Monday, April 30, 2012

Some Salticid Research Results

It’s been eight months since I stumbled across this impressive female jumping spider at the Vanderwater Conservation Area, an active, robust specimen between 15 to 20 mm in length. I strongly suspected it was genus Phidippus, but despite putting in no small amount of time on the 'net researching images of spiders, I was unable to identify it until now.

This spider encountered on the trail a couple of days ago was very similar in size and build, and this time my efforts at IDing it – about two hours of research on the ‘net – met with success. I think this is Phidippus princeps. The irridescent pale bluish-grey chelicerae can be seen in the following image.

The brownish-red on the abdomen is pale compared to the color of the spider I photographed last August. The photos of Jumping Spiders - Genus Phidippus by Tom Murray at PBase illustrate how dramatically variable these spiders can be.

Large forward-facing eyes endow this predator with excellent vision (among the best in the invertebrate world), and the remainder of its eight eyes are mounted high on raised nubs on the carapace, giving it a wraparound view of its surroundings.

The spider felt uncomfortable with my being so close with the camera. In addition to waving its front legs and showing its chelicerae, it did this ...

Interesting behavior ... a Six-spotted Fishing Spider assuming the same posture, again, it was in response to my presence.

A few more trips down memory lane to catch up on Salticidae images that have been sitting in my "unidentified" files for about a year. In the course of my Phidippus princeps research I found Bev Wigney's excellent Salticid Photo Galley at PBase, and I believe this small jumper (about 5 mm in length) is genus Pelegrina, a Peppered Jumper. And she's gravid and ready to lay eggs any time, by the look of her.

This female Jumping Spider has captured a Robber Fly, a fearsome predator in its own right. Had the fly seen the spider first, the predator/prey outcome here might well have been different! With the help of the aforementioned photos at PBase and at BugGuide.Net I was able to identify this arachnid as Phidippus clarus.

The best match I could find for this male is genus Evarcha. Making a species identification solely on the basis of a photograph is chancy, but this Evarcha falcata at the Encyclopedia of Life looks like a dead ringer to my inexperienced eye. But – a little more research divulged that Evarcha hoyi is the only species extant in my area (eastern North America), so E. hoyi it is.

Females encountered in the same location as the males, E. hoyi seems a reasonable conjecture. Is my guess correct?

When I started photographing and researching odonates I had no field guides to help me sort out males and females – which can often appear radically different – of the same species. One way around this was to hopefully observe a mating pair of dragonflies, and this technique works for spiders as well ... a mating pair of Evarcha hoyi.

Despite some obvious differences in the palps, overall shape and slightly different markings, I initially misidentified this jumping spider as possibly a species of Eris (Spider Snapshots), but having done more reading and research I think it's actually genus Pelegrina.

Monday, April 23, 2012

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 ...

Thursday, April 19, 2012

Close encounters of the first kind with a Mustard White (Pieris oleracea) and a Henry's Elfin (Callophrys henrici)

My Peterson Field Guide to Eastern Butterflies gives the Latin name of this butterfly as Pieris napi, and some sources consider P. oleracea to be a subspecies of P. napi, the Green-veined White.

Whatever the case may be ... this species is distinguished from the closely related Cabbage White (P. rapae) by the lack of black markings on the dorsal surfaces of the wings, and the strongly veined undersides of the hindwings. The veins are less pronounced in the summer incarnation of the butterfly.

And true to their names, it seems that Cabbage Whites do have a marked preference for cabbage, whereas the Mustard Whites stick to wild members of the family Brassicaceae (a.k.a. Cruciferae) – Differential selection of host plants by two Pieris species.

The next photo is the only keeper, one of several attempts to capture an image of my first encounter with a Henry's Elfin (Callophrys henrici) ... this small butterfly just wouldn't stop moving. Preferred larval host plants are huckleberries, blueberries, viburnum and plums.

Red Trillium (Trillium erectum)

Also called Wake-robin or Purple Trillium, these striking flowers were found growing in wet, almost marshy soil along the trail, about one kilometer west of town. A picture, as they say, is worth a thousand words ...

Wednesday, April 18, 2012


A leftover from last autumn, this Giant Puffball (Calvatia gigantea) is now sporulating. That's a size eleven running shoe in the picture for scale, but this puffball can grow considerably larger, 60 cm is about average with the record being 5 feet and 50 lbs. A Giant Puffball is estimated to contain a whopping 7 billion spores ... now that ought to ensure reproductive success!

I almost overlooked two Stalked Puffballs (Tulostoma sp.) in the sandy soil along the trail; at first glance they appeared to be the dried stems and heads of last years flowers. No kidding – despite the long, tough, almost woody "stem", this really is a puffball – give the ball at the top a squeeze and it will release a small cloud of brown spores through its apical pore.

A group of Pestle Puffballs (Lycoperdon excipuliformis).

Since these puffballs were rolling around freely, I'm going to hazard a guess and call them Tumbling Puffballs, genus Bovista, possibly B. pila.

Tuesday, April 10, 2012

Along came a Running Crab Spider ...

Always look twice! At first glance I mistook this arachnid for a Wolf Spider, but it is not. This spider is a female Thanatus sp., a Running Crab Spider of the family Philodromidae. Here's a link to an image of Thanatus sp. at BugGuide.Net.

The photo was taken near the same location I encountered the Red Efts, east of Highway #37, about one kilometer south of Actinolite – not far from Buttermilk Falls where I stumbled across the Striped Fishing Spider (Dolomedes scriptus) last autumn.

A mug shot is desirable when identifying spiders as their eye patterns are characteristic for a given family.

I found this Running Crab Spider lurking on the trees near Stoco Lake; I think it's genus Philodromus. Had the spider not moved, I never would have spotted it – its resemblance to the lichens and bark in the background is uncanny.

A tiny male crab spider, about 3 mm to 4 mm long ... I'm going to call this Mecaphesa sp. pending a response to an ID request at BugGuide.Net. However, I might be out of luck on getting an ID, my camera was unable to take a picture of the eyes.

At about 6 mm in length this female Ground Spider is also on the small side, that's my pinky finger she's sitting on. Definitely family Gnaphosidae, probably genus Zelotes. Normally a beautiful glossy black, it took a bit of a dusting when captured it for a closeup shot.

A female Nursey Web Spider (Pisaurina mira) striking a rather dramatic pose on a dead leaf.

No problem getting a good image of the eye pattern of this large spider, its body was close to 25 mm long.

Ouch!!! This is my number one photo from the trip to Presqu'ile Provincial Park back in mid-March ... a tick. I think this is a male Deer Tick a.k.a. Black-legged Tick (Ixodes scapularis), a potential vector of Lyme's Disease – I gave my little friend a nice swim in isopropyl alcohol and kept the specimen just in case.

Images of some tick species

This is not intended to frighten people or discourage them from visiting our parks and conservation areas. The parks I've visited thus far have warning signs posted, and no doubt there are ticks in the Tweed area as well. In all my wanderings through the years in woods and fields, this is the first time I've been bitten by one of these (no pun intended) little suckers. But having said that – be aware.

This is my little hitchhiker with a penny and a toothpick to impart a sense of scale. I didn't get bitten until after I got home, and the bite didn't appear to penetrate my skin. Needless to say I showered with lots of soap and water, washed all the clothing I had been wearing, went over my body with a fine-toothed comb (figuratively speaking, that is), and checked everything else I had taken to the park with me that may have come into contact with ticks.