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Postingestive chemosensation and feeding by leeches
1Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595, USA.
Physiology & Behavior
|December 22, 1999
Summary
Leech feeding behavior relies on more than just initial taste cues. Secondary internal sensors appear crucial for continuing ingestion and rejecting bad-tasting food.
Area of Science:
- Zoology
- Animal Behavior
- Sensory Physiology
Background:
- Biting leeches use dorsal lip chemosensors for feeding.
- The role of continuous peripheral chemosensation in maintaining leech ingestion is unclear.
Purpose of the Study:
- To investigate if continuous peripheral chemosensation is required for leech ingestion.
- To identify potential postingestive mechanisms regulating leech feeding.
Main Methods:
- Leeches (Hirudo medicinalis, Macrobdella decora) fed on artificial solutions.
- Solutions were altered mid-feeding to test responses to different chemicals and concentrations.
- Peripheral superfusion and internal gut injections were used to isolate sensory inputs.
Main Results:
- Leeches continued ingesting altered solutions if palatable substitutes were used.
- Leeches rejected unpalatable solutions and detached from feeding apparatus.
- Bitter compounds added mid-feeding stopped ingestion, with effect dependent on concentration and internal administration, not peripheral superfusion.
Conclusions:
- Leech ingestion initiation depends on peripheral chemosensors.
- Maintaining ingestion and rejecting noxious substances likely involves postingestive, internal chemosensory mechanisms downstream of the dorsal lip.