Simple Hermaphrodite

Free-swimming arrow worms are relatively simple invertebrate animals. These small, transparent creatures are simultaneous hermaphrodites, that is they possess both male and female gonads at the same time. The male sex organs are in the tail and the female ovaries are in the trunk of the body. Usually arrow worms cross-fertilize but some can self-fertilize. They display complex mating behaviour which varies greatly between species. Fertilization can be reciprocal (that is, both individuals donate and receive gametes, as is usual with hermaphrodites) or unilateral (just one individual donates gametes that the other receives).

Peter Parks/Oxford Scientific Films

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Arrow Worm; Hermaphroditism; Invertebrate

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