Published June 6, 2015
J.B.S. Haldane is supposed to have said that the creator must have a special fondness for stars and beetles, because there are so many of them. And some of them — the beetles, not the stars — are awfully small.
There are 350,000-400,000 species of beetle — the exact number is probably impossible to know as new ones are discovered and known ones become extinct — making them the largest order of animal. This little number I found in a window sill.
My first ladybug of the year was spotted on the weekend. It was, no surprise, a Multicolored Asian, Harmonia axyridis, which you should expect to see just about everywhere. I also saw very small lady beetle I’m not yet sure of the identification of. But on Monday, I saw half a dozen Two-spotted, Adalia bicunctata, which made me very happy. (See the essay I wrote about these for Humans & Nature.) This is the classic form.
This is the black form. Yes, that’s a human neck it’s on.
Two of the gardeners at Brooklyn Bridge Park showed me the evidence of Viburnum Leaf Beetle that they were hunting down. The pits in the twig are egg cavities, dug into the tree by the mature beetle. The tiny larvae can just be seen.
The destructive invasive beetle is rampant through most city parks, but is so far kept at bay in BBP, which has multiple species of viburnum growing. Here’s what the damage looks like when it runs wild.
In early November, I found four adult Two-spotted Ladybeetles (Adalia bipunctata). And without looking very hard. I just stood under the tree and looked up.
This is some kind of Lacewing larva. It was found predating under the Catalpa leaves, where the ladybugs are still to be found, too, deep into October. On the rocks below the trees, a lady bug pupa.
A carrion beeetle, also known as a sexton beetle, of the genus Nicrophorus, from the Greek for “carrier of the dead.” Found this on a mammal corpse on a path at Dead Horse Bay. The carcass was in curious state; some exposed bones were already whitened, but the main part of the body still had leathery skin/fur and did not smell pleasant. (Nothing like the Götterdämmerung of rotted chicken used to bait for carrion beetles here, though.) Not sure what the animal was: didn’t look big enough for adult raccoon; perhaps a feral cat, of which there are plenty in the phragmites.
So these Nicrophorus beetles — there are some 15 species in the U.S. — are remarkable for providing not just a nest egg of carrion for their young, but sticking around to help feed the wee larvae when they are just starting out as squirmy little rotten-flesh eaters.
The mites — you can spot two adults and see some young ones clustering on the beetle body as well — are symbionts, not parasites. Sources of carrion are extremely variable and unpredictable: so the beetles range throughout the landscape searching for it, carrying the mites (of at least four families), who eat fly larvae and couldn’t get around so well otherwise; the fly larvae is competition for the beetle larvae.
Nicrophorus marginatus is the most wide-spread of these beetles, but it’s very similar looking to N. obscurus and N. guttula, and they evidently can’t be separated based on overall appearance according to Bugguide.
These 2-spotted ladybug larvae were still active on Thursday. Time to pupate, kids!
Now, here’s something I’m not so sure about: Pupation and eggs generally seem to be set on leaves. These leaves will shortly fall to the ground, many to blow away to who knows where (into the harbor in some cases, in this situation). This seems a real chancy way of surviving the winter. Are there special end of season approaches to getting the genes through the cold months?