Saturday, August 30, 2008

Great Golden Digger Wasp (Sphex ichneumoneus)

The day was windy, which didn't help with keeping the camera in focus. Also, Great Golden Digger Wasps tend to be very active insects, making them difficult to photograph under the best of conditions. Nevertheless, this wasp was not only well aware of my presence, but there were times when it seemed it was posing for the camera.

The Great Golden Digger Wasp comes by its name honestly. The Paper Wasp wanted to dispute which of the two had claim to the goldenrod and makes a convenient scale with which to judge the size of Sphex ichneumoneus.

And this, of course, is THE END ...

BIG Dragonflies

Despite its striking colours this large dragonfly was nevertheless well concealed against the tangled background of vegetation.

Maybe it was torpid because it was early in the morning. Or perhaps it hasn’t been long since it emerged from its nymphal skin and wasn’t wholly adjusted to its new life as a creature of the air. Mosaic Darners or Blue Darners (Aeshna sp.) are wary insects, capable of staying on the wing for hours on end while sustaining high cruising speeds. As a rule they cannot be approached this closely.

Blue darners can be hard to tell apart and the lateral markings would help nail down the species. Unfortunately the dragonfly didn't want to co-operate, so I'll just call this Aeshna sp. and leave it at that. (Edit: Since originally posting this I have acquired field guides and zoomed in on the original photo, and S10 is entirely black, identifying this as Aeshna tuberculifera, the Black-tipped Darner).

The female Fawn Darner (Boyeria vinosa) depicted below had a run in with the local traffic and was a little easier to pose for the photos. She's not too badly hurt and should make a complete recovery.

Tuesday, August 26, 2008

The Meadowhawks ... Sympetrum sp.

The red abdomens tell us the small dragonflies in the first few photos are males but it can be hard to nail down the species. A mature White-faced Meadowhawk (Sympetrum obtrusum) has a distinctly white face and black legs.

The red face on the dragonfly in the next three images indicates a Cherry-faced Meadowhawk (Sympetrum internum) or a Ruby Meadowhawk (Sympetrum rubicundulum). These two species are difficult to distinguish from one another in the field or from a picture.

The abdomen has well defined black markings underneath (this isn't very clear from the photos), this tends to rule out an Autumn Meadowhawk. On the other hand I would expect to see darker legs than this on a Cherry-faced or Ruby Meadowhawk. So I'm not entirely certain as to the species ...

Female meadowhawks are light brownish orange. The black legs and a white face indicate a female White-faced Meadowhawk.

And this? ... yellow legs and a lack of strong black marks on the underside of the abdomen; possibly a female Autumn Meadowhawk (Sympetrum vicinum)? (Note ... I've acquired some excellent field guides since this was originally posted. In addition to the field marks already noted, the triangular ovipositor definitely identifies this as a female Sympetrum vicinum).

Last but not least, a close-up of a male ... whatever species he may be.


The Dogday Harvestfly (Tibicen canicularis) goes through incomplete metamorphosis, having only three stages in its life cycle: egg, nymph and adult. The nymphs live underground sucking juices from tree roots, preferably pine trees.

After three years the nymphs emerge and go through their final molt, changing into winged adults. The cast off exoskeleton may be seen in the picture below. As is the case with many insects the adult cicada does not eat; it lives long enough to reproduce and then dies.

It's going to take a bit of luck to get a shot of an adult cicada as they tend to spend their time high up in the trees.

Dragonflies also go through incomplete metamorphosis, spending the second stage of their life living a predatory aquatic existence. This discarded nymphal exoskeleton (exuviae) is about 2½ inches long and likely belonged to a skimmer or a darner.

The Monarch Butterfly (Danaus plexippus) goes through complete metamorphosis ... egg, larva, pupa and adult. The larva in following image is feeding on Swamp Milkweed and this one seemed to have a marked preference for the seed pods. The caterpillar ingests toxins present in the sap of the milkweed plant and the bold colors advertise its poisonous nature.

I'm going to be keeping an eye out because this caterpillar looks like it will be ready to pupate any day and this looks like a good opportunity to make a photo essay of the change from larva to adult.

These are the seed pods the caterpillar ate in only two days ...

... and it's moved on to the leaves and still going strong!

