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Paraffin tubules secreted by the cuticle of an insect Epipyrops anomala (Epipyropidae: Lepidoptera)

1974; Academic Press; Volume: 47; Issue: 1 Linguagem: Inglês

10.1016/s0022-5320(74)90025-2

1878-2345

A.T. Marshall, C. T. LEWIS, Gareth Parry,

Neurobiology and Insect Physiology Research

The dorsal cuticle of late instar larvae of Epipyrops anomala is densely covered with tubules composed of a paraffin hydrocarbon of C40 to C50 chain length, together with a small protein fraction. The tubules are 3.5–6 μm in diameter and 300 times this in length. The tubule wall is pleated with 6–10 sinusoidal ridges, which may be doublets. Orientation of the paraffin molecules is probably perpendicular to the tubule axis. Chemically the tubules are very inert and resemble polyethylene. They are secreted from lanceolate papillae which have a branched system of longitudinal ridges forming a template for the tubule. The ridges contain numerous epicuticular filaments 100 Å in diameter. The paraffin, or its precursors, is synthesized in the large hypodermal cells and passes across the inner dense, and outer spongy, endocuticle and thence via the epicuticular filaments to the exterior.