20,000 Micrometers under the Debris

The weather has been cool and overcast and most insects have gone into hiding to sit it out. Since there was a paucity of animals to photograph in the woods and fields it looked like a good time to take a peek beneath some rocks, logs and leaf litter. There's an entire world we’re seldom aware of under the surface of the soil, with an ecology of its own that both provides the support for and receives nourishment from the living things above.

Cornfield Ants or Citronella Ants (Acanthomyops sp., a subgenus of Lasius) – due to their subterranean lifestyle these common ants are rarely encountered. This group is scurrying to move their larvae to a safer place.

Even though they seemed on the large side, in the field I still mistook the rounded yellowish objects seen in the next photo for eggs. When I zoomed in on the image on my computer, my wonder of modern technology revealed that these were not eggs, but root aphids.

Many species of ants are symbiotic with aphids, guarding and "farming" them for the honeydew the aphids produce. But – these are called "ant-obligate" root aphids. Obligate meaning what? ... do they totally rely on the ants to complete their life cycle? No one has answered this intriguing question at BugGuide.Net, and I can't find it elsewhere on the Internet.

A "wireworm", the larval stage of a Click Beetle ... I have no idea what species.

Another insect larva – the immature incarnation of a Fishfly (Chauliodes sp.). Having overwintered underwater, it has abandoned its aquatic abode and prepared a cozy place under a rock where it can pupate. The small red "bug" to the left of the Fishfly is a Velvet Mite (an arachnid, related to a spider), and to the right is a Sowbug (actually a crustacean, like a crayfish).

Although it's not an uncommon insect, only those of us who have nothing better to do with our lives than roll over rocks and rotten logs are apt to chance upon the Camel Cricket. This one is probably genus Ceuthophilus, and it is not only virtually blind, depending on its long antennae and legs to navigate its stygian environment, but is wingless and unable to chirp like many other cricket species. The lack of an ovipositor indicates it's a male.

A Wood Cockroach, probably Parcoblatta sp. – judging by their numbers these insects won't be making the endangered species list any time soon ...

One of the common small cylindrical millipedes, probably order Julida. Millipedes have two pairs of legs on each body segment, and in most groups the legs on the seventh ring are modified copulatory organs called gonopods, the shape of which is an aid in identifying species. However, I didn’t examine any of the millipedes in the field, nor did the camera capture enough detail for me to guess at assigning a family, let alone a genus or species name.

If they feel threatened millipedes will often curl up in a spiral defensive posture, presenting their tough exoskeletons to the outside world. Some species also exude fluids that would-be predators find noxious.

Based on the number and profile of the body rings, this millipede found creeping about in the woodland leaf litter belongs to the order Polydesmida. Beyond this, I can’t say whether the two differently colored millipedes belong to different species. For all I know, the pale millipede in the first two images is the same species but has just recently molted.

Lithobius forficatus, the ubiquitous Stone Centipede. Centipedes have one pair of legs per body segment – always an odd number of pairs. The modified first two appendages, called forcipules, bear venom and are a feature unique to centipedes.

A closeup view of the forcipules.

Less often seen is the Soil Centipede (Geophilus flavus). This species can move both backwards and forwards with equal facility. According to one of my field guides these blind centipedes can penetrate as deep as 40 to 70 cm into the soil in search of insect larvae and worms.

Moving on to a couple of representatives of the order Isopoda, terrestrial crustaceans distantly related to crabs, lobsters, and much closer cousins of the freshwater isopods I photographed last autumn. Isopods have seven pairs of similar legs ... "iso" → same, "pod" → foot ... as opposed to, for example, a crab, which has very specialized appendages.

The Sowbug, genus Porcellio, has a three lobed head and two segments on the flagellum, the end of the long antennae. (Also like other crustaceans, Isopods have two pairs of antennae.) This woodlouse cannot curl up in a ball when disturbed.

On the other hand, the European Sowbug (Oniscus asellus) is often called a Pillbug because it can roll up if it feels endangered. The body ends in a two pointed telson (the telson being terminal body segment), and the flagellum consists of three segments.

"Bugging out" when life gets too scary ...

