The Island of the Colorblind

But whereas ‘Latimeria chalumnae is a single species, only managing to survive in the special conditions off the Comoros, cycads (though no longer the dominant flora, as in the Mesozoic) still number more than two hundred species and still thrive in a wide variety of eco-climes, so they cannot really be called ‘living fossils.’

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The unexpected adaptation of crabs to coconut eating fascinated Darwin, who describes them in the Beagle:

I have before alluded to a crab which lives on the cocoa-nuts: it is very common on all parts of the dry land, and grows to a monstrous size: it is closely allied or identical with the Birgos latro.

The front pair of legs terminate in very strong and heavy pincers, and the last pair are fitted with others weaker and much narrower. It would at first be thought quite impossible for a crab to open a strong cocoa-nut covered with the husk; but Mr. Liesk assures me that he has repeatedly seen this effected. The crab begins by tearing the husk, fibre by fibre, and always from that end under which the three eye-holes are situated; when this is completed, the crab commences hammering with its heavy claws on one of the eye-holes till an opening is made. Then turning round its body, by the aid of its posterior and narrow pair of pincers, it extracts the white albuminous substance. I think this is as curious a case of instinct as ever I heard of, and likewise of adaptation in structure between two objects apparently so remote from each other in the scheme of nature, as a crab and a cocoa-nut tree…It has been stated by some authors that the Birgos crawls up the cocoa-nut trees for the purpose of stealing the nuts: I very much doubt the possibility of this; but with the Pandanus the task would be very much easier. I was told by Mr. Liesk that on these islands the Birgos lives only on the nuts which have fallen to the ground.

(In fact, coconut crabs do climb tall palm trees, and cut off the coconuts with their massive claws.)

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It used to be held that cycads were wind-pollinated, like ferns and conifers, though early authors (including Chamberlain) had occasionally been struck by the presence of certain insects in or near the male cones at the time of pollination.

In 1980, Knut Norstog and Dennis Stevenson, working at the Fairchild Tropical Garden in Miami, were struck by the failure of many introduced cycads there to produce fertile seeds, even though healthy male and female plants had been planted just a yard or two apart, whereas the native Zamia was quite fertile. They found that snout weevils would feed as larvae on the male Zamia cones, emerging as adults by boring through the microsporophylls, covered with pollen. Could this be the way in which the female cones were pollinated?