For Whom the Bell Tolls

I have to relate a funny story. Lately I have been going out at night, looking for moths and other insects that fly to the meager outdoor lights here in South Deerfield, Massachusetts. Ok, I have two funny stories, now that I think about it.

The first night I went out looking, I stopped at two banks to prowl around their well-lit ATM and drive-through areas respectively. Naturally, I was stopped by the cops who had received reports of someone with a camera taking pictures of the banks. I eased their fears, and after a computer check I was on my way….Hey, can I help it if banks and the post office are the best-lit buildings in town? Geesh, you don’t have to make a federal case out of it. Well, come to think of it, I guess you do!

Last night I got a start of a different sort. Yet another nicely-lit building is our local library, located right next to a church complete with a bell tower. The library has a wonderful bright light, not one of those non-insect-attracting-good-for-nothing yellow sodium fixtures. Unfortunately, it is located about twenty feet up the side of the building. Thank goodness for the twenty power zoom on my Canon PowerShot SX10 IS.

I had found a neat moth to take an image of, which was apparently at precisely 11:30 PM because, just as I was about to press the shutter…DONG!!! Once my head quit rattling and my heart started again, I got the shot. I guess that will teach me to stay up so late on a work day.

A Day in the life of an Entomologist

I thought I would share just how exciting it is to be in a laboratory doing critically important work as an entomologist, processing pitfall trap samples. I’m kidding, of course, when it comes to the “exciting” part, but it truly is important.

The project I am involved with is striving to develop a protocol for assessing the ecosystem health of forested watersheds, a common yet complex habitat in the northeast U.S. The University of Massachusetts has partnered with the Massachusetts State Department of Environmental Protection and the United States Environmental Protection Agency to carry out this research. Dozens of people have been working in the field and in the lab for nearly ten years already. What started as one person’s project has mushroomed into something much greater. Ok, I know what you’re thinking: How does this affect me, Al Franken?

The habitat under scrutiny here includes many streams that run for most of the year, but run dry in the heat of the short summer. Hence, pitfall traps can be set in mid- to late July in places that are under water the rest of the year. Even then, a freak storm can set the watershed running again and flood the traps, or a beaver can dam the place and do the same thing. The former event happened last year, so I am able to process only a portion of the total pitfall trap samples collected in 2008.

A pitfall trap is a container sunk into the soil (or sand, or other such substrate) such that the lip of the container is flush with the surface of the substrate. Any insects, spiders, mites, and other creatures that come strolling by then fall into the trap. A trap is typically set for a week before being collected and the contents preserved in ethyl alcohol.

The resulting sample I see is in a plastic container with a label detailing the site identification and plot number, and date the trap was set and the date it was collected. Comments indicate the type of location (such as a sphagnum moss mound) and the condition the trap was found in when it was retrieved. I pick out the insects, arachnids, and other invertebrates that I can see with my naked eye, placing each taxon into its own glass shell vial. The vial is labeled both inside and out with the plot number, site ID, and taxon name (Coleoptera – beetles in this photo). The inside label also includes the number of specimens.

I also record the same data on a sheet, counting the number of specimens as I go. Once I’m done with the “big” specimens, I then put the container under the microscope and sort out the smaller things. The effect the alcohol preservative has on the specimens can be dramatic. Spiders fall apart. Even beetles start losing legs and abdominal segments. Springtails, normally pigmented, become literal shadows of their former selves, the alcohol having “cleared” them. It is a strange sight to see a ghostly springtail float across your field of view (cue the spooky music).

The amount of debris in a given sample, and/or the number of invertebrates, can greatly extend the time it takes to process a sample. It can also be very confusing at high magnification to tell a segmented plant part from an insect larva!

Stay tuned for further episodes in the life of an entomologist. Next week, Eric goes insane while trying to identify micro-Hymenoptera to family level….

