Here we have my 'oh so charming' Bot fly/Mango fly inspired Scraplets.
Let's get onto these lovely fellows...

Flight stage:
Scraplets start their lives as flying insectoids rather than larvae!
Using massive sight-organs on their front capable of picking up more than just lightwaves these surprisingly tiny insects locate potential hosts with dangerous accuracy.
The grooves in their drill-like proboscis secrete a numbing agent making their entry into a body very easy, once embedded in they release a Cyber-pheromone that alerts other nearby Scraplets.
This stage of life is primarily used to travel long distances and mate.

Scraplets (main stage):
When you say "Scraplets" these bloated menaces are usually the things that come to mind in any Cybertronian. Once their flight stage has located a host and burrowed into their outer layers, they begin to swell up as they absorb nutrients from the host.
Their fangs, 'horns' and 'hairs' are all designed to make them dangerous to remove if the Scraplet is unwilling.
The Scraplet will usually produce eggs at this point and Scraplet eggs are interesting, if the parent is imbedded in a healthy host the eggs will hatch straight into a Scraplet, if not the eggs will hatch into their flight stage and head off to find a new host.
This means an infestation can spread pretty dang fast if not noticed sooner and a Mech can soon become riddled with the beasts.

Scraplets can be removed from their host in one way or another, but this doesn't leave them defenceless, no, they're surprisingly fast and using small 'feet' as a base they are capable of jumping surprising distances. Their voracious appetite doesn't stop either, while initially content to suck nutrients out of and chew on their host, a Scraplets set of three saw-like teeth are excellently adapted at shredding a Cybertronians armour. They will often travel in swarms and can easily smother large mechs and consume them.

Hive stage:
Once a host has begun to reach the end of it's usefulness to it's 'passengers' the Scraplets employ one of their most sinister tactics.
The swarm can mobilise their host in search of more hosts or a better supply of food. They also carry around a lot of flight-stage Scraplets which hide in the holes.
This stage isn't really necessary for Scraplets to engage in given they can be dangerous enough on their own, but it's assumed it's some sort of instinctual desire to remain 'protected' and 'hidden'.
At this stage there is zero chance of the hosts survival.

Combat methods:
- Scraplets do not like cold and can shut down in the cold waiting for warm temperatures. So using things like liquid nitrogen is good to shock them into either hibernation or death.
- Immediate quarantine of anyone showing any possible signs of Scraplet infestation, and surgical removal of Scraplet in a freezing room.
- Ingestion of medicine that will secrete substances vaguely poisonous to Scraplets (but safe for the host) to cause the Scraplet to leave the body.
- Amputation of limbs.
- Flamethrowers.