The Relationship of Clutch Size and Frequency to Body Size in Loggerhead Turtles, Caretta caretta

1986 ◽  
Vol 20 (1) ◽  
pp. 81 ◽  
Author(s):  
Nat B. Frazer ◽  
James I. Richardson
Author(s):  
Peter V. Lindeman

In evaluating optimal egg-size theory and the effects of anatomical constraints on egg size in turtles, pivotal questions concern the significance of the relationship of egg size to female body size and whether the relationship is isometric or hypoallometric. In a central Texas population of the kinosternid turtle Sternotherus odoratus in which clutch size of a sample of turtles was nearly fixed (seven of eight females had two eggs while the largest female had three eggs), there was an isometric increase in egg width with body size among the females with two-egg clutches and significantly reduced egg width in the largest female’s three-egg clutch. Allometric analyses of populations that exhibit little variation in clutch size, as well as analysis of modal clutch sizes in populations with more variable clutch sizes, both have the potential to further illuminate the competing demands of increasing egg size vs. increasing clutch size as females grow larger, enabling them to optimize their reproductive output as it increases with body size.


1992 ◽  
Vol 226 (2) ◽  
pp. 321-327 ◽  
Author(s):  
G. C. Hays ◽  
J. R. Speakman

Oecologia ◽  
1999 ◽  
Vol 121 (2) ◽  
pp. 224-235 ◽  
Author(s):  
Justin D. Congdon ◽  
Roy D. Nagle ◽  
Chirstopher W. Beck ◽  
Owen M. Kinney ◽  
S. Rebecca Yeomans ◽  
...  

1989 ◽  
Vol 46 (4) ◽  
pp. 614-623 ◽  
Author(s):  
P. R. Boudreau ◽  
L. M. Dickie

Earlier ecological studies showing regularity in the relationship of certain indices of production to body size are used to develop a predictive equation of fish production on a year to year basis, with biomass and body size as independent stock variables. The prediction system makes use of the observed regular adjustments of local biomass density with body size and the parallelism of the functional relationships of production and biomass with body size both between and within stock cohorts. The method obviates the need to invoke assumptions of population equilibrium. The model is applied to three data series for individual species exploited by commercial fisheries on the Scotian Shelf. The results suggest that despite the vagaries of population sampling, ecological information can provide practical estimates of the production potential of fish stocks.


1973 ◽  
Vol 69 (3) ◽  
pp. 71-89 ◽  
Author(s):  
Ann R. Sanderson

SynopsisKaryograms prepared from ovarian and blastoderm cells of the parthenogenetic Australian Brown Vegetable Weevil demonstrate a consistent triploid condition with 30 chromosomes which can be grouped into 10 sets of homologues. Meiosis is replaced by a single mitotic-like division in which 30 univalent chromosomes, each composed of two chromatids, divide equationally between an ootid nucleus and a single polar nucleus. Prior to the differentiation of the oocytes a peculiar bouquet stage occurs in the cells of the end chamber of each ovariole, but the significance of this phase is not known. Arrested development in eggs from individuals of low fertility is investigated and the relationship of body size and chromosome number is discussed.


2020 ◽  
Vol 3 (2) ◽  
pp. a18-25
Author(s):  
AHMAD FITRI AZIZ ◽  
CHARLIE JUSTIN MERGIE LAMAN

The Energy Equivalence Rule (EER) is an unresolved issue in ecology. This rule states that the amount of energy used for each species in a population is independent of its body size. A study on the relationship between abundance and body size of bird assemblages was conducted in Western Sarawak. Abundance data of bird assemblages from seven selected sites in Western Sarawak were used to produce a regression line of log absolute species abundance versus log average body mass. Data from all selected sites were combined to represent bird assemblages in Western Sarawak and the slope produced was -0.216. The slopes obtained for each site were 0.808, -0.080, -0.258, -0.067, -0.161, -0.072 and -0.237, respectively. Statistical analysis shows that the slope of combined data did not differ significantly from -0.75, as expected under the EER. Thus, this study shows that the EER can be applied as a general rule of community structure of bird assemblages in Western Sarawak.


1973 ◽  
Vol 59 (1) ◽  
pp. 255-266
Author(s):  
H. J. ATKINSON

1. The rate of oxygen consumption of individual males of Enoplus brevis and E. communis was measured at 15 °C and at each of four oxygen tensions, 135, 75, 35, and 12 Torr, after at least 12 h experience of these conditions. 2. It was clearly demonstrated that the level of oxygen consumption of both species was reduced by each lowering of the imposed oxygen tension. 3. In all cases the oxygen consumption of each species fell with increasing body size. On a unit dry-weight basis the oxygen consumption of E. brevis is greater than that of the larger E. communis, but after allowing for the difference of body size the two species have more or less similar oxygen uptakes at all oxygen tensions. 4. In E. brevis oxygen tension influenced the relationship of body size and metabolism, the slope relating oxygen consumption and body weight becomes steeper with decreasing oxygen tension. This effect was not shown by E. communis. 5. Some general factors influencing the availability of oxygen to nematodes are considered.


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