no. 39] odonata of connecticut 15 



Parasites and Enemies 



The dragonfly, although itoclf predaceous, has enemies. Chief 

 among these are fishes and birds. Fishes are particularly fond 

 of the nymphs, which are reported to form 25 per cent of the 

 food of a bullhead (Baker 191 6) ; 25 per cent of the food of the 

 grass pickerel (Esox vermiculatus) ; and about 13 per cent of 

 the food of crappies (Pomoxis annularis and P. sparoides) , and 

 pirate perch {Aphredoderus sayanus Forbes 1888). The size of 

 the fish, however, is important in determining the amount of 

 Odonate food eaten. Wilson (1917-18, p. 229) claims that very 

 small fish do not eat Odonata nymphs at all but that they are very 

 fond of the eggs. Fish under 9 mm. in length eat no nymphs 

 whatsoever, while fish such as the large-mouth bass, blue-gill, 

 common sun fish, and calico bass, reach 22-25 mm. (about i inch) 

 before they begin. Fish 75-105 mm. (3-4 inch) were found by 

 Wilson to feed almost entirely on dragonfly nymphs, under some 

 conditions. 



Dragonfly nymphs are reported to be in demand as fish bait 

 in several localities. Wilson (1917-18, p. 225) says that small 

 boys in the vicinity of Torrington, Conn., collect and sell them as 

 "perch bait," and in other localities they are used as bait for trout, 

 rock-bass and perch. He also reports that adult damsel flies are 

 more frequently eaten by fish than is supposed, and that fishes 

 will snap up quickly any damsel fly that has been injured and is 

 unable to rise from the water. 



Birds are next in importance as enemies of Odonata, and their 

 greatest success lies in capturing tenerals. English sparrows, 

 robins, red-winged and yellow-headed blackbirds, shrikes, cuckoos, 

 king birds, fly-catchers, and herons have been observed by various 

 authors to eat Odonata. Herons feed upon the nymphs, the 

 remainder upon adults. Shrikes, cuckoos, and king birds, espe- 

 cially the last, are said to be quick enough to capture fully mature 

 adults. Walker, in fact, reports (1912; p. 36) that the appen- 

 dages of Epiaeschna heros, one of the largest and swiftest dragon- 

 flies, have been taken from the stomach of the chuck-will's widow. 



Turtles, terrapins and frogs (bullfrogs and cricket frogs) are 

 enemies of Odonata. Bullfrogs are reported to feed upon nymphs 

 and adults, and the cricket frog upon the adults of damsel flies. 



The larger species of Odonata destroy the smaller and are there- 

 fore enemies. Aquatic Hemiptera and Coleoptera are vigorous 

 insect feeders and will feed on Odonate nymphs when they 

 encounter them. Dytiscus, Z ait ha, Ranatra, B el stoma, and 

 Notonecta have been reported in this connection, while ants and 

 robber flies (Asilidae) are sometimes able to capture and over- 

 power adults. Several egg parasites have been observed (Hymen- 

 optera and Diptera), and the eggs of the damsel fly family Lestinae 



