Here are some dangerous insect to be aware of you when are in Thailand. There are many more and you should familiarize yourself with the insects located in your area.
For Instance, the Thai Black Tarantula, (they bite when feeling in danger and have quite a strong venom), are located all over Khao Sok National Park.
All of these following insects should be avoided.
Centipedes
Red Back Spider
Scorpions
Fire Ants
Mosquitos
Asian Giant Hornet
Paper Wasp
The highest threat with insects is not their venom by itself, but the possible allergic reactions resulting from a bite.
If you have any insect-related allergies (or any allergies for that matter), do the smart thing and always, always carry an EpiPen or similar device with you – it may save your life.
With mosquitoes, there’s always the risk of a nasty mosquito-borne illness, like dengue or malaria. You can reduce the risk considerably by applying mosquito repellant on your skin whenever heading out at evenings or nights when the mini-vampires are most active.