Wild Side

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Why choose venomous victuals when you could sup on a butterfly?

For this robber fly, supper will be a bumblebee. Sort of a mixed blessing, if one is not careful. (Photo by Matt Pelikan).

Predation of one insect by another is not surprising: entire orders of insects, like the dragonflies, are predatory; and among flies, beetles, and many other orders, some families have turned their back on eating plants and evolved into hunters. What surprises me is that, amid the vast variety available to an insect that eats other insects, some predators court danger by specializing in prey that fights back.

A robber fly preys on an ichneumon wasp. (Matt Pelikan)
A robber fly preys on an ichneumon wasp. (Matt Pelikan)

An example that I’ve been fascinated by lately is a dark gray robber fly called Proctacanthus (like most insects, it isn’t well enough known to have a common name). About an inch and a quarter long, Proctacanthus ranks among the largest robber flies found on the Vineyard, and although it seems to be rather solitary and territorial, it also seems to be fairly common and widespread. And, as far as I can tell, all it eats are bees and wasps.

Like all robber flies, Proctacanthus is harmless to people but bad news for other insects. Robber flies specialize in aerial ambush, picking flying insects out of the air, piercing their bodies with a sharp beak, and injecting the prey with chemicals that paralyze it and break down its tissues. The robber fly then, quite literally, drinks its dinner, using its pointed mouthparts like a straw to slurp up its liquefied prey. When the fly has drawn as much nourishment as it can from its victim’s body, it drops the empty husk and resumes hunting.

Suitable for their predatory habits, robber flies are powerful fliers, and their legs are equipped with long spines that help them capture and hold their victims. While many robber flies are generalists in terms of diet, others specialize. One species of robber fly is a notorious slayer of butterflies; another eats spiders right out of their webs. But none seem quite as wedded to taking dangerous prey as Proctacanthus.

The first Proctacanthus I ever found was clutching a bumblebee. A while later, I found one eating a black-and-white ichneumon wasp in a woodland clearing. Passing the same spot two hours later, I found what I feel sure was the same robber fly eating a different ichneumon wasp, this one bright orange. Almost every Proctacanthus I see is eating something when I find it; and every Proctacanthus I’ve seen with food has been consuming something that stings. When you’re not much larger than a wasp yourself, the possibility of death or serious injury from a sting is very real. So I found myself wondering how and why this fly evolved to live so dangerously.

The “why” is easy. Bees and wasps are a fine choice to specialize in, if you can avoid getting stung. Few other insects are looking to tangle with a wasp, so there is not much competition for prey. Because bees and wasps are abundant and diverse, they represent a plentiful, season-long source of food. And the fondness of bees and wasps for taking pollen or nectar from flowers makes them easy to find: a typical tactic for Proctacanthus seems to be to stake out a flower-rich area, wait for a bee to come close, and nail it.

Surely the size of Proctacanthus helps it successfully vanquish stinging insects. The wealth of spines lining its powerful legs undoubtedly help it keep a firm grip on its prey, and a fine layer of dense hair that covers parts of the fly’s body may offer a little protection against stings. But it was not until I saw Proctacanthus actually hit a prey item that I figured out its secret.

A female Proctacanthus had been hanging around my yard for a day or two; I had disturbed it several times and had seen it eating a tiny, iridescent green bee. Then as I was watching a yellow-jacket taking pollen from a flower, the wasp was suddenly swept out of my field of view by a swooping robber fly. Holding its prey, the fly landed briefly on a twig, quickly adjusted its grip on the yellow-jacket, and flew to another perch in a lilac bush.

I approached carefully, so as not to disturb the fly, but even so, I was enjoying close looks within about 15 seconds of its initial attack on the wasp. And at that point, the wasp already appeared to be totally paralyzed by the fly’s venom! Wrapped in the fly’s spiny arms, the yellow-jacket was utterly inert; the fly, with its beak embedded in the back of the wasp’s thorax, already appeared to be eating.

