Ultrastructure of spherites in the midgut diverticula and Malpighian tubules of the harvestman Amilenus aurantiacus during the winter diapause

Saska Lipovsek*, Tone Novak, Barbara Daris, Ferdinand Hofer, Gerd Leitinger, Ilse Letofsky-Papst

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Amilenus aurantiacus overwinter in diapause, a natural starvation period, in hypogean habitats. The structure of spherites in the midgut diverticula (MD) and Malpighian tubules (MT) has been studied comparatively by light microscopy and TEM to detect eventual differences in mineral consumption in the beginning and at the end of the starvation period in these organs (MD and MT) associated with digestive processes. The chemical composition of spherites was examined by combining energy-dispersive X-ray spectroscopy (EDXS), electron energy-loss spectroscopy (EELS) and energy-filtered TEM (EFTEM). The structure of the spherites changed during overwintering in both organs. At the beginning of overwintering, the spherites were composed of densely packed concentric layers of electron-dense and electron-lucent material. In the middle and at the end of overwintering, the electron-lucent layers between the layers of material indicated the loss of some material. The chemical composition of the spherites changed only in the MD; at the beginning of overwintering, these contained Si, O, C and Fe, while later there was no more Fe. In contrast, spherites in the MT were composed of Si, O, C and Ca throughout overwintering. A less intensive exploitation of the MD spherites was probably due to complete cessation of digestive and other cell activity in this organ during the winter diapause; activity of the MT slowed, but continued removing the cell metabolites.

Original languageEnglish
Pages (from-to)107-118
Number of pages12
JournalHistochemistry and Cell Biology
Issue number1
Early online date2021
Publication statusPublished - Jan 2022


  • Analytical electron microscopy
  • Arachnids
  • Malpighian tubules
  • Midgut diverticula
  • Opiliones
  • Spherite structure

ASJC Scopus subject areas

  • Materials Science(all)
  • Medical Laboratory Technology
  • Molecular Biology
  • Cell Biology
  • Histology

Fields of Expertise

  • Advanced Materials Science

Treatment code (Nähere Zuordnung)

  • Basic - Fundamental (Grundlagenforschung)

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