Locusts laying on thier backs and twitching :(

[GoldenBellTreeFrog]

Well, about 20minutes ago i heard my 3 adult locusts making alot of noise so i pulled them out of the enclosure and here they are twitching with brown fluid coming out of thier mandibles. i've had them for about 4 months now and they have been doing fine, the only thing i can think of that might be doing this is pesticides. 10minutes before they started doing this i had put in some lettuce that i got from a super market and it said 'no sprays' on the side of it. This is the first time iv'e got lettuce from this company and i think maybe its this that is making them sick. I would like some opinions, because i didn't think insecticides could work this fast? has anyone ever had this happen to thier locusts?. It's so sad watching them twitch in pain ):


Update: Sadly all 3 have now died ):