ORANGE-SPOTTED SUNFISH, LEPOMIS HUMTLIS. 



11 



noted that the orange-spotted sunfish feeds primarily on crustaceans 

 and insect larvae but that it occasionally eats a small fish and prob- 

 ably accidentally ingests some algae. From the Fairport reservoir a 

 small huTnilis 7.5 cm. long has been taken in December, in which veere 

 found two small individuals of its own species. 



Table 4. — Fofnl of 57 Lepoviis htimills and, 77 Gamhusia nfflnis compared — Fish 



collected at Mo^ind, La. 



[Figures indicate estimated per cent.) 



1 Predominant. 



A fish living on large numbers of minute crustaceans and insect 

 larvae is of particular value in the annual turnover of these micro- 

 scopic animals into flesh that may in turn serve the food requirements 

 of larger predacious fish. The value of hiimUis in this particular 

 field is pointed out on page 12. 



Another consideration of interest with resj^ect to the possible use- 

 fulness of the fish comes to light when the records of the contents of 

 the stomachs of the Louisiana sunfish are compared with those of 

 the recognized mosquito-control agents {Gamhtisia af/inis) caught in 

 the same region and environments and at the same time. The com- 

 parison of the figures representing percentages of the different or- 

 ganisms found shows that the sunfish and top minnow eat about the 

 same percentage of crustaceans, Cladocera being predominant in both 

 fishes' diet. The sunfish record of insect larvae ingested gives 50.81 

 per cent against 2.8 for Gambusia. It is of particular significance 

 to note here again that in both fishes Chironomidae were the most 

 numerous of the insect class, although the sunfish surpassed the min- 

 now by about 20 times in the frequency of its feeding on immature 

 Diptera. Finally, it is significant that while humilis contained 2.28 

 per cent of vegetable food Gambusia contained 60 per cent. It is 

 probable that the plants of the humilis diet are accidentally taken, 

 but the top minnow makes some choice of algal food. In view of 

 the fact that the food habits of the orange-spotted sunfish are so sim- 

 ilar to those of Gambusia, especially with regard to the crustacean 

 and insect larval consumption, and also because the immature insect 

 ingestion of humilis is 20 times as frequent as in Gambusia and* the 



