12 The Animal Ecology of the Cold Spring Sand Spit 



Of the herbivorous feeders on the wreckage of the sea may be mentioned, first 

 of all, the Amphipoda, marine Crustacea which are so adapted to a terrestrial life that 

 they are rarely submerged. At Cold Spring Harbor two species are found — the small, 

 dark Orchestia agilis and the large, sand-colored Talorchestia longicornis. Both may 

 be seen in great numbers by turning over some of the cast-up Ulva fronds, under 

 which they live and upon which they feed. Here they dwell in a saturated atmos- 

 phere and so need no special modification of the respiratory apparatus to fit them for 

 breathing air. They both burrow, also, forming holes varying from three to five 

 millimeters in diameter in the fine sand under or slightly above the line of wreckage. 

 These holes enable the amphipods to reach moisture, they prevent them from being 

 swept away by the sea, and they may serve as nests for eggs. For some reason the 

 Talorchestia only is found at the tip of the spit. If it be asked why these Amphi- 

 pods have left the water thus to assume a half -terrestrial life, I think it is a sufficient 

 answer to say, first, that they find here abundant food ; second, that they are here com- 

 paratively immune from the attacks of their greatest enemies — the fish; and, third, 

 that their organization permits them readily to assume a semi-terrestrial life, as is 

 shown by the fact that some of their allies have become even more terrestrial than 

 they. (Compare Talitrus platycheles, and Talitrus saltator, Semper, 1881, p. 188.) 

 That the Talorchestia is no longer an aquatic animal is shown by the way it retreats 

 before the tide, especially if abnormally high. 



Secondly, rove-beetles (Staphylinidse) of the genus Bledius are found in the 

 debris. This terrestrial insect is here found side by side with the marine Talorchestia, 

 even burrowing into the sand. It feeds upon decaying vegetable matter. A third 

 organism found under the debris is a minute white earthworm of world-wide distribu- 

 tion. This is Enchytrseus albidus Henle (Halodrilus littoralis of Verrill, 1873). 



As the plant debris is being devoured by the amphipods, staphylinids, and 

 Enchytrseus, so the animal remains are being carried off by a number of scavengers. 

 Among these the ants are the most important; there are two species of them. The 

 first, Formica rufa var. obscuriventris Mayr, is reddish brown and about four milli- 

 meters long (see Emery, 1893). It digs holes in the sand in the upper part of the 

 upper beach, the grains of sand being brought individually to the surface and 

 deposited in a ring around the hole. This ant also occurs under the shelter of boards 

 and logs. Immediately after the tide has begun to fall and dropped its burden of car- 

 casses these ants sally forth in paths that run perpendicularly to the high-tide line and 

 begin to seize and carry to their nests the drowned insects that have been left there 

 stranded. A second species of ant has its home somewhat farther out of reach of the 

 tide; but its habits are quite similar. 



There is, however, a larger carrion fauna to be utilized. I have already referred 

 to the dead horseshoe crabs and the dead molluscs that are left on the shore. These 

 soon attract great numbers of the flesh flies (Sarcophaga carnaria) which lay their 

 eggs in the carrion. A second fly with bronze abdomen (undetermined) is also found 



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