The Elements of Evolution (43-15-13) Bad Taste

 Bad Taste

Brightly colored pitohuis are endemic to New Guinea. These birds take advantage of another animal’s culinary taste to keep themselves safe.

Flashy pitohuis are an advertisement of aposematism (warning coloration). These omnivorous birds are toxic.

Pitohuis are fond of melyrids: small beetles stuffed with batrachotoxins, which are unique steroidal alkaloids more poisonous than strychnine. This is much the same toxic brew found in poison frogs.

Like pitohuis, poison frogs of the Amazon forest are outrageously colored, in a variety of patterns, depending on locality. Poison frog subspecies stew their own variety of toxin. 28 different poison frog alkaloids are known.

Frog-eating snakes learn to recognize the pattern of local dart frogs but will peck at those that don’t match the local coloration pattern; local being 10 km or less. A snake risks death in swallowing one of these frogs if the snake is not adaptively tolerant to the specific toxin.

The poisons in the birds and frogs are hand-me-downs from their diet. The ultimate source of the toxin is not known but is most likely the ultimate food-chain producer: plants.

This predator-prey dynamic of locality in aposematism accounts for the wide variety of warning patterns in a single-prey species. Localized patterning such as this have been observed in butterflies, bees, and other animals. Pitohui and poison frogs are exemplary of innumerable animals that mark themselves and their eggs as inedible.