CULT: answering my own questions re: aphid ecology

At the risk of boring everybody, here's what I learned about aphid
ecology from a quick scan of my small tattered collection of beginner's
insect books.  Most of the general information comes from Peterson First
Guide to Insects of North America, 1987, by C. Leahy:

Aphids are in the same 'large and exceptionally varied [insect] order'
as cicadas, plant hoppers, and scale insects.  'Their life histories are
impossible to stereotype'.  Which maybe explains why nobody said
nothin'.  'Many [in the order] are strange and beautiful'.  In NA there
are about 6500 species in the order, but I wasn't able to find how many
of these are aphids or how many genera of aphids there are.

'The life cycle of aphids is complex.  It typically involves several
generations of winged and wingless females, which reproduce without
mating, and a generation of both males and females, which mate.  The
fertilized females lay eggs in bark crevices or near buds...aphids are
eaten by many birds and insects.'

Insect Pests, 1966, by G.S. Fichter, ed by H.S. Zim, A Golden Nature
Guide makes mention of several different species and genera of aphids,
including: the cotton (Aphis gossypii), pea (Acyrthasiphon pisum), bean
(Aphis fabae), cabbage (Brevicaryne brassicae), melon (same species as
cotton), corn root (Anuraphis maidiradicis), chrysanthemum
(Macrosiphoniealla sanborni), wooly apple (Eriasoma lanigerum), rosy
apple (Anuraphis rosea), apple (Aphis pomi), and Spirea or green citrus
(Aphis spiraecola) aphids (printed in TINY letters, so I hope I got
these spelled right).

This book says:
'In the typical life cycle of aphids that live in temperate climates,
winter is passed in the egg stage [either this is no longer a temperate
climate or they just don't know it's winter here yet], glued to the stem
or to other parts of the plant.  Nymphs that hatch from the eggs the
following spring grow rapidly to become wingless adults, called stem
mothers.  Stem mothers give birth to their young, holding their eggs
inside their bodies until they hatch.  Within about a week [!!] these
aphids produce young in a similar manner.  More than a dozen generations
occur in a short time, producing a feeding cluster on the plant.  At
intervals, some or all of the young produce wings and migrate to other
plants, starting new colonies.  In some species, the winged stages
settle on plants of the same kind; in others, they always settle on
different kinds of plants.  In autumn, males and females are produced,
and the females lay fertilized eggs that overwinter.  In warm climates
reproduction is continuous.
	Aphids are eaten by birds, preyed on by various lady beetles, and
parasitized by wasps.....
	All aphids have similar life histories and habits.  A few species feed
on the roots of plants, but most kinds suck sap from leaves or
stems....Corn root aphids [this is really getting away from irises.]
infest the roots of corn ..[and].. winter in the nests of cornfield ants
[Lasius alienus].  As soon as the eggs hatch in spring, the young are
pastured first on the roots of weeds or grasses, then on corn plants. 
The aphids produced winged generations that fly to other plants, where
they are captured by ants and put to work.'  

I'll skip the details of the life history of root aphids of woody
plants, tho it is equally fascinating.

Linda Mann East Tennessee USA


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