. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. N. EGG CAPSULES 321. Figure 9. Charactenslics of species-specific predation on N. cmari>inata egg capsules by: Idolea nc\cii\kii (A. El. llcmigrapxus spp. (B, F), Mupalia spp. (C, G). and an unknown predator (D. H), possibly an intcrtidal gastropod. For each type of predator, a whole mount of the opened capsule is shown (Mag: 8X), with a close-up below illustrating the characteristic bite-marks (Mag: 25-50X). Grappler Inlet or Seppings Island (Table IIIA, B). In 10 trials, 35 Ross Islet (thin-walled) ca
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. N. EGG CAPSULES 321. Figure 9. Charactenslics of species-specific predation on N. cmari>inata egg capsules by: Idolea nc\cii\kii (A. El. llcmigrapxus spp. (B, F), Mupalia spp. (C, G). and an unknown predator (D. H), possibly an intcrtidal gastropod. For each type of predator, a whole mount of the opened capsule is shown (Mag: 8X), with a close-up below illustrating the characteristic bite-marks (Mag: 25-50X). Grappler Inlet or Seppings Island (Table IIIA, B). In 10 trials, 35 Ross Islet (thin-walled) capsules were opened compared with 15 Grappler (thick-walled) capsules (Fish- er's Exact Test, P = ). Ross Islets (thin-walled) cap- sules were also opened more frequently than Seppings (thick-walled) capsules, although this difference was not quite significant (16 Ross Islets capsules versus 10 Seppings capsules; Fisher's Test, P = ). In contrast, isopods did not exhibit any preferences for Seppings versus Grappler capsules (10 Grappler versus 9 Seppings capsules; Fisher's Test, P = ; Table IIIC), and in two of six trials no capsules were eaten during a ten-day period. Hence, thick- walled capsules from Grappler Inlet and Seppings Island were more resistant to predation than thin-walled capsules from Ross Islets. Discussion Intraspecific variation in capsule morphology The morphology of N. enuirginata capsules varies ex- tensively among populations. In the present study, both capsule wall thickness and strength differed significantly among the three intertidal locations examined. Such vari- ation in capsular structure may reflect (1) physical con- straints associated with female body size, (2) phenotypic differences in response to variable environmental condi- tions, or (3) genetic divergence caused by selection. Intraspecific differences in the wall thickness and strength of TV. emarginata capsules may reflect constraints associated with female size. Although the
Size: 1880px × 1329px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