Perhaps all robber flies are equipped with venom that effective. But for Procatcanthus especially, the ability to quickly paralyze its prey is vital. Tackling wasps may sound dangerous. But with the right tactics and a fast-acting venom, Proctacanthus makes it look safe and easy, paralyzing its victims before they realize they’ve been attacked.

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The focus of the natural world shifts, on balance, from exploiting this year to preparing for next.

A female Carolina grasshopper, working her abdomen into the ground in order to lay eggs. (Photo by Matt Pelikan).

The standard division of a year into four seasons is a mighty coarse approximation. Shifts of light, air, and growth as the earth’s orbit progresses call for a much more nuanced taxonomy. This past week, for example, clearly registers in my mind as something like “early late summer” — a period of a week or two, around the third week of August, when you suddenly realize that the show is ending. The focus of the natural world shifts, on balance, from exploiting this year to preparing for next.

As with other subtle seasonal shifts, the onset of this brief moment is evident everywhere I look: hints of color in the trees, the ascension of goldenrod’s yellow on the landscape, the occasional call note of a migrating songbird overhead if you happen to be outside at night. The natural world poises to dive toward the shortest days.

Perhaps because every organism, in its own way, must respond to the approach of winter, this time is of particular interest to the naturalist. Certain of our butterflies, for example, have run their course for the year, at least as adults: they’re still out there, of course, as eggs, caterpillars, or dormant pupae, but the adults have died or, or if they’re still here, it’s only as worn individuals bereft of much of their color. But the biology of the life stages left behind is as elegant, if harder to observe, than the activity of the adults.

Each type of butterfly has its preferred form for overwintering. For some, it’s a simple egg, laid, in a wonderful tribute to optimism, near where the proper food plant for the caterpillar grew this year and might, with luck, appear again next spring when the egg hatches. For other species, partly grown larvae overwinter; in a few cases, like the Orange Sulphur, the caterpillars might even wake up to take advantage of warm days in the winter to feed and grow a little. Still other species overwinter as chrysalids, homely lumps unrecognizable as butterflies, buried in the leaf litter or stuck to senescing stems. When the right time comes next year, an adult butterfly will emerge, unfurl its wings, and seek to pass on its genes.

The complexity of this process of “winterization” is astounding. For many insects, each summer sees just a single generation, and their developing progeny are programmed to cease activity at the right time, hunker down, and wait for spring. But what triggers this response, and what happens, physiologically, inside the young insect to prepare its body for freezing weather? And for butterflies with more than one generation per year, how does the final generation know to shut down rather than mature?

Sure, there are a few general principles at work here. Day length, for example, is a reliable factor, and many plants and animals use it to time their life cycles. Likewise common in the insect world is the production of chemicals that protect cells against damage from freezing. But each species has its own rules, and it seems to me that to fully understand the life of just a single insect species would be the work of more than one human lifetime.

For some insects, late summer is the season for adults. Some of these species eat seeds, and need to wait until plants have done their part by maturing. Other late-season insects probably evolved their life schedule to avoid certain predators or parasites that are more prevalent earlier in the season. Others, like many of our grasshoppers and katydids, simply have large, complex adults that need a full growing season to make it to maturity. But these later-season insects have much to do and not long to live.

I make a sweep through the quasi-meadow in our front yard for insects. Numbers and diversity have dropped precipitously from even just a week ago; many flowers have finished blooming, fading to brownish stems and seeds. Yet bees are still working the flowers that remain in bloom, loading their pollen sacks with yellow powder to provision their young.

One grasshopper, my old friend Chortophaga viridifasciata, is present again in numbers. Adults of this species, which spent last winter half-grown and matured by May, have long since petered out. But the young produced by this year’s generation have just hatched. Tiny nymphs smaller than rice grains are already prodigious jumpers. Some of these same individual insects will likely furnish my first insects of 2015, miniature grasshoppers cavorting in the yard on a warm February day.

And in the state forest I find a Carolina grasshopper, laboriously waggling her abdomen into the ground to lay eggs. It’s hard work; with only her body weight to work against as she digs, she hoists her hind feet off the ground to muster all possible leverage. I watch for 20 minutes, my patience expiring before her job is done. But I’m grateful to her for her efforts, because she’s making provision for the year to come.

