How brilliant and terrifying nature can be: These buds on my asclepias incarnata ‘Ice Ballet’ — a white swamp milkweed — appeared Friday.
Yesterday, I took this photo of one of the two red and black bugs on that milkweed. (Not easy … they scurry back and forth to the other side of the leaf or flower when they sense a presence.)
The bug is called Oncopeltus fasciatus … large milkweed bug.
HOW do they know? Did they grow from larvae laid here last year by their parents and bide their time waiting, waiting, for the buds to appear? Did they sniff the air from miles away and smell the scent of goodness wafting their way? Were they created from whole cloth on the spot the moment the buds shown forth?
Here’s a photo from last year, same critter on the flowers and buds in mid July:
And also from previous summers, a few to show that other insects visit it as well:
(Even in late October, asclepias is a show worth watching:
Really, how do insects get to plants so quickly?
I had an aphid infestation in my lupines this spring. I kept waiting for ladybugs to visit and eat them but no such luck.
But it does happen that insects that both eat my plants and prey on those that eat my plants can show up before the dinner bell finishes ringing. It’s one premise of integrated pest management (IPM), organic gardening, and permaculture, that predatory insects can control herbivorous insects, especially given polycultures (not monocultures) and insectary plants; it’s embedded in the 5th permaculture design principle, Using Biological Resources (see #2, Pest Control).
“One of the maxims of the new field of conservation biological control is that to control insect herbivores, you must maintain populations of insect herbivores.” ― Douglas Tallamy
Tallamy’s comment seems paradoxical, but he means that we need some insect herbivores (i.e., crop pests) to keep populations of predatory insects fat and happy so they will remain on the site.
This handy page lists plants to grow (insectary plants) to attract various beneficial predators, including lacewings, ladybugs, miniwasps, hoverflies, braconid wasps, ichneumonid wasps, tachnid flies, and damselbugs. The plants can primarily be summarised as umbels (Apiaceae) like angelica, anise, carrot, chervil, cicely, cilantro, dill, fennel, lovage, parsley, Queen Anne’s lace; composites (Asteraceae) such as daisies, asters, marigolds, chrysanthemums, zinnias; and mints (Lamiaceae), which, besides the mints themselves, includes lemon balm, bee balm, basil, rosemary, sage, oregano, thyme, and lavender. I grow most of these all over the yard.
This short blog post, at Wandering Upward, explains how ants, aphids, parasitic wasps, and fungus all interact as prey, as predator, and in mutually beneficial relationships. Kind of fascinating.
And to answer my original question, how do insects — plant-eating and predatory — show up so fast?, apparently it’s a bit of a mystery, but scent, visual cues, eggs laid on the host plant, and learning may all play a role. And some plants “cry for help” (release volatile chemicals) when being attacked, calling on what we (and they) would consider beneficial insects to save them!
Everybody says they love Nature, but nobody ever invites her over to their yard. We mow plant life to within an inch or two of its life, relentlessly spray toxic chemicals to kill all the bugs, be they good or bad, and then wonder where all the birds went. — Neil Diboll, Prairie Nursery