A Myrmecological View of Nature

It's always kind of neat to be able to see the commonplace things we take for granted from a different perspective, so it's back to Laurie Campbell's digital microscope. In keeping with the title we'll start with some images of Lasius neoniger. This little brown ant's crater mounds are a familiar sight on lawns and in sidewalk cracks during the summer months. The objects on the end of the toothpick are the eggs...

... this is the grub-like larva ...

... and the pupa, note how it has the profile of an adult.

The pupa is generally encased in a protective cocoon. I have no idea why the pupa in the image above is exposed as it is.

This is the adult, a sterile female worker.

The next group of images are a tandem pair of bluets, Enallagma sp. Many of these small damselflies are so similarly patterned and colored that they cannot be reliably identified in the field, and an examination of the male's cerci and female's mesostigmal plates is necessary to determine the species. In the following two views, the male's cerci conform to the diagrams in my field guides for a Tule Bluet (Enallagma carunculatum).

While I had the damselfly in hand I took the advantage of the opportunity to get a picture of the unique odonate labium. In naiads this part of the jaws is hinged and extensible, and can shoot out with lightning speed to capture passing prey with the needle sharp tips. (Vestiges of the larval labium can be seen in the images of the Canada Darner exuviae).

Females of many Enallagma species can be tan (like this one), olive, or blue. The mesostigmal plates are a bit difficult to make out, but they too agree with the drawings for Enallagma carunculatum in my reference books. The head and prothorax have been removed in the second image.

A few years ago I was watering my house plants and noticed what looked like a small tick about 2 mm long moving around in the potting soil. Actually, this is a pseudoscorpion, Chelifer cancroides, not something one sees every day. These tiny arachnids don't possess a stinging tail like a true scorpion; their venom glands are contained in their claws.

Pseudoscorpions prey on mites, clothes moth and carpet beetle larvae, and other small arthropods. For more information about these seldom encountered arachnids follow this link to a Photographic key to the Pseudoscorpions of Canada and the adjacent USA.

A couple of closeups of two local centipede species: Lithobius forficatus, the common Brown Centipede often encountered under stones, and Scutigera coleoptrata, the House Centipede which frequently enters older houses. A centipede's venom glands are contained not in its jaws, but the first pair of modified front legs called forcipules, visible just under the heads.

Moths and butterflies belong to the order Lepidoptera, which means "scale wing". In some species the patterns created by the tiny scales are only visible in ultraviolet by others of their kind. These are the scales on the hind wing of a Blinded Sphinx (Paonias excaecatus) ...

... a Twin-spotted Sphinx (Smerinthus jamaicensis) ...

... and an Underwing Moth (Catocala sp.)

The hind leg and wing of a Leaf-footed Bug, a Western Conifer Seed Bug (Leptoglossus occidentalis).

Details of the head, legs and wing of an as yet unidentified gnat; possibly Family Sciaridae, a Dark-winged Fungus Gnat

This spider is a female Furrow Orbweaver (Larinioides, probably sclopetarius).

A closeup dorsal view of the carapace ...

... and a front view. The microscope's depth of field is very narrow making it difficult to focus, but there's enough detail in the image to make out the eyes. The arrangement of a spider's eight eyes are one of the criteria used to determine species.

A ventral view of the cephalothorax. I was hoping to get a picture of the chelicerae but the spider's naturally dark coloring makes it difficult to light this area with an LED side light.

A dorsal shot of the beautifully patterned abdomen.

Ventral views of the cephalothorax and abdomen. The focus in the area where the legs are attached to the cephalothorax is satisfactory and the epigynum is visible, but I was also hoping to capture an image of the lung slits. Unfortunately this was another body part that was troublesome to illuminate. Although somewhat out of focus the spinnerets can be seen at the end of the abdomen in the second picture.

Despite its tiny size, half a millimeter at most, this pupa is my most unusual photo of this year. The closest thing that resembles it is the pupa of a Minute Tree-fungus Beetle, of the family Ciidae (or maybe, as the author in the link to BugGuide.Net wrote "... it could have been a miniature penguin ...").

The pupa seemed to be quite aware of its environment, including my presence, and would rock back and forth about its point of attachment to the grape leaf if disturbed. The following two clips are a shoo-in for the most boring videos of the year ...