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Pelidnota punctata, also called a grapevine beetle. — Photo by Matt Pelikan

The great outdoors can produce baffling mysteries. MVTimes Wild Side columnist Matt Pelikan tries his best to solve them. Got a question for the Wild Side? Send it to onisland@mvtimes.com.

Hi Matt: lived here all my life and don’t recall ever seeing one of these before. What is it? Thanks, Angie Waldron

Hi Angie.

This impressive beetle is Pelidnota punctata, sometimes known as the grape or grapevine beetle. It seems to be reasonably common and quite widely distributed around Martha’s Vineyard. But like a the vast majority of our beetles, its habits and life history mean that it isn’t often seen.

Adults, which can exceed an inch in length, are unmistakable with their yellowish color and array of six black spots. They eat grape leaves (as the beetle’s common name suggests) but are largely nocturnal; they roost for most of the day on the underside of leaves, where you’re unlikely to spot them unless you’re specifically looking. This beetle, though, is active at night, feeding and searching for a mate, and it is attracted to artificial lights. So most of the time when humans encounter it, Pelidnota is hanging from a shingle or window-screen near someone’s porch light. Despite their daunting size, these beetles are harmless, rather sluggish, and quite easy to handle.

The grub-like larvae of this beetle are even harder to find than the adults. They hatch from eggs laid on rotten logs and stumps and spend most of their youth feeding either on the decaying wood or on roots and detritus underground. As is not unusual for very large beetles, it takes a long time for a Pelidnota larva to mature: two full years may elapse between when an egg is laid and when the adult beetle finally emerges.

The grapevine beetle is a scarab beetle, belonging to the same family as the scarab that was sacred to the ancient Egyptians as well as more familiar species such as the Japanese beetle. There are many thousands of scarab species worldwide, but the members of this very large group can be recognized by their characteristic stocky shape, often glossy or colorful exterior, and short, bent antennae, tipped with a little group of finger-like tabs. These tabs are actually organs that are exquisitely sensitive to chemical signatures — in other words, scarab beetles smell with their antennae, and they do it very well. Scent helps these insects find others of their species and locate suitable food plants or sites to lay their eggs.

Pelidnota punctata has a broad geographical range, occurring across the eastern and central United States and in most of southeastern Canada. Across this vast area, this species shows a good deal of variation in features such as leg coloration and the size and placement of the six black spots. In fact, at one point entomologists have treated this beetle as multiple species — as many as 10 at one point! But current thinking is that only a single species is involved.

In theory the grapevine beetle might be undesirable because it feeds on grape leaves, and under the right circumstances this insect can get common enough to cause commercially significant damage in vineyards. But it’s rare for Pelidnota to occur in numbers large enough to amount to any harm, and this beetle plays useful roles breaking down old wood as a larva and serving as a prey item for birds as an adult (one of these beetles makes a significant snack for a bird like a blue jay or catbird). So on balance the grapevine beetle is a positive addition to our world, and given its striking looks, imposing size, and docile manner, it’s a beetle you should be happy to find visiting your porch light.

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Bembix americana

Few things look less auspicious than a patch of bare sand. With no plants or animal visible to the casual observer, it’s easy to assume that bare ground scores an ecological zero. But in nature, nothing is useless, and barren soil is a crucial element in the lives of a surprising number of species.

How a patch of bare ground became empty in the first place has a big effect on what will use it, and over what time frame the spot will become inhabited. An empty patch in our front yard, for example, must surely have resulted from a spill of something toxic, maybe oil or antifreeze, in an area once used as a driveway: the spot remained utterly barren and compacted for years, and only now, after years of rain have leached away whatever was dumped here, has a crust of lichen and moss finally gotten established.

