Subject: Giant Grub
Geographic location of the bug: Vista, CA
Time: 02:50 AM EDT
Your letter to the bugman: This big guy was spotted this afternoon making its way around and around the inside edge of a #3 pot where a small Cherimoya sapling is growing. I estimate it to be about 4″ long and nearly 3/4″ in diameter.
How you want your letter signed: John L.
We have a general identification for you that we are certain about and a possible species identification that we would love verification on from an expert. This is definitely a Hornworm, the caterpillar of a Sphinx Moth or Hawkmoth in the family Sphingidae, and because of the texture on the caudal horn that resembles members of the genus Ceratomia like the Waved Sphinx Hornworm or the Four Horned Sphinx, we suspect it is a member of that genus or a related genus in the subfamily Sphinginae, but alas, we couldn’t match it to a single caterpillar on Sphingidae of the Americas California page. Knowing a food plant is often very helpful, so we searched Sphingidae and Cherimoya and we found this unidentified individual from Peru in our archives that we now believe might be a Giant Sphinx Moth Caterpillar thanks to images and information on the Cheadle Center for Biodiversity & Ecological Restoration site from the University of California, Santa Barbara in an article entitled Search for the Giant Sphinx Moth that includes this information: “This meeting’s species of interest was the giant sphinx moth, Cocytius antaeus, which originates from Mexico and has never been recorded in California before its first appearance in Santa Barbara in 2015. Since then, Russell has documented 48 observations, and this number will likely increase as the weather warms and citizens (like you!) keep an eye out and report moth sightings to the Museum. … The giant sphinx moth prefers tropical climes. Prior to its appearance in Santa Barbara, it had only been found regularly in South America, Mexico, Texas and Florida, with a few records in Arizona. C. antaeus is unique in that its long proboscis makes it the only pollinator of the rare ghost orchid (Dendrophylax lindenii) of Florida, Cuba, and the Bahamas. The moth has also been associated with the cherimoya tree (Annona cherimola), which produces fruits also called “custard apples” and is grown throughout Southern California. Where this tree is cultivated, it has to be hand-pollinated to bear fruit. Russell’s hypothesis is that the giant sphinx moth’s appearance in the States is directly linked to the transport and cultivation of cherimoya trees.” If our identification is correct, the Hornworm you found might have been attempting to feed off the cherimoya in the pot, or perhaps, it was searching for good soft dirt in which to pupate. Many Sphingidae larvae pupate underground, and many green caterpillars turn pink just prior to pupation. Do you perhaps work in a nursery or have you recently purchased the cherimoya from a nursery that imports stock from Mexico? Once we had a tentative ID, we went back to Sphingidae of the Americas and noticed that except for being green, the images of the Giant Sphinx Hornworms look very much like your individual, including the presence of a pink stripe along the dorsal surface. We are going to try to contact Bill Oehlke to get his opinion on our identification.
Thanks for sending your video of a Giant Sphinx pupating. We have included a still from the video in the posting. It sounds like you are treating this Sphinx caterpillar appropriately. We would love images of the pupa and adult if you are able to provide them.
Update: August 26, 2018
Here are links to pics:
Pupa – https://drive.google.com/open?
Specimen got away before I could get a good shot of it fully developed.
Thanks so much for providing images of the metamorphosis of the Giant Sphinx, Cocytius antaeus. They are a wonderful addition to the image of the Hornworm you submitted last month.