. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. LOCALIZED REPRODUCTION IN A MARINE BRYOZOAN 289 100 u Q Z W U 20 I 10 JULY 18 JULY DATE 25 JULY Figure 1. Percentage of control colonies producing spermatocytes or oocytes at three dates. Median percentages were calculated from five zooids haphazardly sampled from each of three regions in 11 colonies (A. M, E = Ancestral. Mid. and Edge regions). Both within-colony lo- cation (X2 = , P = ) and date (\- = P = ) significantly affect the frequency of reproductive colonies. 10-13 days after contact. Five zooid
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. LOCALIZED REPRODUCTION IN A MARINE BRYOZOAN 289 100 u Q Z W U 20 I 10 JULY 18 JULY DATE 25 JULY Figure 1. Percentage of control colonies producing spermatocytes or oocytes at three dates. Median percentages were calculated from five zooids haphazardly sampled from each of three regions in 11 colonies (A. M, E = Ancestral. Mid. and Edge regions). Both within-colony lo- cation (X2 = , P = ) and date (\- = P = ) significantly affect the frequency of reproductive colonies. 10-13 days after contact. Five zooids were again sampled from each region, and the median of those values ana- lyzed. Because the shapes of colonies became so distorted in the crowding treatment due to compensatory growth away from the interaction, it was impossible to consis- tently sample the same three regions as on the controls (A, M, E). We therefore divided the crowded colonies into regions of two (M, E) instead of three equal radii for sampling. Results Tim ing of reprodi ict ion Under normal, good-growth, field conditions, colonies begin reproduction as males at an age of approximately 40-60 days and would be approximately 2500 mm2 in area (Harvell. 1992). The pattern of reproduction in un- manipulated colonies is for older zooids near the ances- trula and in the mid regions of colonies to reproduce first (Fig. 1). Most zooids are producing spermatocytes and oocytes by late July. The significant results of the log-linear test reflect the transition in ancestral and mid regions of colonies from a non-reproductive to reproductive state between 18 and 25 July (Fig. 1). By 25 July, the percentage of ancestral and mid-colony regions that are reproductive has in- creased from 0 to 25%, respectively, to 100%. These data do not allow us to differentiate timing of reproductive events in ancestral and mid-colony regions because both regions became equally reproductive; zooids from the edge were still not reproducti
Size: 1994px × 1254px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
