Authors Posts by Matt Pelikan

Matt Pelikan

Matt Pelikan
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The right equipment is just part of the formula for identifying insects in the field.

A bee-fly in the genus Villa, a conclusion drawn because of the clear view of the wing veins. Photo by Matt Pelikan

Photography in general, and the study of insects in particular, has been revolutionized by digital cameras. Examination of a specimen — usually a dead insect — remains the route to a definitive identification. But as field guides, reference websites, and amateur knowledge all advance, a good photo or two, compared with known examples or emailed to an expert, often suffices for a firm ID.

When I first began the serious study of insects, about 25 years ago, my camera had manual focus and exposure control and was loaded with Kodachrome 64 slide film. Film and processing costs were daunting on my graduate student budget, so I tripped the shutter only when everything seemed perfect; two dozen frames represented a busy day in the field, and if one of those images was a good one, I was ecstatic.

These days, I routinely shoot 10 times that number of frames, since they don’t cost anything. Modern long-zoom “bridge cameras” or digital single-lens reflexes with telephoto lenses can produce respectable pictures of larger insects from 10 feet away. Even cheap digital “point-and-shoots” or the cameras in modern smartphones make a decent insect image far easier to obtain than it was with my beloved Pentax K1000 film camera.

Physocephala tibialis, a thick-headed fly, whose identification is made possible by the details of the face and the pigmentation in the wings. Photo by Matt Pelikan
Physocephala tibialis, a thick-headed fly, whose identification is made possible by the details of the face and the pigmentation in the wings. Photo by Matt Pelikan

But a key thing to remember about photography of any kind is that equipment is only part of the battle. The right camera and lens, and the right settings, make the most of your opportunities — but the opportunities themselves are still created by the photographer. Just blasting away still won’t do it; you need to think not only about how to optimize the quality of your images, but about what those images should consist of.

I leave aside the question of how to make an artistic image of an insect (a wonderful goal but not necessarily the same as taking an identifiable photo). For identification, you need not just a sharp image, but one showing the right details. Regrettably, what details are “right” depend on what group of insects you’re working on, and while a good overall view often suffices, there is no substitute for experience in knowing what details are most important in any particular case.

For bees and flies, for example, it’s helpful to have a photo showing the wing veins clearly. For beetles, the antennae are curiously useful for ID; for spiders, the eye arrangement. Details of facial structure can be important, and the number or location of spines on the body or legs may matter. For katydids, the reproductive appendages at the tip of the abdomen are the crucial thing. These are the kinds of characteristics that govern insect taxonomy, and the more of them you can capture (in multiple shots, if necessary), the more precisely you’ll be able match a bug to pictures in a field guide or on a reference website (my favorite is BugGuide.net).

The amazing powers of digital cameras notwithstanding, the best images still come from shooting in bright light, holding the camera rock-steady, getting as close as you can to your subject to minimize the “zoom” length required for a frame-filling shot, timing your shots to avoid motion of your subject (either from its own movements or from wind), and making sure the camera is focused on the right details.

Once you’ve attended to these basic rules of photography and settled on camera settings that produce a good compromise (it’s always a compromise) given the prevailing conditions, you need to think about your camera in relation to the subject. Move slowly as you approach as close you can — just a few inches, if you and your camera can manage it, for a small insect. Broad surfaces such as wings need to lie in the same plane as the camera’s sensor if you’re going to get the entire surface in sharp focus. Your view of the insect, of course, should be unobstructed by vegetation, and your angle of view needs to foreground the details you’re seeking. Often, this means a combination of patience and contortion; be ready to sit, kneel, or lie down in order to hold the camera steady from the right angle.

I don’t mean to discourage would-be bug photographers; on the contrary, nearly everybody has a camera that can do an adequate job shooting larger insects at least, and I’m heartened by the number of people who seem interested in trying. But the ease of digital photography means that many people have lost sight of, or never learned, the laws that govern capturing images. And the nuances of identifying insects once they’ve been photographed were never widely known. The study of insects by means of photography is within anyone’s reach — but you need more than just a blob to work with!

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Try to get a look at the tiny, exquisite hairstreak butterflies while you can.

An oak hairstreak. Photo by Matt Pelikan

July is hairstreak month on the Vineyard. Now, that’s a remark that needs some explaining, partly because many people have no idea what a hairstreak is, and partly because even among people who do, it’s an imprecise term.

To keep things simple, the hairstreaks are a group of delicate butterflies, each wing about the size of dime, gray (with a few exceptions) overall but equipped with intricate stripes and patches of color on their wings. The “hair” in their name refers to tiny, thread-like tails extending from the margin of their hind wings, usually adjacent to patches of color. Characteristically, hairstreaks perch with their wings raised over their backs, rubbing them together. The combination of tails and patches is thought to resemble an eyes and antennae, an adaptation to make it harder for a predator to know which end is the front of the butterfly.

If one took a broad definition of “hairstreak,” the Island hosts about a dozen species. That number would include the elfins, four species of brown, early-season butterflies, with stumpy tails instead of hairs, because taxonomists put them in a genus with some less questionable hairstreaks. Less debatable members of the group would include the gorgeous juniper hairstreak, green with white striping, which flies in May and then again in late July. And it would include two gray hairstreaks that exhibit three flight periods per year, in May, July, and September — the gray and the rare white-M hairstreak.

But it is the genus Satyrium, represented by four, perhaps five species here, and the genus Fixsenia, with just one member here and a rare one at that, that constitute our roster of true July hairstreaks. With just one generation a year, these species appear as adults in the last days of June or the first ones of July, flourish for a few weeks, and then are gone until the next year.

