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Elaborate ultrastructure of the Hirudo (Annelida: Hirudinae) cocoon surface
Author(s) -
Saidel William M.,
Saglam Naim,
Salasde la Cruz David,
Saunders Ralph,
Shain Daniel H.
Publication year - 2018
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.20787
Subject(s) - biology , ultrastructure , desiccation , hirudo medicinalis , biophysics , botany , leech , world wide web , computer science
Species of medicinal leeches ( Hirudo medicinalis, H. verbana , and H. sulukii) secrete hard‐shelled cocoons. When initially deposited, a cocoon is surrounded by a foam. Over a short time, the foam is transformed into a three‐dimensional structure. We show here that this peripheral structure likely forms by the solidification and dehydration of a moderately viscous, proteinaceous substance that surrounds bubbles of various sizes. The resulting matrix‐like structure comprises a network of curved branches juxtaposed at ∼120° and taper in width as a function of distance from the outer cocoon wall. The material is proteinaceous, and traps environmental material in its composition, especially silicon. The geometry of compartments and abundance of silicon on branch surfaces suggest a mechanism for trapping water to prevent desiccation in a terrestrial environment.