Navegando por Autor "Santos, Leonardo Rodrigues dos"

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O papel das galhas senescentes sobre a estrutura de comunidades de formigas arbóreas em Eremanthus erythropappus (DC.) MacLeish (Asteraceae).
(2015) Santos, Leonardo Rodrigues dos; Carneiro, Marco Antonio Alves; Feitosa, Rodrigo dos Santos Machado; Souza, Roberth Fagundes de; Coelho, Marcel Serra
A grande ocorrência de formigas na copa das árvores pode ser atribuída a diversos fatores como, por exemplo, à presença de estruturas de plantas que fornecem alimento e abrigo às formigas. Estruturas induzidas por outros insetos em plantas hospedeiras, como as galhas senescentes nas candeias, podem servir de abrigo e sítio para nidificação de várias formigas. Este trabalho teve como objetivos principais descrever a comunidade de formigas encontradas na copa de árvores de candeias e de formigas que utilizam as galhas para nidificação, verificar o papel da presença e forma das galhas na composição da comunidade de formigas em candeias e, finalizando, conduzir um experimento para verificar a ocupação de galhas artificiais. As coletas de galhas senescentes e das formigas foram realizadas em regiões da porção sul da Cadeia do Espinhaço: em torno da cidade de Ouro Preto (MG) e no Parque Estadual do Ibitipoca. Ao todo, 3195 galhas foram coletadas e apenas 179 estavam ocupadas por formigas pertencentes a 11 espécies. As galhas ocupadas possuíam maiores volumes e diâmetros do que as galhas não ocupadas. Não houve relação da riqueza de formigas na copa de indivíduos de candeia com a disponibilidade de galhas senescentes para nidificação. Ao todo, 55,5% das galhas artificias foram ocupadas por diferentes espécies de formigas. Porém, não encontramos nenhum efeito da presença de galhas artificiais na riqueza de formigas na copa das árvores de candeia, bem como o aumento da disponibilidade de galhas para nidificação não afetou a comunidade de formigas em copas de candeias. Galhas senescentes são utilizadas por formigas para nidificação e abrigo em árvores da região Neotropical e mesmo não sendo um recurso essencial, permitem a ocorrência de diversas espécies de formigas nas plantas.
Senescent stem-galls in trees of Eremanthus erythropappus as a resource for arboreal ants.
(2014) Almeida, Maria Fernanda Brito de; Santos, Leonardo Rodrigues dos; Carneiro, Marco Antonio Alves
Senescent stem-galls in trees of Eremanthus erythropappus as a resource for arboreal ants. Members of the dipteran families Tephritidae and Cecidomyiidae are inducers of stem-galls in Eremanthus erythropappus (DC.) MacLeish (Asteraceae), a tree common in the state of Minas Gerais, Brazil. When senescent, these galls become available to other organisms, such as ants. The present study describes a community of ants having benefitted from this process of ecosystem-engineering. The colonies in question inhabit the senescent stem-galls of trees of E. erythropappus and were examined in view of answering the following questions: i) whether the presence of stem-galls had any bearing on the richness, composition, or size of the ant colonies therein; and ii) whether the ants displayed any preferences regarding the shape and/or size of the galls. The study was conducted in populations of E. erythropappus trees near the city of Ouro Preto, MG. A total of 227 galls were collected, 14% of which were occupied by ants, belonging to eight different species. Half of the species occupied galls of both morphotypes (fusiform and globular), although we observed a marked preference for larger, globular shapes. Overall, our results showed the galls to be an effective and abundant resource, helping to maintain the diversity of the ants in the canopy. We also observed the occurrence of outstations and polydomic nests, although an in-depth examination of the influence of galls on this type of structuring has not been investigated.
The role of senescent stem-galls over arboreal ant communities structure in Eremanthus erythropappus (DC.) MacLeish (Asteraceae) trees.
(2017) Santos, Leonardo Rodrigues dos; Feitosa, Rodrigo dos Santos Machado; Carneiro, Marco Antonio Alves
The extensive occupation of canopy trees by ants can be attributed to many factors, such as the presence of structures that provide food and shelter. Structures induced by other insects in host plants, like senescent galls, can provide shelter and a nesting place for many species of ants. The main objectives of this work were: (1) to describe the ant communities found in canopies of candeia trees (Eremanthus erythropappus), including the species which use galls as nesting sites; (2) verify the role of galls in determining the structure and composition of the ant communities and (3) to evaluate whether the size and shape of galls are important to the choice of nesting sites by ants. Specifically, the following questions were investigated: 1 – Are larger galls more frequently occupied by ants than smaller galls? 2 – Does gall shape (globular and fusiform) influence occupation? 3 – Which species of ants are present in the canopies of candeias and which are occupying galls? Senescent galls were collected in locations in the southern portion of the Espinhaço Mountain Range, state of Minas Gerais, southeastern Brazil. In total, 3,195 galls were collected and 19 ant species were recorded. Only 176 galls (5.5%) had been occupied by ants, and these were represented by 11 species. The most frequent species found occupying galls were Myrmelachista nodigera, with 48 colonies; Nesomyrmex spininodis, with 37 colonies; and Crematogaster complex crinosa sp. 1, with 29 colonies. The ants occupied galls with greater volume and diameter. Even considering the low occupation frequency, senescent galls in E. erythropappus are used by ants, either as outstations or satellite nests of polydomic colonies, and may be important in determining ant species composition in canopy trees.