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 34 Batesian satellites DHJanzen100198.jpg high resolution
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| This is an array of butterflies and moths collected in one rainforest over a few days (Rincon de Osa, Costa Rica) by Woody Benson in 1967 and laid out on a table. They are drawn from many different taxonomic portions of the Lepidoptera, and their mimicry of each other is an example of a) convergent evolution (similarity selected for in different evolutionary lineages by a selective pressure in common), b) mutualism (they are - at least theoretically - all gaining from each others presence), and c) a Mullerian mimicry ring with (presumed) Batesian satellites. Number them from left to right, top to bottom, and perhaps study them in high resolution. 1. A heliconiine nymphalid (see DHJanzen100219.jpg for another heliconiine), famous for being toxic through defensive chemicals (such as cyanide) sequestered from larval food plants in the Passifloraceae. 2. A danaiine nymphalid, a relative of the monarch butterfly (toxic chemicals from larval food plants in the Asclepiadaceae). 3. An ithomiine nymphalid, a relative of the ithomiines in image DHJanzen100197.jpg (toxic chemicals from Solanaceae). 4. A nymphaline nymphalid, belonging to a group that contains highly edible species (though not always), and therefore possibly a Batesian satellite - though to be certain, feeding tests should be conducted. 5 and 6 - two more Ithomiinae, but of a different evolutionary lineage than the one at the 3 position. 7. A pericopine day-flying moth (Arctiidae) that either makes its own noxious defensive chemicals or gets them from the Boraginaceae or Asteraceae that its caterpillar feeds on. 8. Another danaine monarch relative, and here you can see a hint of the characteristic monarch wing shape (though notice that it has been lost in the danaine in the 2 position). 9. Yet another different lineage of ithomiine. 10. A skipper butterfly (Pyrrhopyge cosyra, Hesperiidae) - another very likely candidate for a Batesian satellite, since most hesperiids are edible. However, it should be added that its caterpillar feeds on Clusiaceae and is brilliant black with yellow markings and exudes green liquid from its sides when touched, and may therefore be indeed a Mullerian mimic. 11 and 12 are two more ithomiines. In general terms of abundance, the ithomiines are the most abundant in the forest, and the other species here occur at very, very low density. Also the ithomiines are probably, overall, the most toxic when consumed. It is not hard to visualize very intense selection favoring any mutant of yet another species of Lepidoptera that somewhat resembles one of these Mullerian mimics, and one can also visualize that any species of this general color pattern arriving ecologically (immigration from another area) might gain a respite from predation occurring in its habitat of origin. In other words, the colors of the residents may be part of the determinant as to whether a newly arrived immigrant survives. | ||
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