Florida Agricultural Experiment Station


 Ahpids suck the juices from the plant on which they live,
stunting its growth, causing the leaves to curl, turn yellow, and
finally, the plant to die. They multiply with great rapidity, often
beginning when only a week old and producing several young
each day. During warm weather, which means the entire year
in Florida, the individuals of most species bring forth young
 parthenogenetically, that
 is without mating between
 Sthe sexes. Indeed, during
 S. that time of the year males
 "/ are usually not produced
 S" at all. Usually the young
 are born alive and active,
 S the eggs hatching before
Fig. 22.-Cabbae-aphid: a. Wined female: b, they are laid. But with
 wingless female. Greatly enlarged. (From U. the coming of winter, in
 S. Bur. of Ent.)
 more northern states,
males and true females are produced and eggs are laid which do
not hatch until spring. Most individuals never acquire wings,
but from time to time winged individuals are produced and
spread the species from plant to plant.
 Farther north the green peach aphid spends the winter in
the egg stage on peaches, plums, etc. The first two or three
generations in the spring feed on the tender unfolding buds of
those trees. The first generation is pink in color but their
young are green and never become pink. The second or third
generations usually develop wings and leave the trees for tender
vegetables where they live all summer. This annual migration
is common among aphids, and the last generation returns to
the trees in the fall to lay eggs, enabling the species to get an
earlier start in the spring than would be possible were it neces-
sary to wait for herbs to grow.
 Aphids give off a sweet substance called honeydew of which
ants are very fond. For the sake of this honeydew ants care-
fully tend aphids, often protecting them from their enemies
which they drive away. They may carry the aphids or their
eggs from place to place where the "pasture" is good, carry
the eggs into their nests to winter over, or even build adobe
sheds over them for protection from rain and enemies. For
this reason aphids are often called "ants' cows." Hence it
happens that the presence of excited ants on a plant is often
the most evident sign of the presence of aphids.