Zealously sought by butterfly enthusiasts, hairstreaks generally are both challenging and rewarding for the observer. The rewards come from the sheer beauty of these insects. On a casual glimpse, they may appear dull gray and nothing more. But observed closely — and with care, you can get within inches of a comfortably perched one — they are simply gorgeous animals, ornately marked.

The challenges, though, are many. Some species are almost always scarce, and in some years, members of this group are nearly impossible to find. They are tiny and hard to spot. And their flight is erratic and incredibly rapid; were it not for a happy proclivity to return to the same perch, a hairstreak in flight would be gone for good most of the time.

But like all butterflies, there are tricks that make observation easier. For one thing, being highly active insects, hairstreaks are all avid drinkers of nectar — that is, of sugary liquid produced by flowers to attract pollinators such as butterflies. Hands down, the easiest way to find July hairstreaks is by checking milkweed blossoms for butterflies engaged in nectaring.

The social habits of hairstreaks also work for the observer’s benefit. They are fairly social insects; if you find one, others are likely around. And the males often perch on tips of leaves, looking gorgeous and exuding pheromones with the goal of attracting a female, and the silhouette of a perched hairstreak is tiny but sometimes surprisingly obvious.

Edwards’, banded, striped, and oak hairstreaks are all enjoying a banner season this year. (Coral hairstreaks, named for a reddish cast to their ground color, have been curiously absent so far, but they are usually the latest species to fly, and may simply not have begun their season yet.) The caterpillars of all these species feed on hardwoods of various kinds, so the habitat to look for them is easy to determine: fields or clearings in or near deciduous woods and rich in milkweed or other nectar sources. I doubt your eyes will work as well as my experienced ones, but in mid-July, I can often find more than 100 hairstreaks in a day.

The star of this year’s show has been the oak hairstreak, which as its name suggests associates with oaks. You’d think they’d be abundant on the Vineyard, which is so dominated by oaks, but think again. This is among the rarest of our butterflies, and I miss it altogether in more years than I see it. It is rare enough to be listed as a Species of Special Concern under the Massachusetts Endangered Species Act.

But along with other hairstreaks, the oak hairstreak seems to hit random peaks of abundance every few years, presumably when conditions over the past year have suited it. Adults are relatively plentiful for a few weeks — I’ve found about 10, at six different locations, this year — presumably dispersing and laying eggs in many corners of the Island, and then for the next few years the species fades into the background again. So this bountiful season has been one of delight for me.

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Nature could care less about human aesthetics.

A parasitic bee in the genus Sphecodes, feeding on American holly flowers. Photo by Matt Pelikan

From ticks to tapeworms, parasites lead the list of reviled animals. And the insect world takes parasitism to particularly repellent extremes: The young of entire families of wasps and flies, for example, comprising tens of thousands of species, mature inside their hosts, literally eating them from the inside out.

But nature has no regard for human ethics or aesthetics. The only point is survival, and parasitism, which involves appropriating resources rather than producing your own, offers obvious advantages. Why work yourself when you can steal the fruits of someone else’s labor?

A bee in the genus Nomada taking pollen from a coreopsis blossom.Photo by Matt Pelikan
A bee in the genus Nomada taking pollen from a coreopsis blossom.Photo by Matt Pelikan

Bees currently (and rightly) enjoy widespread human approval for their role in pollinating plants, lending productivity to agriculture and helping native plants flourish. So it might be dismaying to find that parasitism is a common strategy among these popular insects. One rough estimate is that about 15 percent of all bee species are parasitic, a ratio that is not far off among the bees known on the Vineyard.

The name “cuckoo bee” is often loosely applied to these parasitic species, after the Old World cuckoos of the bird world, which lay their eggs in the nest of other birds and stick the host with the labor of raising the hatchlings. Cuckoo bees generally parasitize other bees, laying their eggs in the nests that have been built and provisioned by the victimized species. While the colonies of social bees, such as bumblebees, are sometimes the target, most parasitic species exploit so-called solitary bees, which nest individually, often in burrows dug in the ground. Often the parasite/host relationship is a very specific one, with a cuckoo bee parasitizing only one or a small number of other species.

In evolutionary terms, cuckoo bees descended from species that built their own nests, and the parasitic lifestyle has evolved many times, in multiple bee families. Somewhere along the line, some bees simply began laying their eggs in the nests of other species, rather than building their own, giving rise to parasitic lines of descent. With no need to gather pollen for their offspring, parasitic bees gradually lost the physical traits — hairiness, the presence of hairy “baskets” on the hind legs for transporting pollen — that help other bees provision their nests. As a result, most parasitic bees look rather wasplike, often spiny but lacking hair.

Parasitic bees do visit flowers, eating pollen as a source of energy. And in the process of such visits, they do pick up small amounts of pollen on their legs and bodies (I’ve taken photos that show this). However, these bees clearly carry much less pollen around than do their hairier, nonparasitic relatives. Moreover, because they only take pollen to satisfy their own needs, not the needs of all their offspring-to-be, cuckoo bees spend much less time visiting flowers. As a result, they are probably much less helpful as pollinators than nonparasitic bees.

They spend a good deal of their time patrolling promising habitat, looking for the burrows of suitable hosts. In my yard, parasitic bees in the genus Nomada patrol with a seemingly mathematical precision, crossing open areas in a series of tight S curves, and pausing to investigate promising holes in the ground. I’ve yet to see a parasitic bee actually entering a host’s burrow, but they locate those burrows reliably, and often spend several minutes at a time walking around a burrow’s mouth, perhaps determining if it belongs to a suitable species, or if the owner is at home.

