Dave General of the Phillipines wrote:
 
>I didn't see Layne's post but I would like to add to Garth's
>explanation. Soap is a surfactant, eg. it changes the surface tension of
>a liquid. In addition, soap also overcomes the natural repulsion of
>water by an oily substance. Thus, soapy water "wets" the normally
>waterproof exoskeleton of the insect, particularly the hairs covering
>the spiracles or breathing holes. These hairs would normally prevent
>water from entering the spiracles. The surface tension of water is not
>breached by the hairs of the spiracles. Since insects respire directly,
>that is, they cannot "hold their breath", they drown in soapy water.
>Even aquatic insects will drown in soapy water.
 
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   That is the best explanation I have yet seen on this topic.  One hit
with a stream of soapy water, and a yellow jacket wasp turns over and dies.
 
 
                                                        Adrian
 
Adrian M. Wenner                    (805) 963-8508 (home phone)
967 Garcia Road                     (805) 893-8062  (UCSB FAX)
Santa Barbara, CA  93106
 
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* "...in the drift of the years I by and by found out that a Consensus *
* examines a new [idea] with its feelings rather oftener than with its *
* mind.  You know, yourself, that is so.  Do those people examine with *
* feelings that are friendly to evidence?  You know they don't."       *
*                                                                      *
*                                                Mark Twain            *
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