Carpinteria Bluffs, 2016-02-20It was overcast at the bluffs…
Carpinteria Bluffs, 2016-02-20
It was overcast at the bluffs today, but the clover (Oxalis sp.) and black mustard (Brassica nigra) were in bloom and doing their best to brighten the scene. They’re non-native, and so are frowned-upon from a restoration-ecology perspective, but so far that patch of ground has been left to its own devices. In a coastal SoCal field a month or so after a rain that usually means clover and mustard. Anyway, I thought it was pretty.
One of the benefits of restoring native plants is that they tend to host a nice assortment of insect associates. There was evidence of that in the nearby coyote brush (Baccharis piluarlis), where a new outbreak of green leaf beetles (Trirhabda flavolimbata) is under way. It’s early on in the outbreak, so I didn’t see any adult beetles, but the larvae are definitely getting bigger then they were a few weeks ago, when I first noticed them coming back.
If this outbreak follows the pattern of the last few I’ve seen there eventually will be multiple generations of beetles from tiny larvae to shiny green adults crawling all over the plants, many of which will end up completely defoliated. The coyote brush doesn’t seem to mind too much; a year after the last outbreak they were back in business.
The last photo above is of a small coast live oak (Quercus agrifolia) that was heavily galled with stem galls. I’m thinking those are probably the work of the cynipid wasp Callirhytis quercussuttoni. According to Russo’s Plant Galls of California and Other Western States (which I love), the generation of wasps that emerged through those exit holes you can see were all females; they lay their eggs on leaf buds, which produces a generation of small leaf blister galls that host both males and females. After mating, the adult females of that generation oviposit into young, growing stems, which eventually results in the big stem galls you see here.
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Tags: insects, coyote brush, galls, carpinteria bluffs, coast live oak, insects anonsally may or may not wish to see, though the beetle larvae in one image are pretty small, and probably safe, and she'd be compensated, by a landscape covered with yellow flowers, that made me think of her.
