Extension Communications
Extension 4-H Youth Building
Ames, Iowa 50011-3630
(515) 294-9915
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Extension Communications |
2/12/04
Contacts:
Mary Harris, Reiman Gardens, (515) 294-2567, maharris@iastate.edu
Jean McGuire, Continuing Education and Communication Services, (515) 294-7033,
jmcguire@iastate.edu
Love is in the Air
By Mary Harris
Curator,
Christina Reiman Butterfly Wing
It is clear when you visit to the Christina Reiman Butterfly Wing at Reiman Gardens that love is in the air. Male and female butterflies engaged in various courtship behaviors can be seen throughout the exhibit.
Butterfly mating behavior can be broken down into two types. First, individuals must find a mate. Second, courtship of the potential mate must occur. Courtship behaviors are as varied as the number of butterfly species visitors can observe at the exhibit.
Perhaps it is the language chosen by researchers who study and describe such butterfly behavior and not the behaviors themselves, but there are some striking similarities between butterfly mating and our ideas of human romance. For example, we celebrate Valentine's Day and weddings with perfumes, gifts and getaways such as honeymoons. Butterflies similarly use pheromones, nuptial gifts and postnuptial flights.
A closer examination across species of butterfly mating behavior reveals two basic methods males employ to locate potential mates. Male butterflies will either perch and wait for a mate to fly by or patrol and actively search for a mate. One species that patrols for a mate is the Queen, Danaus gillipus. Male Queen butterflies fly throughout the day searching for females. You might guess the male is looking for the distinctive orange color of other Queens, but instead he is assessing shapes and sizes of the butterflies he encounters. Among butterflies, mate location is a behavior based on visual cues whereas courtship is based on the sense of smell.
Male and female Queen butterflies are quite similar in appearance but can readily be differentiated by the presence or absence of a large black patch on each of the hindwings. These patches are pockets that contain a pheromone-producing gland. Pheromones are chemicals, usually very volatile, that are released by one individual and have an effect on another individual. Such chemicals are highly species specific and often derived from the host plants on which the insects feed. Queen males produce the ketone named danaidone for the family to which this species belongs, the Danaidae (now considered a subfamily of the family Nymphalidae or brush-footed butterflies).
When a patrolling male Queen spots a female, he overtakes her and extends his hair pencils, which are brush-like scales on the tip of his abdomen. He then runs his hair pencils through his wing pocket, picking up pheromones. He brings his pheromone-laden hair pencils near the female's antennae causing her to fly more slowly and finally to land. Once she has set down, courtship begins.
The outcome of courtship may be one of success or failure. Noted lepidopterist, James Scott, writes in his text The Butterflies of North America: "as in humans, unreceptive females tend to have a more complicated courtship than do receptive females."
Queen butterfly courtship continues after the female lands with the male continuing to fly around her in semicircles. If she is receptive to his attentions she folds her wings and he then lands on her side, palpating her with his antennae as they join. The male then commences a postnuptial flight with the female dangling below. The male transfers sperm packaged in what is called a spermatophore that the female will absorb over time. The spermatophore is considered a 'nuptial gift' providing protein for the maturation of the female's eggs.
So be prepared if you visit the Christina Reiman Butterfly Wing at Reiman Gardens in the next few weeks, you are likely to see a display of male butterflies perching and patrolling, engaging in various courtship maneuvers and females either accepting or rejecting the males.
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Editors: A color photo, suitable for publication, is available at right. Click on the thumbnail photo to go to the fullsized photo. The picture's fullsize photo is 228K. Caption: Queen butterfly |
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