[SymeAaro (OP)]

He IUCN uses the species total number to see what it's rating would be.
But, surely it would be different for insects? If not, u could literally just breed two insects and boost the population to endangered from a critically endangered start. But then insects die out easily... essentially, what I'm asking is... does the number of insects or other numerous invertebrates have to be higher to qualify as the same IUCN rating as a given mammal. E.g, a mammal would be CR at... I dunno... 200 individuals (not accurate), but then an insect would be CR at 5000. Or do they just assume the same. If so, wouldn't insect conservation be dead easy?

[Kryptid]

A single pair of insects breeding (or any other very small number) would have the same problem associated with it as any other pair breeding: little genetic diversity. Inbreeding would negatively affect the fitness of the insect pair's descendants, as well as the fact that the population would be very genetically uniform. That uniformity would make it less resistant to things like disease, predation, and environmental changes because they would all react to these things in similar ways. You'd be much better off taking efforts to keep the population from becoming small in the first place.

[evan_au]

I did a search for insects in the IUCN Red List.

It only came up with 10 matches (maybe there other other insects there, but they don't mention "insect" in the title?).

See: http://www.iucnredlist.org/search

[atrox]

He IUCN uses the species total number to see what it's rating would be.

This is just partly true. While indeed those numbers are used, they are only part of a rating system that uses different criteria and usually not the only factor (this is only true for very small populations). They also take other factors into account, like development of total population (is there a decline), range and shape of distribution (e.g. are the habitats scattered), risk exposure and so on. The total asessment is carried out by experts on the species.

Of course, it does not make sense to just compare populations numbers without any backround information. In that case predators would always be rated higher, as they are usually present in much smaller numbers then possible prey species.

Numbers that are necessary to sustain a healthy population are very different between species and will be taken into account.
Species that get very old are usually abundant in much smaller numbers than species with a short lifespan, which does not necessarily mean that they are at higher risk of extinction. However, if the number of individuals decline it could have much worse implications for long-lived species than for short lived ones (that usually fluctuate much more).
Species with a very restricted range are at higher risk than species that are distributed worldwide.
Species that are very specialized (in food, habitat ..) are at higher risk then species that are generalists.
Species that face a momentary danger (hunting, desease..) and thus declining numbers are at higher risk.

One number alone can not be a valuable factor for assessing the risk. You at least need an idea of the development behind that number.

[SymeAaro (OP)]

Thank guys, lot of help!