Would a scientist let herself get bit by a poisonous insect for research?

Some have been known to. But if the toxin is delivered by a bite, the insect is venomous, not poisonous.  Like a bee.  

A poisonous insect is one that will make you sick if you eat it - or too many of them.  Like a ladybug.

They do it all the time. 

Yes. Clonorchis sinensis, the Chinese liver fluke was brought into the USA for research by a parasitologist who deliberately ate infected water chestnuts. Live flukes in a jar would have been confiscated at Customs.