EARTHWORMS AS PLANTERS OF TREES 



E. A. ANDREWS 



That squirrels aid the forester by burying nuts, some of which 

 may be left to germinate and so start new trees, has long been 

 known; but that common earthworms play a like part in the drama 

 of the woods has not been suspected. The following observations, 

 however, show that the earthworm may be of use in aiding the 

 germination of at least one important kind of tree and raise the 

 question whether they do not do the same for some other trees as 

 well as for many smaller plants. 



The earthworm assists in planting by bringing the seeds into 

 close contact with the soil, even burying them. Here, as in the 

 case of the squirrel, the object sought by the animal is not the 

 germination of the seed. The squirrel is following a strong food 

 instinct in hiding away nuts, many of wliicli it will find again and 

 eat; the earthworm is also obeying a very strong instinct, which is, 

 however, only in part a food instinct. This instinct expresses 

 itself in the somewhat mysterious hal)it the eartiiworni has of 

 plugging up its burrows. 



As is well known, some of our common kinds of earthworms 

 make holes in the ground and inhabit thorn for long as ])lac'es (»f 

 protection from dryness and from various (Micinic-v. In tii-o niulit 

 time, however, these earthworms may leave tlu'ir burrows inort' or 

 less completely, to seek on the surface of the groimd vari(.iis objects 

 to be used as food, and to associate with .)th(M- earthworms. They 

 then seize and eat both live and dead v(>g(-tal.Ie matter, and soft 

 animal matter wlien a\ ailal>le; and tlnw also drag back to or into 

 their Inirrows b.^th edible and ine.hl.le ol.jeets. At times the 



objects that may have been upon the surface, sticking up here 



711 



