Just A Couple Of Lovebugs
Ah, romance. Because insects are so numerous, a good deal of work goes into finding a suitable mate. Females can be fickle, with such a wealth of insect bachelors from which to choose. If a male stands a chance at passing on his genes, he's got to do something to stand out in the crowd. Courtship rituals in insect mating include serenades, dances, nuptial gifts, physical touch, and even aphrodisiacs.
Courtship songs differ from calling songs, which are broadcast from a distance to help females find the males. Crickets use distinct calling and courtship songs, for example. Once the female cricket is nearby, the male suitor sings his best courtship song to sweep her off her six feet. Fruit flies have no calling song, but do sing when a mate is in close range. The fruit fly male vibrates his wings in a pulsing, rhythmic pattern. His song lets the female know he is of the same species, and available to mate. Mosquitos sing harmonic duets with each other, adjusting the frequencies of their songs simultaneously as they near the moment of copulation.
Dances and Foreplay:
Any woman is a sucker for a man that can dance. Some male insects and spiders "cha cha cha" their way to love, performing elaborate dances for their chosen mates. Jumping spiders are famous for their ballroom skills. They can perform a linear dance, a zigzag dance, and even a sort of can-can with their forelegs. Certain male flies perform aerial dances around a female to attract her attention and win the right to mate with her.
Some female insects like to be cuddled and caressed to get in the mood. This is especially true of the more primitive, wingless insects. Springtails, for instance, will touch each other with their antennae. Sperm transfer in apterygotes takes place externally, with the male depositing his sperm on a surface and then gently coaxing his partner to take it. Some dung beetles engage in a different kind of foreplay. Together, the pair rolls a ball of dung to serve as a nursery for their offspring.
Gift giving is another clever strategy employed by some male insects in their pursuit of a mate. Before seeking a partner, hangingfly males hunt and capture arthropod prey. They then lure a female closer using a chemical signal, and offer her the food gift. She examines the prey, and if she finds the meal to her liking, they mate. If the gift is insufficient, she refuses his advance.
Balloon flies take gift giving a step further by wrapping the prey in pretty, silken balloons. Females fly into a mating swarm of males and choose a partner, who presents her with his silk package. Don't give the males too much credit, though. They've actually learned to trick the females by offering them empty balloons.
Some male insects, like Mormon crickets, produce a spermatophylax, a protein-rich wad which they attach to the female's genitalia. The female eats the sperm-free offering, which may have cost the male a full 30% of his body weight. That's a pretty substantial gift.
When all else fails, insects may try an aphrodisiac to make a partner willing to copulate. Male queen butterflies dust prospective mates with an aphrodisiac produced by "hairpencils," brush-like appendages on the tip of the abdomen. If his magic dust works, she will fly to a nearby plant. He dusts her once more to be sure she's ready, and if she is, they consummate the marriage.
On the other hand, insects sometimes employ anti-aphrodisiacs to turn away suitors. Certain ground beetle females produce methacrylic acid, a potent anti-aphrodisiac that not only repels males, it can knock them out for several hours. Male mealworm beetles apply anti-aphrodisiac pheromones to their female partners after mating, to make them less attractive to other males.