A Naturalist at Large 
With a Little Help 
from My Friends 
Many creatures depend on others for protection 
by Milton Love 
As a young boy, I was short, bookish, 
and wore incredibly thick glasses — attri- 
butes I enjoy to this day. Naturally, I 
was the prime target of every bully in 
the neighborhood. In desperation, I 
searched for a bodyguard, cultivating 
the friendship of a boy who was, as 
Arthur Conan Doyle would have re- 
marked, “more accustomed to using his 
muscles than his wits.” Fortunately, 1 
never had to call upon my friend’s singu- 
lar talents, but many organisms regu- 
larly depend on others for protection. 
Hedgehogs are Old World relatives of 
moles and shrews. Although fairly small 
animals, they are infrequently preyed 
upon, despite their rather charming 
habit of advertising their sleeping sites 
with assorted wheezes, snores, and 
gasps. Certainly one reason for their 
comparative immunity is their covering 
of stiff, springy hairs — while another is 
their ability to use the toxins in toad 
skins for their own defense. 
A number of toads possess glands, 
lodged just below the skin surface, that 
secrete a variety of poisons, one of which 
has the ability to arrest beating hearts 
(including human). In spite of what 
might seem ample deterrent, hedgehogs 
often capture and eat toads with every 
sign of satisfaction. Before dining, the 
animals chew on the toad’s large, poison- 
bearing granular glands and take the 
toad venom into their mouths, where 
contact with mucous membranes cre- 
ates frothing. With their tongues, the 
hedgehogs slather the froth on their 
spines, apparently as a protective de- 
vice. Occasionally hedgehogs will rub an 
entire toad skin over their spines. 
In the laboratory, this self-anointing 
can be stimulated by a variety of sub- 
stances, including tobacco and sour 
milk. The behavior seems to be specific 
to somewhat irritating substances, as 
hedgehogs eat bullfrogs and mice 
(which lack toxins) without such cere- 
mony. 
Internal retention of toxic substances 
from prey is another method of adding 
to one’s defensive posture. Carminic 
acid is a potent defensive compound 
found in cochineals, small scale insects 
of the genus Dactylopius. Present in 
blood, muscles, and eggs, the bright red 
acid is apparently distasteful to such 
potential predators as ants, which give 
even dead cochineals wide berth. How- 
ever, the caterpillar larvae of the moth 
Laetilia coccidivora circumvent and 
even utilize this chemical barrier. These 
caterpillars subsist entirely on scale in- 
sects and store cochineal remains and 
carminic acid in the front part of their 
gut. When disturbed by an ant predator, 
the caterpillar twists around and deftly 
deposits a drop of this fluid on its 
attacker. Moreover, the caterpillar may 
roll about in this extruded liquid, coat- 
ing its body, a stunt that seems to deter 
further harassment. 
Many other insects, including grass- 
hoppers and butterflies, feed on plants 
containing various toxins, storing these 
in body tissues. For example, glycosides, 
the powerfully emetic compounds pro- 
duced by milkweeds (family Asclepia- 
daceae), are ingested by the larvae and 
retained in the tissues of adult monarch 
butterflies (Danaus plexippus ). Birds 
attempting to prey on glycoside-contain- 
ing monarchs quickly develop a strong 
aversion toward their prey. However, 
some recent evidence indicates that not 
all monarchs in a population contain 
enough glycosides to produce an emetic 
response. Moreover, it appears that 
some birds can distinguish emetic and 
nonemetic individuals. On Mexican 
overwintering grounds, orioles and gros- 
beaks were observed capturing and re- 
leasing some monarchs while ingesting 
others. The birds were also selective as 
to what body parts were eaten. Abdomi- 
nal and thoracic regions were favored, 
while wings (known to have high gly- 
coside concentrations) were discarded. 
Apparently, some predators are not only 
able to distinguish (by taste) nontoxic 
monarchs but can also select the least 
distasteful parts of the prey. 
The defensive system of the brightly 
colored sea slug Flabellinopsis iodinea 
is artfully appropriated from its food 
source, the hydroid Eudendrium ramo- 
sum, which possesses numerous stinging 
cells called nematocysts. Nematocysts 
contain a coiled, whiplike structure that 
is suffused with toxin and often lined 
with barbs. When the cell is triggered by 
mechanical or chemical stimulus, the 
whip lashes out, impaling the nearest 
tissue. Although nematocysts vary in 
potency, some, such as those of the 
Portuguese man-of-war and various 
Cubomedusae can kill large organisms 
including humans. The sea slug ingests 
and stores the cells in cerata — elongated 
tubes extending from its back. 
F. iodinea feeds by grasping a hy- 
droid in its jaws and rasping off pieces 
with its toothlike radula. The food mate- 
rial, containing nematocysts, is funneled 
through a buccal (mouth) cavity and 
esophagus lined with a tough collagen 
material that seems to protect the un- 
derlying tissues from any discharged 
nematocysts. Churning action of the sea 
slug’s stomach separates the nemato- 
cysts’ triggers from the stinging cells. 
From the stomach, the otherwise intact 
cells flow into a digestive gland that has 
connections to each cerata via cilia-lined 
canals. The nematocysts travel up these 
canals to cerata tips, where they are 
housed. The whole process, from hy- 
droid to cerata, is rapid, taking as little 
as twenty minutes to complete. There 
are no known predators upon F. iodinea, 
for which this defensive maneuver may 
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