Originally Posted by
rockport
I'd say it has something to do with the behavior and/or requirements of mature bucks but it is definitely harder on mature bucks.
I'm sure big mature bucks require more water which leads to more exposure.
In my area EHD is very clearly related to drought.
Maybe the water drying up forces the larvae to pupate and turn into mature flies? They are kind of forced to mature all at once or nearly so and the fly density spikes?
They must have some sort of mechanism to survive winter, either the eggs, larvae or pupae must go dormant for long periods. I've seen the same with Maggots, if they run out of food they will pupate early (under size).