With a suitable burrow located, a female cuckoo bee waits until the burrow’s proprietor is out foraging. Descending into the vacant burrow, the parasitic bee often eats any eggs or larvae present, lays her own eggs near the pollen supply in the burrow, and then seals the tunnel on the way out. The interloping larvae hatch and then mature, eating the pollen that was gathered by the nest’s original owner.

If bees in general are beneficial insects, does that mean that cuckoo bees, which victimize other bees and are less efficient as pollinators, are bad? My answer would be, in part, that we should avoid thinking of wildlife as “good” or “bad.” Insects simply are, and to my mind, every species has a right to life. (Well, except the deer tick.)

But in a backward kind of way, parasitic bees may benefit their hosts. Think of it this way: The best way a host species can defend against nest parasitism is by spending as little time as possible away from her nest. Host bees that select sites close to rich supplies of pollen can spend relatively little time foraging, and as a result, may experience less likelihood of being parasitized.

Assuming that some innate tendency, and not just luck, guides a bee’s nest-site selection, cuckoo bees would prey more heavily on individuals with poor judgment about nest sites. In other words, parasitism may be a selective force that lets the most fit members of the host species reproduce more often than less fit members.

In any event, cuckoo bees are beautiful insects with complex and interesting behavior. My advice is to set value judgments aside and appreciate these animals as unique, highly adapted pieces of an infinitely complicated natural world.

 

 

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‘Quercus velutina’ was almost 200.

The writer's feet on the massive stump of the oak.– Photos by Matt Pelikan

We are sorry to report the passing of Quercus velutina, a.k.a. Black Oak, sometime during the winter of 2014–15 at the approximate age of 200. A lifelong resident of Oak Bluffs, Quercus never budged beyond her birthplace in what is now Everett Park. The cause of death was infestation by Bassettia ceropteroides, a gall-forming wasp in the family Cynipidae. No burial or memorial service is planned; the remains were mostly removed on Friday, June 5, in stove-length chunks.

Arborists at work on the black oak 'Quercus velutina'.
Arborists at work on the black oak ‘Quercus velutina’.

Back in 1815, plus or minus, a particular acorn uncurled in meager clay soil in Oak Bluffs. Around this time, the oak-built frigate U.S.S. Constitution offered inspiration to oak trees everywhere by singlehandedly defeating the British sixth-rates Cyane, 34 guns, and Levant, 21 guns, the last of her victories.

From the acorn, a strand of rapidly dividing cells sought the center of the earth; another strand craved the sky, fanning out into leaves, fighting to stay a step ahead of other seedlings in her cohort. In 1850, after 35 years of growth, Quercus was merely five inches through at the base of her single trunk — a meager if densely-wooded young tree.

As Quercus struggled, human Vineyarders came and went. The first Methodist Campground Meeting convened in 1835, when she was about 20. At the time, says the historian Henry Franklin Norton, “what is now Oak Bluffs was a sheep pasture,” thigh-deep in huckleberry. But I’ll bet my arm that the site of Everett Park was wooded. Browsing or mowing does slow the growth of a tree, but black oaks respond to being cut or browsed by resprouting multiple stems. The tree rings and her massive, single trunk say Quercus grew in woodland, earlier generations stealing her light but shielding her from harm.

A pocket knife on the stump, intended to show the scale of wide growth rings from the 1930s, the decade of fastest growth for this tree. – Photos by Matt Pelikan
A pocket knife on the stump, intended to show the scale of wide growth rings from the 1930s, the decade of fastest growth for this tree. – Photos by Matt Pelikan

First the sheep industry, then the whaling industry peaked and went sour for the Vineyard’s humans. The late 19th century must have been bleak indeed here, and some periods of especially tight annual rings in Quercus suggest that drought may have added to the Island’s woes. But as the 20th century dawned, Quercus, still a slender 10-incher, began growing steadily faster. Perhaps she finally reached a height at which her topmost leaves could see the sun; or perhaps the preceding generation of oaks began to senesce, lose limbs, and die, creating openings through which light and rain could pass.

Quercus began stretching out, becoming the shader instead of the shadee. Other mature trees must have been thinned from what was now a grove on the edge of town, for Quercus had room to send out huge horizontal limbs. During the 1930s, a banner decade for her if not for humanity, her trunk diameter increased by almost six inches. As World War II raged and Quercus’s luck began to run out, she was in her pride as a fully mature tree, two feet in diameter and rising perhaps 50 feet to the sky.

Human Islanders of a certain age will associate the year 1954 with the dual hurricanes Carol and Edna, both category 3, the first a near miss, the second not a miss at all. One victim was Quercus, her growth rate abruptly halved by lost branches or root damage; the premature defoliation September hurricanes unfailingly cause may have weakened her, as well. It was not until the 1980s ended that Quercus’s wrenched limbs fully recovered.

But if you’re a tree, you learn patience. Somewhere along the line, Everett Park was cleared of all but a few huge oaks, but it made little difference to Quercus, because she already stood tall above her neighbors. Rapid growth resumed. In early spring, migrant grackles squeaked from the peak of Quercus, choosing the highest perch around. Northbound northern parula warblers, born for life amid the highest twigs, sang from Quercus every May. Reaching perhaps 80 feet in height and spreading nearly as wide, Quercus ranked among the grandest trees on the Island. Her base was four feet thick, and her girth increased by seven full inches in the first decade of this century.

Then, disaster. Around 2010, gall-forming wasps in the genus Bassettia, tiny, mysterious bane of black oaks across the Cape and Islands, began laying their eggs in Quercus’s twigs. Swellings formed, blocking the tiny tubes that carried water to the leaves and sugar back down into the tree. Growth virtually halted. In 2014, only a few tufts of green leaves appeared on Quercus; sometime during the following winter, she died. And in a single day, arborists dropped her to the ground and trucked off air, water, and sunlight trapped across two full centuries.

