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-23- submarine. However, some species, such as Thinopictus
pictus LeConte, which burrow in the wet sand in day time and come out to
feed only at night, might be so considered. They should be investigated for
tolerance to total submergence for an extended length of time. Species, such
as those of Cafius, which are found largely in wrack and which leave
the wrack immediately when it is wetted by sea water, must be called
littoral. All inhabitants of salt marshes should probably be called littoral. Many
staphylinids are temporarily attracted to decaying organic material which is
not their normal habitat. However, many species are found in masses of
seaweed (wrack) which are deposited on the beach with each high tide. The
wrack provides food, probably first in the form of entrapped small marine
organisms and later in the crustacea and the larvae of flies which soon
appear. Staphylinids begin to appear in the wrack as soon as it arrives on
the beach only to leave it again if it is wetted once more by salt water. The
wrack which is deposited by the highest tide of any tidal period stays on the
beach the longest and consequently accumulates the largest population of
insects. This period can be as long as 15-20 days. Staphylinids do not breed
in the wrack. Few larvae, and those of a few species of Cafius, are even
found there. Occasional specimens of staphylinids encountered in the wrack or
carrion on the beach should not be included in lists of marine insects if it
is suspected that they are only accidental visitors. It is possible that a
few such records are in the existing literature. Some records of Fowler
(1888) are suspect in this regard, particularly where the insect is also
reported from other habitats. It is of
interest that the marine insect fauna of Pacific North America, which extends
for a distance north to south of over 3000 miles from the Aleutian Islands to
part of the way down the coast of Baja California, shows definite correlation
with the provinces outlined or described by marine biologists. Some species
of staphylinids, and of other insects, have a range which encompasses the
entire coast. Other species are restricted to part of the coast. There are at
least two regions on the coast where a partial change in fauna takes place.
These are at Point Conception and near Monterey. This is illustrated in
Tables 2 and 3. Steinbeck and Ricketts (1941) considered the region between
Point San Eugenio, Baja California and Point Conception, California, to be an
overlap area between the Panamic Province and the North Temperate Province.
Further collection of insects along the west coast of Baja California is
needed to substantiate this conjecture. ACKNOWLEDGEMENTS
We are
pleased to extend our thanks to J.M. Campbell, Saul Frommer, Sam Harter,
Melville Hatch, Lee Herman, David Kavanaugh, Horace Last, Hugh B. Leech, Vincent
Lee, Helen Moore, Dale Meyerdirk, Robert E. Orth, John Pinto, Vincent Roth,
Kohei Sawada and Mary Ann Walsh, all of whom have helped in our study of the
marine fauna. |