Two Butterflies, Three Tips, Two Questions

One small, one large, one white, one black — both beautiful!  Two new butterflies for our species list.

Checkered White, Pontia protodice.

Checkered White, Pontia protodice. Wingspan about 1.5 inches (4 cm).

Black Swallowtail, Papilio polyxenes. This is the fifth swallowtail species we have had here.

Black Swallowtail, Papilio polyxenes. This is the fifth swallowtail species we have had here.  Wingspan about 4 inches (10 cm).

A few weeks ago,  I went to a butterfly talk and I learned a few things:

  1. A good way to find butterflies is to look for their food sources and especially for the host plants where they lay eggs.   “While adult butterflies sip nectar from a wide variety of flowers, the caterpillars have a much more limited diet.  Many are confined to a single plant genus or family.  The female butterfly detects the proper host visually and then lands to sample it with sensory cells on her legs or antennae.” (Butterflies of Houston and Southeast Texas, by John and Gloria Tveten.)  So knowing that the Checkered White uses peppergrass as a host plant, I could look for her on those plants.
  2. Butterfly populations can be hugely affected by small local events.  One of the speakers started with a question he is often asked, “Is climate change affecting  butterfly populations?”  He said it is hard to tell.  For one thing, good butterfly records don’t go back as far as bird records do, and butterfly numbers tend to vary more from year to year anyway.  He listed about 8 smaller events that can change those numbers drastically.  A freeze or drought could knock out local populations, and then it might take years or decades for them to come back in from surrounding areas.  He said our drought in 2011 caused population fall-offs especially in butterflies that use grasses as host plants.   That fits in with my experience, because Little Wood Satyrs lay their eggs on grasses, and I never saw any here until this year, when I have seen dozens.  If they died off in 2011, they may just now be recovering.
  3. If you plant flowers to attract butterflies, one of the best is the plain old-fashioned zinnia.  He said that the double-flowered, fringed, fancy ones produce less nectar, so it’s best to stick with the basics.  I have certainly found zinnias to be a great butterfly attraction, and very easy to grow.
    White-striped Longtail on zinnia.

    White-striped Longtail on zinnia.

    Gulf Fritillaries on zinnias.

    Gulf Fritillaries on zinnias.

So, Tip One brings up some questions.  I see lots of swallowtails flitting around here, but I don’t think we have any of their host plants growing.  Black Swallowtails like dill, fennel, and parsley, which we don’t have.   We do have cilantro and dog fennel growing wild in huge quantities – are those in the same families as their preferred plants?  Could they be utilizing those?

Online researching tells me that dog fennel (Eupatorium capillifolium) is in Asteraceae, the sunflower family, but cilantro (also known as coriander, Coriandrum sativum) is indeed in the same family, Apiaceae, or the celery, carrot, and parsley family.

Now whether it is close enough to suit the butterfly remains to be seen, but I will be paying much more attention to the plants I see the butterflies land on.