About 15 feet of lower trunk remain to be removed as I write this, a massive column now fallen, and the ground is still powdered with sawdust reeking of tannins. Quercus’s stump has been ground level with the soil’s surface, and what used to be her corner of Everett Park looks strangely natural already as an open area rather than part of a grove of giants. In months or maybe just weeks, there will be no sign left of Quercus’s struggles or her grandeur. But I’ve read her autobiography.

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You probably haven’t seen one in your kitchen.

The ability of brown recluses to get to the Vineyard on their own is questionable. – Courtesy Wikimedia Commons

I love a good natural history question to ponder! And the brown recluse spider, Loxosceles reclusa, furnishes a fine one. Academic spider researchers consider this species, one of very few spiders capable of giving humans a serious bite, a creature of the south-central portions of the United States. Although an avid student of bugs of all kinds, I’ve never seen a recluse here (or indeed anywhere else). Yet I regularly receive reports of brown recluses on the Vineyard, and recurring discussion of this species on a Vineyard Facebook page I frequent shows many Islanders firmly persuaded that brown recluses are an abundant and well-established peril here.

Biologists, more often than they like to admit, overlook data or miss changes in the distribution of wildlife. But also, untrained observers routinely misidentify spiders, often letting fear, rumor, or expectation influence their perceptions. So what’s the reality?

Well, some help comes from the basic biology of the recluse, which, because it represents a significant human health hazard, has been well studied. While its core range appears to be slowly expanding northward, perhaps as the result of our warming climate, it remains essentially a spider of the southern plains states, ranging north about to the level of downstate Illinois.

They're smaller than you'd think. – Photo courtesy Pinterest
They’re smaller than you’d think. – Photo courtesy Pinterest

Newly hatched recluses don’t “balloon” like some other spiders do, drifting on the wind with a strand of silk for buoyancy. And adults don’t generally range far from their home site. So this is not a species that disperses well on its own. Moreover, the brown recluse, the northernmost of a mostly tropical and subtropical complex of species, does not like cold: One experiment found that prolonged exposure to temperatures in the low 20s reliably kills this spider. So the ability of brown recluses to get here on their own, or to establish enduring outdoor populations on the Vineyard, is questionable.

However, brown recluses, like many other species, sometimes disperse with the unintentional aid of humans. Recluses are known to hide in produce, packaging, or other goods being shipped, and in theory they could arrive nearly anywhere by this means. Once arrived, a recluse could certainly bite someone, and if a fertile female were transported, her offspring could start a new population. There are documented cases, mainly around port areas in warmer parts of the East and West Coasts, of such transported recluses setting up shop.

But even this mechanism for establishment turns out to be far less frequent than rumor would have it. A biologist with the Florida Department of Agriculture, investigating hundreds of purported brown recluses bites in the Sunshine State (edis.ifas.ufl.edu/in576), was only able to verify a handful of solid records of this spider occurring in Florida, and was able to identify only a single bite that could unequivocally be attributed to a recluse.

Other studies have found that most skin lesions blamed on brown recluse bites actually have other causes, with secondary bacterial infections following minor cuts or nonvenomous bites perhaps the most common one. A major 2008 study in the Journal of Arachnology, viewable at americanarachnology.org/JoA_free/JoA_v36_n1/arac-36-1-150.pdf, presents the best summary of such research.

Moreover, the spider ID skills of the general public prove to be pretty sketchy: According to the Wikipedia account for this spider, of nearly 600 spider specimens submitted to researchers as suspected recluses in California, only one proved to be the real thing. Even doctors and pest control specialists, unless they’ve had special training dedicated to spiders, are demonstrably not up to the task of correctly IDing recluses, or their bites, consistently. For many people, any orange butterfly is a monarch; likewise, many observers, motivated by fear and not well informed on the diversity of spiders or the proper means of identifying them, summarily execute any brown spider they find because they’re “sure” it’s a recluse.

The brown recluse is a smallish spider, its body roughly half an inch long and its stout legs spanning about the diameter of quarter. The legs have fine hair on them, but no spines or markings. Recluses have a distinctive arrangement of eyes, six of them (eight is the most common number in spiders), arranged in three pairs. If you’ve killed a “huge” spider, or a “hairy” one, or one with more or fewer than six eyes, or one with spindly legs, you didn’t kill a recluse. And as its name suggests, this spider is mainly nocturnal, a skulker in dark crevices. So if you killed a spider walking about in daylight, that one probably wasn’t a recluse, either.

So what does this all add up to? While some uncertainty remains about the status of the brown recluse on the Vineyard, I’m unaware of any evidence rising much above hearsay that they occur here. Most reports of the species come from people with no particular ID skills, and don’t involve a good photo or (an intact) specimen. If the patterns established elsewhere outside this spider’s core range also apply on the Vineyard, most Island reports are incorrect and most lesions blamed on brown recluse bites are the result of other causes.

Absence of proof, to be sure, is not proof of absence. There’s no reason individual brown recluses couldn’t be transported here, and they could establish colonies, though probably small and short-lived ones, within human structures. If your house had such a colony, you’d likely have the impression that recluses were everywhere! Likewise, there could surely have been genuine recluse bites here. Given that the lesions caused by the bites of this spider can be gruesome and slow to heal, we should not complacently dismiss the possibility of brown recluses here: This is one of the few spiders that really does represent a threat, and nobody wants to see it become established.

