Journal of Biosciences

, Volume 28, Issue 6, pp 753–764 | Cite as

Silk formation mechanisms in the larval salivary glands ofApis mellifera (Hymenoptera: Apidae)

  • Elaine C. M. Silva-Zacarin
  • Regina L. M. Silva De Moraes
  • S. R. Taboga


The mechanism of silk formation inApis mellifera salivary glands, during the 5th instar, was studied. Larval salivary glands were dissected and prepared for light and polarized light microscopy, as well as for scanning and transmission electron microscopy. The results showed that silk formation starts at the middle of the 5th instar and finishes at the end of the same instar. This process begins in the distal secretory portion of the gland, going towards the proximal secretory portion; and from the periphery to the center of the gland lumen. The silk proteins are released from the secretory cells as a homogeneous substance that polymerizes in the lumen to form compact birefringent tactoids. Secondly, the water absorption from the lumen secretion, carried out by secretory and duct cells, promotes aggregation of the tactoids that form a spiral-shape filament with a zigzag pattern. This pattern is also the results of the silk compression in the gland lumen and represents a high concentration of macromolecularly well-oriented silk proteins.


Bee electron microscopy larval salivary gland light microscopy polarized light microscopy silk gland 

Abbreviations used


Mass of fibroin fibers


scanning electron microscopy


transmission electron microscopy


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Copyright information

© Indian Academy of Sciences 2003

Authors and Affiliations

  • Elaine C. M. Silva-Zacarin
    • 1
  • Regina L. M. Silva De Moraes
    • 1
  • S. R. Taboga
    • 2
  1. 1.Depto. Biologia, IBUniversidade Estadual Paulista (UNESP)Rio Claro (SP)Brasil
  2. 2.Depto. BiologiaIBILCE, São José do Rio Preto (SP)Brasil

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