. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 72 F. GHERARDI AND P. M. CASSIDY ance: H = , df = 5. P < ). peaking in the third day and then falling off abruptly after the fifth day. Hatching occurred exclusively at night, and mostly during the neap phase of the tide (Mann-Whitney test: U = 0, H = 7 and 7. P < ). when the mean tidal current is consistently slower (Fig. 5). For our comparison, we defined neap (or spring) phase as the day of the minimum (or maximum) tidal excursion for a lunar tidal cycle plus the 3 days preceding and following that da
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 72 F. GHERARDI AND P. M. CASSIDY ance: H = , df = 5. P < ). peaking in the third day and then falling off abruptly after the fifth day. Hatching occurred exclusively at night, and mostly during the neap phase of the tide (Mann-Whitney test: U = 0, H = 7 and 7. P < ). when the mean tidal current is consistently slower (Fig. 5). For our comparison, we defined neap (or spring) phase as the day of the minimum (or maximum) tidal excursion for a lunar tidal cycle plus the 3 days preceding and following that date. Parasite distribution Peltogaster boschmae was the most common rhizoce- phalan parasite in our samples, affecting of the specimens; Tliilacopletlnis ( = Tho»ipsonici) reinhardi in- fected ; and the two rhizocephalans co-occurred in These figures are similar to the percentages reported by Lutzen (1992) for a previous study in the same area. A sexual difference in the degree of infestation was seen in both the number of externae per individual (males: average = , SE = ; females: average = , SE = ; X2 = , df = 2, P < ) (Fig. 6) and the prevalence of parasitism ( the percentage of the parasitized her- mits; Margolis el 1982) (males females: vs. , X2 = , df = 1, P < ). Similar results were obtained from the winter samples, where parasitized males and females scored and respectively (X2 = , df = l,P< ). The number of parasitized specimens did not differ between sampling periods (sum- mer: 60 out of 281. winter: 19 out of 110; X2 = , df = 1, ns). The maximum number of externae from the summer samples was 15 in males and 18 in females. We counted 23 externae in one female collected in winter. None of the ovigerous females in our sample had parasites (0 vs. 20% in nonovigerous ones: X2 = , df = \.P< ). Only one female has been collected bearing both eggs and hat
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