Let Sleeping Wasps Lie

Awhile back I wrote an entry about the sleeping habits of solitary bees (“Let Sleeping Bees Lie”) that I observed and photographed in Tucson, Arizona. Here in western Massachusetts, I was fortunate enough to observe the sleeping habits of solitary wasps in the genus Ammophila, family Sphecidae. Known commonly as thread-waisted wasps, the females are energetic hunters of caterpillars, which they paralyze and store in a subterranean burrow as food for a single offspring.

There are many species of Ammophila found across most of North America, but they reach their greatest diversity in the arid west. More on that in a later post.

Get a grip!

How these wasps manage to get any sleep in this incredibly awkward position is beyond my comprehension. Maybe it is the wasp version of yoga, I don’t know. Simply gripping a twig with your jaws must be hard enough, let alone propping your body at an angle away from your perch. Though solitary, it is not at all uncommon to find loose aggregations of several thread-waisted wasps bedding down in a small area, like this. I once found a cluster of them at Smith Rock State Park in Oregon that was packed so densely that I initially mistook them for some strange flowering plant.

Like solitary bees, the wasps tend to turn in early, just around dusk. They can also appear to be in torpor (the scientific word for inactivity), but actually be quite alert and able to rapidly disengage from their perch. I approached another specimen on a later date, and it quickly regained “consciousness,” much to my chagrin.

There are sleeping bees here in Massachusetts, too, that adopt the same “look ma, no hands” biting grip as the cuckoo wasps in Tucson. This little bee is another parasitic type, in the genus Nomada, family Apidae. They are parasitic on other solitary bees, especially members of the genus Andrena.

Keep a careful eye out for these sleeping insects, especially in open areas with dry, twig-like vegetation, and around forest edges, even around your yard or garden. Solitary wasps and bees can be approached fearlessly, as they are not aggressive and females will not sting unless physically molested. The males possess no stingers. Well, all this talk about sleep has me yawning. I think I’ll turn in early. I also have a strange compulsion to bite the bedpost….

More moth fashions

While some moths came to the “Moth Ball” all gussied-up in their best black and white, or subtle and elegant pastels (please see the initial entry in my companion blog Sense of Misplaced), others sported complex patterns that rendered them virtual wall flowers, easily camouflaged on the bark of a tree, if not the wood siding on David Small’s shed.

Chief among these was this amazing tufted thyatrin, Pseudothyatira cymatophoroides, a member of the family Drepanidae that includes the hooktip moths and false owlet moths. It was one of the specimens to draw real oohs-and-ahs from the human spectators mingling among the winged wonders.

A wonderful salt-and-pepper pattern was displayed by this aptly-named “oak beauty,” Nacophora quernaria, one of the inchworm moths in the family Geometridae.

A chip off the old tree branch was what this “white-headed prominent” in the genus Symmerista resembled, its lovely white accent line adding to its disguise by imitating an exposed shard of underlying wood.

Perhaps the ultimate in obscurity was this slender little owlet moth in the subfamily Acontiinae that came incognito as, of all things, a bird dropping. Even more stunning, it is only one of over eighty species in that group, the majority of which are also bird-dropping mimics. Well, there is no accounting for taste, I suppose. More to come….

The "Moth Ball"

The evening of Saturday, June 13, 2009 I had the pleasure of attending a delightfully informal event christened the “Moth Ball” by host David Small and his wife, Shelley. The site of this outdoor gala was their home in Athol, Worcester County, Massachusetts. I was among several honored human guests, all anxious to meet the nocturnal Lepidoptera that we hoped would be dancing under the blacklights.

Unfortunately, the weather was patently awful, raining incessantly all night long and into the following morning. No worries, though, as many moths, and other intriguing insects, showed up anyway, and all the people found plenty of entertainment indoors getting to know one another, perusing David’s library, looking at online moth websites and photo galleries, drinking, eating, and occasionally braving the elements to see new arrivals at the lights.

