Suicidal Sex

A brown antechinus. Males of this species mate like crazy
for two weeks, then die. Photo by Alan at Wikimedia.

Although most species breed repeatedly over their lifetimes, a select few invest everything they’ve got in a single reproductive bout, after which they keel over and die. This strategy, called semelparity, can be beneficial in species that can have many offspring at once and that are not likely to survive long enough for a second breeding attempt anyway. It is most commonly seen in plants, invertebrates and some fish. It is a rare strategy in mammals, in part because mammalian females do not have many offspring at once and they need to live long enough to care for their young after they are born, which dying early would obviously prevent. Despite this, there are over a dozen species of mammals of which all the males die after their one and only breeding season. How could this possibly be adaptive?

Today at Accumulating Glitches, I talk about how patterns of insect abundance and competitive sperm have pushed some mammals to mate themselves to death! Check out the article here.