FIGURE 3.8 Number of regional endemic vs. nonendemic species of reef stomato-pods and those occurring on high vs. low islands.

Number of endemics and nonendemics on high vs. low islands did not vary significantly across regions (P > 0.05), so all regions were combined. Significantly fewer endemics occur on low than high islands (x² = 19.16, df = 1, P < 0.001; Fig. 3.8).

We propose that the ecological and environmental factors that govern body size and life history traits drive patterns of diversity and endemism in reef organisms. Large body size in reef stomatopods is significantly correlated with massive reproductive output (more and larger eggs; Figs. 3.9 and 3.10), greater planktonic larval dispersal, larger geographic ranges, and greater saturation of available reef habitat within ranges (Fig. 3.11), whereas small body size correlates with restricted reproductive capacity, restricted larval dispersal, and relative rarity (low abundance, few sites, small geographic ranges) (Reaka, 1979, 1980; Reaka and Manning, 1987a; Reaka-Kudla, 1991; Wilkinson, 2004). This correlation occurs because small body size constrains reproductive traits in marine organisms. Small-bodied species cannot produce enough small plankton-feeding larvae to leave one surviving offspring given the high mortality rate suffered by these long-lived larvae. Small species must endow fewer, larger larvae with yolk supply, often brooding them before a relatively brief planktonic period, to increase survivorship. The body volume of larger species allows them to produce sufficient numbers of small larvae that feed in the plankton for long periods that some offspring survive despite heavy mortality (Menge, 1975; Strathmann and Strathmann, 1982). Size frequency distributions for both body size (Fig. 3.12) and geographic range (Fig. 3.13) are strongly shifted toward diminutive sizes (particularly in endemic species) and