David has a great sense of humor, is laid back, and was always looking to make his guests comfortable. Shelley must have stocked the place with every beverage known to man, and then made strawberry shortcake. We were all well fed and watered. David and most of the guests are “amateur” naturalists, each with their own specialty and command of that group of organisms. Most of them knew far more about moth identification than myself, and I learned a great deal.

Some folks stayed overnight and were treated to comfortable sleeping accommodations and a fantastic breakfast the next morning. Many of the moths apparently liked the place well enough to hang around themselves, or else they had hangovers and were sleeping it off.

Someone made a rough tally of the lepidopterans seen over the prior evening and that morning and it totaled over sixty species, bad weather and all.

For a peek at the more interesting moths snapped by the paparazzi, please visit my companion blog, Sense of Misplaced, and keep an eye out here for additional items related to the Moth Ball. Better yet, hold your own event. It is a sure cure for the summer doldrums.

Giant ichneumon wasps

Prowling around a pile of cut logs near my temporary residence in South Deerfield, Massachusetts on the evening of June second, I almost literally stumbled upon one of the most spectacular wasps on the continent. Female giant ichneumon wasps in the genus Megarhyssa may look menacing, wielding a whip-like “tail” that can exceed their own body length, but they cannot sting and in fact are quite shy, easily startled by sudden movements. It is a pity that people are often so alarmed by these insects, as they have an extraordinary life cycle.

That long, streaming appendage at the end of her abdomen is not a stinger, as the uninitiated tend to assume, but an egg-laying organ called an ovipositor. What she does with it is truly remarkable. She is seeking the grubs of another stingless wasp, the “pigeon horntail,” Tremex columba. Horntail grubs bore in the solid wood of dead, dying, or severely-weakened trees. Along comes a giant ichneumon wasp. The ichneumon somehow “divines” the location of the horntail grub inside the tree or log, then arches her back to pull her ovipositor into position to drill into the wood to reach the horntail grub. Whether she actually penetrates the solid wood, or winds her thread-like organ through existing cracks and crevices is still a mystery, but she manages to deliver her nearly fluid egg to its target host. The ovipositor is actually three filaments: two form a sheath for the actual ovipositor, bracing the animal’s abdomen and allowing the ovipositor to work smoothly without undo bowing.

Once her mission is accomplished, and her egg is attached to the horntail grub, the adult female ichneumon slowly withdraws her ovipositor and begins the process over again, walking the log or tree with antennae outstretched like divining rods.

Meanwhile, her egg eventually hatches, and the larval ichneumon attaches to the exterior of the horntail grub. It will wait patiently for its host to reach a large, nearly mature size, then begin consuming it. The horntail grub is doomed, destined to yield an adult ichneumon rather than a horntail wasp.

Look for giant ichneumons around dead or dying trees at all times of the day. While ovipositing, females are vulnerable, and one can sometimes see where a wasp was taken by a predator. A hair-like filament protruding from a log is all that is left of the wasp in such cases.

Male giant ichneumons like this one can also indicate the presence of females as they vie for mating opportunities. Note that they almost resemble a different species of wasp! Many males may gather at the site where a female is about to emerge. It is quite a spectacle.

Four species of giant ichneumons collectively occur over most of North America. The ones shown here are probably the species Megarhyssa macrurus. Females can vary considerably in size depending on the size of their host as larval wasps. Smaller individuals tend to have reduced spotting on the wings (or no spots at all). Enjoy looking for these insects and observing their amazing behavior.

Housemates

Besides the human and canine residents at 24 Sugarloaf Street, our house is also occupied by a variety of arthropods, mostly spiders. Crystalyn says she is not fond of spiders, so I’m hoping she doesn’t read my blog, at least for the sake of the health of these arachnids living with us.