Elsewhere, a sufficiently hot wildfire can burn off all the organic material, leaving empty mineral soil behind. Or repeated disturbance can produce a similar effect: think of a heavily worn footpath, or the tire ruts on a regularly traveled dirt road. When the fire is past, or if the pattern of disturbance is interrupted, these spots embark on a trajectory of regrowth. Simple plants like mosses colonize the site by means of airborne spores, or lichens (amazing amalgams of algae and fungi) may appear. Over time, the organic remains of these colonizers form the beginnings of soil; other plants arrive, adding more organic matter and sending down roots through sand grains to loosen the substrate. Wait long enough and you’ll have a forest.

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Cicindela punctulata

But before all that happens, the very barrenness of the spot is a resource that wildlife can use. The punctured tiger-beetle, for example, Cicindela punctulata, spends most of its time hunting on the emptiest, flattest, and most compacted ground it can find. A visual hunter that relies on speed to run down its prey, this half-inch-long beetle eats ants and other smaller insects that venture across the bare soil. With no vegetation to obstruct its view, the tiger-beetle readily spots a target, and like a tiny, six-legged cheetah, it sprints so quickly after its victim that the eye can barely follow it. For this insect, bare ground furnishes the ideal place to hunt.

Many bee and wasp species use open ground not for hunting but for building their nests. Kicking sand through their legs like a terrier digging up daffodil bulbs, these ground-nesting insects move impressive amounts of soil as they dig the tunnels where they will lay their eggs. These nest burrows may be surprisingly long and elaborate, descending inches or even feet beneath the surface and sometimes branching into networks of side-tunnels and chambers. Each chamber will hold one or more eggs, and it will be stocked by the adult insect with either pollen or a paralyzed prey item for the young wasp or bee to feed on as it grows.

It’s not clear why such bees and wasps prefer bare ground. It may be as simple as making it easier to relocate the nest when they return from a foraging trip. Or perhaps bare ground signals a site where you can burrow with no interference from roots. But whatever the reason, the soil must be bare, and moreover, each species of burrowing wasp or bee has a strict preference for the type of soil it will nest in: sand or clay, coarse or fine, wet or dry, loose or compacted. So maintaining populations of all these beneficial insects requires not just the odd patch of bare ground, but many such patches, in different places and with different characteristics.

For some of the species that use bare ground, it seems like a very limited expanse will suffice. Some insects will dig their burrows in the space between clumps of grass or weeds. For other ground-nesters, it seems like a large bare area is required, or at least an area with many small bare spots in a small area. For instance, a bee called Bembix americana (it has no common name, though it is a common and widespread bee) prefers to nest in loose colonies of dozens or even hundreds of individual burrows. In an abandoned construction site near my home, such a colony covers an area of bare soil about 30 feet in diameter.

You probably already have some insects in your yard using snippets of bare ground. I’ve actually encouraged some bare spots to get larger and stay bare, and the result has been rewarding: new insects turn up, ones with interesting lives, beneficial habits, and, in some cases, exquisitely beautiful appearance. In nature, no niche goes unoccupied for long: even nothing is something, for the right creature.

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Widow or no? — Sarah Andresen

Is this a black widow? It’s living in a bat house just outside our barn door in Chilmark! Are they common on the Vineyard?

The Pelikan Brief:

Wow. Yes, it appears to be a southern black widow, Latrodectus mactans. I’ve never heard a reliable report of one occurring naturally on M.V., though some sources say the range of the species extends as far north as Mass. A close relative, the northern black widow, L. variolus, is a lot more likely in our region and probably occurs here, though I’ve never found one on M.V.

The rest of the answer:

Yes, indeed it is a black widow, and a very interesting find! The small size, shiny black body, round abdomen, and especially the red “hourglass” mark this as a female black widow. Interestingly, though, there are several species of black widow, and this is not the one that is normally expected on the Vineyard. The complete hourglass marking, with the two lobes clearly connected, marks this as a southern black widow, which is generally believed to be rare at best in our region. Much more likely is the northern black widow, which is quite similar but features an “hourglass” that is broken into two parts. The northern black widow seems to be sparsely distributed but reasonably common in the Cape and Islands Region. The only ones I’ve ever seen have been in natural settings, not in human-made structures.

