Invertebrates
Aphid
Aphididae · also called plant lice, greenfly
A single aphid settles on a fresh plant shoot, and within days its genetically identical daughters, granddaughters, and great-granddaughters have covered the stem, every one of them born without a single mating ever taking place.
Overview
The aphid, family Aphididae, is a tiny plant-sap-feeding insect found on host plants across nearly every terrestrial habitat worldwide. Its capacity for rapid asexual reproduction and its close, mutually beneficial relationship with tending ants make it one of the more ecologically influential small insects on the planet.
A population explosion built into its biology
Few animals turn a single individual into an entire colony as efficiently as the aphid, which sidesteps the usual constraints of finding a mate entirely, converting a good patch of plant growth into an exponentially growing population within a matter of days.
Status
Not Evaluated — extremely abundant as a group, with many species considered agricultural pests rather than a conservation concern.
Aphid: common questions
Can an aphid reproduce without mating?
Yes, an aphid can reproduce through parthenogenesis for much of the year, with females giving birth directly to genetically identical live young without needing to mate at all, a reproductive strategy that allows aphid populations to grow explosively within just days under favourable conditions.
Why do ants protect aphids?
Many aphid species are actively tended by ants, which protect the aphid colony from predators and sometimes move the aphids to fresh plant growth, doing so in exchange for the sugary honeydew the aphids excrete as a byproduct of feeding, an arrangement that benefits both species.
Why do some aphids suddenly grow wings?
When a host plant becomes overcrowded or begins to decline in quality, some aphids within the colony develop wings, allowing those individuals to disperse away from the deteriorating plant and establish entirely new colonies on fresher host plants elsewhere.
What eats aphids?
Aphid colonies are a primary food source for numerous natural predators, most notably ladybugs and lacewing larvae, both of which can consume large numbers of aphids over their lifetimes, making them important natural checks on aphid population growth in gardens and farms.