NO. 3595 ANOLIS LINEATOPUS — RAND 9 



Harris (1964) showed conclusively that in Agama agama the dif- 

 ferent size classes of lizards were taking largely different sized prey. 

 Since adult males are larger than adult females and share the same 

 home ranges, this difference must reduce the possibility of intersex 

 competition for food. 



Kennedy (1956) demonstrated differences between juvenile and 

 adult Sceloporas olivaceous in size of prey and suggested that this 

 produces "a minimum degree of intraspecific food competition between 

 juvenile and adult S. olivaceous which is highly advantageous in the 

 rapid development of juvenile lizards . . ." (p. 345). Blair (1960), 

 however, in writing of the same species in the same area concluded 

 that the juveniles never approach the limit of their food supply. 



A difference in food size between adults and juveniles has been re- 

 ported for lizards as varied as Eumeces fasciatus, Fitch (1954), and 

 Basiliscus vittatus, Hirth (1963a). 



A habitat difference between juvenile and adults like that seen in 

 A. lineatopus seems common in iguanids. It occurs in at least Basilis- 

 cus vittatus, Hirth (1963a), Iguana iguana, Hirth (1963b), Uta stans- 

 buriana, Tinkle et al (1962), Sceloporus olivaceous, Blah* (1960). This 

 habitat difference must certainly reduce the possibility of one sort of 

 intraspecific competition for food. It also reduces the possibility of 

 the adidts eating the young. 



Certain falcons are sexually dimorphic in size and the larger females 

 catch larger prey (Cade, 1960). Storer (1952) has discussed the 

 possibility that this reduces intersex competition for food. Rand 

 (1952) has reviewed a number of additional types of sexual dimor- 

 phisms in birds that may also reduce intersex competition for food. 

 In bii'ds as in lizards it is difficult to prove the applicability of these 

 ideas to any particular case however plausible they are in general. 



To evaluate food as a limiting factor in the ecology of these anoles 

 would require a knowledge of both the food requirements of the ani- 

 mals and the availability of food to them. Blair (1960) , for Sceloporus 

 olivaceous adult females, and Milstead (1957a), for four species of 

 Cnemidophorus, concluded that food was at least potentially limiting. 

 Their arguments are convincing, but their proof is not rigorous. For 

 -1. lineatopus I suspect that food is potentially limiting but the data 

 are adequate only to demonstrate that in the study areas food is 

 neither superabundant nor in very short supply. 



My impression is that insects of suitable size are common in Jamaica 

 but this idea must be treated cautiously for not all of the insects 

 present are available to A. lineatopus as food. wSome insects are too 

 active or too wary to be frequently caught. Others are noctm-nal 

 and still others too hard or protected by a nasty taste or smell. 



