No.
Edit (in case just a simple answer doesn't sate your curiosity): They covered this card in the Amonkhet Release Notes (found
here).
Amonkhet Release Notes wrote:
Decimator Beetle
3BG
Creature — Insect
4/5
When Decimator Beetle enters the battlefield, put a -1/-1 counter on target creature you control.
Whenever Decimator Beetle attacks, remove a -1/-1 counter from target creature you control and put a -1/-1 counter on up to one target creature defending player controls.
- Decimator Beetle's second ability can target any creature you control, not just one with a -1/-1 counter on it. It'll put a -1/-1 counter on the opponent's creature even if there isn't one to remove from your creature.
- If one target of Decimator Beetle's second ability becomes illegal, the other will still be affected.