death of pair of beardies

Question
One of my beardies (male-about four years) had eaten a firefly and died sometime throughout the night.  Within 18 hours, the other (female-about three and a half years) also died.  Is there a specific reason why this happened?  Could the dead beardie pass some kind of illness in it's death?  Could it be because they had been raised together and had never been separated?  We are extremely distraught over losing a very integral part of our family and we really would be thankful for your help.

Answer
 They may have both had fireflies, or the male vomited the insect and the female ate a part of it. Only a proper necropsy could have made a definite diagnosis as to why the girl died too.  Fireflies phosphorescence is the lethal poison in this case, it kills very fast.  I know the pain of losing a beloved dragon and I am so sorry for your loss.