Bees and GM Food

In America and Europe, honey bees are disappearing. I have also been missing fire flies lately. Atlanta and Augusta used to have many of both but now the last time I saw fire flies was up in North GA way up near Hiawassee, GA. Some are thinking that GM food may be the cause. I used to think that spraying for mosquitoes to prevent West Nile Virus was the cause, but GM food is another possibility. If GM food with genes for round up, kills bees and fire flies, what does that do to humans after a while?