The New Neotropical Companion

patterns? Even though potentially lethal to any animal

it happens to bite, a coral snake could still be killed or

suffer extensive harm if attacked. Some bird species

prey on snakes, and at least one, the Laughing Falcon

(Herpetotheres cachinnans), has been observed to kill

and devour coral snakes. A coral snake’s well- defined

red, black, and often yellow pattern is presumably easy

for birds (all of which see color) to recognize, remember,

and avoid. Avoidance of coral snakes appears to be

innate in some bird species. Both the Turquoise-

browed Motmot (Eumomota superciliosa) and the

Great Kiskadee flycatcher (Pitangus sulphuratus) have

been shown to instinctively avoid coral snake patterns.

Others likely do as well.

Certain nonvenomous snakes, including some king

snakes, closely resemble coral snakes and are thought

by many to be coral snake mimics (plates 11- 26– 27).

Experiments have demonstrated that the avoidance of

ringed patterns typical of both coral and king snakes

is strong in areas where coral snakes are present,

suggesting that the king snakes have evolved to mimic

the coral snakes. But not everyone agrees. King snakes

are aggressive when attacked, and thus it is not fully

clear whether king snakes are mimicking coral snakes or

coral snakes are mimicking king snakes— or both. The

complexities of mimicry will be discussed later in this

chapter. Coral snakes are discussed further in chapter 16.

Bold patterning is common in some large caterpillars

of the tropics. The larva of the False Sphinx Moth

(Pseudosphinx tetrio), for instance, has a pattern somewhat

suggestive of that of coral snakes (plates 11- 28– 29).

The Neotropical Pharmacy: Plant

Chemical Defense Systems

Do you like salads? Suppose you were somehow

stranded inside a tropical rain forest. You are

surrounded by tons of fresh greenery. Should you

choose a few tender leaves and chow down? Maybe

not.

A look at any random sample of leaves in a rich

tropical humid forest will usually reveal insect damage.

Some leaves will show heavy damage, some little or

none. Herbivore pressure on plants in the tropics is

relatively constant because there is no cold winter (as

in higher latitudes) when herbivores (at least most of

them) become inactive. Plants cannot hide or run from

potential herbivores. Their leaves are, in essence, always

vulnerable. But in general, tropical herbivores take a

notably small percentage of what is potentially available

to them. That is why rain forests are always green. How

do tropical plants defend against herbivorous hordes,

not to mention invasive pathogenic bacteria and fungi?

Let us count some of the ways.

Leaves and stems may be covered with thorns of

various sorts. Leaves grow to be thick and fibrous,

with reduced nutritional value, difficult for herbivores

to digest. Leaves of both tropical and temperate- zone

plants are known to contain numerous chemicals that

function in various ways to potentially defend the

Plate 11- 28. The large and colorful False Sphinx Moth

caterpillar will writhe and twist violently when squeezed, such

as would happen should a bird grab it. Photo by John Kricher.

Plate 11- 29. This Ecuadorian caterpillar also represents an

example of aposematic (warning) coloration, and then some.

Note its bright coloration (it appears to have “headlights”) but

also that it’s covered with dense spines. These are urticating

hairs that, like nettles, cause extreme itching and discomfort if

handled. Not only that, if you do pick this caterpillar up, it will,

like the False Sphinx caterpillar, spasm so that you are likely to

drop it immediately. Photo by John Kricher.

chapter 11 evolutionary arms races: more coevolution, more complexity 187