Courtship
Courtship
Courtship is a complex set of behaviors in animals that leads to mating. Courtship behavior communicates to each of the potential mates that the other is not a threat. It also reveals information to each animal that the species, gender, and physical condition of the other are suitable for mating. Premating activities are for the most part ritualistic. They consist of a series of fixed action patterns that are species-specific. Each fixed action triggers an appropriate fixed reaction by the partner, with one action stimulating the next. Courtship allows one or both sexes to select a mate from several candidates. Usually the females do the choosing. In some species of birds, males display in a lek, a small communal area, where females select a mate from the displaying males. Males generally compete with each other for mates, and females pick the best quality male available. The danger of courtship is that it can attract predators instead of mates.
Several basic factors influence a female’s choice of mate. First, if a female provides parental care, she chooses as competent a male as possible. For example, in birds such as the common tern, the female selects a good fish catcher. As part of courtship, the male birds display fish to the female, and may even feed them to her. This demonstrates his ability to feed the young. In addition, females tend to select males with resources such as food or shelter, which help a mating pair to produce more offspring that survive. In the long-jawed longhorned beetle that lives in the Arizona desert, males battle each other for saguaro cactus fruit. The females mate in exchange for access to the fruit. A male endowed with large mandibles can defeat other males, take over the fruit, and thus attract females. Genetic fitness is another important factor in mate selection. In species that lack parental care, offspring rely for survival on qualities that they inherit from their parents. During courtship, energetic displays and striking appearance indicate good health. Vigorous, attractive parents generally pass immunities to their offspring. Attractiveness may depend on the intensity of secondary sex characteristics, which in birds, for example, include colorful plumage and long tails. Another advantage is that inherited attractive features make offspring desirable to mates.
Courtship in insects
Insect courtship is ritualistic and has evolved over time. Male balloon flies of the family Empididae spin oval balloons of silk. Then they fly in a swarm, carrying their courtship objects aloft. Females approach the swarm and select their mates. As a female pairs off with a male, she accepts his balloon. In some species of balloon flies, the male brings the female a dead insect to eat during copulation. This may prevent her from eating him. In other species, the male carries a dead insect inside a silk balloon. Apparently, in the course of evolution, the suitor’s gift-giving began with “candy,” then a “box of candy,” and finally just the empty “box.”
Other courtship strategies in insects include female moths that release a scent signal (or pheromone) that males of the same species recognize. When a male detects the signal, he flies upstream to the female. In queen butterflies, courtship is complex and requires steps that must occur in the proper order. First, the female flaps her wings to draw the male’s attention and make him pursue her. As he hovers nearby his hairpencils (brushlike organs) release a pheromone. Then the receptive female lands on a nearby plant. Next, the male brushes his hairpencils on her antennae. She responds by closing her wings. This signals the male to land on her and begin mating. In other courtship behavior, male crickets rub their forewings together and produce a pulsed courtship song. In fireflies, the male’s flashing light and the female’s flashing answer is another type of courtship behavior. In fireflies, both sexes respond to a specific set of intervals between flashes.
Courtship in fish
In 1973 Niko Tinbergen won a Nobel Prize for his work on animal behavior. One of the topics he studied was courting in the stickleback, a small freshwater fish. At breeding time, the male stickleback changes color from dull brown to black and blue above and red underneath. At this time, he builds a tunnel-shaped nest of sand. Females swollen with unfertilized eggs cruise in schools through the male territory. The male performs his zigzag courtship dance toward and away from the female fish. Attracted to the red color on the male’s belly, a female ready to lay eggs displays her swollen abdomen. The male leads her to the nest. He pokes the base of her tail with his snout, and the female lays her eggs and then swims away. The male enters the nest and fertilizes the eggs. In this manner, he may lead three or four females to his nest to lay eggs. Tinbergen showed in his studies that seeing the color red caused increased aggressiveness in males and attraction in females.
Courtship in birds
Adult birds generally return to their nesting grounds each mating season. A male claims a territory by singing a distinctive song. He then sings a song that attracts a female. Birds have different courtship rituals. Some use song, while others display colorful plumage. Woodcocks fly upward in a spiral, and birds of paradise do somersaults. Male frigatebirds— large birds with wings that spread wider than 6.6 ft (2 m)—breed in late winter on the coast of tropical islands in the western Atlantic and Pacific Oceans. The male perches in a low tree or brush and his red throat pouch inflates like a balloon. Its red color attracts females hovering overhead. Then the male spreads his wings, shakes them, and makes a whinnying sound. Finally, the pair come together, mate, and build a nest.
Courtship in mammals
Mammals use various strategies in courtship. Pheromones act as sexual lures that bring members of the opposite sex together. These attractants are so powerful that a male dog can smell a female in estrus more than half a mile (1 km) away. The fact that at puberty humans begin to produce odorous sweat suggests the role of pheromones in primate courtship. Sex selection also exists in primates. Females usually choose their male partners, but sometimes the reverse occurs. Recent research reveals that male lion-tailed macaques remain aloof during the day. At night, however, they seek out sleeping estrous females for mating. Until this study, biologists thought that it was the females who initiated mating. In humans, various cultures determine the customs of courtship. For example, in some societies, marriages are arranged by relatives. In these cases, a woman is matched to a man with the appropriate resources. Just as other female animals select mates with resources, humans tend to select mates with wealth and status. Further, even if a woman has no say in the selection of her husband, she may help arrange the marriage of her offspring.
See also Sexual reproduction.
Resources
BOOKS
Batten, Mary. Sexual Strategies. New York: G.P. Putnam’s Sons, 1992.
KEY TERMS
Display— Showy exhibition by an animal that reveals information to others.
Lek— Communal area used by birds and insects for courtship and mate selection.
Pheromone— Chemical odorant that provides communication between animals.
Ritual— Species-specific behavior pattern or ceremony used for communication between animals.
Chinery, Michael. Partners and Parents. Crabtree Publishing, 2000.
Otte, Jean Pierre. Marjolijn De Jager, trans. The Courtship of Sea Creatures. New York: George Braziller, 2001.
PERIODICALS
Davies, Nicholas B. “Backyard Battle of the Sexes.” Natural History (April 1995).
Dennis, Jerry. “Mates for Life.” Wildlife Conservation (May-June 1993).
Fernald, Russell D. “Cichlids in Love.” Sciences (July-August 1993).
Hancock, Leah. “Whose Funny Valentine?” Natural Wildlife (February-March 1995).
Jackson, Robert. “Arachnomania.” Natural History (March 1995).
Robert, Daniel, and Ronald R. Hoy. “Overhearing Cricket Love Songs.” Natural History (June 1994).
Wilson, J. F., et al. “Genetic Evidence for Different Male and Female Roles During Cultural Transitions in the British Isles.” Proceedings of the National Academy of Sciences of the United States of America 98 (2001): 5078-5083.
OTHER
Behavioral Ecology. “Courtship Displays and Coloration as Indicators of Safety Rather Than of Male Quality: The Safety Assurance Hyposthesis” <http://beheco. oxfordjournals.org/cgi/content/full/11/4/444> (accessed November 16, 2006).
Films for the Humanities and Sciences. The Rituals of Courtship. Princeton, 1994-5. Films for the Humanities and Sciences. Mating Signals. Princeton, 1994-1995.
Bernice Essenfeld