title used in learnabout sections of A SNAIL'S ODYSSEY
  Reproduction
 

Polychaetes as a group have a broad spectrum of reproductive modes. Within tubeworms are ones that have asexual reproduction, considered here, while modes of sexual reproduction include SPECIES THAT BROOD INSIDE OF TUBE, SPECIES THAT BROOD OUTSIDE OF TUBE, SPECIES THAT ARE POICILOGONOUS, and SPECIES THAT BROADCAST GAMETES. There is also a general introductory section on tubeworm LARVAE.

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Asexual reproduction

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Research study 1
 

photograph of cluster of tubeworms Phyllochaetopterus prolificaA researcher at Pacific Biological Station, Nanaimo describes asexual reproduction in the chaetopterid worm Phyllochaetopterus prolifica occurring by a type of autotomy or fragmentation. The species lives solitarily, but in many areas of the west coast it commonly occurs in large aggregations or colonies perhaps explained, in part, by this reproductive mode. The tubes inhabited by P. prolifica are slender, often branched, and each branch may contain up to 6 individuals. An individual undergoing fragmentation does so commonly in the mid-body region but not always in a specific location, with the pieces regenerating in both directions from the place of rupture. The author comments that regeneration is often a bit slap-dash (not his words), and may result in individuals with varying segment sizes and numbers. As in other chaetopterids that fragment in this way, some sort of disruptive stimulus, such as stressful temperature or perhaps attack by a predator, may be involved. The author does not witness sexual reproduction but, as it has been reported in at least one other Phyllochaetopterus species, it most likely occurs. Potts 1914 Zool Soc Lond, Proc 67: 955. Photograph courtesy Douglas Mason, California.

NOTE with several individuals in a single tube, it may be crowded at the tube opening for extension of feeding palps. In such cases, the author observes individuals frequently changing places. Another observation is that in crowded tubes with worms facing every which way, water flow and feces removal may be disrupted, the end result in some cases being blockage of large sections of the tube by fecal masses. This may lead to abandonment of old tubes and formation of ne.w ones, thus extending the colony

NOTE other chaetopterids that undergo asexual reproduction, such as Chaetopterus sp. in Britain, may fragment in a specific location (e.g., between the 1st and 2nd segments of the middle body region)

 

A "colony" of chaetopterid worms Phyllochaetopterus prolifica
at Asilomar, California. Note the absence of branched tubes 2X

 
  photograph of unidentified syllid polychaeteNeil: people have published on the pattern of the cirri, whether they go up or down and their relative positioning. The down ones are supposed to be short andthe up ones, long, but I don't see it in this species. They seem of equal length to me (note the ones on far Right). The question is whether they stay always in the same relative positioning, especially when the worm is crawling or swimming. That's where a video would come in handy OR in situ observations. When I passed this one in 1982 I recall I was in a current and just managed this quick and slightlly blurry photo. I saw a second specimen in 1986, also in Barkley Sound, but my brain must have been dead at the time, as I spent zero time studying it for whatever reason. Tom
 
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