Aphids are born pregnant
It is known that many insects and wild animals have babies very soon. Sexual maturity is the age at which any being can reproduce, but Aphids seem to have something special.
First of all, what are they?
Aphids are small, soft-bodied insects that feed by inserting their slender mouthparts into phloem cells, the food conduits of plants. Most aphid species feed on only one species of plant and closely related aphid species tend to feed on closely related species of plants. Once an aphid finds the correct plant species, it simultaneously feeds and reproduces. Offspring settle close to their mothers, spawning large colonies. Newborn nymphs molt four times, each time growing larger but otherwise looking similar to their previous incarnation. – US National Library of Medicine National Institutes of Health
Ed Spevak, curator of invertebrates at the St. Louis Zoo says Aphids are “essentially born pregnant”, because they can reproduce asexually by creating a kind of miniature replicas of themselves. When that happens, a newly hatched female has eggs already growing inside of her.
Aphids can also use sexual reproduction if the wheather becomes favorable, but it is different for each organism.
source: National Geographic