I’m afraid I can’t say just what is going on: southern black widows may be extending their range northward and colonizing our region. (Like many spiders, I imagine they can disperse as baby spiders by “ballooning” on the wind on strands of silk). They may have been here all along, but were overlooked. Or this individual arrived from elsewhere on a load of vegetables or landscaping material. Hopefully, a pattern of sightings (or an absence of sightings) in the near future will clarify the picture.

Black widows generally are famous as the most venomous spiders in North America, one of very few arthropods on the continent that is capable of killing a human being. (I set aside the special case of fatal allergic reactions to wasp or bee stings.) Being small spiders, they can inject only a tiny quantity of venom. But the venom is incredibly potent, acting on the victim’s nervous system to cause cramping, paralysis, and on rare occasions death when the muscles necessary for breathing shut down. There is an effective antivenin, and the thing to do if you think you’ve been bitten by a black widow is seek medical care immediate and, if possible, bring the spider with you so its identity can be determined.

But don’t panic! Black widows are timid spiders that rarely bite humans. The main use for their jaws and venom is to subdue small insects that blunder into the widow’s untidy web system. Given the chance when disturbed, a black widow, like other spiders, will hide rather than bite, and it is only when a black widow is faced with squishing that it bites in self-defense. Moreover, fatalities are very rare: one source reports that only about one percent of black widow bites are fatal, and that fatalities almost always involve children or elderly victims who are frail and have a small body size.

Black widows like dark, shady, enclosed spots (a classic black-widow bite scenario, back in the old days, involved spiders getting sat on in outhouses). Pay attention when you’re working or reaching into such places, and you will have little reason to fear this spider, which is (in my opinion) best thought of as an interesting and generally beneficial part of our ecosystem.

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I now see that these assumptions affected how I spent my time in the field — where, when, and in what habitats I looked.

a spotted-wing grasshopper. — Photo by Matt Pelikan

In observing nature, one goal is to see what’s truly there, and not impose your own wishes or expectations on the world. The classic example of what to avoid is the sort of wishful thinking to which birders can be subject. It’s easy to see field marks that don’t exist if you’re burning to find a rarity, and equally easy to miss a rarity because you’re expecting just the common stuff.

A pasture grasshopper.
A pasture grasshopper.

But even when you have no personal stake in what you see, it’s still possible for benign assumptions or inaccurate knowledge to distort what you see. Though I’ve had more than 40 years of practice in trying to be an impartial observer of nature, I can’t say I’m never guilty of making errors of this sort. I like finding a rarity every bit as much as the next guy, and I’m just as prone to ignorance. So it doesn’t surprise me too much when I find I’ve botched things. And so it was with me and the Gomphocerinae.

“Gomphocerinae” is a mouthful, but it’s shorter than the usual common name for this family of grasshoppers, “stridulating slant-faced grasshoppers.” They stridulate, or produce sound, by rubbing body parts together, and species within this family tend to have faces that slant sharply down and back from an overshadowing forehead.

In beginning my ongoing survey of Vineyard grasshoppers, I had drawn up a list of species I felt were possible here, based on range maps in field guides. And I now realize that, even as I drew up that list, I began forming misconceptions about the grasshopper species that I would find. Some that were familiar to me from my mainland days I thought of as common, and I assumed, without any real basis in fact, that I’d find them here, too. Certain other species, such odd-looking ones or ones that have unusual life histories, I now realize I classed as “exotic” — rare or specialized species that I couldn’t imagine occurring here.

To some extent, I now see, these assumptions affected how I spent my time in the field — where, when, and in what habitats I looked. And one group that I had unconsciously decided wasn’t worth sinking much time into was the Gomphocerinae, those grasshoppers of the stridulation and the slanting faces. But it wasn’t just a time allocation error: when trying to identify grasshoppers, I tended to start with the assumption that what I was looking at belonged to one of the families I expected.

