Lepidópteros associados a plantios de eucalipto na região amazônica do Brasil:diversidade alfa e beta e impacto de fatores ambientais / Lepidoptera associated to eucalypt plantations in the Amazonian region of Brazil: alfa and beta diversity and impact of environmental factors

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The data of this research were obtained from a monitoring program of Lepidoptera associated with Eucalyptus urophylla plantations in four areas of the Municipalities of Almerim and Laranjal do Jari, States of Pará and Amapá, respectively. The insects were collected every two weeks from September 1992 to August 1997 with light traps from 18:00 h P.M. to 06:00 h A.M. of the following day. The Lepidoptera species collected were divided in primary and secondary pests besides those without defined importance to the eucalypt culture. A total of 324, 347, 330 and 304 species and 31.857 individuals were collected, being 13.865 of the primary pests, 1.590 of the secondary ones and 16.402 of those species without defined importance for the eucalypt culture during five years in Ponte Maria, Pacanari, Caracuru and Felipe, respectively. The primary pests were represented by four families and 10 species: Arctiidae (Eupseudosoma aberrans and Eupseudosoma involuta), Geometridae (Glena sp., Oxydia vesulia, Stenalcidia grosica and Thyrinteina arnobia), Lymantriidae (Sarsina violascens) and Saturniidae (Misogada blerula, Nystalea nyseus and Psorocampa denticulata) and the secondary ones by six families and nine species: Amatidae (Cosmosoma auge), Arctiidae (Idalus admirabilis), Eucleidae (Phobethon hypparchia), Megalopygidae (Megalopyge albicollis), Mimallonidae (Mimallo amilia) and Saturniidae (Automeris illustris, Eacles ducalis, Eacles magnifica imperialis and Dirphia rosacordis). The average values for species richness calculated with the Jackknife procedure showed no differences among primary and secondary pests between areas of collection wit 95% probability. The curves of species accumulation of the primary and secondary pests showed a stability from a certain time for each group and area. This indicated that the methodology used to monitor these species was adequate because the population dynamics, mainly of the primary and secondary pests was similar between the areas sampled. The sampling effort to evaluate the species richness and to monitor the population fluctuation can be reduced by optimizing operational costs to monitor these insects. The beta diversity for the primary pests was zero and it was low and similar for the secondary pests in Ponte Maria, Pacanari and Caracuru but differing between these areas and Felipe. The species without defined importance for the eucalypt culture presented larger beta diversity among places, possibly, due to the greatest differences in the species richness for this group while Felipe presented the largest dissimilarity. T. arnobia and S. grosica were the most important species in the four areas, with larger frequency and abundance, mainly, in the last two years being, also, the most frequent ones with 78.21% of individuals collected for the primary pests. However, T. arnobia, considered the most important Lepidoptera pests of the Brazilian eucalypt culture, was, in most years, accidental or accessory while S. grosica was constant in all areas. T. arnobia presented a negative correlation with the rainfall in Ponte Maria and S. grosica a positive correlation in the other places, especially, with the rainfall accumulated in periods previous to the collection. The secondary pests presented, individually, low correlat ion with the climatic factors. Though, the species of this group had a positive correlation with rainfall in all situations analyzed. The interaction between the age of the plant and the abundance of insects showed that the secondary pests were more abundant when the plants were younger. The distance between the eucalyptus plantation and the areas of native forest influenced the abundance of Lepidoptera. Primary and secondary pests had lower number of individuals in Felipe and Ponte Maria that were, respectively, 800 and 2600 m distant from the native forest. T. arnobia and S. grosica were responsible, respectively, for 17.3 and 6.67% and together by 14.8% of all individuals of the primary pests collected in these areas. There were, practically, no qualitative or quantitative variations in the Lepidoptera fauna collected in the four areas although they were distant about 50 kilometers from each other. This is, possibly, due to the similarity of soil, climatic factors, vegetation and altitude.

ASSUNTO(S)

diversidade alfa diversidade beta lepidópteros geographic distribution distribuição geográfica beta diversity eucalypt eucalipto armadilhas para insetos population fluctuation Índices faunísticos insect trap lepidoptera flutuação populacional fitossanidade alfa diversity

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