We conducted an 8—yr study of flower and acorn production in three species of oak in east—central Missouri: white oak (Quercus alba), red oak (Q. rubra), and Black oak (Q. velutina). The goal was to evaluate whether mast—fruiting, the synchronous production of large seed crops followed by small seed crops, is simply a response to weather conditions or is actually an evolved reproductive strategy. In this paper, we address four specific questions: (1) Are annual fluctuations in acorn crop size the result of synchronous production of acorns by individuals? (2) Are large acorn crops the result of large flower crops and/or high survival of those flowers to mature fruit? (3) To what extent do weather variables account for variation in acorn production among years? (4) Does acorn crop size correlate negatively with prior acorn production? Red oak and white oak showed a greater degree of mast—fruiting than did black oak. Within a species, individuals tended to produce large acorn crops in the same years, but each species differed in which years they produced large crops. The size of a given acorn crop was determined by both flower abundance and survival of flowers to fruit. Principal components and multiple—regression analyses were used to describe the relationship between weather variables and acorn production. The first principal component explained the largest amount of the variation in black oak (R2 = 0.55) and the red oak (R2 = 0.89). In white oak, two principal components combined to explain 77% of the variation in acorn production. The weather variables that were associated with these principal components included spring temperature (positive effect) and summer drought (negative effect). Past acorn production had a major impact on the size of the current acorn crop, with each species showing a different pattern. In black oak, the current acorn crop was negatively correlated with the crop 3 yr prior but positively correlated with the crop 2 yr prior. In red oak, acorn crop size 1, 2, and 3 yr prior had negative correlations with current acorn crop, while acorn crop size 4 yr prior was positively correlated. In white oak, there were negative correlations between acorn crop size and crop size 1, 2, and 4 yr prior but a positive correlation with the acorn crop size 3 yr prior. These data are consistent with the hypothesis that mast—fruiting species must store resources during some years in order to produce a mast crop. We discuss the possibility that these three species may have inherent cycles of reproduction that are modified by the impact of weather conditions, black oak with 2—yr cycles, white oak with 3—yr cycles, and red oak with 4—yr cycles. We conclude that the patterns of acorn production for black oak, red oak, and white oak are not simply responses to weather events but are also a function of prior reproductive events. This suggests that masting is an evolved reproductive strategy.

THE ANNUAL CYCLE OF Chrysemys ACTIVITY 117 A Brief Synopsis of the Annual Cycle. 117 The Prevernal Season. 118 The Vernal Season. . 119 The vernal emigration am! the emigrants 120 Environmental features of Crane Pond and surrounding areas during the vernal emigration. 1''" The influence of water temperature and current on emigration 123 The extent of the dispersal movements 124 129 Features common to plants utilized by Chrysemys 131 Advantages of the T-structure. 132 Distribution within plant beds. 133 Activities of Chrysemys on mats of floating vegetation 133 Return of Chrysemys to activity areas of former years 134 The Autumnal Season 134 DISCUSSION .

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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.

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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.

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