On the exposed Desertas?

Does "on the exposed Desertas" mean "in the area of the exposed Desertas"?

Context:

inhabiting Madeira, are so far deficient in wings that they cannot
fly; and that, of the twenty-nine endemic genera, no less than
twenty-three have all their species in this condition! Several facts,
namely, that beetles in many parts of the world are very
frequently blown to sea and perish; that the beetles in Madeira,
as observed by Mr. Wollaston, lie much concealed, until the wind
lulls and the sun shines; that the proportion of wingless beetles is
larger on the exposed Desertas than in Madeira itself; and
especially the extraordinary fact, so strongly insisted on by Mr.
Wollaston, that certain large groups of beetles, elsewhere
excessively numerous, which absolutely require the use of their
wings, are here almost entirely absent. These several
considerations make me believe that the wingless condition of so
many Madeira beetles is mainly due to the action of natural
selection, combined probably with disuse.