But the biology of the species, and what is known of it from studies conducted elsewhere, suggest that there’s no need to panic. Brown recluses appear unsuited to establishing themselves here in any meaningful way. The arrival of introduced individuals is probably infrequent. And even in areas where this generally docile spider is common, it doesn’t live up to its fearsome reputation. Stay alert for the brown recluse, by all means. But you can put down the blowtorch.

 

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Give these helpful animals a hand

A honey bee with an oddly pale strain.–Photo by Matt Pelikan

Much has been made recently, in both the popular and the scientific press, of a “pollinator crisis” — sharp declines in the populations of the insects that transfer genetic material in the form of pollen from one flowering plant to another. The mingling of genes that results is essential to the well-being of many species of plants, and many insect studies and surveys suggest the crisis is a real one.

Poster child for the worrisome situation is the honeybee, a semi-domesticated species native to Eurasia that is now a worldwide workhorse for agricultural pollination. A mysterious syndrome, apparently the result of converging stresses including pesticides, parasites, and climate change, has been decimating honeybee hives, reducing the productivity of many food plants for want of adequate pollination.

Receiving much less attention, among the general public if not among biologists, is a similar decline in the numbers of many pollinators that are native to our continent, including hundreds of species of native bees. Again, the reasons behind the trend are not entirely clear, but habitat loss and toxins in the environment are surely factors. Partly because of the concerning state of our bees, and partly because bees turn out to be fascinating little animals, a lot of my time in the field so far this year has focused on bees.

And it is getting to be prime time for observing these diverse insects, many of which play fascinating ecological roles and/or display surprising beauty. My sense is that despite any downward trend in numbers, many of our native bees are especially abundant this season. Perhaps the deep snow cover during much of winter represented an insulating layer that enhanced survival.

Nearly any kind of flower will attract bees, though some flowers work better than others and some bee species show a strong preference for particular plants. Among the wild plants currently in bloom, American holly seems to be a particular favorite of bees; a holly bush with even just a few flowers in bloom will often prove to have a half-dozen types of bees working on it.

In contrast to the honeybee, famous for forming huge colonies presided over by a single queen, the vast majority of our native bees are so-called solitary species: They may nest in loose aggregations, but each nest is built, maintained, and provisioned by only a single bee. In most cases, the nests are tunnels dug into the ground by a female bee, which lays eggs in the bottom of the tunnel and stocks the nest with pollen for the young bees to eat when they hatch.

Other types of bees nest in wood, either hollowing out the pith of a dead stem or chewing a hole into a dead branch (or, inconveniently, untreated wood on someone’s house). Wood-nesting bees do not appear to be especially well represented on the Vineyard, but that doesn’t mean they’re not important: Some of these bees are important pollinators for particular flowering plants.

A multiyear study led by entomologist Paul Goldstein, with assistance in the field from dozens of Vineyard “citizen scientists,” produced a valuable general picture of our bees. The study collected thousands of bees, and documented more than 160 species on Martha’s Vineyard — about half the bee species known to occur in Massachusetts. This study, with fieldwork completed in 2011, provides a precious baseline of data on the Island’s bees.

Still more information is available online or in scientific publications. Since bees play such important ecological roles, they are rather well studied by insect standards, and with a little digging, it’s often possible to identify a bee you photograph well, or to learn about its life history. But many questions remain unanswered, and because of the sheer diversity of bees (which translates to many closely related species), identifying them is often difficult.

For example, I recently photographed an elegant, half-inch-long bee visiting holly blossoms outside my office. Endowed with a bright red abdomen, this insect was easy to pin down as a “sweat bee” in the genus Sphecodes. But on referring to Dr. Goldstein’s study, I found that a full dozen Sphecodes species have been documented here, all virtually identical in their external appearance! The odds of determining the actual species my bee belongs to are slim indeed.

Other groups are easier. We have, for instance, only one large carpenter bee (and it’s one of the few native bees that might be considered harmful to humans, since it chews deep tunnels in shingles and trim on houses). And the Island has only three other carpenter bees, smaller insects in the genus Ceratina (and all much more benign, since they generally tunnel into dead branches).

Our native bees are ecologically helpful animals, and they’re gentle ones, too, disinclined to sting unless seriously molested. Help them out by minimizing your use of toxic chemicals, and by tolerating some untidiness in your yard and garden: Standing dead vegetation, downed tree limbs, and exposed mineral soil — all anathema to most gardeners — are resources that bees depend on for survival.

 

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Perfectly timed for the Felix Neck Bird-a-thon.

Maureen Williams and her son Gregory Clark spotted this "mystery stork-like bird" on Middle Road in Chilmark the other day. – Photo by Maureen Williams

Rarities are unpredictable by their very nature, but here are two certainties about rare birds on the Vineyard: They’ll keep turning up, and when they do, word will get around.

The arrival of vagrant birds, much sought after by birders, is guaranteed by geography. For a storm-driven bird or a disoriented migrant, Martha’s Vineyard is often either the last chance to stop before crossing an ocean, or the first chance to land after a long, long flight. Lost and wandering birds, from across the continent or even across the globe, find us with amazing frequency.

The seemingly instantaneous distribution of news about rare birds is, in contrast, a purely social phenomenon. Simply put, interest in birds runs wide and deep on the Vineyard, fostered by the Island’s underlying orientation toward the natural world. And within this large birding community, information about birding hot spots, rare birds, or the identification of birds flows fast and freely.

It’s hard to estimate the number of active birders on the Vineyard. There may be a dozen or two truly hardcore birders here, veterans with solid field skills who build at least a little birding into nearly every day. But one Vineyard birding Facebook group, Martha’s Vineyard Bird Alert, has almost 800 members. And a sizable chunk of the population knows the common birds well enough, and pays enough attention, to notice when something unusual shows up. One result is that many of the Island’s best birds are found and reported by people on the outer fringes of the birding community.

