Research from The University of Western Australia’s School of Biological Sciences, led by PhD graduate Dr Genevieve Hayes, has confirmed the extreme and unusual mating behaviour of the kaluta, Dasykaluta rosamondae.
The kaluta is a small, relatively unknown, carnivorous marsupial found in the Pilbara region in Western Australia. It weighs between 20 and 40 grams.
Dr Hayes said male kalutas die after a single, intense breeding season, and don’t live to see their young. This synchronised death, known as male semelparity, is the result of an immune system collapse.
“Males were regularly captured in healthy numbers throughout the study, except immediately after the mating seasons, when no males were captured. This, coupled with other research in the field and laboratory, strongly suggests that males die after the mating season,” Dr Hayes said.
“We found that female kalutas mate frequently and with different males and, in our study, a single litter of up to eight young could have as many as three fathers. That means that males also have to mate a lot, and have good quality sperm (and lots of it), to outcompete rival males. This intense investment in reproduction, evidenced by their large testes, appears to be fatal for males. ”
Dr Hayes said the team had found that the kaluta, so far, was the only arid-zone dasyurid to have male semelparity.
“By confirming semelparity in kalutas, we have shown this mating strategy has evolved at least twice in the family of carnivorous marsupials,” Dr Hayes said.
“The study sheds some light on the life of this relatively unknown creature. Despite its extreme mating behaviour, the kaluta appears to be doing well, making it an interesting case study.”