Abstract The ants of the genus Atta are considered important pests to agriculture in the Americas, although Atta species are also important contributors to ecosystem functions in the various habitats in which they occur. The aim of this study was to assemble four complete mitochondrial genomes of the genus Atta, construct the phylogenomic tree, and analyze the gene content, order, and organization. The mitogenomes of A. colombica, A. opaciceps, A. texana, and A. sexdens rubropilosa comprise 18,392, 19,257, 19,709, and 19,748 bp, respectively. The four Atta mitogenomes showed the charactistics typical of those of insects, with 13 protein-coding genes, 22 tRNAs, and 2 rRNAs, with genes displayed in the conventional order. Analysis for intergenic spacer regions showed that Atta intergenic spacers are larger than those of the outgroups. Phylogenomic analyses using partial cytochrome oxidase I gene sequences showed similar topologies to previous phylogenetic analyses, with high clade support values. We conclude that Atta mitogenomes are characterized by high conservation in gene order and have giant intergenic spacers in the genus Atta.

RESUMO Este trabalho avaliou a influência ambiental e dos modelos de colmeias (caixa de madeira e pote cerâmico) na atividade de voo da abelha de nidificação natural em solo, Melipona quinquefasciata. O experimento aconteceu na Chapada do Araripe, Ceará, entre julho de 2014 e junho de 2015. O estudo acompanhou colônias em três potes cerâmicos e quatro caixas de madeira. As observações do fluxo de voo das abelhas e do clima foram realizadas durante cinco dias em cada mês, sendo cada colônia monitorada por 5 min, em intervalos de uma hora, das 5h às 17 h. Ao longo do ano, foram ainda coletadas a temperatura e umidade relativa do ar internas das colmeias a cada hora. A temperatura correlacionou-se, positivamente, com entrada e saída de abelhas, enquanto a umidade do ar correlacionou-se negativamente. A intensidade de luz influenciou positivamente os dois fluxos. A entrada de abelhas foi maior no período seco do ano (seco = 2,82±0,22; úmido=1,19±0,22). As médias de temperatura interna dos potes cerâmicos foram maiores (p<0,01) (seco = 23,34±0,48 ºC) (úmido = 23,20±0,25 ºC) do que as das caixas de madeira (seco = 22,08±0,31 ºC e úmido = 21,89±0,29 ºC), bem como a umidade do ar interna (seco = 87,41±0,56% e úmido = 89,35±0,94%) foi maior (p<0,01) (seco = 82,24±0,74% e úmido = 86,47±0,11%). Concluiu-se que a atividade de Melipona quinquefasciata relacionou-se ao clima e à sazonalidade dos recursos. O modelo de colmeia usado influencia a homeostase das colônias e seu forrageio.

ABSTRACT This study evaluated the influence of the environment and of two models of beehive (wooden box and ceramic pot) on the flight activity of the ground-nesting bee, Melipona quinquefasciata. The experiment took place in the Chapada do Araripe, in the State of Ceará, Brazil, between July 2014 and June 2015. The study followed colonies in three ceramic pots and four wooden boxes. Observations of the flight activity of the bees and of the climate were made on five days every month, each colony being monitored for 5 min, at intervals of one hour, from 0500 to 1700. The internal temperature and relative humidity of the hives were also recorded every hour throughout the year. The temperature correlated positively with the bees' entering and leaving the hives, while air humidity correlated negatively. Light intensity positively influenced the two flows. Bee entry was higher during the dry period of the year (dry = 2.82 ± 0.22; wet = 1.19 ± 0.22). The mean internal temperature of the ceramic pots was higher (p<0.01) (dry = 23.34 ± 0.48 ºC) (wet = 23.20 ± 0.25 ºC) than of the wooden boxes (dry = 22.08 ± 0.31 ºC and wet = 21.89 ± 0.29 ºC), as was the internal humidity (dry = 87.41 ± 0.56% and wet = 89.35 ± 0.94%) (p<0.01) (dry = 82.24 ± 0.74% and wet = 86.47 ± 0.11%). It was concluded that the activity of Melipona quinquefasciata was related to the climate and the seasonality of the resources. The model of beehive used influences the homeostasis and foraging of the colonies.

ABSTRACT This study aimed at evaluating whether 10 years of fallow was sufficient to restore a degraded hillslope in the semi-arid Caatinga biome, Brazil. For this purpose, runoff, erosion, loss of nutrients and organic carbon were measured on two comparable hillslopes: one was left fallow and the other degraded caused by overgrazing. Fallow management reduced runoff (36%), soil loss (65%) and organic carbon loss (81%) in comparison with the degraded hillslope. However, the fallow did not significantly reduce nutrient loss. Animal grazing has been shown to influence the nutrient cycle in the soil. The loss of organic carbon shows significant correlation with the loss of other nutrients, and may be used to estimate nutrient loss. Results show that a decade of fallow did not promote significant changes in the loss of nutrients, but was enough to reduce runoff, erosion and loss of organic carbon.

O milho (Zea mays L. ssp. mays) possui diversas espécies relacionadas, chamadas teosinto, que estão distribuídas em várias subespécies de Zea e em diversos outros gêneros. Entre os tipos de milho, o milho doce apresenta um grande potencial para consumo in natura, sendo originário de mutações que aumentam o teor de polissacarídeo no endosperma. No Brasil existem populações de milho doce, comum e teosinto, cujo nível de variabilidade genética não é conhecido. O objetivo desse trabalho foi analisar a variabilidade genética em duas populações de milho doce (BR 400 e BR 402), duas de milho comum (Pampa e Suwan) e uma de teosinto, usando marcadores microssatélites. Os resultados mostraram baixa variabilidade genética intrapopulacional nas populações de milho, e relativamente alta para a população de teosinto, sugindo que essas populações de milho podem apresentar limitações em futuros ciclos de melhoramento genético.

The maize (Zea mays L. ssp. mays) has several related species, called teosinte, which are distributed in various subspecies of Zea and other genera. Among the different types of corn, sweet corn shows a great potential for human food. This type was originated from mutations, which increased the amount of polysaccharide in the endosperm. In Brazil there are populations of sweet corn, common maize and teosinte, however, little is known about their genetic variability. Hence, the aim of this present paper was to analyze the genetic variability in two populations of sweet corn (BR 400 and BR 402), two common corn (Pampa and Suwan) and teosinte, using microsatellite markers. The results showed a low intra-population genetic variability in populations of maize, and high variability for the population of teosinte, suggesting that the maize populations may have limitations in future cycles of breeding.