Readers’ wildlife photos

Roger Sorensen provides a series of development photos of a moth. I’ve indented his words:

I hope your readers won’t get too “squirmish” with these. If you’re interested, I can provide a Monarch report as the two I’m rearing (photos below) grow. It takes about 3 weeks to reach adulthood.
I maintain a patch of various milkweeds in my pollinator garden and every year have Monarchs (Danaus plexippus) on them. This year though seems to be a banner year for another milkweed grazer, the Milkweed tussock moth (Euchaetes egle).  I think these are good examples of Müllerian mimicry, which Wikipedia describes as “…two or more well-defended species, often foul-tasting and that share common predators, have come to mimic each other’s honest warning signals, to their mutual benefit.” The Tussock and the Monarch share the black-white-yellow coloration.
 
Here’s a cluster of early instar tussock moth caterpillars on the underside of a Common milkweed (Asclepias syriaca). They can rapidly skeletonize leaves or even whole plants.

Here’s the same leaf 2 days later and the colony on another nearby leaf. Note how much the caterpillars have grown. They’re also starting to get “tussocky.”

Here’s a whole plant that was consumed by a caterpillar colony – and with a few Oleander aphids (Aphis nerii), a common pest of milkweeds – and also showing aposematic coloration.
Here’s a later instar of the caterpillar (at left) after having molted. This happens among leaf litter on the ground.

Here’s the caterpillar of milkweeds most are familiar with, though perhaps not when so small. I usually find a few eggs during the summer to rear indoors and right now I have two “kids.” The one of the left hatched on 7 August and is now a few millimeters long. The egg on the right looks to be recently laid but should hatch within a few days. Close-up photos follow of the hatchling and egg. The leaves are presently in a plastic food storage container with the petioles wrapped in wet paper towels. Once they grow larger I’ll move them to a rearing cage.

13 Comments

  1. Posted August 14, 2020 at 8:02 am | Permalink

    Nice photos Roger.

    Does anyone know if Great Black WaspsSphex pensylvanicus prey on Monarch caterpillars (Danaus plexippus)?

    We’ve had resident Great Black Wasps for a few years now. And it seems that during the same time, our Monarch larvae never make it to chrysalis stage. (We finally found one chrysalis this year).

    Great Black Wasps are supposed to favor Orthopterans …

    • Posted August 14, 2020 at 9:10 am | Permalink

      The GBW (as I call them) hunts katydids, as you say. I doubt they would go after caterpillars. Solitary wasps that feed paralyzed insects to their larvae tend to be specialized.
      I don’t know how well monarch cats are protected from hunting wasps or internal parasitic insects, but there is at least one microbial disease that takes out a lot of them.

      Interesting that you get GBW regularly. The adults favor certain flowers. They really go nuts over horsemint (aka beebalm), ignoring all others if that is around. That flower also brings in the great golden digger wasp; another solitary wasp that is pretty impressive.

      • C.
        Posted August 14, 2020 at 9:18 am | Permalink

        In my little bit of ground, the GGD wasps got nuts over my unruly patch of goldenrod, which should be blooming any day now. Everybody in the insect neighborhood seems to like the goldenrod. It really puts on a bountiful buffet. Not sure about the GBW’s. I’ll have to pay more attention.

    • Diana MacPherson
      Posted August 14, 2020 at 12:59 pm | Permalink

      I have had black wasps hanging around this summer too & I hadn’t noticed them before.

  2. C.
    Posted August 14, 2020 at 9:13 am | Permalink

    Very nice. Three cheers for Asclepiadaceae!

    I’m trying to put together a pollinator garden of sorts. I’ve got some A. syriaca that’s established and spreading but alas, no monarchs. I did find two caterpillars denuding my two pitiful A. incarnata, though they mostly ate the flowers (!) not the leaves. This year I planted some A. verticillata and I gathered local seeds from some A. viridiflora and bought some A. speciosa seed from Prairie Moon Nursery. If you plant it, they will come…
    The Asclepias family is second only to Silphium as my favorite local genus.

    Whenever I’ve found tussock moths, they’re usually munching away on Cynanchum laeve, the angle-pod vine that so many suburbanites hate and rip from their chain-ling fences. I think it looks and smells quite lovely and wish people would learn to appreciate it more.

    • Posted August 14, 2020 at 11:19 am | Permalink

      You seem to know your plants! For attracting butterflies in particular I am quite smitten by joe pieweed and by ironweed. Also purple cone flowers, though they don’t look it, they are very attractive to leps. Of course there is the ever-reliable butterfly bush, but I like natives.

      • C.
        Posted August 14, 2020 at 2:33 pm | Permalink

        Thanks. I try. I figure the best way to know a plant is to grow a plant. I also try to read a lot. I’ve got several field guides, one (of the three) flora of Missouri books, several text books on botany, (just got a new old one from 1929) and a few books (orchids, fertilization, insectivorous plants) from some old dead guy named Darwin, including one by his son Francis on plant physiology, and I love the Crime Pays But Botany Doesn’t podcast and youtube videos. Never took botany in college, sadly, but there are so many ways to get info cheap or free, some of the ways are even legal! In the end, though, I’m just an amateur who plays in the dirt.

        • Posted August 14, 2020 at 8:58 pm | Permalink

          Well, that has gotten me to start watching the Crime Pays… on YouTube. Hilarious and educational! Thanks for the heads up. 👍

  3. Diana MacPherson
    Posted August 14, 2020 at 1:01 pm | Permalink

    I always thought those Tussock moth caterpillars looked like little bits of shag carpet. I had forgotten what they were called & usually just refer to them as “those carpet looking caterpillars” when I see them. 🙂

  4. Terry Pedersen
    Posted August 14, 2020 at 1:02 pm | Permalink

    Will you post the butterfly that emerges from the Caterpillar shown?

  5. Mark R.
    Posted August 14, 2020 at 1:39 pm | Permalink

    Great photos. I’m always amazed at how many insects milkweed attracts. Perhaps it’s the toxic nature of milkweed that the insects have evolved to utilize.

    • C.
      Posted August 14, 2020 at 2:24 pm | Permalink

      Yeah, it’s the Cardenolides, aka cardiac glycosides in the milkweed that monarchs, tussock moths, and milkweed bugs sequester in their bodies that makes them toxic. But, if I understand this correctly, the milkweed still throws that milky latex at them, so they have to carefully snip the veins to cut off the flow lest it gum up their mouth parts before they can really chow down. I should read up on the bio-mechanisms that allow various species to ingest toxins and put them to use without poisoning themselves, as poison dart frogs and our lovely monarchs do. Fascinating stuff but probably a bit over my head. I know little to nothing of biochemistry.


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