. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. HYDROMEDUSAN PHOTIC BEHAVIOR 305 TABLE I Mean (±1 SE, n = 36) number of swimming contractions in the 5 s period after a rapid 100% shadow of four different absolute light intensity changes. Comparisons of the mean shadow response frequency at four absolute light intensity changes by one-way ANOVA showed no significant (P > ) difference in the responses Light intensity (microeinsteins/m2-s) () () () () (Table II). The highest swimming frequency was observed during
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. HYDROMEDUSAN PHOTIC BEHAVIOR 305 TABLE I Mean (±1 SE, n = 36) number of swimming contractions in the 5 s period after a rapid 100% shadow of four different absolute light intensity changes. Comparisons of the mean shadow response frequency at four absolute light intensity changes by one-way ANOVA showed no significant (P > ) difference in the responses Light intensity (microeinsteins/m2-s) () () () () (Table II). The highest swimming frequency was observed during the most rapid light intensity reductions, but the total number of swimming contractions in the response was small (Table II). Smaller medusae showed a greater overall swimming frequency and were more responsive to rapid shadows (, exhibited greater swimming frequency than larger medusae). For slower shadows, however, larger medusae showed a greater swimming frequency. During increasing light intensity, medusae rarely swam and often crumpled, re- sulting in marked differences in swimming frequencies from those seen during de- creasing light intensity (Fig. 6). Crumpling behavior was most obvious during the slower light intensity increases and consisted of progressive tentacle contractions, bell margin involutions, and radial muscle contractions. Once fully crumpled, medusae often remained so for several minutes. If a medusa was in the crumpled position at the start of a successive decreasing light intensity trial, it usually relaxed the severe contractions, responded to the shadow with a swimming contraction, and began to swim at a frequency proportional to the rate of light intensity decrease. There were LU 80 CO z O 60 o_ CO LU tr 40 20. 425 450 475 500 525 550 575 600 625 650 675 700 WAVELENGTH (nm) FIGURE 5. Percent of the maximum possible number of shadow responses to rapid shadows of mono- chromatic light. Solid columns indicate individuals with bell heights less tha
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
