28 September 2014

Giant Swallowtail Butterflies are Papilio cresphontes Cramer

Giant Swallowtail butterflies are a thrill. We don't get a lot of them and I watch for their appearance every fall when they come to nectar and lay eggs on the Rue plants. 


Called Orange Dogs in citrus growing areas because their caterpillars eat Rue to the stems.

According to the U of FL, "Its range extends from southern New England across the northern Great Lakes states, into Ontario, through the southern portions of the Central Plains to the Rocky Mountains. The species ranges southward to Florida and the Caribbean, into the southwestern United States, and on through Mexico to Central and South America."


Two Giant Swallowtails in flight
The caterpillars go through five skins but each one looks like bird droppings of one kind or another. 

It's one of those things: If you grow the host plant and avoid all chemical sprays and applications, you will get an opportunity to enjoy these gorgeous creatures in your garden or patio.



Rue has beautiful blue leaves

Rue or Ruta Graveolens, is fairly easy to grow from seed since the seed pods are as large as 4-O'Clock seeds. The yellow flowers you can see in my photo of the plant are not large but there are lots of them. Evidently the pollinators love them because they make hundreds of seeds.

 When the seeds fall to the ground a grove of tiny Rue plants emerge. I pull out the smallest and leave the largest plants in place.
 
Mature plants last only 3 to 5 years here but by then we have replacements growing in place. I'm not sure but my guess is that we have less than a dozen mature plants around our beds.
Giant Swallowtail Caterpillar - last instar

And, other swallowtail caterpillars have eaten the plants, also. The Giants are so easy to recognize that you'll know when you see a green and yellow striped caterpillar on the plant that it's not a Giant.

Either way, they are all welcome!

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