How much control does a player have over the Infestation cantrip?

Question

While searching XGE for interesting passages, I took another look at the spell Infestation to better understand it:

You cause a cloud of mites, fleas, and other parasites to appear momentarily on one creature you can see within range. The target must succeed on a Constitution saving throw, or it takes 1d6 poison damage and moves 5 feet in a random direction if it can move and its speed is at least 5 feet. Roll a d4 for the direction: 1., north; 2, south; 3, east; or 4, west. This movement doesn’t provoke opportunity attacks, and if the direction rolled is blocked, the target doesn't move.

Though I must admit that I see it gives a specific damage an effect, I was wondering what "and other parasites" could mean. Could someone summon a swarm of wasps (the parasitic beetle wasp to be exact) if they also wanted to use the buzzing for their wizard to hide the somatic components of a spell?

Could the swarm of parasites also have other abilities like a swarm (or individual) rot grub?

P. 208 of VGM:

The target is infested by 1d4 rot grubs. At the start of each of the target's turns, the target takes 1d6 piercing damage per rot grub infesting it. Applying fire to the bite wound before the end of the target's next turn deals 1 fire damage to the target and kills these rot grubs. After this time, these rot grubs are too far under the skin to be burned. If a target infested by rot grubs ends its turn with 0 hit points, it dies as the rot grubs burrow into its heart and kill it. Any effect that cures disease kills all rot grubs infesting the target.

And do they appear and disappear magically or naturally? In other words, is it like you point and suddenly a cloud of parasites gathers from somewhere beyond and then goes back to where they were, allowing someone to capture some of them for material components? or do they not really exist at all?

Answer 1

There are few related questions, but the ultimate answer is the usual:

Spells do only what they say they do!

You cause a cloud of mites, fleas, and other parasites...

Nothing in here suggests you can pick and choose what insects appear though even if a DM allowed it, it shouldn't make a difference. Since whatever parasites appear they will never do more than the indicated poison damage and movement effect. It would certainly be well outside the bounds of the spell to allow creatures to be summoned that cause additional (potentially deadly) effects.

A very rough comparison would be to compare it to Conjure Animals and similar spells where, it has been previously pointed out, the player only chooses from the available options (the number/CR of the creatures) but its the DM that has ultimate say on what creatures appear within this option.

...appear momentarily

This seems pretty conclusive: The insects appear from "nowhere" (effectively) and last momentarily - meaning they disappear back to wherever they came from after causing the effects noted in the spell.

Again, a lenient DM may allow some to be captured, but this wouldn't be RAW and shouldn't be allowed if the intention is to "game the system" by making a low-level spell do far more than intended.