The first spider to meet my acquaintance was this very gravid (egg-laden) female “prowling spider” of the family Miturgidae, on the ceiling of the bathroom. She is most likely a member of the genus Cheiracanthium, known also as “longlegged sac spiders.” The genus used to be in the family Clubionidae, but was moved to the Miturgidae in 1997, a decision still being debated in arachnological circles.

These spiders are mostly nocturnal, prowling during the night then spinning silken retreats in which they spend the day. This girl spun a bivouac as I watched.

Later I would find her mate in the kitchen. Well, it was an adult male at least, evidenced by the modified palps. They appear as the dark “boxing gloves” near his mouth. The palps (or pedipalps) are leg-like mouthparts that double in the male as intromittent sex organs. He deposits sperm on a mat of webbing, then draws it into each palp. These are complex appendages, designed to fit like a key in a lock, the lock in this case being the female’s sex organ called the epigynium. Like the female, the male also “sacks out” during the day.

Cheiracanthium had long been considered a genus of spiders at least mildly venomous to humans, but research has proven that this is a myth. So, I let them roam and carry out pest control activities. We definitely have too many mosquitoes here!

Crane flies of the family Tipulidae are very abundant now, some species being attracted to lights at night, and inevitably one strays indoors. This one has patterned wings. It is on the bathroom ceiling, too, but I don’t know whether one of the spiders got it. Crane flies are often mistaken for giant mosquitoes, or are referred to as “mosquito hawks,” but the adult insects probably do not feed, let alone take prey. Their size is deceptive as they are fragile insects. Look at one cockeyed and a leg will fall off. Their lifespan as winged insects is brief, just long enough to find a mate and reproduce. Crane fly larvae live in an incredibly variety of habitats, with diets that vary with the genus to which they belong.

A more permanent guest is yet another spider. This is what I imagine is a juvenile long-bodied cellar spider, Pholcus phalangioides, because adults are much larger. This one is well on its way, though, especially if it continues catching prey in the bathroom doorjamb like this. Cellar spiders are totally harmless to people and pets. While they do build tangled webs, they will also stray from those webs into the webs of other spiders and kill and devour them. Pholcids are frequently referred to as “daddy longlegs,” but that colloquial name is also given to harvestmen, arachnids of the order Opiliones (not spiders), and, ironically, to crane flies, especially in England. A crane fly would be more than this little one could handle.

Crystalyn is so busy that she sometimes forgets to turn the oven off, let alone observe the room for roaming arachnids. Her dog Ruby did see one, once, in the dining room, and drew our collective attention to it as it crossed the ceiling out of reach.

The Lab

Welcome to Holdsworth Hall on the campus of the University of Massachusetts (Amherst), my home for the next six months. The campus is largely deserted now, graduation having happened about a week ago, and my supervisor, Theresa Portante, herself a grad student, is leading her team in the field for the summer. I will be pretty much alone for the next three months.

There is not much to set my workspace apart from any other scientific technician, but I am grateful for a very nice microscope, illuminator, computer with internet, a small clock radio, and lots of ethyl alcohol. No, the alcohol is not for stress relief! It is the preservative used for the trap samples I will be sorting through.

Right now I am sorting through pitfall trap samples taken on each of last year’s study plots, all of them in wetland habitats that dry out during the heat of summer. Each sample comes in a labeled plastic cup with a locking lid. My job is to segregate the invertebrates contained therein into separate shell vials. Each “order” level of classification gets its own vial. It is not as easy as it sounds. Globular springtails and wingless barklice are easily confused, for example.

Lunch is my chance to get outdoors and breathe some fresh air after sniffing alcohol all morning. My favorite haunt thus far is the ”Campus Pond,” a surprisingly lush, well-landscaped water feature. Aside from being mobbed by ducks accustomed to being fed by everyone that lingers on the shore, I find it is a peaceful spot to enjoy a brown bag meal.

At some point I hope to include an entry in this blog that details what it is like to process a sample. Meanwhile, coming soon….let sleeping wasps lie, giant ichneumons, and other stories from the field.