Aphids
What are they?
Aphids are abundant insects and are well-known to many a gardener or farmer for the damage they can do to horticultural plants and crops. Typically, species have a number of wingless, summer generations which arise through perthenogenesis - all individuals are essentially female and produce young independently of males. Toward the end of the season, winged individuals are produced which migrate to wintering plant hosts. These individuals often also reproduce sexually and produce eggs which become the method of overwintering. Though aphids can be troublesome in the garden, they are an integral part of the ecosystem. Aphids are visited by many species of ants, wasps and flies who feed on the 'honeydew' excreted by the aphids, while other groups such as lady beetles, lacewings and various wasps feed on aphids, or parasitize them.
Identification
There is an almost overwhelming variety of aphids out there and many are best identified by the plant species that they are feeding on - though many species have alternate hosts, using one group of plants for feeding during the summer and another group for overwintering on. Sometimes size and color can be important too.
Oleander Aphid Aphis nerii
Native to the Mediterranean region, this species is now widespread in North America and favors feeding on milkweed species, though it will also feed on related plant species in the dogbane family. It's bright orange-yellow color, contrasting with black extremities make this a very obvious and distinctive species.
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