Chapter 28, Problem 11PIAT

Is long-distance sex possible in mosses?

Moss sperm are motile and capable of swimming short distances to fertilize an egg. However, it was unknown until recently how sperm make their way from male to female gametophytes that may be separated by a distance of several centimeters or more.

QUANTITATIVE Researchers hypothesized that small animals called springtails (a type of arthropod) facilitate sperm transfer in mosses. To test this hypothesis, the researchers grew patches of male and female mosses at varying distances from each other and in the presence or absence of springtails. They later checked to see how many sporophytes were found in each female patch (as an indicator that fertilization had occurred). Their results are shown below (** means P< 0.01, * means P< 0.05; see Bioskills 3 for help interpreting P values). What conclusions can be drawn about the role of the springtails during the reproductive cycle of the mosses?