264 Phylum Arthropoda 



remarkably long period compared with the 10 or 12 days required by 

 the eggs of Achorutes socialis under the same conditions; and in the 

 insect's natural environment incubation would doubtless have been even 

 longer. 



Springtails feed largely on the vegetable molds and minute algae which 

 flourish in such situations. Fungi are a favorite food of many species 

 and both spores and pieces of mycelium are often found in their stomachs. 

 Liquid food also attracts these chewers, and in the spring several species, 

 particularly of the genus Achorutes, may be seen in large numbers feed- 

 ing on the sweet sap exuding from freshly cut maple stumps. 



Species that live on the surface of pools and streams, such as Isotoma 

 palustris and Sminthurus aquaticus, often pick up diatoms and desmids, 

 and in the spring feed largely on the pollen which the conifers lavish 

 upon the wind. 



Our pollen-eating species go direct to the flowers of various plants. 

 In Switzerland, Handschin says, Sminthurus hortensis is always found in 

 the blossoms of Ranunculus glacialis, and in this country the same 

 species is common on dandelion blossoms. In America Achorutes 

 armatus sometimes makes a nuisance of itself in beds of cultivated mush- 

 rooms, and a few other species have some bad marks against them. 

 Sminthurus hortensis feeds upon beans, beets, cabbage, cantaloupes, car- 

 rots, clover, corn, cucumber, kale, lettuce, mangolds, onions, peas, po- 

 tatoes, radishes, rye, spinach, squash, tobacco, tomatoes, turnips, violets, 

 watermelons, wheat, wild cucumber. Its depredations make it the most 

 widely known of the springtails. 



The species definitely known to be carnivorous are few, but further 

 study of Collembolan life histories will probably reveal others. An un- 

 doubted flesh-feeder is Anurida maritima, an inhabitant of the seashore. 

 Folsom says the insect's principal food is the soft tissues of the mollusk, 

 Littorina littorea, as well as dead fish cast up on the shore. Imms slightly 

 extends the diet to include an occasional desmid or other green alga. 

 Motter's courageous study of the fauna of the grave brought to light 

 another carnivorous springtail in Isotoma sepulcralis, which was abun- 

 dant with a large percentage of the 150 corpses examined. 



Anurida maritima and Isotoma sepulcralis feed on dead fish. Two 

 other carnivorous species, Friesea sublimis and Isotoma macnamarai, 

 are raptorial and devour living prey. The food habits of /. macnamarai 

 were mostly observed in vials where the specimens were kept with small 

 pieces of damp, rotten wood to provide the moisture so necessary to all 

 these thin-skinned insects. Cannibalism in captivity was noted in these 

 two last named species and the two species were found to eat each 

 other. 



Arthropleona would not eat at all in captivity. m. e. d. 



