Articles
On
Aphids, ‘lions’ and
Ants
By Mark Stewart
If you were to ask a farmer what he thinks of aphids, he may make
your ears tingle. These tiny insects suck the sap from stems and
tender leaves in his crop and can do a great deal of damage.
On the other hand, beekeepers in Germany prize aphids highly. In
the Black Forest there resides an aphid that gives off a substance
called honeydew, which bees love. Beekeepers from far away travel
there with their bee colonies. After the bees get honeydew from the
aphids they can make expensive, famous fir honey for their owners.
Other insects are divided in their disposition toward aphids, just
as people are. Certain species of ants are so fond of aphids (for
their honeydew!) that they protect their little friends from their
enemies and even hide them underground.
The fact is that aphids are already well equipped for survival,
even without the aid of the ants. They have a bewildering sex life,
for one thing, which for all practical means assures rapid multiplication.
Several generations of aphids may not even have to mate in order
to produce offspring! The aphids are born with eggs for other aphids
right inside them. These eggs hatch and are born as live aphids with
more eggs inside!
In other species,
the aphids do not grow wings if a food supply is plentiful where
they are, but let the supply run short and the
wings begin to grow! Soon they fly off to find more food. As one
source puts it, “Here it is literally true that hunger gives
wings.”
If it were not for their natural enemies, the earth might be overrun
with aphids. But what happens when their friends, the ants, protect
aphids against their enemies?
The “aphid lion” (the
larva of the green lacewing) is a creature that has a voracious
appetite for aphids. It is gray,
bristled, and big, while the aphids it likes to eat are white, small,
and covered with a fluffy wax-like secretion. As soon as the aphid
lion shows up for dinner, alert ants attack it, driving it off.
What does the
aphid lion do? Some aphid lions sneak up on aphids and snatch bits
of the fluffy wax from their backs, using them to
disguise themselves until they appear like overgrown aphids. Then
these ‘lions in aphids’ clothing’ sneak into the “flock” while
the ant “shepherds” are unaware. If an ant gets suspicious,
the disguised lion hides its huge jaws by lowering its head down,
and stays very still. Generally, it is inspected and then left alone.
As soon as the guardian ant walks away, too bad for the nearest aphid!
To most people, aphids are just tiny dots on a leaf, at most a
nuisance. Closer examination, however, reveals the amazing handiwork
of the Creator.
Hegner, Robert W., College Zoology, 5th edition, (New York: The
Macmillan Company, 1944), pgs.291, 306, 315
Moore, John N. and Harold Schultz Slusher, editors, A Search for
Order in Complexity, 9th printing, (Grand Rapids, Michigan: The Zonderman
Corporation, 1982), pgs.127, 209, 216, 218,
Mader, Sylvia S., Biology: Evolution, Diversity, and the Environment,
2nd edition, (Dubuque, Iowa: Wm. C. Brown Publishers, 1987) pgs.403,
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