Transcript:

Today on Animal Fact Files we’re discussing rock bristletails.These arthropods are called bristletails because of their rear end: it looks like the bristles of a sparse paint brush! These little brush-like filaments help with sensing the bristletail’s surrounding environment and steering the insect while jumping– don’t worry, we'll come back to that shortly. The “rock” part of their name may come from their behavior of basking on rocks during the day, although this also feels like a bit of a stretch. It may instead come from their stone-like coloration, but even this is difficult to say. There are two main families of bristletails alive today. Between these two families there are more than 500 bristletail species, and about 150 of these species are rock bristletails. The families are somewhat geographically separated because most rock bristletail species are distributed throughout the southern hemisphere. The jumping bristletails, which make up the other main bristletail family, are mostly confined to the northern hemisphere.

Bristletail common names are confusing because, although rock bristletails are classified in a separate family, both rock and jumping bristletails jump! It’s also worth noting that jumping bristletails can also be found on rocks, so their common names don’t really focus on anything specific to their family. They’re generally separated simply based on where they live, but rock bristletails can also be more active during the day and occur in drier areas such as dunes and deserts. They’re most often found in leaf litter, on tree trunks and bushes, and under rocks and fallen logs. To make the naming even more confusing, rock bristletails are also known as humpbacked bristletails. This is a logical common name, however, because it alludes to the hump shape that appears along their back. In fact, this hump helps separate rock bristletails from silverfish who are flat backed. Bristletails superficially resemble silverfish but these invertebrates are not closely related.

Rock bristletails have long antennae, compound eyes on top of their head, no wings, and silvery, rock-colored scales. Their scales help them escape predators such as spiders, flies, beetles, and other predatory insects because the scales fall off upon contact, making the rock bristletails “slippery” and difficult to hold onto. Rock bristletails can reach up to an inch (2.5 cm) in body length, and they themselves are not predatory. Instead, these insects are scavengers who consume the carcasses of other arthropods as well as lichen, algae, and other plant material. Rock bristletails scrape their food off hard surfaces with their mandibles. These mandibles are not strong enough to pierce human skin so they are not harmful to humans. In fact, rock bristletails help break down organic material in the environment, so they’re considered beneficial to have around. Sometimes these lovely animals even clean up after themselves by eating their own poop!

Depending on the species, it takes rock bristletails two years to reach adulthood. To reproduce, males produce a sperm packet, called a spermatophore, and lays it in the ground. The female then picks up the sperm packet and takes it into her abdomen in order to fertilize her eggs. Rock bristletails laid their eggs in small batches in leaf litter, grass, under rocks, and other secluded places. The eggs incubate from two months to over a year depending on the species along with other environmental factors. The babies hatch looking like smaller versions of the adults, and they molt as they grow which continues into adulthood. The lifespan for longer-lived rock bristletail species is about four years but some may develop faster and not live quite as long.

For more facts on rock bristletails, check out the links below. Give a thumbs up if you learned something new today. Thank you to our Patrons SpikeSpiegel93, Dad, and everyone else for their support of this channel! And thank you for watching Animal Fact Files!