科研之友
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摘要
On the basis of macroscopic aspects (body and eye colour, lipid droplets), it was possible to sort specimens of Gammarus pulex (Linnaeus, 1758) into five categories that correspond to moult periods and stages (A, B, C, D-1 and D-2) based on integument features (tergite cuticle stiffness, layers and thickness). These stages also correspond to changes in digestive tract histology (gut content, cell ultrastructure, and lipid storage). With reference to the pereion tergite integument, this makes it possible to standardize moulting stage terminology and criteria with those applied to decapods while validating a quick, simple, moult-staging method that avoids injury and informs us about the physiology of the whole organism. The moult cycle was very short (about 12-15 days), with a %26quot;virtual,%26quot; practically non-existent, anecdysis or %26quot;integument resting period%26quot; between post-ecdysis and pre-ecdysis. The pore canals previously known to be %26quot;open to the outside%26quot; appeared closed at early post-ecdysis by a lipid-rich filling material that could be responsible for the cuticular waterproofing barrier allowing mineral deposition. In the digestive tract, the main structural changes were late post-ecdysial loss of midgut cells and digestive gland B-cells (probably by extrusion) when restarting the feeding cycle. Pre-ecdysial increase and post-ecdysial decrease in storage lipids are also obvious. We present a quick moult-staging method to sort a great number of G. pulex for physiological or toxicological assays investigating how animals at specific periods of their moult cycle respond to both natural and anthropogenic environmental changes.
- 出版日期2014-9
