Ultrastructure of last larval instar fat body cells of Pachycondyla (= Neoponera) villosa (Formicidae: Ponerinae): cytochemical and chemical analysis

Animal Biology , Vol. 53, No. 1, pp. 1-16 (2003) Ó Koninklijke Brill NV, Leiden, 2003. Also available online - www.brill.nl Ultrastructure of last larval instar fat body cells of Pachycondyla (= Neoponera) villosa (Formicidae: Ponerinae): cytochemical and chemical analysis FERNANDO JOSÉ ZARA 1 ; ¤ , FLÁVIO HENRIQUE CAETANO 2 ; ¤ , AIVLÉ CECILIA G. CABRERA 3 , KLAUS JAFFÉ 3 1 Faculdade de Ciências Matemáticas, da Natureza e Tecnologia da Informaçao – UNIMEP, Campus Taqvaral – Rod. do Açúcar km 156, 13400-911, Piracicaba, São Paulo, Brazil 2 Departamento de Biologia, Instituto de Biociências de Rio Claro – UNESP, P.O. Box 199, 13506-900, Rio Claro (SP), Brazil 3 Laboratorio de Comportamento, Universidad Simón Bolívar (USB), Caracas, Venezuela Abstract —The ultrastructure of the fat body cells (trophocytes) of the last larval instar of Pachy- condyla (D Neoponera) villosa is presented. The cytoplasm is restricted to the cell periphery and to the smaller strips among the vacuoles, protein granules, lipid droplets, and around the nucleus. Cyto- chemically, the presence of basic amino acids in the protein granules and in the nuclei was observed by using the ethanolic phosphotungstic acid technique (EPTA). The lipid droplets stained for unsatu- rated lipids. This result was further conŽ rmed by gas chromatography and mass spectrometry, where the unsaturated fatty acids were identiŽ ed as oleic and linoleic acids together with saturated fatty acids such as palmitic and stearic acid. Carbohydrates (glycogen) were also detected in the fat body. The glycogen is present as ¯ particles distributed among the lipid droplets and sometimes attached to them. Keywords : chromatography; cytochemistry; fat body; larva; Pachycondyla villosa ; ultrastructure. INTRODUCTION The fat body takes on distinct arrangements in different insect orders (Keeley, 1978). In larvae the fat body is disposed in layers, sheets or strands which permit good contact between this tissue and the haemolymph (Chapman, 1975; Goiten, 1989). The cells appear as compact masses, or as loose aggregates, freely dispersed in the haemocoel, covered by a thin basal lamina (Chapman, 1975; Locke, 1984; Dean et ¤ Corresponding authors; e-mail: [email protected] or [email protected]