Subject: Caterpillar eating plumeria leaves
Location: Puerto Vallarta
May 10, 2017 6:37 am
Normally, the only caterpillars that eat plumeria leaves are tetrio and an occasional starving monarch. This young one, munching away in Puerto Vallarta this May, has everyone stumped – no one has seen one before. Any ideas?
Signature: Diana

Hornworm:  Isognathus leachii

Dear Diana,
The forward facing, filamentous, caudal horn is quite unusual in this caterpillar, and we suspect like the Tetrio Sphinx, it is a Hornworm in the family Sphingidae.  We do not recognize it either and we are going to request assistance from Bill Oehlke.  It if is a Sphingiid, we suspect Bill may request permission to use the images on his very comprehensive site.

Hornworm:  Isognathus leachii

Update:  Thanks to a comment from Bostjan Dvorak, we have learned that this Hornworm is Isognathus leachii.  According to Sphingidae of the Americas:  “Larvae have long tails; colouration suggests they are unpalatable to birds.”

Hornworm:  Isognathus leachii

Many thanks for the follow-up: I’ve posted in the plumeria Facebook forums. You now have Mexican Pacific coast to add to the confirmed range, and plumeria as a larvae host plant, and like tetrio, they eat a lot of leaves! I’ve also alerted Dr. Criley at the Univ of Hawaii in case it shows up in their groves.  Excellent work!

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Location: Puerto Vayarta, Mexico

5 Responses to Hornworm eating Plumeria in Mexico

  1. Bostjan Dvorak says:

    What a nice and sweet creature! Thanks for sharing.
    It is a young Isognathus caterpillar; it seems to be an Isognathus leachii.
    The caudal horn is thin and very mobile. They sometimes eat Plumeria, like those of Pseudosphinx.

    Best wishes
    Bostjan

  2. Bostjan Dvorak says:

    What a nice and sweet creature! Thanks for sharing.
    It is a young Isognathus caterpillar; it seems to be an Isognathus leachii.
    The caudal horn is thin and very mobile. They sometimes eat Plumeria, like those of Pseudosphinx.

    Best wishes
    Bostjan

  3. Jean Michael says:

    I was the one who took the picture. Thank you for clarifying. This particular caterpillar eats a lot of Plumeria leaves and will clean a seedling in a day if you don’t take them off. There are fairly common in my yard so I will provide more pictures in the future.

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