Excuse me, what kind of insect is this (such as flowers, birds, fish and insects)? Does it bite? And whether it is toxic. Thank you.

According to the photos you provided, this insect looks like Megalodon. Megalodon is an insect that feeds on other insects. It usually lives in water and has high requirements for water quality.

As for biting and toxicity, Megalodon sharks generally don't bite people. Their main food is other insects, so they pose no threat to human beings. However, if you catch it or threaten it, it may bite people and release some chemicals to protect itself, but these chemicals usually do not cause serious harm to human beings.

In a word, megalodon sharks are generally harmless to human beings if they are not deliberately caught or threatened. If you have any questions or feel unwell after being bitten, please consult a doctor or a professional in time.