Swallowtail butterfly eggs!

The wheel turns, another cycle begins …  Just last week two of the butterfly chrysalises that we’ve been sheltering emerged.  They’re anise swallowtail butterflies.  The first one was a male – if you can get a good close look, one set of the black lines on the male’s wings is thicker than on the female’s —

Anise swallowtail butterfly

Anise swallowtail butterfly

We let him go quickly because the weather was really nice.  The anise swallowtails can remain in the chrysalis stage for years.  We’ve had some for more than two years.  You can tell they’re still alive because if you touch the chrysalis gently it will move.  It’s very different with monarch butterflies — the timing for the stages monarchs go through from egg to emergence are always the same.

A day or so later another one of the swallowtails emerged – this one was a female.  As we released her I said what I always say to the lady butterflies: “Come back to our garden and leave babies!”

So, as for the cycle of nature turning — today I found three eggs on the fennel in our garden!  The native plant the anise swallowtails lay eggs on is called yampah.  This great online resource,  CalFlora.org,  has lots of information about yampah and other native plants.  We have some yampah in a pot, but it grows very slowly.  Here’s a picture I took last year.  The egg is the tiny yellow dot near the center of the picture.  It’s about the size of the head of a pin.

Since yampah is very hard to find in the wild around us (not much wild left hereabouts  …), the anise swallowtails have turned to the fennel plant, which grows very easily here, to lay its eggs and as its larval food source.  Fennel grows in vacant lots and along the highways.  Many people cut it down as it gets rangy later in the summer, which is too bad, because they’re probably killing hundreds of swallowtail eggs and caterpillars.   Here’s a photo of an egg on fennel:

This is roughly three times larger than life size.  These last 2 pictures are from a series I did on the entire life cycle of the anise swallowtail butterfly.  You can see all of the photographs on my smugmug gallery.

What butterflies have you been seeing your garden?   Do you plant milkweed for monarchs or other plants to attract and feed butterflies?

8 comments on “Swallowtail butterfly eggs!

  1. I still cannot believe that you guys find those tiny, tiny, tiny eggs . . . and then give them homes until they grow into these amazing creatures. Great work!!!!

  2. Heidi Rand says:

    Tamara, I know! It’s hard to find them at first, but then they just start popping out at you. The monarch eggs are much harder because they often lay them on the bottom side of the milkweed leaf. We only find those if we’re lucky enough to see the mother flitting around our milkweed. Otherwise, forget it…

  3. Gary says:

    Will they lay their eggs on any kind of fennel? I live in Texas and could buy fennel seeds at a nursery. Also, can you raise swallowtail caterpillars indoors?



    • Heidi Rand says:

      Gary, It depends what kind of swallowtails you have in your area. Different kinds of swallowtails will lay eggs on different plants. If you do have the anise swallowtails there, yes – they will lay their eggs on the fennel that you buy at a nursery. And yes – we raise all of our caterpillars inside, then release them. You need to provide them with the plants that they feed on as caterpillars, then a safe place for them to build their chrysalis. Raising them inside increases the chance that they’ll survive, since there are so many threats to them outside. Thanks! heidi

  4. Megan Csoke says:

    Cool I would like to know more because I am doing a project on them!

  5. Jeff Loomans says:

    Heidi – thanks so much for the detailed photography and descriptions. Here in N California we’d found caterpillars on the wild fennel in our yard, and with our 7-yr old daughter’s help brought them in to pupate and ultimately emerge as beautiful butterflies; because we have so many Western Tiger Swallowtails in San Francisco I’d assumed that’s what they were, but reading your writeup and a few others now realise they must be Anise.

    Question: do you know if females return to *specific* host plants, possibly ones near where they were born, to lay eggs? I ask this because once we realized they were food for the cats, we’ve specifically preserved three sets of wild fennel in our garden as hosts plants – and have since noticed a number of caterpillars (and this morning, fresh eggs!) in one particular plant; yet another has never shown signs of any at all, and literally across the street the numerous wild fennel plants I’ve examined have never shown signs of hosting caterpillars either. (Making me more determined than ever to keep our plants healthy and growing…)


    – jeff

    • Heidi Rand says:

      Hi Jeff,
      So wonderful that you’re leaving the fennel in your garden and raising the butterflies!

      We often wonder if the females we release come back to our fennel, but we can only guess. And we’ve had the same experience, we’ve found nearly 30 eggs so far on the two fennel plants in our backyard, and when we check the other fennel plants in our neighborhood, have found only a couple of eggs this year.

      We have tagged some of the monarch butterflies we raised and released, and I suppose we could tag the female swallowtails we release, but then we’d have to be present when they’re laying the eggs. Otherwise, I’m not sure there’s any way to know for sure.

      I finally got a good photograph of a swallowtail depositing eggs on our fennel – I’ll get a blog post up this weekend.

      Thanks! Heidi

      • Jeff Loomans says:


        Thanks for your reply! Wish we would get Monarchs here in SF – I’ve planted milkweed in the back yard, but the most I’ve seen in five years is one wanderer; we are less than twenty miles from some major overwintering spots up the coast, so I’ve wondered if they simply aren’t laying close to where they “hibernate”. Sounds like Monarchs travel quite a bit to/from overwinter spots before their next cycle, but not clear if that’s what’s at work here.

        Our three new host plants seem to have worked in attracting the local Anises; I was even lucky enough to snap some (iPhone only unfortunately) pictures of the mother laying – and then later of a pupating caterpillar just prior to chrysalis formation, and then of a brand-new emerged Swallowtail, drying off below her broken chrysalis! Inspired by your blog posts I tossed them up on my regular site on a private page at http://barelydigestible.com/swallowtails.

        Next year I’ll have to get my wife to lug out her real photography equipment and snap better-quality pics…

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