In a population of Uta stansburiana stejnegeri, in Crane Co., Texas, summer rainfall influenced p... more In a population of Uta stansburiana stejnegeri, in Crane Co., Texas, summer rainfall influenced prereproductive growth rate and two of three variables the following spring: (1) the sizes of adult females and (2) size of their first clutch but (3) not of their eggs or offspring in the first clutch. Some of the environmental effect on clutch size was indirectly due to the effect on body size. However, most (73%) of the variance of clutch size was independent of that of body
This study compares the perch heights and densities of male Anolis grahami, A. sagrei and A. line... more This study compares the perch heights and densities of male Anolis grahami, A. sagrei and A. lineatopus at four localities near Ocho Rios, Jamaica during the spring of 1983, 1987, 1994, 1996, 1998 and 2000. This is the first report of an Anolis perch height study sampling the same study area for a period of almost two decades. The finding of stability over the long-term in this system lends validity to numerous short-term studies. Data analyses included assessment of perch height and densities. Mean perch heights were signifi-cantly different among species during the study. However, there was still significant overlap in this niche dimension in many years of the study. Anolis sagrei is an invader that has integrated into the Anolis community at this locality. Implications of these findings are discussed regarding reasons for coexistence and potential competition between these species.
Life-history theory predicts that the allocation of energy to current reproduction is associated ... more Life-history theory predicts that the allocation of energy to current reproduction is associated with a decrement in future fecundity, future survival, or both. I treated this notion as the “cost hypothesis”, and tested the assumption that current reproduction exacts a “cost” in future survival and fecundity. Surgical manipulations of egg production were applied to natural populations of the tree lizard, Urosaurus ornatus, in south western New Mexico by yolkectomy surgery in two different years. I reduced the number of eggs produced in the first clutch during vitellogenesis by approximately 50% in yolkectomized females relative to controls. Subsequent survival, fecundity, and growth of females were followed for two or three years, depending on the cohort. Treated females in both cohorts showed significantly higher growth and survivorship throughout the experiment than in controls. After 2 years, yolkectomized females had grown an additional 2 mm (snout-vent length) compared to controls, enough for them to add on average an additional egg to their next clutch. This demonstrated a cost in terms of future fecundity through a reduction in growth and an increase in mortality in these lizards.
In a population of Uta stansburiana stejnegeri, in Crane Co., Texas, summer rainfall influenced p... more In a population of Uta stansburiana stejnegeri, in Crane Co., Texas, summer rainfall influenced prereproductive growth rate and two of three variables the following spring: (1) the sizes of adult females and (2) size of their first clutch but (3) not of their eggs or offspring in the first clutch. Some of the environmental effect on clutch size was indirectly due to the effect on body size. However, most (73%) of the variance of clutch size was independent of that of body
This study compares the perch heights and densities of male Anolis grahami, A. sagrei and A. line... more This study compares the perch heights and densities of male Anolis grahami, A. sagrei and A. lineatopus at four localities near Ocho Rios, Jamaica during the spring of 1983, 1987, 1994, 1996, 1998 and 2000. This is the first report of an Anolis perch height study sampling the same study area for a period of almost two decades. The finding of stability over the long-term in this system lends validity to numerous short-term studies. Data analyses included assessment of perch height and densities. Mean perch heights were signifi-cantly different among species during the study. However, there was still significant overlap in this niche dimension in many years of the study. Anolis sagrei is an invader that has integrated into the Anolis community at this locality. Implications of these findings are discussed regarding reasons for coexistence and potential competition between these species.
Life-history theory predicts that the allocation of energy to current reproduction is associated ... more Life-history theory predicts that the allocation of energy to current reproduction is associated with a decrement in future fecundity, future survival, or both. I treated this notion as the “cost hypothesis”, and tested the assumption that current reproduction exacts a “cost” in future survival and fecundity. Surgical manipulations of egg production were applied to natural populations of the tree lizard, Urosaurus ornatus, in south western New Mexico by yolkectomy surgery in two different years. I reduced the number of eggs produced in the first clutch during vitellogenesis by approximately 50% in yolkectomized females relative to controls. Subsequent survival, fecundity, and growth of females were followed for two or three years, depending on the cohort. Treated females in both cohorts showed significantly higher growth and survivorship throughout the experiment than in controls. After 2 years, yolkectomized females had grown an additional 2 mm (snout-vent length) compared to controls, enough for them to add on average an additional egg to their next clutch. This demonstrated a cost in terms of future fecundity through a reduction in growth and an increase in mortality in these lizards.
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