Effects of competition on sexual and clonal reproduction of a tunicate: the importance of competitor identity

摘要: Individual fitness and the structure of marine communities are strongly affected by spa- tial competition. Among most common space holders colonial ascidians, which have ability to monopolize large areas hard substrate, overgrowing other competitors. The effects competition on colony growth gonad production ascidian Didemnum perlucidum were studied in southeastern Brazil experimentally removing surrounding Colonies D. competing for exhibited a rate 9 times less than that colonies competitor free. subject competition, rates unrelated percentage border was free However, identity important outcome contacts. At beginning experiment, encounters with solitary organisms, cases overgrown. These progressively replaced ascidians bryozoans, resulting mostly stand-off interactions. Besides reducing asexual growth, spatial also female pro- duction. competitors had significantly higher proportion zooids ovaries. Thus, our findings show reduces both size production.