Comb organ
The comb organ , also called pecten , in the plural pectines , is a sense organ that is only found in scorpions .
For scorpions, tactile stimuli are very important, which are caused by vibrations of the ground (movements of other animals, for example), air currents and contact (active or passive). In addition to numerous other sensory organs for the absorption of stimuli, the pectines are also involved in the absorption of stimuli. They are found on the ventral side (ventral) on the second mesosomal segment of the opisthosoma . The paired combs were probably created from extremities and are held across the ground while walking. The pairing also makes it possible to identify a direction for incoming stimuli. According to Polis (1990), females have narrower pectines with shorter and straighter comb teeth. For a long time their function was unknown or stimulated the most varied of interpretations (should serve the sense of smell , breathing , pairing or balance ).
The olfactory function of the comb organ can now be considered secure: According to Wolf (2008), there are several chemosensitive bristles ( pegs ) on each individual comb tooth , each of which is filled with lymph and connected to the outside world via a terminal slot. Olfactory (olfactory) sensory cells embedded in the lymph conduct their stimuli via the comb nerve into the subterranean ganglion . As a strong argument in favor of an olfactory function of the comb organ, Wolf (2008) points out that the part of the sub-canal ganglion associated with the comb nerve has a glomerular (nerve-ball-like) organization, as is also the case for the olfactory centers of insects , crustaceans and z. B. Centipede is characteristic.
The numerous bristles of the cuticle , however, serve to absorb tactile stimuli. According to Schneider (2002), irritation of the bristles also affects the posture of the body when running. Scorpios usually keep their body low above the ground and only when there is an obstacle will it be raised.
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- Gary A. Polis: The biology of scorpions . University Press, Stanford, Calif. 1990, ISBN 0-8047-1249-2 .
- Wolfgang Schneider: Investigations into the influence of tactile sensors on the running behavior of scorpions . Diploma thesis, Rheinische Friedrich-Wilhelms-Universität, Bonn 2002 Digitized version (PDF) ( Memento from June 10, 2007 in the Internet Archive ).
- Harald Wolf: The pectine organs of the scorpion, Vaejovis spinigerus : Structure and (glomerular) central projections. Arthropod Structure & Development 37 (2008), pp. 67-80.