Francis E. Lloyd — 36 — Carnivorous Plants 



like creatures parasitize pitcher inhabitants. The caterpillars of a 

 moth live in burrows formed by feeding on the tissues of the rhizome, 

 and form characteristic, more or less upright, above-ground tubes 

 of the debris. This is Papaipema appassionata, the moth being maroon 

 and yellow in color. Of especial interest here are those which habitu- 

 ally use the pitchers as their homes, and live in them and nowhere 

 else. They fijid their food either in the tissues of the pitcher walls, 

 or in the mass of dead insects caught by the trap, or merely live in 

 the water from which, however, they must derive their food. Animals 

 other than insects include a small tree-toad and a small chameleon 

 lizard, whose bones are sometimes found in the inclosed debris. The 

 toad rests just inside the mouth of the pitcher, doubtless awaiting 

 the chance of capturing prey. But to come to the obligate inhabit- 

 ants : 



A small mosquito {Wyeomyia Smithii) lays its eggs in the pitchers 

 of Sarracenia purpurea. In the pitcher fluid (always diluted by 

 rains) the larvae grow to maturity, hibernating frozen in ice during 

 the winter. It is harmless to man. It is said not to breed elsewhere, 

 and is found well beyond the Canadian border, though it is tropical 

 in its affinities. 



Similarly the larvae of a minute gnat, Metriocnemus Knabi, breeds 

 in the same manner. A closely related species, M. Edwardsii, de- 

 scribed by Jones (191 6), was discovered to occur in the pitchers of 

 Darlingtonia californica by Mrs. Austin about the year 1875. The 

 larvae are minute thread-Uke "worms" circulating in the decaying 

 insect debris, which appears as writhing masses, so numerous are the 

 larvae. According to Hepburn and Jones (1919), such forms pre- 

 serve themselves against the digestive action of the surrounding fluid 

 by means of antienzymes. In this connection it may be mentioned 

 that, in discussing the anthelmintic action of papain (in the crystal- 

 line form), Berger and Asenjo (1940) tested the effect of this enzyme 

 on Ascaris lumhricoides (from pig intestine) and found that these 

 organisms were attacked, that is, ulcerations were formed on them 

 inside of 16 hours in a 0.02% solution in a phosphate buffer of pH 5, 

 and the animals were completely digested in 16 hours in a 0.11% solu- 

 tion. The same authors showed that the bromelin of fresh pineapple 

 juice acts similarly. Evidently Ascaris has no sufficient protection 

 against this enzyme in the concentrations used, though presumably it 

 has an antienzyme which protects it within its normal environment. 



The most intriguing of all the animal associates are three closely 

 related species of a small moth of the genus Exyra, because of the 

 striking adaptations which they display to a special environment 

 (Jones 192 i). These moths lay their eggs singly or in groups in the 

 mouth of the pitcher. When laid singly, the hatched larva enters 

 the tube and feeds on the superficial tissues of its wall. This is true of 

 the species Ridingsii and semicrocea. If more than one larva happens 

 to occupy a pitcher, one of them ruthlessly drives out or kills its 

 neighbors. The third species, Rolandiana, lays a group of eggs in a 

 pitcher of a single plant (of S. purpurea), and when hatched the 

 larvae spread to various closely placed pitchers, readily possible in 

 this species because of the dense massing of the pitchers (z — 3). 



