UK butterflies mud-puddling

[Michael Gochfeld]

Pieris rapae in New Jersey, does engage in puddling. Of course we 
haven't had any puddles in several weeks.  It's not a prominent 
activity, in that most of the time when there are Whites and puddles we 
don't see any puddling.  But sometimes there will be 20 or more, so 
there may be a social component in addition to or instead of a nutritive 
component.  Or it may be that they all experience the same nutritive 
stress simultaneously.  Somewhere I had data on the sex ratio at puddles 
and flowers simultaneously. 

M. Gochfeld