Christmas Beetles

     Hello everyone
     
     During my morning walk this morning I came across about 500 dead 
     Christmas beetles under a single streetlight in the suburb of Hawker, 
     ACT.  The dead beetles were under only one light in the whole row of 
     lights in the street.  
     
     There was a considerable amount of chopped up foliage on the ground 
     from the narrow leafed gum trees in the street (I don't know what they 
     are - they are smooth barked a bit like spotted gums, but not a lot of 
     spots).  I assume the beetles had been chewing on the gum trees along 
     the street, judging by the amount of chopped up leaf remains on the 
     ground.
     
     My question is:  why were they all under the one light? and not under 
     others?  
     
     Has anyone else observed anything like this?
     
     Cheers
     
     Paul Fennell