New evidence for facultative male die-off in island populations of dibblers, Parantechinus apicalis

The post-mating mortality of males in dasyurid species is thought to be a s pecific life-history strategy, associated with a tightly synchronised breed ing season, that may enhance survivorship of juveniles. Parantechinus apica lis has been reported to exhibit male die-off in island populations but not in mainland populations, and males originating from both island and mainla nd populations are known to survive post-mating in captivity. However, male s in the island populations have been reported to sometimes survive to bree d in a second year. This study monitored captive and island populations ove r a three-year period (April 1997 May 2000) to examine the extent of male d ie-off. In captivity, males showed no evidence of post-mating mortality. Ma les on one island were also found to survive post-mating, while another isl and population appeared to have high mortality of males in three years, and a complete male die-off after the 1999 breeding season. We conclude that P . apicalis may warrant inclusion in a new category of life-history strategy for species exhibiting facultative male die-off.