A splendid example of how this all works took place last week. First of all, a well-documented report of a rare visitor came on Wednesday, May 13, from an unexpected source: Sharp spotting by 12-year-old Gregory Clark, who says he’s not really a birder, but nevertheless noticed a tall, stork-like bird in a pasture as his family drove west along Middle Road. Skeptical at first, Gregory’s mother, Maureen Williams, turned around to check out the “tall, orange bird” her son had noticed, and was able to snap some stunning frames of a sandhill crane — a once-every-few-years vagrant to the Island.

Aware that unusual birds are of interest to the local press, Ms. Williams sent photos and a brief account of the sighting to the Times, which in turn passed them on to me. I put the word out via two Vineyard birding Facebook groups, one focused on rarities and one on general birding. And meanwhile, Ms. Williams, Gregory, and Gregory’s 87-year-old grandmother Joan Williams, described by her daughter as “an encyclopedia of facts,” independently arrived at the correct ID for their mystery bird.

Several birders were able to re-find and photograph the crane. Maureen Williams observed the bird again the next day, while she was working at Squibnocket; the crane passed high overhead, giving its distinctive call. Roger Cook noted what was surely the same bird almost simultaneously, word of that confirmation making it onto Facebook. Ms. Williams, guessing accurately based on the bird’s direction, drove once again to Middle Road, where she found it in the same pasture it had originally appeared in.

Local birders would have gotten a kick out of this bird under any circumstances: Sandhill cranes are striking birds, standing about four feet tall, and they often engage in fascinating foraging or social behavior. But interest was heightened because the sighting coincided with Massachusetts Audubon’s annual Bird-a-thon, a birding and fundraising event that is one of the high points of the Vineyard birding year (massaudubon.org/get-outdoors/birds-birding/bird-a-thon).

In a birdathon, observers have a set period of time, usually 24 hours, to find and identify as many species as they can. Typically, conservation supporters pledge a certain amount of money per species, with the money going as donations to the sponsoring organization. The Massachusetts Audubon Bird-a-thon adds an element of competition through teams representing each of the organization’s sanctuaries. Island birders pull out all the stops to uphold the honor of our local sanctuary, Felix Neck.

“Bird-a-thon brings together the best aspects of birding,” says Felix Neck Sanctuary Director Suzan Bellincampi; “exploring nature, watching wildlife, and bringing together folks of all ages and interests.” Plus, Ms. Bellincampi reports, it raised about $8,000 for Felix Neck this year, while tallying almost 120 species.

About two dozen Island birders, as young as 8 years old, formally participated, while virtually every other birder at least kept eyes and ears cocked for anything unusual. Online and telephone discussion ensured solid coverage of the Island and fed good discoveries to a central species list.

With this year’s event running from 5 pm last Friday until the same time Saturday, you may be sure that information on the crane was in demand, and a contingent of up-Island Bird-a-thon participants added this bird to their list of targets for the day.

However, the fact that vagrants often turn up here doesn’t mean that they stay put, or that you can find them at will. Scott Bermudes reported seeing the crane leave the pasture on Middle Road on the afternoon of Thursday, May 14, and that was the last anyone saw of the bird until after the Bird-a-thon. Island observers, in birding parlance, “dipped” on their target (though the event generated reports of some other notable rarities).

The sandhill crane was refound along North Road late in the day on Sunday. How long it will stay is of course unknown. My guess is it is a returning migrant heading toward one of the few locations (in Maine, western Massachusetts, or Vermont) at which this species seems to be establishing a breeding presence in New England. Cranes have been slowly expanding as a breeder into the Northeast over the past couple of decades, and so this visitor may be reflective of a long-term regional trend of increasing numbers.

So there you have it: discovery, identification, dissemination of the news, tracking of a rarity — and, alas, the not-infrequent outcome of a bird that no one can find when the chips are down. To some, birding may seem like an odd or pointless activity. But to its enthusiasts, the search for birds is enlivened by the possibilities and challenges of living on an Island that acts like a catcher’s mitt for vagrants. And the process of birding is enhanced by the existence of a loose but large and welcoming community that freely exchanges information, assistance, and photographs.

In addition to the Facebook group referenced above, the birdily inclined can get updates on what’s around from a weekly column, “Bird News,” either in the print edition of the Vineyard Gazette or on its website, vineyardgazette.com. Editors at both the Gazette and the Times happily receive bird questions or reports of rarities, passing them on to freelancers or community members qualified to respond. Birders in the field are almost invariably willing to offer advice, answer questions, or share what they’re looking at. And it’s not too late to donate in support of Felix Neck at firstgiving.com/team/291682. Feel free to join the flock.

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Sex orgies and all.

Blister beetles industriously mating. – Photo by Matt Pelikan

Learning to identify a species — connecting its characteristics with the often arbitrary name humans have assigned it — is a gratifying first step. But it’s an incomplete step, in the same way that being introduced to other people differs from actually getting to know them. What do they do? What things matter to them? What is their life history?

A ground-nesting bee guarding the entrance to its nest burrow.
A ground-nesting bee guarding the entrance to its nest burrow.

Happily for contemporary naturalists, it is increasingly easy to get help with both identifying and understanding wild plants and animals. Print and electronic sources are proliferating while growing in accuracy and reliability. But there is still a huge difference between reading about a species and truly knowing it.

To take an example, for years now I’ve had a nodding acquaintance with blister beetles of the genus Meloe. While individual species are hard to distinguish, learning the genus as a whole was easy: These are large, leathery beetles, about an inch long, glossy black, with hugely distended abdomens and tiny, vestigial wings.

