Transcript:

Today on animal fact files we’re talking about aphids. There are currently more than 4,500 living, classified species of aphids. In terms of their relationship to humans, aphids are considered pests. These animals eat plant sap and may negatively affect every crop humans raise. But, they’re just doing what they enjoy doing and that’s eating! Aphids are very small - as in usually around a millimeter in length, small. These arthropods eat by piercing the outside of a plant with a structure called a stylet - it’s basically a built in straw. The stylet is coated in slick aphid saliva to help facilitate this process. Once inside the plant, the aphids suck up plant sap. As a plant loses sap, it weakens. This is why aphids are viewed in such a negative light and are considered the greatest competitors to human agriculture! There’s a lot more to aphids than their sap sucking, though.

Throughout the eating process aphids produce a substance called honeydew. Honeydew is released through a cauda on the end of their abdomens. This may be round and knobbed to long and finger-like depending on the species. Many aphid species live in a symbiotic relationship with ants who protect the aphids from predators and are allowed to eat the honeydew produced by the aphids as payment for this protection. Predators to aphids include ladybugs, flower bugs, parasitic wasps, and more. These distinct arthropods also have a unique feature in the form of paired pores that can release an alarm pheromone to warn nearby family members of danger. Technically these family members are very closely related indeed, but we’ll be coming back to this in just a bit.

In general, the life of an aphid is short with some species producing multiple generations in a single year sometimes even switching their primary host plant throughout their lifetimes! Many animals, including most aphid species, have a specific host and stick with that host for the entirety of their lives. For example, tobacco worms, a species of hawk moth, tend to stick to a certain family of plants - that being the nightshade plant family. The larvae aren’t usually found on any other plants because plants of the nightshade family are their host plants. The same can’t always be said of aphids. Some aphid species will stick to one plant type for one season and then switch to another plant type for another season. This plays a part in their life cycles.

Probably one of the most complex aspects of aphids is their unique life cycle. Aphids reproduce via parthenogenesis meaning the females produce offspring without fertilization from a male. These offspring are essentially female clones of the mother - so in a way this means when a female aphid releases alarm pheromones to warn of a predator she’s essentially warning… herself. If that’s confusing, just imagine what an aphid family reunion must be like. The mother aphid gives birth to live young, not unlike the hissing cockroaches we’ve talked about previously; but what's so impressive about aphids in particular is that when a female gives birth to her daughters, the daughters already have babies developing inside of them! That means when an aphid gives birth to her daughters, she's essentially also giving birth to her granddaughters! Not all aphids do this, and sometimes things change based on the season. Some aphids do lay eggs and even come equipped with ovipositors to do this.

An ovipositor is an egg-laying structure found in many arthropods - it’s essentially the reason female wasps can sting and males can’t! Then again, the aphids who do reproduce without fertilization will, on occasion, give birth to different kinds of babies. During the early summer these females produce via parthenogenesis, but when a plant gets too crowded they’ll produce winged babies. These winged babies will fly to new plants. As the season wears on, both female and male offspring will be produced. These will mate and these females will produce eggs that overwinter, thus ensuring the generation continues. Species in warmer areas may not do this; others may enter a period of dormancy during the heat of summer; and other species may even switch the plant they’re eating all together for example jumping from a tree to a shrub-like plant in summer and then back to a tree in the fall!

For more facts on aphids, check out the links in the description. Thank you to Zainul for today’s request. Give a thumbs up if you learned something new today, and thank you for watching Animal Fact Files.