Cheap Scorpionflies
To attract partners, male scorpionflies produce pheromone- and nutrient-laden spitballs on which females feed as they mate. Some males, however, run out of spit. "They actually offer females a dead insect instead," said Lewis. "A lot of times they'll re-use the same insect, again and again. By the end, it's been sucked dry."
These males enjoy less reproductive success than their more prodigious brethren, Lewis said.
Image: Scorpionflies mating. (Daryl Gwynne/University of Toronto)