Thursday, May 07, 2009
Well, ladybird beetles, then. They are here in all life stages now, making the journey from egg to adult and back in a few weeks in order to create the most coleopteran life while the aphid supply holds up.
On a recent expedition to the backyard, I found three species of adult in the garden: the 7 spot (Coccinella septempunctata) was gleaning aphids from Juan's aeonium; the handsome spotless (Cycloneda sanguinea) was perched on a lantana bud just before flying away; and the ever-present Asian (Harmonia axyridis) acting shy on a basil leaf. Asian ladybirds come in a surprising variety of color and pattern combinations offering up a sort of pseudo-diversity of species; you think you've found some new exciting ladybird, but you can identify them as H. axyridis by the W-shaped marking on the pronotum (exoskeletal plate just behind the head). I don't remember which ladybugs I noticed 20 or 25 years ago, but according to what I've read, this beetle was not common until it was introduced into North America in a serious way in the 1980s for bio control of aphids on crops. It has become well established throughout the US and often out-competes other ladybird species at the aphid feast. Some people (and probably a lot of other ladybirds) consider the species a scourge. I guess I feel good that I have as much ladybird diversity as I do.
The pupa on Juan's aeonium is that of the 7 spot. The other one, the bright orange newly molted one on an alyogyne leaf, may be too fresh to identify because spots and the coloration hadn't cured yet; however I suspect this is H. axyridis.
The larva at the top of the page looks like that of H. axyridis, and so does this smaller on on the salvia discolor leaf.
One larva happened to get caught in the web of my friendly neighborhood common house spider (parasteatoda tepidorium) on the front porch. Or should I say spiders. In the first photo you can see the female spider on the larva and the male is lurking or hiding behind the leaf off to the left. Yes that is a miniature holiday light off in the background. In the 2nd picture, the larva is wrapped in silk and the male spider (on the right) has joined the female in the feast. My questions is: how did a ladybird larva get caught in the web which is located 5 feet over concrete from the nearest plant. My best guess is it was picked up from the garden on someone's (moi?) clothing and fell off in a very unlucky spot as that person walked across the porch and opened the front door. And so spider predation ensued.