Currently viewing the category: "swallowtail caterpillars"
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Subject: Bright red caterpillar
Location: Southern Arizona ( Santa Cruz county)
August 25, 2017 7:58 pm
I have been noticing these bright red caterpillars during my evening walks.
They are on a plant that I have not found on our property, so that may be their host plant
Do you know what is caterpillar is ?
Signature: Len Nowak ( Salero Ranch )

Pipevine Swallowtail Caterpillar

Dear Len,
This is a Pipevine Swallowtail Caterpillar, and according to BugGuide:  “Larvae feed on
Aristolochia species. These include ‘Pipevine’ or ‘Dutchman’s Pipe’, Aristolochia species (tomentosa, durior, reticulata, californica), as well as Virginia Snakeroot, Aristolochia serpentaria. Larvae presumably take up toxic secondary compounds (including Aristolochic acid) from their hostplant. Both larvae and adults are believed toxic to vertebrate predators, and both have aposematic (warning) coloration.”  The adult Pipevine Swallowtail is sometimes called a Blue Swallowtail and it is a gorgeous butterfly.

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Subject:  False-eyed caterpillar in San Diego County, California
Geographic location of the bug:  Oceanside, San Diego County, California
August 25, 2017  4:27 PM
Hi! I found this little critter outside my front door after I was away for a while. (There’s a large tree beyond the sidewalk, so it could’ve easily fallen there.) It didn’t want to move, so I had plenty of time to get a good shot.
It had green/grayish skin. It seemed that it was trying to change its skin color to match the pavement below it. I left and came back to find no trace of it. I wonder if a bird spotted it…
Anyway, what kind of caterpillar is this? I haven’t seen it before and it has false eyes that extend further inward than the ones I’ve seen pictured on this site. I’m on USA’s west coast, in Southern California. (We also have green jewel-scarab beetles that fly around in the daytime here. Not sure if that helps.)
Signature:  Lightwulf

Western Tiger Swallowtail Caterpillar

Dear Lightwulf,
Based on your location, we are leaning towards this being a Western Tiger Swallowtail Caterpillar, because of this BugGuide image.  BugGuide states:  “Larvae very similar to those of Pale Tiger Swallowtail, but black pupil of false eye-spot larger, and yellow spot inside eyespot entirely separated from it, not just notched.”  BugGuide also states:  “Larvae feed on foliage of deciduous trees, including cottonwood, birch, elms, willow, alder, sycamore, and aspen.”  When it was still feeding, this Western Tiger Swallowtail caterpillar was green, but as the time for transformation into a chrysalis approached, it darkened to the brown color your images depict, though some individuals turn orange.  Caterpillars often travel away from the food source to find an appropriate place to undergo metamorphosis.  The similar looking Two Tailed Swallowtail Caterpillar is another possibility for your critter’s identity.

Western Tiger Swallowtail Caterpillar

What's That Bug? does not endorse extermination

Subject: Catapillar ?
Location: Montclair, NJ 07042
August 16, 2017 2:52 pm
Hello Bugman 🙂
I saw this lil critter on the sidewalk in Montclair, NJ . Can you tell me what kind of bug it is ? Thank you !
Signature: Angela- I❤️Bugs

Prepupal Tiger Swallowtail Caterpillar

Dear Angela,
The last time we posted an image of a prepupal Tiger Swallowtail Caterpillar, the posting got 37 Facebook “likes” and we hope your posting can beat that.  When they are still growing and feeding, Tiger Swallowtail Caterpillars are green to blend in with the leaves.  When pupation time approaches, many individuals turn brown or orange.

What's That Bug? does not endorse extermination

Subject: MY BUG
Location: Taylors Falls Mn
August 7, 2017 12:46 am
This little guy fell out of a tree and landed next to my daughter. He sure made her jump. We took some pics , moved him to a safe place, and went on with our afternoon. Everyone is still wondering what he was.
Signature: Lane T.

Tiger Swallowtail Caterpillar

Dear Lane,
This is a Tiger Swallowtail Caterpillar and it will eventually become a large, beautiful, yellow and black striped adult Tiger Swallowtail.  We are tagging this posting with the Bug Humanitarian Award.