Unless I find another caterpillar it looks this photo study of a larva metamorphosing into an adult Monarch won't be finished.

I checked out the caterpillar the following morning; it was torpid and looked like it was ready to pupate. Two hours later ... it was gone. Maybe a bird got it. Birds have to learn to avoid the warning colors and it seems like one might have tested its luck.

Working the Night Shift ... Little Brown Bat (Myotis lucifugus)

This little fellow just was hanging out waiting for the sun to go down. I wanted a picture of his (or maybe it's a her, I didn't check) face so I puffed on his fur to wake him up. He seems annoyed ... do we need a translation of what he's saying ... ?

Monday, August 25, 2008

Praying Mantis (Mantis religiosa)

It's fair to say that this is the insect that piqued my amateur interest in entomology so many years ago. The eyespot visible under the forelegs of the green mantis identifies this as the European mantid, Mantis religiosa.

Their form and color conceal mantids from both potential prey or predators but when it comes to camouflage our local species can't compete with their tropical cousins ... they go absolutely over the top to imitate leaves, or flowers such as orchids.

Exoprosopa decora and Systoechus sp.

As its name suggests this fly is indeed decorated. Bee flies are quite wary and it took a good deal of patience to approach closely enough to catch this handsome insect nectaring.

Some bee flies such as Systoechus sp. have a long fearsome looking proboscis but they do not sting ... it serves as a straw. As a rule these flies sip nectar while hovering (to avoid exposing themselves to Ambush Bugs?) and I seldom see them actually alight on a flower.

Saturday, August 23, 2008

Can't touch this ...

There were a couple of dozen of these Black Blister Beetles (Epicauta pennsylvanica) ... for some reason all clustered on one goldenrod out of hundreds of others.

When it comes to survival strategies nature is endlessly inventive and blister beetles have evolved an interesting deterrent against predation. If disturbed they bleed a fluid containing cantharidin from their joints. Should a budding entomologist come in contact with this chemical it can cause painful swelling and blistering of the skin.

Tangled Webs

Actually, not so tangled, and not all spiders spin webs. A spider is guided by instinct in building a web characteristic of its species. The webs are marvels of geometry ... it seems that no matter where we look, mathematics is "hardwired" into the universe.

The orb weaver snacking on the hapless hoverfly in the first three photos looks like a Shamrock Spider (Araneus trifolium). The coloration of this spider is highly variable and some individuals are nearly white. This female had a nest above its web made of rolled up leaves held together with silk. A line connected the redoubt and the web, transmitting vibrations to alert the spider to the presence of prey snared in its net.

Mangora gibberosa ... same spider as in an earlier post.

The same Long Jawed Orb Weaver (Tetragnatha sp.) as in the last post. Despite its limited vision the spider was very well aware of my presence ...

An immature Flower Spider (Misumena sp.), this specimen is approximately one third the size of an adult.

A different species of Crab Spider. It was windy, making it difficult to capture details (especially the eyes), my best guess based on this sole out of focus image is Xysticus sp.

An immature Cross Spider (Araneus diadematus).

The following picture is the ventral view of an adult female Cross Spider. It's hard to judge the scale from a photo ... this spider is actually twice the size of the spider in the two pictures above.

A dorsal view of the adult female Cross Spider seen above.

The next three photos show an adult male Cross Spider. Male spiders deliver their sperm with their pedipalps and the customized organs can clearly be seen in the lateral and dorsal views of the spider.

Female Funnel Weaver Spider, Agelenopsis sp.

This is the smaller Agelenopsis sp. male

A female Nursery Web Spider, Pisaurina mira. Judging by the pale color this one looks like it has molted recently.

Since I caught it in the act of making its web, it's probably safe to say the spider in the next two pictures is an orb weaver. The photos were taken at night against a green background so the quality of the images leaves something to be desired (some of the green was removed and the images sharpened after being downloaded to the hard drive). Some of the orb weavers can be hard to identify even from a good image, based on the information at hand I'm going to go with Larinioides sp. , most likely Larinioides sclopetarius.

The spider in the next picture is a male Larinioides sp., note the large modified pedipalps (he also seems to have misplaced a leg). Male and female spiders appear so different from one another that sometimes it's hard to believe they are the same species.