It’s almost August, so I’m going to have to check my Chilocorus kuwanae river birch trees soon! C. kuwanae has no common name in English, and has been introduced to North America for biocontrol. It is a beautiful species, glossy black with two red spots.
There are a lot of lady beetle species with this pattern, and they’re not even all in the same subfamily! C. kuwanae is one of the easier ones to identify because of the shape and location of its red spots. They are squared-off, rectangular rather than round or oval, and positioned at or behind the midpoint of the body. If you flip one over, you’ll see that its underside is half black and half red (black head and thorax, red abdomen). This distinguishes it from the most similar species, Chilocorus tumidus, whose underside is red on both thorax and abdomen. Other species of Chilocorus have round or oval spots positioned towards the front of the body.
The river birch trees where I find them here in Philadelphia are the “weeping” type of birch, with long whippy branches that dangle down, forming a canopy with an open space beneath. The lady beetles aren’t visible from outside because they and the scales are on the undersides of the leaves. The first time I pushed aside the branches and walked under one of the trees, I was astounded to see literally hundreds of lady beetles! I couldn’t look three inches from one without seeing another.
I collected live adults and they mated in captivity – quite enthusiastically and frequently! – but the females didn’t lay eggs and I couldn’t photograph a life cycle sequence. Fortunately, one of my friends was able to photograph a larva to adult life cycle this year and posted it to BugGuide.net:
C. kuwanae life cycle
The photos show the spiky larvae, pupae, freshly-emerged adults “coloring up,” and finally two adults mating. Hopefully I can find and photograph eggs this year and BugGuide.net will show all four life stages of this species!