Basic information about them is readily available. Like all blister beetles, they exude a caustic, yellowish juice from their joints when they’re irritated (hence their name). Adults are herbivorous, and the youngsters are parasites on other insects, especially ground-nesting bees. But until recently, I’ve encountered Meloe infrequently and in small numbers; typically I find one or two adults per season, usually in early spring in Correllus State Forest. This is a thin basis for acquaintance!

This past weekend, however, I hit the jackpot, observing more than 60 of these beetles as they applied themselves conscientiously to the reproductive part of their life cycle. I still can’t tell which species I’m finding, but with this first-hand immersion in the lives of these insects, I finally feel like I’m getting to know them.

For one thing, I had no idea that mating was such a social activity for Meloe. The individuals I recently found were all participants in mating aggregations, ranging from about 10 to more than 30 individuals, clearly associating with one another over an area perhaps 10 feet across. There’s really no way to describe these groups other than as blister beetle sex orgies: Single beetles and pairs in various stages of courting and mating were intermingled, with single males watching mating pairs closely and occasionally trying to cut in on the action.

And courtship, specifically, was fascinating to watch. Males and females approach other, interweaving their long antennae and rubbing their faces together almost as if kissing. As with most other insects, actually mating occurs with the male perched precariously on top of the female; a critical part of this process involves mutual antenna-rubbing, which looks both urgent and almost tender (if one can use that term with bugs!) at the same time. The male’s goal, it appears, is to catch the female’s antennae in distinctive little kinks in the male’s own antennae (these kinks are obvious, and the easiest way to tell males from females). Whether the interweaving of these organs results in chemical or just tactile signals is more than I can say, but every pair I watched engaged in it.

Once her eggs have been fertilized, a female seeks to lay them in a place where the larvae, when they hatch, can readily find larval bees, which the immature beetles eat to fuel their own development. In some cases, it’s known, larval blister beetles perch on flowers, wait for a bee to visit, and attach to the bee to obtain a free ride back to the bee’s nest. But the species of Meloe I was observing does it differently: I found two females positioning themselves at the mouth of the burrows of ground-nesting bees, which were plentiful in the area I was exploring, and carefully backing down into the bee burrow, presumably to lay eggs in underground chambers prepared and provisioned by the bee for her own offspring.

The fit is tight, given the bulbous abdomen of a female blister beetle, but each beetle backed in far enough to be completely out of sight, emerging after about five minutes underground. I’ve noticed many of the burrows of these ground-nesting bees occupied by adult bees, poised just inside the burrow’s entrance. Presumably this is guarding behavior, and also presumably, egg-laying blister beetles are high on the list of things the bees are guarding against.

It’s a quandary for the bee, I imagine. On the one hand, they surely want to spend lots of time gathering pollen so they can richly provision their larval chambers. But each trip abroad for pollen leaves the burrow vulnerable to parasitism by blister beetles. Likewise, being a larger than average bee probably helps with pollen gathering — but the larger-diameter burrows dug by larger bees must surely be easier for blister beetles to invade.

it’s a fascinating interrelationship. I still have a lot to learn about these impressive beetles. But with good luck and an hour’s observation, I learned more about them than I did in the past several years combined. There’s nothing like firsthand observation!

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Tachinids are essential to human society

Not just another housefuly: It's hard to tell one Tachinid from the other 10,000 (or more) Tachinids. But they're all crucial to human civilization. – Photo by Matt Pelikan

This column is about some of the unsung heroes of the insect world. While you’ve almost certainly seen one, you’ve likely never heard their name. But without their role in controlling numbers of other insects — and I mean this quite literally — human society would have a hard time functioning.

I mean the myriad members of the fly family Tachinidae (most entomologists pronounce it “tak-IN-adee”). Tachinids, as they’re called, are numerous, diverse, and highly variable flies. Some 10,000 species have been described worldwide, and many tens of thousands more are surely out there, waiting for someone to notice their existence.

Flies, including tachinids, are hard to identify; pretty much all of the dozens of fly families have some members that look like your basic, generic fly: gray, hairy, and sporting no traits that stand out as distinctive. While there are certainly many distinctive flies, even experts can have trouble assigning a photographed fly to a particular family. Identification often relies on viewing tiny anatomical details under magnification.

But if I had to pick one feature as a mark of the family Tachinidae, I’d point to their bristly butts: The abdomen of a typical tachinid is well-endowed with strong bristles, and many times this trait is enough to put an unknown specimen into this family. (Actually identifying a tachinid to species, once you’ve recognized its family, is another, often harder task. But students of the insect world get quite comfortable with tentative or imprecise identifications.)

But despite enormous variation in the size and appearance of tachinids, members of this family share one crucial life-history trait that gives this group its importance: The larvae of tachinids (I’m trying to avoid the word “maggots”!) are parasites on other species of insects. From an egg laid on or near a suitable host, a tachinid larva hatches and, if it’s lucky, succeeds in burrowing into its host. Maturing inside the unfortunate victim, the tachinid develops by eating the living tissue of its host, and when mature, it eats its way out, finishing its maturation in another location but leaving behind a dead host.

Within this enormous family, there are countless variations on this basic theme. Some tachinids are highly host-specific, using just a single species or genus as their larval host. Others are quite ecumenical in their tastes, laying eggs on a wide range of victims. Immature flies use different methods of entering their hosts: some chew their way in, while others may be ingested (even while still in egg form) as their hosts-to-be feed. Many adult tachinids, much more genial than their larvae, visit flowers to eat pollen (helping pollinate the flowers they visit as a side effect).

