A study of the reproductive cycle of three species of lizards, a forest form, Anolis limifrons, a forest edge species, A. tropidogaster, and a grassland species, A. auratus, was carried out in the Isthmus of Panama from November 1965 until September 1969. The collecting sites were: Pacific side for all three species, mid—Isthmus for A. limifrons and A. auratus and Caribbean side for A. limifrons. Females of all three species of all sites were reproductively active during the wet season (May through December). For A. tropidogaster and A. auratus egg production almost ceases during the dry season. In A. limifrons egg production essentially ceases at the drier Pacific site and is reduced at the other two wetter ones during the same January—to—April period. The testes of males of all three species have mature spermatozoa during the dry season but mean testis weight declines from wet season highs. The male changes occur before the corresponding ones in their females so that the cycles of the two sexes may be controlled by different factors. Lipid levels of adults from the mid—Isthmus site show high values in the late dry season and lower ones throughout much of the wet season. Precipitation, food level, temperature, photoperiod, soil and leaf litter, wind, and evaporation are considered as cues influencing the cycle. The most likely candidate for the female cycle is precipitation with certain limitations. The flexible reproductive system of A. limifrons enables it to reproduce at low rates in some areas where the other two species must cease reproduction during dry periods.

The seasonal food habits of Anolis limifrons, an iguanid lizard, were studied by examining the stomachs of 512 individuals collected on Barro Colorado Island, Panama Canal Zone, during three periods. Frequency and length of prey and length of predators were determined. Frequency distributions of different size classes of potential prey were obtained from leaf litter and low vegetation samples.The lizards selected larger size classes of potential prey. All size classes of predators captured the smaller size classes of prey, but the larger prey were taken by larger predators. More female than male lizards had food in their stomachs. There was no wet season-dry season difference in frequency of food found in the stomachs.

During a 15-day experiment, green anoles, Anolis carolinensis, were: (i) presented with one of two aposematic insects, Oncopeltus fasciatus or Photinus pyralis, during days 4, 6, and 8; (ii) maintained on one of four different food levels during days 9-14; and (iii) presented with the original model on day 15. Lizards on low rations tended to capture more Photinus on day 15 than did anoles on higher rations. No such correlation was observed with Oncopeltus.

No abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. This content downloaded from 130. ABSTRACT:Thirty adult female Chrysemys picta were tested in a Y-maze to determine what factors caused orientation. The turtles were found not to have any innate (or to develop any right or left) turning tendencies. At warm temperatures (23 -30C) the turtles did not orient to current or to different strengths of currents. When kept at 6C for 24 hours prior to testing, there was a marked tendency to avoid current. The turtles had a marked orientation to light and responded positively to differences of 0.1 ft-c in intensity. Chrysemys kept at temperatures of 6 to 17C prior to testing oriented to warmer water currents. When kept at warmer temperatures ranging between 23 and 20C, they oriented to cooler water currents. The turtles did not orient to a current bearing aromatics from aquatic plants. There was no significant orientation to currents having red, green, or brown dye introduced.