Darwin did use tuning forks for experiments with spiders.

201· · You may seek it with thimbles--and seek it with care;
202· · · · You may hunt it with forks and hope;
203· · You may threaten its life with a railway-share;
204· · · · You may charm it with smiles and soap--

I think that The Hunting of the Snark alludes to many events in the Victorian era. Among those, Charles Darwins Beagle voyage, his discoveries and the resulting challenge to religious beliefs surely were important issues to the Reverend Dodgson (aka. Lewis Carroll) and his Snark illustrator, Henry Holiday.

The image:

Illustration by Henry Holiday to the chapter The Hunting in Lewis Carroll's The Hunting of the Snark (1876).

Inset: Charles Darwin, photo probably by Messrs. Maull and Fox, around 1854, see also commons.wikimedia.org/wiki/File:Charles_Darwin_aged_51.jpg.

Inset in inset: Charles Darwin's "I think" sketch of the evolutionary tree (about July 1837, 1st notebook 1837-1838, page 36) compared to a "weed" in the lower left corner of Holiday's illustration. I learned, that Darwin did not keep his notebook secret after the publication of On the Origin of Species, but I do not know of any presentation of his sketch before 1876. Thus, the resemblance between the "weed" and Darwin's evolutionary tree sketch may be purely incidental.


Remarks:
(1) I also left a copy here: commons.wikimedia.org/wiki/File:CharlesDarwinHuntingSnark.jpg, License: CC-BY-SA-3.0
(2) The person on the right side in Holiday's illustration is "The Banker". This figure has different faces in different illustrations.
(3) Henry Holiday may have been inspired by Darwin's "tree of life" sketch when he did his illustrations to Lewis Carroll's The Hunting of the Snark. However, the problem with my guess is, that (as far as I know) the sketch still may not have been known to the public when Lewis Carroll and Henry Holiday worked on The Hunting of the Snark.