Photos by Lenora Larson.
A mating pair, the female is on top. Her swollen belly contains eggs ready to be fertilized.
The caterpillar flicks its red smelly osmetaria to scare predators.
A sideview of the Giant Swallowtail. In addition to flowers, the males puddle on moist gravel to collect salts for their spermatophores.
The romantic male showers his intended mate with pheromones to get her in the mood.
Gentle Giant Swallowtails
Y
ou are relaxing in your garden when suddenly a dark shadow blocks the sun. Is it a bird? A plane? No, it’s a Giant Swallowtail, the largest butterfly in North America and a native of Kansas and Missouri. The Giant Swallowtail is differentiated from our other five species of swallowtails by its immense size and the black and yellow patterned upper surface which looks like a clown’s gaping grin, while the undersurface is dusty yellow. In the insect world, females are larger than the males and this lady can have a wingspan up to 6 inches, while the males top out at about 5 inches. Why is this tropical-looking butterfly native to the Midwest? Simple, we have two native citrus trees, Hop Tree, Ptelia trifoliata and Prickly Ash, Zanthoxylum americanum.
The Very Hungry Caterpillar Herb gardeners may also see the Giants because their caterpillars eat Rue, Ruta graveolens. Who would ever guess that, despite their common names, Rue, Orange and Lemon Trees, Prickly Ash and Hoptree all belong to the Citrus family? The Giant Swallowtail butterfly knows and she only lays her eggs on Citrus plants. In the south the host plants are Orange, Lemon and Grapefruit trees. The caterpillars, also known as Orange Dogs, incur the wrath of citrus growers who relentlessly spray insecticides to kill them. Fortunately, in the Midwest the host plants are not eaten by humans so we don’t compete for food and can enjoy this beautiful butterfly. Do the caterpillars taste like veal piccata from eating citrus plants? To hide from hungry diners, the caterpillar looks like a bird dropping, the best possible defense.
LENORA LARSON Butterfly Maven 18
June 2022 | kcgmag.com
The Giant lays her eggs on top of citrus leaves and the caterpillar sits motionless all day because a crawling turd would attract a curious bird. When the sun goes down and the birds are sleeping, the caterpillar moves about feeding. It then returns to the same spot at dawn because a bird would notice if the turd had moved. The 2” full grown (fifth instar) caterpillar resembles a snake and when disturbed it displays bright red osmetaria, looking like a snake flicking its tongue. We typically have two broods each year so the adults are seen flying from April through September. The fall caterpillar over-winters as a chrysalis, disguised as a small twig. Please do not clean up your garden in fall because you risk killing next year’s butterflies. Love Is in the Air Many male butterflies are ag-
gressive serial rapists, but the Giant Swallowtail gently romances in the afternoon as he patrols his territory near Citrus plants. When he spies a lady in flight or nectaring, he approaches fluttering from above and showering her with pheromones, his male “cologne”. If she’s interested, she joins him in flight, spiraling upward with synchronized wingbeats. And if he is judged suitable to be the father of her children, the pair land and link tail tips. They may remain connected for several hours as he pumps in his spermatophores, little packets containing sperm as well as proteins, carbohydrates and salts to provide extra nutrition for the female. Adults live only 6 to 14 days, so the lady must act quickly to find the best mate. She will die when she has laid all her eggs, exemplifying a “live fast, die beautiful” lifestyle.
A Marais des Cygnes Master Gardener, Lenora is a member of the Idalia Butterfly Society and Kansas Native Plant Society. She gardens in the clay soil and cruel winds of Paola, KS. She may be contacted at lenora.longlips@gmail.com.
