. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SPKRMATOZEUGMATA WAVEFORM DYNAMICS 41. Figure 7. Spermatozeugma of Membranipora iin-inhniiuici'ii crawling out of a paternal tentacle tail-end forward by producing a reverse waveform. Images are 20 ms apart. Arrows indicate the position of the wave along the aggregate. Scale bar = 20 /um. lation to deliver spermatozeugmata to the spermatheca of mating partners. The spermatozeugmata produced by many species of marine and freshwater oligochaetes, marine bi- valves, gastropods, insects, and fish differ from the sperm aggregates
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SPKRMATOZEUGMATA WAVEFORM DYNAMICS 41. Figure 7. Spermatozeugma of Membranipora iin-inhniiuici'ii crawling out of a paternal tentacle tail-end forward by producing a reverse waveform. Images are 20 ms apart. Arrows indicate the position of the wave along the aggregate. Scale bar = 20 /um. lation to deliver spermatozeugmata to the spermatheca of mating partners. The spermatozeugmata produced by many species of marine and freshwater oligochaetes, marine bi- valves, gastropods, insects, and fish differ from the sperm aggregates of Menthmniporu membranacea in that they consist of dimorphic sperm (, Ferraguti cl ai, 1989; Healy and Jamieson. 1993: Buckland-Nicks et til., 2000; Jespersen et ai, 2001. 2002; Hayakawa ct <//.. 2()()2a: Sahara and Kawamura, 2002). One type of sperm, euspermatozoa, fertilizes eggs; the other type, paraspermato/.oa, does not fuse with eggs, but instead is thought to enhance the fertil- ization success of euspermatozoa through a variety of mech- anisms, including preventing sperm from other conspecih'c males from fertilizing eggs (see Buckland-Nicks ct i/l., 1999; Hayakawa et <;/., 2002b; Sahara and Kawamura, 2002). The production of spermatozeugmata by M. nienihriiiui- cea may increase fertilization success in three ways. First, "packaging" sperm together may reduce the loss of sperm during the transfer from paternal to maternal individuals (, Braidotti and Ferraguti. 1982; 6 Foighil. 1989; Lynn, 1994; Jespersen and Lutzen, 2001; Hayakawa 2002b). Among gymnolaemate bryozoans, M. inciiihruiuicea has an uncommon reproductive biology (see Reed, 1991; Temkin and Zimmer, 2002). In most gymnolaemate bryozoans, the maternal zooids produce only one or a few eggs during each reproductive period; these are spawned to an external brood site, where they develop into lecithotrophic larvae, either coronate or pseudocyphonautes. In contrast, maternal zoo- ids
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
