Nearly-Easter nearly-egg

cyldindrical cocoon
It’s 5mm long and elegantly decorated, but what is it?

There is always something new to see on a walk around the park and on our stroll with Wildlife Queensland folk last Sunday I noticed this beautiful little egg dangling from a shrub. Its silken thread suggested to me that it might be a spider’s egg-case (I knew the little dewdrop spiders create similarly rigid egg-cases and suspend them from a thread like this), and everyone knows that caterpillars make cocoons from silk and some suspend them from plants.

A little creative internet searching revealed, however, that it was neither of the above but the cocoon of a small parasitic wasp in the family Campopleginae, one of the 1500+ subfamilies of the Ichneumonidae.

That level of identification is as close as I will get, but this link will take you to a splendid international collection of photos of the adult wasps. Sometimes I love the internet!

Bookshelf entomology

Everyone knows about bookworms, even if all they know is the name, but bookworms are not the only small wildlife found in bookshelves, particularly in the tropics, as a recent bout of librarianship associated with repainting a couple of rooms has demonstrated to me very clearly.

mud wasp nests on book
Exhibit 1: Wasp nests

Wasp nests like these were by far the most common sign of insect life in our bookshelves. Female mud-dauber wasps (Sceliphron sp.) construct a cell, lay an egg inside and provision it with food for their larvae then, if they can, repeat the sequence nearby. A string of cells like this will have been constructed in a short time (days or weeks) by a single wasp and, if all went according to plan, her children would have emerged and followed suit.

The empty cells stay there for ever but don’t cause any real harm. They are just dirt, and nearly all of it will brush off. The easiest prevention is to push books all the way to the back of the shelf, making the gap too small to be tempting. The wasp will probably build a cell in a corner of the shelf instead.

Exhibit 2a: Resin bee nest
Exhibit 2a: Resin bee nest
Exhibit 2b: Resin bee nest occupied by mud wasp
Exhibit 2b: Resin bee nest occupied by mud wasp

Mud wasp nests are so common around our house that we hardly notice them until they do something odd but the resin bee nests did surprise me.

The pine bookshelves are adjustable, via a double row of holes about 5mm in diameter down each side for the shelf brackets. The empty holes seem to have been just right for our Fire-tailed Resin Bees (the second species described here).

In turn, the empty resin bee cell seems to have been just right for a tiny mud wasp to build its own cell. We often see tiny nests like this in odd nail-holes and screw-holes and, less often, in resin bee nests outside the house.

The resin bees are not doing any harm here except that the shelves are no longer so adjustable as they were meant to be. The resin is very tough, so removing it may mean drilling it out.

book eaten by silverfish
Exhibit 3: Silverfish damage

Our books don’t suffer as much from silverfish here as they did in Melbourne, I think because our climate is (usually) too dry for their liking, but this is their typical handiwork (mouthiwork?): superficial nibbling at the cover or dust-jacket, sometimes extending deeper into the bulk of the book. This damage may actually have occurred in Melbourne – we have had the book that long.

book attacked by borer
Exhibit 4a: Bookworm

The Britannica notes that a bookworm is, “any insect (e.g., moths, beetles) whose larval (or adult) forms injure books by gnawing the binding and piercing the pages with small holes. No single species may properly be called the bookworm because a large number of insects feed upon dry, starchy material or paper and may damage books.”

More specifically, however, bookworms are the larvae of beetles. Their damage is more distinctive than they are: tunnels one or two millimetres wide, often though book covers and sometimes through the pages, with a scattering of sandy droppings tending to fall out when the book is handled.

They are the most destructive of our book pests, and a book has to be really special before we will go to the trouble of trying to save it from them. They are not very choosy and it is obvious that one of ours veered out of its book and into the side of the bookshelf.

wooden shelf attacked by bookworm
Exhibit 4b: Bookworm, lost

Online references such as “Bookworms: The Most Common Insect Pests of Paper in Archives, Libraries, and Museums” compiled by Dr. John V. Richardson Jr., PhD, Ecological Informatician (nice specialisation!) list various other pests but we don’t see many of them.

Spiders, often Daddy-longlegs, sometimes lurk in corners of the shelves but do no harm at all; “booklice” (Psocoptera) don’t seem to be a problem here (again, probably because our climate is too dry) and cockroaches don’t go near our books except by accident.

Dr Richardson also mentions termites and these can indeed be a problem in North Queensland. There is a wonderful passage in Alex Miller’s Journey to the Stone Country in which visitors to an abandoned homestead investigate a bookcase and find that it has been transformed into one solid mass of termite-mound.

I will leave you with that thought as I return to my re-shelving.

Insects enjoying the nectar

long skinny wasp
Gasteruptid wasp

Bug hunters love flowers, not just for their own sake but for the bugs they attract. This set of photos shows most of the insects I saw in just ten or fifteen minutes on one profusely flowering shrub in Anderson Park, beginning with the wasps.

blue-black wasp on white flowers
Blue flower wasp, Scoliidae

This wasp is possibly a Blue Flower Wasp, Scolia soror, and certainly a close relation if not that particular species. There was another similar one feeding on the same shrub, distinguishable by a bright yellow patch on the back of its head; it may have been Scolia verticalis (see them both here, on Graeme Cocks’ site).

Scoliidae is just one family of wasps, the Flower wasps. Gasteruptidae (top pic) is another (BugGuide calls them “Carrot Wasps” and you can see why, but I don’t think they have a genuinely common name), and there are many more including Polistinae, the Paper wasps. This index page on Graeme’s site shows them with their nearest relations, the bees and ants.

small green bee on white flowers
Green native bee

This small native bee (Colletidae) is similar to one which appeared on my earlier all-on-one-plant post. The beetle below is not just similar – it is definitely the same species:

brown beetle on white flowers
Brown Flower Beetle, Glycyphana stolata
small fawn butterfly on flowers
Lycaenid butterfly

The odd angle of this shot was forced on me by my uncooperative subject but does allow me to point out a neat bit of mimicry: the eye-spots and tails on the lower part of the wings are a surprisingly good imitation of the butterfly’s head and antennae (there’s an even more striking example here, on a related butterfly). I’m sure this is not a coincidence, since tricking predators into attacking non-vital parts is great for survival.

blue dragonfly perching on twig
Palemouth Shorttail dragonfly, Brachydiplax denticauda

All the other insects here were attracted to the flowers. This dragonfly just wanted to perch for a while and found a suitable bare twig. He happens to be the first carnivore (insectivore?) on the page and he may well be looking out for prey amongst the smaller bugs attracted to the flowers. As I said in the beginning, bug hunters love flowers.

Accidental artistry

black and yellow wasp
Hunter

I have been photographing insects for several years now and usually know, for better or for worse, how a shot will turn out. I still get surprises, of course, and most of them are deleted very quickly. This one was a surprise – the combination of lighting, lens and camera settings gave me an effect I didn’t expect – but I rather like it.

The subject is a common mud-dauber, Sceliphron laetum.