Moth Mutualism with Cycads

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Moth mutualism with cycads described in articles in ScienceDaily 14 June 2010 and American Journal of Botany, doi:10.3732/ajb.0900251. A tiny moth currently known to exist only on the islands of Guam and Rota has been found to have a mutualistic relationship with cycads that goes beyond the usual plant-pollinator relationship. Cycads are cone bearing plants that produce pollen in male cones, which must be carried to separate female cones. Unlike pine cones, which disperse their pollen on the wind, cycad pollen is collected and transported by insects. Therefore, the insects must have some incentive to visit the cones. In the case of the moth the cones are an ideal nursery for their larvae. After the insects have laid their eggs and departed with the pollen, the insect larvae hatch out and feed on the cones. This was assumed to be the end of the story.

Thomas E. Marler of Western Pacific Tropical Research Center, University of Guam, has studied the cycad Cycas micronesica and its pollinating moth and found that cycads whose cones had been used as moth nurseries not only got the benefit of pollen transport, but also developed new cones more rapidly than plants that were not pollinated by the moth. Marler summarised his results: “This is the first documented case where removal of a postdispersal cycad pollination organ speeds up subsequent reproductive events, and the current paradigm that the offering of cone tissue as a nursery is a sacrifice by the plant in return for the pollination services is therefore inaccurate.” This is also the first case of a cycad being found to be pollinated by a moth.


Editorial Comment: The growth stimulating effect of having an insect nursery living in the spent cones is a reminder the world was originally designed to work in a very good way, without competition and struggle. Having their cones eaten after their pollen has been gathered and transported is not a bad thing for the plant. The plant no longer has any need for the cone, and Genesis does tell us green plants were designed to be food for all other living creatures. In a very good world insect numbers would be under control, and would not have ravaged the vegetation like they do now.

Cycads are believed to be fairly primitive land plants that evolved long before conifers (pines) and the flowering plants. The pollinator relationships between plants and insects was once believed to have evolved following the advent of flowering plants, but recently evolutionists have had to revise this theory as cycads have now been found to have a pollinator relationship with several kinds of insects, including thrips, weevils and beetles.

Our Jurassic Ark site has many cycads growing in the gardens. We have observed a number of different insects, including beetles and native bees, entering the male cones to collect pollen.

Evidence News 24 November 2010