What's That Bug? does not endorse extermination

Subject: A new creature for me
Location: SW Orange County –
June 3, 2017 1:17 pm
I have lived in NC, in the woods, for over 25 years but this was new. I didn’t even know where to begin looking it up: Beetle? Bug? Caterpillar? Poisonous for my hens or safe?
Signature: Virginia

Pipevine Swallowtail Caterpillar

Dear Virginia,
This is the caterpillar of a Pipevine Swallowtail,
Battus philenor.  Adult Pipevine Swallowtails are lovely greenish-blue butterflies with orange spots on the undersides of the wings.  According to BugGuide:  “Caterpillar is quite distinctive, may be a mimic of the tropical onychophorans, called velvet worms. Dark brownish black (occasionally smoky red) with soft fleshy tentacle-like projections, usually red-orange dorsal warts over abdomen. Tentacles on T1 twice as long as those on following segments. ”  We are post-dating your submission to go live later in the month when our editorial staff is away on holiday. 

Thank you!  Yes, what a beautiful butterfly from such a distinctly different caterpillar.  And the caterpillar was so large!  I really appreciate learning more about my friends in Nature.  Virginia Leslie

What's That Bug? does not endorse extermination

Ed. Note:  Our editorial staff will be on holiday for a few weeks, so we are post-dating submissions to go live during our absence.  We hope you enjoy this gorgeous series of images of the life cycle of the Anise Swallowtail

Subject: West Los Angeles sighting – Anise Swallow Tail #1
Location: West Los Angeles
June 1, 2017 12:19 pm
Hi Daniel,
Here’s the first of my sets of pictures you asked me to trickle in. Since I can attach only 3 images, I’m going to send in 4 sets for the swallow tail. If this is too much, please let me know.
Hope you enjoy these.
Signature: Jeff Bremer

Anise Swallowtail Eggs

Thanks Jeff,
We will put together a nice life cycle posting with the images you have sent.  We will distill them down to the best images and we will postdate your submission so it goes live during our absence mid month.  We feel we have to provide you with a challenge though.  Your spectacular life cycle images are lacking critical two stages.  We hope someday you can capture the actual emergence of the adult from the chrysalis, and of course, we always love to post images of mating insects to our Bug Love page.

Anise Swallowtail Caterpillar: Early Instar

Newly hatched Anise Swallowtails somewhat resemble bird droppings which may help to camouflage them from predators.

Anise Swallowtail Caterpillars

As they grow and molt, later instars of the Anise Swallowtail Caterillar take on the characteristic green color with black and yellow spots.

Anise Swallowtail with Osmetrium

When threatened, the Anise Swallowtail Caterpillar reveals its osmetrium, a forked orange organ that releases a foul smell to deter predators.

Prepupal Anise Swallowtail Caterpillar

As pupation time nears, the Anise Swallowtail Caterpillar spins a silken girdle to help keep it from hanging down.

Anise Swallowtail Chrysalis with Chalcid Wasp

This Anise Swallowtail Chrysalis is being visited by a parasitoid Chalcid Wasp.  Here is a posting from BugGuide that shows a close-up of the Chalcid Wasp.  Butterfly Fun Facts has an excellent description of this Parasitoid, including:  “A healthy chrysalis will have light membranes between its abdominal segments. As wasps grow inside the chrysalis, the membranes turn dark.  Infected chrysalises turn darker and often have a reddish tinge to them.  Remember! When a chrysalis is first infected (eggs laid in the chrysalis) it will appear healthy, have the correct colors and shades, and will move normal. Once the wasp larvae have grown for a few days, the color of the chrysalis will darken.  A chrysalis that has a mature butterfly inside it will also turn dark the day before the butterfly emerges. If a butterfly is inside, you will see the wing pads the day before the butterfly emerges. If it darkens and wing pads cannot be seen, it is a danger sign.”  Unfortunately, a percentage of Swallowtail Chrysalides will never produce an adult if they are preyed upon by parasitoid Chalcid Wasps.

Anise Swallowtail Chrysalis

The Anise Swallowtail Chrysalis darkens just before an adult is ready to emerge.

Anise Swallowtail

This is a gorgeous, adult Anise Swallowtail.

Anise Swallowtail

Ovipositing Anise Swallowtail

And the cycle begins anew as a female Anise Swallowtail deposits her eggs on the host plant.


What's That Bug? does not endorse extermination