19£1] The Age of Insects 45 



For the past few years I have been giving some attention to a prob- 

 lem in field ecology that is very interesting to me and perhaps a 

 statement of this problem will do more than anything else that I might 

 say to make the whole matter clear. We have along our ocean front, 

 our sounds, bays and rivers a narrow strip of land that is flooded twice 

 each day by the rising tide. This strip of land may be known as the 

 tidal zone. The part of the tidal zone lying along the ocean front 

 where it is affected also by the direct action of the waves may be known 

 as the strand. While that portion of the tidal zone along the sounds, 

 rivers and bays where it is not much subjected to wave action may be 

 known as tidal belt. While these two areas may be generically re- 

 lated yet they are very distinct. The strand is usually devoid of vege- 

 tation and is frequented by a group of animals that we will call beach 

 combers. All of them are scavengers and they feed upon whatever the 

 ocean may cast up before them. Their existence would seem to be a 

 precarious one but when we note the abundance of beach fleas, sand 

 scabs, ghost crabs and beach tiger beetles we are inclined to believe 

 that nature must be very lavish with them after all. 



The tidal belt is far more interesting to us, however, chiefly be- 

 cause it usually supports a luxuriant growth of sedges and grasses 

 which in turn support a wealth of leaf hoppers and plant hoppers 

 which are my special interest in all of the groups of insects. The 

 ecological relations of some of these insects are most interesting. Here 

 we have strictly terrestrial air-breathing arthropods living in an en- 

 vironment that is strictly aquatic for longer or shorter periods twice 

 each day. Here we have strictly terrestrial forms living in close prox- 

 imity to strictly aquatic forms like the sea snails and fiddler crabs. 

 Naturally we wonder why these insects have adopted this habitat. 

 Perhaps we can explain it by stating that these insects attached them- 

 selves to their host plant when it was a xerophyte and simply followed 

 it into its half hydrophytic environment. This may be historically 

 correct, but whatever is the past history of this peculiar relation Ave 

 know that it is not simply a strict host relation at the present time but 

 it seems rather a matter of fixity of environmental factors. This is 

 borne out by the fact that one of the most abundant species of plant 

 hoppers in the tidal belt region lives on no less than three species of 

 grasses and one sedge. Another species was described originally from 

 Long Island where it was secured from a species of the genus Spartina 

 but on our coast where Spartina is replaced by the sea oats (Uniola) 

 the same species of the plant hopper occurs on the Uniola and occupies 