Because a single female tachinid can lay dozens of eggs, and each egg is a potential assassin, these flies can exert a powerful downward pressure on the populations of their hosts. And a sort of feedback loop can amplify this effect over the course of a few generations: If a host species increases in number, more Tachinid eggs find their target, producing a much larger next generation of flies. Often with just a generation or two, the flies have parasitized their excessively abundant host back down to normal numbers.

While many types of insects (and even, occasionally, other types of arthropods such as millipedes) can host tachinids, as family these flies focus mainly on Lepidoptera — that is, on moths. Many moths have larvae that eat plants of concern to people (crops and ornamentals); and many moths are capable of staging huge population explosions (think of gypsy moths or the winter moths that have helped defoliate large tracts of Vineyard woodland in recent years). Tachinids are not the only things that control such outbreaks, but they can be among the most effective. Without the regulating role of these flies, human agriculture and horticulture would be far more difficult undertakings.

Tachinid flies are sometimes deliberately deployed as “biological controls” of problematic insects such as invasive moths introduced to new regions, away from the effect of the predators of their native range. While a few ecological catastrophes have resulted from well-meaning introductions of tachinids, with the flies decimating desirable species once they’ve brought their original target under control, biologists have learned a great deal from such situations. As more and more invasive insects get established around the world, the use of tachinids to control them will likely be an increasingly frequent human response. One tachinid, Cyzenis albicans, is currently being used (with promising results and no discernible bad effects) to control the invasive winter moth in our region.

I have no real sense of how many tachinids live on the Vineyard — certainly hundreds of species, maybe many hundreds. But members of this family turn up everywhere I go. You’ve probably mistaken some for common house flies. But in doing so, you’ve overlooked an important ally.

 

In the bird world, there’s a lot more to consider than looks and talent.

An Eastern phoebe. – Photo courtesy of Wikimedia Commons

The past week, featuring warmer weather and — at last! — the obliteration of most of the snow on the Island, saw a huge change in the bird life of the Vineyard. Sea ducks, after a winter in our waters, headed north in droves to breed. And on land, a strong wave of early songbird migrants hit our shores.

Among these was one of my personal favorites, the eastern phoebe. Drab birds, smaller than a robin and belonging to the flycatcher family, all our phoebes generally arrive almost at once: just a few days after the first report of the spring, virtually all of our breeding phoebes are here.

Flycatchers as a group are among the dullest songbirds, and the eastern phoebe, grayish brown on the back and off-white underneath, is dull even by flycatcher standards. You might say that the lack of distinct field marks is the most reliable field mark for this bird — though its habit of bobbing its long tail up and down is a valuable behavioral clue. To my eye, a phoebe glimpsed quickly has a faint yellowish cast; this is a subtle and perhaps illusory trait, but a useful one for a birder. Overhead, a phoebe shows rather squared-off wings and a narrow-based tail with a distinct notch at the end — again, subtle but reliable cues to the bird’s identity.

Still, you’re more likely to hear your first phoebe of the year than to see it. These are chatty birds, often giving a sharp “chip” note and singing (if that’s what you call it) from the moment they arrive: a sneezy “PHEE-bee” is the best this bird can manage. But it’s a welcome sound in late March or early April. While the bulk of the singing is done by the male, I believe that this is a species in which the females also sing.

More so than nearly any other bird, the phoebe tolerates, or even prefers, life around humans. The species originally nested, and sometimes still does, in wholly natural settings, building its mossy nest on a rocky ledge or at the base of a tree branch. But when humans began building barns, sheds, and houses in the phoebe’s world, these birds were quick to recognize an opportunity. These days, a typical phoebe nest is tucked up tight under the eaves of a human structure, safe from the weather.

A pair of phoebes often starts multiple nests, sometimes getting them all well along toward completion before deciding which one to lay eggs in. This habit may help fool would-be nest predators, and in a seasonal human community like the Vineyard’s, it may give the birds some flexibility in adjusting to changing patterns of human activity as the season progresses: if the frequency of disturbance around one nest gets too great, the birds simply forget about that one and focus on a nest in a quieter spot.

The arrival of these birds seems to coincide quite precisely with the first real blooms of insect life, often in the form of swarms of ephemeral flies. But as the spring advances, phoebes show remarkably varied tastes in their insect prey. As with most flycatchers, phoebes prey heavily on bees and wasps. But studies of their diet have shown that they happily eat beetles, flies, and moths, with even the odd tree frog or salamander thrown in. They’re also able to handle vegetable food, mainly berries — an ability that helps them survive if they’re caught by unexpected wintery weather.

Most of a phoebe’s prey is taken on short aerial sallies: The bird perches on a twig, locates its target by sight, launches its attack, and often nabs its prey on the first attempt. The bird’s bill, broad with a distinct hook at the tip, is a formidable cruncher of bugs. But phoebes also pick food — spiders, or insect eggs and larvae — from branches or structures, and they will even forage on the ground, tossing dead leaves aside to search for arthropods.

Phoebes enthusiastically try again if they lose their first clutch of eggs, and if they fledge their first set of young, I believe, they’re capable of pulling off a second brood. Our nesting phoebes will be with us into the early fall, with adults leaving before the young of the year. And while we don’t get many transient phoebes here in the spring, fall migration can bring large numbers of phoebes from farther north. The species continues to pass through well into October, and a few individuals even try to winter in our region, with some surviving until spring at least in mild seasons.

Their ecumenical diet means that phoebes eat many insects that humans consider beneficial. But they eat harmful insects with equal zeal, and like most insectivorous birds, they adjust their diet to take advantage of any prey species that gets especially common. So the phoebe is a powerful force for balance, tending to regulate insect populations. This makes them helpful birds from our perspective, and if you have a pair nesting on your house shed, consider yourself fortunate.