Removing the Competition
Male dragonflies have specialized penises that scoop out sperm from previous males before depositing their own.
Dragonfly penises are remarkable tools of sperm competition. Before delivering their own sperm, males use specialized structures to remove sperm from previous matings.
The male's penis is equipped with: - Horns and spines that scrape the walls of the female's sperm storage organ - Inflatable lobes that pack previous sperm to the back - Hooks that physically scoop out rival sperm
Studies show males can remove 90-100% of sperm from previous matings before depositing their own. This gives the last male to mate a significant advantage in fathering offspring.
Dragonfly mating itself involves a unique position called the "wheel" or "heart" position. The male grasps the female behind her head with claspers at the end of his abdomen. The female then curls her abdomen forward to connect with the male's secondary genitalia on his abdomen. It's one of the most distinctive mating positions in the animal kingdom.
Males are highly territorial and will fiercely defend prime egg-laying sites. A male that controls good territory can mate with many females, making the sperm-removal ability even more valuable for late-arriving males.