goal of this study was to analyze if temporal variations in the guild of drosophilids breeding in fruits of Mauritia flexuosa (Arecaceae) can be explained by the shortage of this resource during the dry season. Fruits of M. flexuosa were collected over one year in a gallery forest located in the Central Brazilian Savanna. The drosophilid assemblage varied over time, with a lower density of species and of individuals in the dry season, when the percentage of colonized fruits was also smaller. These findings suggest that although the fruits were available during the dry season, they were underused. This way, the resource availability does not seem to regulate the community in the dry season

Wing symmetry in wild drosophilids (Insecta, Diptera) is not affected by season in the Brazilian Cerrado

The development of an organism is a controlled process, which can be disrupted by genetic or environmental stress. Although fluctuating asymmetry is widely used as an indicator of developmental instability, its effectiveness has been questioned due to the contradictory results produced by this technique which, at least in part, probably reflects methodological inappropriateness. Here, we investigated if wing asymmetry of drosophilids increases when they develop during the dry season in the Brazilian savanna, considered a stressful season for these insects. Using protocols designed to avoid methodological problems, we analysed the wings of Zaprionus indianus and three species of the genus Drosophila (D. mercatorum, D. simulans, and D. sturtevanti). There was no significative difference in wing asymmetry in any of the four species between the dry and rainy seasons. The similar wing asymmetry levels between seasons may mean that during the dry season drosophilids are submitted to strong natural selection and the asymmetric individuals have less chance of surviving. Alternatively, environmental drought may not affect the wing symmetry. Although our study added more data to the relationship between asymmetry and stress, this discussion seems to be far from being solved

Differential attraction of drosophilids to banana baits inoculated with Saccharomyces cerevisiae and Hanseniaspora uvarum within a Neotropical forest remnant

Background. Yeasts are a necessary requisite in the diet of most Drosophila species that, in turn, may vector their dispersal in natural environments. Differential attractiveness experiments and the isolation of yeasts consumed by Drosophila may be informative for characterizing this association. Hanseniaspora uvarum is among the most common yeast species isolated from Drosophila crops, with high attractiveness to drosophilids. Saccharomyces cerevisiae has been widely used to collect flies, and it allows broad sampling of almost all local Drosophila species. Pronounced differences in the field concerning Drosophila attractivity to baits seeded with these yeast species have been previously reported. However, few explicit generalizations have been set. Since late fifties, no field experiments of Drosophila attractivity were carried out in the Neotropical region, which is facing shifts in abiotic and biotic factors. Our objective is to characterize preference behavior that mediates the interaction in the wild among Neotropical Drosophila species and yeasts associated with them. We want to set a broad generalization about drosophilids attracted to these yeasts. Here we present the results of a differential attractiveness experiment we carried out in a natural Atlantic Rainforest fragment to assess the preferences of Drosophila species groups to baits inoculated with H. uvarum and S. cerevisiae. Methods. Both yeast species were cultured in GYMP broth and separately poured in autoclaved mashed banana that was left fermenting. In the field, we collected drosophilids over five arrays of three different baits: non-inoculated autoclaved banana and banana inoculated with each yeast. In the laboratory the drosophilids were sorted to five sets according to their external morphology and/or genitalia: tripunctata; guarani; willistoni; exotic; and the remaining flies pooled in others. Results and Conclusions. Uninoculated banana baits attracted virtually no flies. We found significant departures from random distribution over the other two baits (1:1 proportion) for all sets, except the pooled others. Flies of the sets willistoni and exotic preferred H. uvarum over S. cerevisiae, while the remaining sets were more attracted to S. cerevisiae. Previously, various authors reported similar patterns in attraction experiments with S. cerevisiae and H. uvarum. It is also noteworthy that both yeast species have been isolated from natural substrates and crops of Drosophila species. Taken together, these results suggest that the preferences among Drosophila species groups may be reflecting deep and stable relations with yeast species in natural environments. They can be summarized as: forest dwelling species from subgenus Drosophila (such as tripunctata and guarani groups) are attracted to banana baits seeded with S. cerevisiae; while exotic (as D. melanogaster) and subgenus Sophophora species are preferentially attracted to baits seeded with H. uvarum

Diagnóstico e controle de espécies exóticas invasoras em áreas protegidas

Trazemos, neste sexto número de Biodiversidade Brasileira, 17 artigos que tratam de espécies exóticas invasoras em áreas protegidas. O objetivo desta compilação é consolidar informações, registrar experiências de manejo e fomentar o debate e a tomada de decisão visando conservar a biodiversidade nessas áreas. Manejar espécies exóticas é proteger os ecossistemas nativos, com suas funções e diversidade, o que é essencial no caso de unidades de conservação e outras áreas protegidas. Entretanto, em termos geopolíticos e de ações estratégicas em nível nacional, o manejo proporciona também a proteção de lavouras e da saúde humana, uma vez que mesmo os sistemas antropizados persistem como sistemas ecológicos e estão sujeitos a processos análogos aos que ocorrem nos locais mais preservados. Em diferentes graus, todos estes sistemas estão fortemente afetados pela degradação de processos ecológicos e pela homogeneização biológica. A dinâmica de chegada de espécies exóticas ocasionada pelo intenso transporte de bens e pessoas oriundos de todos os cantos do planeta, aumenta a chance de introdução de espécies invasoras. Associado a isso está a alteração acelerada dos ecossistemas, o que facilita ainda mais o estabelecimento de invasoras. Além da constante introdução e estabelecimento de novas invasoras, há as invasoras já estabelecidas e amplamente disseminadas que são de difícil controle como javalis, búfalos, capins africanos e pinheiros, e centenas de outras com impactos mais ou menos perceptíveis ou percebidos. Se há alguns anos havia a expectativa do controle efetivo e erradicação de espécies exóticas em áreas protegidas, atualmente as palavras mais frequentes são prevenção, convivência e manejo adaptativo. O editorial traz breve apresentação do conteúdo do número temático, com que esperamos contribuir significativamente com o reposicionamento das exóticas invasoras no leque de desafios centrais de manejo das unidades de conservação