Nice theme flavor - you have some cards that I like, but use them differently. I don't know if you are going for budget, but the new Bolas Gods look pretty insecty. They only high price now because the set hasn't come out yet.
You have but 6 cards to do negative counters and
crumbling ashes is expensive. I would drop it, or build bigger synergies with negative counters.
Love the
Viridian Longbow with deathtouch. 3 mana to equip, kill. Repeat as necessary.
Quiet Disrepair is also a card that does not get enough credit.
Maybe this deck needs to decide to go all in on theme, and really use insects and spiders deathtouch - there are so many cards - or build up the infect/wither/negative counter aspect. Lots of options in GB for negative counters or get bigger creatures (wither and infect always small power) It looks fun to play and find out what will be best. Also, maybe add opportunities to draw new cards or interact with opponent's threats. Thanks for sharing your idea.