. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FERTILIZATION SUCCESS IN POLYCHAETES AND STAR1 ISM 39 100 •n p—- a. 75- 50- (A): Aremcola manna P. 0 12 24 36 -48 60 72 84 96 IOC-, (Bl: Astenas rubens. Sperm Age (hi ! Water —D— Seawater Figure 4. Fertilizing capacity of dilute sperm from Arenicola manna (A) and Asterias rubens (B) stored either in seawater or in conspecific- egg-conditioned seawater. Note the difference in timescale over which oocytes were viable for each of the species. Standard errors were calculated from the arcsine-transformed percentage data and back-
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FERTILIZATION SUCCESS IN POLYCHAETES AND STAR1 ISM 39 100 •n p—- a. 75- 50- (A): Aremcola manna P. 0 12 24 36 -48 60 72 84 96 IOC-, (Bl: Astenas rubens. Sperm Age (hi ! Water —D— Seawater Figure 4. Fertilizing capacity of dilute sperm from Arenicola manna (A) and Asterias rubens (B) stored either in seawater or in conspecific- egg-conditioned seawater. Note the difference in timescale over which oocytes were viable for each of the species. Standard errors were calculated from the arcsine-transformed percentage data and back-transformed for presentation. impeded for some embryos as a consequence of oxygen tensions or biotic factors (, infection). The blastula/early gastrula stage, which lasts for a number of hours, also allowed the success (or otherwise) of early embryonic de- velopment to be examined and scored without the need for fixation of the samples. Very few data exist on the longevity of unfertilized gametes among marine invertebrates. That there is a limited life span of gametes was recognized by several early work- ers (, Lillie, 1915). Recent work has quantified the length of time that gametes are viable, but as Benzie and Dixon (1994) point out, this has not been discussed in an ecolog- ical context. It is generally reported that sperm become senescent more rapidly than eggs in free-spawning inverte- brates, their longevity being measured from minutes to 1 or 2 hours (see Levitan, 1995; Table 1). This extends across a range of invertebrate groups including chelicerates (Brown and Knouse, 1973), echinoids (Pennington, 1985; Levitan ft ul., 1991), asteroids (Benzie and Dixon. 1994), bivalve molluscs (Andre and Lindegarth, 1995), and hydroids (Yund, 1990). Ooc\te longevity There are marked differences in the oocyte longevity of the species studied here. Arenicola marina oocytes remain fertilizable and capable of developing to blastula for more than 96 h (Figs. 1 and 2). Oo
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
