. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CRAB ALLOMETRY AND INTRODUCED SHELLS 383. ASL FIGURE 2. Camera lucida tracings of the calcified parts of a Pagurm longicarpus hermit crab. Anterior shield length (ASL) is shown on the dorsal tracing, while right cheliped length (RCL) is shown on the ventral tracing. length on anterior shield length. The high correlation coefficients obtained indicate that other bivariate linear methods would yield similar results (Yates, 1950; Gould, 1966; Rayner, 1985). The slope of these regressions represents the relationship be- tween th
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CRAB ALLOMETRY AND INTRODUCED SHELLS 383. ASL FIGURE 2. Camera lucida tracings of the calcified parts of a Pagurm longicarpus hermit crab. Anterior shield length (ASL) is shown on the dorsal tracing, while right cheliped length (RCL) is shown on the ventral tracing. length on anterior shield length. The high correlation coefficients obtained indicate that other bivariate linear methods would yield similar results (Yates, 1950; Gould, 1966; Rayner, 1985). The slope of these regressions represents the relationship be- tween the specific growth rates of the two parts (Huxley, 1932; Teissier, 1960; Laird, 1965; Shea, 1985). If this slope is greater than unity, the right cheliped has a faster specific growth rate than the anterior shield. Differences among regions were tested using analysis of covariance tests for homogeneity of slopes. Estimating shell availability Samples of empty shells not only are rarely obtainable, but cannot be used to measure shell availability with certainty (Wilber and Herrnkind, 1982; Blackstone and Joslyn, 1984). Abundances of living gastropods have different implications de- pending on the ecological circumstances (Spight, 1977; Wilber and Herrnkind, 1982). Here, data on shell use provide insight into shell availability as perceived by P. longi- carpus. Observed shell use reflects perceived shell availability, shell preference, and ecological factors (Reese, 1962, 1969; Young, 1979). Studies of the shell preferences of P. longicarpus (Mitchell, 1975; Blackstone, 1984; Blackstone and Joslyn, 1984) indicate: (1) preferences for shells that provide adequate fit (defined above), and (2) preferences for high-spired shells (defined above) at small sizes and low-spired shells at larger sizes (greater than mm anterior shield length). Patterns of shell use from geographic samples may thus be interpreted; if a crab occupied a shell which is not of the preferred fit or shape, tha
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
