Presenting: Awbury’s 2018 series on pollinators– from wasps to wind!
Monthly articles will correspond with our programming and our “Pollinators FOUND at Awbury Arboretum” art show and scavenger hunt.
Articles written by La Salle student and Awbury intern Dan Sardaro.
DECEMBER 2018 – MILKWEED BEETLE
It’s December, and you probably know that that means – the last month of the Year of the Pollinator. It’s crazy how time flies… or buzzes, crawls, or whatever suits your fancy. Everyone at Awbury Arboretum is grateful that we got the chance to help advocate for the forces and insects that help keep our Earth green and healthy throughout the past year. But while the Year of the Pollinator programming and blog posts will conclude this month, we hope the fight for pollinators does not end there. We hope that our neighbors now have the knowledge and know-how to help support the pollinator cause!
With that, let’s get to our last pollinator, the milkweed beetle, which has become a personal favorite of mine. With its unique coloring resembling some sort of orange and black shield, this little beetle is pretty cool looking, and it has an interesting pollination story to boot. Our final Karen Signer tilework aptly shows the beetle on top of a milkweed flower cluster.
The Milkweed Beetle (Tetraopes tetrophthalmus) belongs to the family Cerambycidae, and it gets its name, tetraophthalmus (Latin for ‘four eyes’), from its eye structure. Interestingly enough, the beetle underwent a rather extreme evolutionary process, so much so that the insect’s antennae split both eyes in two, resulting in a beetle with four eyes. There’s two each above the antennae and two below. The bug’s back, a geometric pattern of orange and black, make it quite easy to point out in a garden. I know I’ve seen many atop flowers in my walks around preserves where I live. It also serves as a warning for predators, signaling that they’re poisonous. This due to the plant that it feeds on, the milkweed plant. Remember how milkweed was critical in the life of monarch butterfly larvae, turning them into brightly colored, poisonous insects? The milkweed beetle eats the same plant and thus has the same deadly secret.
To explain just how milkweed beetles pollinate, a little backstory is needed about the milkweed. Milkweeds are perennials that tend to produce clusters of small, tightly condensed flowers with abundant nectar. But unlike other flowering plants, the milkweed doesn’t produce loose pollen. Instead, it houses what are called pollinia – waxy sacs of milkweed pollen in winged shaped pairs – that are found within a small chamber at the center of the flower. The orchid is the only other flower that uses these types of pollen packages. It’s only when a hungry insect lands on the flower that the plant can have a chance to distribute its pollen. In this case, as the milkweed beetle feasts on nectar, one or more of its appendages will inadvertently poke through into the chamber where the pollinia lay waiting. The pollinia’s stickiness helps attach it to the beetle’s legs until the insect flies to another flower of a different plant, where it’s likely that the insect will again slip its leg into the flower’s center chamber. Free delivery service!
“Milkweed Pollinia.” Virginia Tech Insect Collection, WordPress, 5 Aug. 2016, www.collection.ento.vt.edu/?p=302.
“Milkweed Beetle – Facts, Information & Pictures.” Animal Corner, 2015, animalcorner.co.uk/animals/milkweed-beetle/.