The excretion in the ileum of australisants (Formicidae: )

Caetano, F.H.‘; Zara, F.J.‘; Tomotake, M.E.M.’ and Camargo-Mathias, M.I.‘.

-l Departamento de Biologia- UNESP - Campus de Rio Claro - SP - CEP 13506-900 2 Fat. Fil. Ci$ncias e Letras de Guarapuava - Guarapuava - PR - Brazil

The excretory system of is made up by the Malpighian tubules, rectal Papillae and urate cells. Some authors have postulated the participation of posterior intestine in the excretory process, but they have not specified which of the posterior intestine regions would be involved in the excretory process of calcium and urate. (I) lt has been demonstrated in the participation of the stomach in the calcium excretion process, besides of the Malpighian tubules (2), using histochemical techniques. Generally, the Malpighian tubules are rich in concentric structures (3, 4) which, for some authors, are excretion forms of calcium and urate salts (5). For the purpose of this paper, ileum of Dinoponera ausfralis were used, which were prepared for ZIO techniques (Zinc- iodide) according to Reineck & Walther, 1978. The material was embedded in Epon- Araldite (l-l), the sections obtained, using diamond knives, were stained with uranyl acetate and lead citrate and examined using TEM Philips CM100 in the Electron Microscopy Laboratory of UNESP, Rio Claro. The ileum of D. ausfralis is marked by a strong circular musculature and presents the epithelium cells with long microvilli. The cytoplasm presents concentric figures (Figs ? ,2 and 3), similar to that observed in the stomach and Malpighian tubules of other ants. The center and borders of these figures have been heavily marked by the ZlO, revealling a Proteic composition. Most of the material, found between the border and the center, has shown low electrondensity. These figures, in opposition to that found in the stomach and the Maipighian tubules, are not perfectly round (Fig. I, 2 and 3). The data gathered make US to believe that the ileum takes part in the excretion of metabolic residues, as an auxiliary part of the excretory system.

References

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Supported by FAPESP and CNPq b+& ;’ F 6.‘. .; “...” ‘i

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FIG 1 - General aspect of concentric figures present in ileum cytoplasmic ceils (arrow), n = nucleus, m = mitochondria. FIG 2 and 3 - Details of concentric figures (arrow) showing heavily 210 positive reaction in center and borders of these structures.