Movements of pteropids in Australia and Malaysia appear to be dictated by food supplies, and birthing and lactation appear to coincide with food abundance. When the birthing/lactation period coincides with fruiting failure, attacks on fruit orchards result. Fires in the summer of 1997 and a particularly severe ENSO-induced drought in 1997/8 may have led to fruiting and flowering failure in primary forest, a particularly important foraging area for P. vampyrus. There is evidence of commercial crop failure, but primary forest data are missing.
The behaviour and life histories of pteropids suggest high contact rates between species in shared camps. It seems extremely likely that any virus present in urine, saliva, or birthing fluids can be efficiently transmitted to conspecifics through normal grooming and sexual behavior and/or (if urine) ingestion of contaminated foliage in camps.
Author: S. Cobey.