Termite assemblages (Blattaria, Isoptera) in two montane forest (Brejo de Altitude) areas in northeastern Brazil / Taxocenoses de térmitas (Blattaria, Isoptera) em duas florestas de altitude (Brejo de Altitude) no nordeste do Brasil

Abstract: Wet enclaves of montane forests in Caatinga domain, locally known as "Brejos de Altitude", are associated with plateau at altitudes greater than 500 m a.s.l. and to orographic rainfall. Termite assemblage structures were studied in two areas of montane forest (Brejo de Altitude) located in the municipalities of Bezerros and São Vicente Ferrer, Pernambuco State, Brazil. Sampling was performed in 65 x 2 m transects, totaling 300 m2/per area; the densities of nests in each area were estimated using six 1300 m2 plots. A total of 35 morphospecies were recorded that belonged to 21 genera and three families, with 133 encounters. The soil-feeders feeding group predominated, followed by wood-feeders species. A total of five species constructing conspicuous nest were recorded in the two areas. The mean density of active conspicuous nests was 2.6 ± 6.3 nests/ha (mean ± sd) in Bezerros, and 21.8 ± 21.4 nests/ha in São Vicente Ferrer. Termite richness in the study areas were within the amplitude ranges recorded in other montane forests. Thus, the results presented here, combined with data from literature, reinforce need additional studies of the termite fauna in montane forest areas, once the "Brejos" are currently under high ecological pressure and their preservation is urgent.

Resumo: Enclaves de floresta úmida de altitude nos domínios da Caatinga, localmente conhecidos como "Brejos de Altitude", estão associados a áreas com mais de 500 m de altitude e às chuvas orográficas. O presente estudo teve como objetivo caracterizar a estrutura da taxocenose de térmitas em duas áreas de Brejo de Altitude localizadas nos municípios de Bezerros e São Vicente Ferrer, Estado do Pernambuco, Brasil. A amostragem foi realizada através de transectos de 65 m x 2 m, totalizando 300 m2/por área. Em cada área, a densidade de ninhos foi estimada em seis parcelas de 1300m2. Trinta e cinco morfoespécies foram registradas nas duas áreas, pertencentes a 21 gêneros e três famílias, com 133 encontros. O grupo alimentar dos humívoros foi predominante, seguido pelos xilófagos. Um total de cinco espécies construtoras de ninhos conspícuos foram registradas nas duas áreas. A densidade média de ninhos conspícuos ativos foi de 2,6 ± 6,3 ninhos/ha (média ± dp) em Bezerros, e de 21,8 ± 21,4 ninhos/ha em São Vicente Ferrer. A riqueza de térmitas das áreas estudadas ficou dentro da amplitude já registrada para áreas de Brejo de Altitude. Assim, os resultados aqui apresentados, combinados com dados da literatura, reforçam a necessidade de estudos adicionais da fauna de térmitas em áreas de floresta montana, uma vez que os Brejos estão atualmente sob alta pressão ecológica e sua preservação é urgente.

High termite richness in an urban fragment of Atlantic Forest in northeastern Brazil / Alta riqueza de térmitas em um fragmento urbano de Floresta Atlântica do Nordeste Brasileiro

Termites are very abundant in tropical ecosystems and have active roles in nutrient cycling and soil formation, but few studies of their assemblages have been undertaken in the Brazilian Atlantic Forest. The present study analyzed the composition of termite assemblages in a fragment of Atlantic Forest embedded within an urban matrix in northeastern Brazil. Five standardized sampling protocols of termites were applied, with a total sampling effort of 1500m2. We encountered 45 species of termites belonging to 25 genera and three families. The soil-feeders group demonstrated the greatest species richness, while wood-feeders species were the most abundant. The species richness of termite in the study area was the greatest yet recorded for an Atlantic forest site in Brazil, indicating the importance of urban fragments for conserving tropical biodiversity.

Térmitas são muito abundantes em ecossistemas tropicais e possuem papéis ativos na ciclagem de nutrientes e formação do solo, mas poucos estudos sobre suas taxocenoses têm sido realizados na Floresta Atlântica. O presente estudo analisou a composição das taxocenoses de térmitas em um fragmento de Floresta Atlântica inserida dentro de uma matriz urbana no Nordeste do Brasil. Cinco protocolos padronizados de amostragem de térmitas foram aplicados, o que totalizou um esforço amostral de 1500m2. Foram encontradas 45 espécies de térmitas pertencentes a 25 gêneros e três famílias. O grupo alimentar dos humívoros demonstrou a maior riqueza de espécies, enquanto as espécies xilófagas foram as mais abundantes. A riqueza de espécies de térmitas na área de estudo foi a maior registrada até o momento para uma área de Floresta Atlântica no Brasil, indicando a importância dos fragmentos urbanos para a conservação da biodiversidade tropical.

Caste differentiation pathways in the neotropical termite Armitermes holmgreni (Isoptera: Termitidae).

The present study investigated the caste differentiation system of Armitermes holmgreni in natural colonies from the Atlantic Forest in northeastern Brazil. Thirteen measurements were made of the termites encountered in three colonies. The morphometric differences among the instars were analyzed using principal component analysis (PCA). The differentiation patterns of the nymphal lineages of A. holmgreni agreed with earlier descriptions of species of the Termitidae family, with one larval instar followed by five nymphal instars and alates. Nymphoid neotenics became differentiated starting at the fourth or fifth nymphal instar. Two larval instars were observed in the apterous lineage before the appearance of workers, presoldiers, and soldiers. Both workers and soldiers had only one instar each. The A. holmgreni workers consisted of male and female individuals, without sexual dimorphism, a situation that had not been previously recognized among the Syntermitinae. The A. holmgreni soldiers consisted only of female individuals, a pattern observed in most species of Termitinae and Macrotermitinae. The differentiation of nymphoid neotenics starting at the fourth or fifth nymphal instar has also been reported for Armitermes euamignathus. The general patterns of differentiation of A. holmgreni were similar to those previously observed in other species of Syntermitinae.

Wood litter consumption by three species of Nasutitermes termites in an area of the Atlantic Coastal Forest in northeastern Brazil.

Termites constitute a considerable fraction of the animal biomass in tropical forest, but little quantitative data are available that indicates their importance in the processes of wood decomposition. This study evaluated the participation of Nasutitermes corniger (Motschulsky) (Isoptera: Termitidae), N. ephratae (Holmgren), and N. macrocephalus (Silvestri) in the consumption of the wood litter in a remnant area of Atlantic Coastal Forest in northeastern Brazil. The populations of this species were quantified in nests and in decomposing tree trunks, while the rate of wood consumption was determined in the laboratory using wood test-blocks of Clitoria fairchildiana Howard (Fabales: Fabaceae), Cecropia sp. (Urticales: Cecropiaceae), and Protium heptaphyllum (Aublet) Marchand (Sapindales: Burseraceae). The abundance of the three species of termites varied from 40.8 to 462.2 individuals/m(2). The average dry wood consumption for the three species was 9.4 mg/g of termites (fresh weight)/day, with N. macrocephalus demonstrating the greatest consumption (12.1 mg/g of termite (fresh weight)/day). Wood consumption by the three species of Nasutitermes was estimated to be 66.9 kg of dry wood /ha/year, corresponding to approximately 2.9% of the annual production of wood-litter in the study area. This consumption, together with that of the other 18 exclusively wood-feeders termite species known to occur in the area, indicates the important participation of termites in removing wood-litter within the Atlantic Coastal Forest domain.