Thus it was that my grasshopper list, closing in on a dozen species as this season began, lacked any representative of Gomphocerinae. But about a month ago, while tidying up my office at work, I came across a box of insect specimens labeled “Orthoptera.” These turned out to be the result of field work done 20 years ago; the specimens were meticulously mounted and labeled with date and location information but had not yet been identified.

The first thing I noticed was, you guessed it, a prime example of a stridulating slant-faced grasshopper — an “exotic” species I had offhandedly tossed in the “impossible” bin. It was a short-winged toothpick grasshopper, a bizarre, elongated insect with sword-like antennae and ludicrous stumpy wings. I had never imagined I’d find it here, even though its habitat is one that is easy to find on the Vineyard: dry, sparse, “bunch grass” habitat dominated by little bluestem. Bunch grass just hadn’t looked like good grasshopper habitat to me, and accordingly, I hadn’t explored it much.

I may have made some wrong assumptions, but you may be sure that at this point I was realizing that I had made them. I altered my strategy based on what I had learned and deliberately targeted a number of Gomphocerinae associated with bunch grass. First, I quickly located another location that had that most excellent toothpick grasshopper; here weren’t a lot and they were not yet mature, but this is a bug you can’t mistake.

I also found and photographed a second member of the family, a spotted-wing grasshopper, a nondescript bug that in years past I may well have written off repeatedly as a dully marked member of a different family. (They turn out to be common, common!) Finally, I went back through my file of unidentified grasshopper photographs and quickly picked out another member of Gomphocerinae, a lovely green species called the pasture grasshopper.

Better still, I began to get a sense for the entire family: what conditions its members like, what characteristics mark the family itself or help you sort out its members. In short, I learned something! I find this fun.

There are, presumably, other biases and misconceptions lurking in my understanding of grasshoppers (not to mention the other types of wildlife I observe). I haven’t discovered them yet, but with luck I will eventually. There’s always a moment of dismay when you realize what a bonehead you’ve been. But having realized it, at least you can get things right in the end.

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Who’s this lady??

Ladybug larvae — Photo by Danielle Zerbonne

The great outdoors can produce baffling mysteries. MV Times Wild Side columnist Matt Pelikan tries his best to solve them. Got a question for the Wild Side? Send it to onisland@mvtimes.com.

What is this creature? It was on plants outside my office… I’m not sure what the bush is so I took a picture of its growing berries in case that helps… Beach plums?

The Pelikan Brief:

That is a seven-spotted Ladybug on beach plum!

The rest of the answer:

Ladybugs love beach plums.
Ladybugs love beach plums.

These colorful but homely creatures are the larvae, or immature stage, of a ladybug. As most gardeners are aware, ladybugs are highly beneficial insects (at least from the human perspective) because both adults and larvae eat a wide range of insects that are harmful to plants. They specialize in preying on soft-bodied insects such as aphids, scale insects, and mites, which suck vital juices from plants and can also carry disease. Most ladybugs pass through four distinct larval stages as they develop, before morphing into an adult, and the energy source that powers all that growing and molting is the caloric content of a ladybug’s prey.

There are somewhere around 500 species of ladybugs in North America and, to make a rough guess, perhaps 20 species on Martha’s Vineyard. These particular larvae appear to be those of the seven-spotted ladybug, which is a Eurasian species that has been introduced widely in the U.S. to help control agricultural pests. It is now widely established — so widely, in fact, that it may be out-competing many of our native ladybugs, such as the two-spotted ladybug that is the official state insect of Massachusetts. (I bet you didn’t even know we had a state insect!)

Many, perhaps most, ladybug species are mildly toxic, producing chemicals that give them a foul smell and taste. The bold, distinctive patterns these beetles show — black spots on a red or orange background, or in some cases red spots on black — serve to warn away would-be predators that have had first-hand experience trying to eat a ladybug.

The plant the larvae are on happens to be a beach plum, and this is not just coincidence. Beach plum, like its close relatives the shadbushes and wild cherries, is notorious for attracting sucking and leaf-eating insects of a wide variety. The plants of this family, in other words, furnish a prey-rich environment for ladybugs, and as a result are good places to look for these most excellent beetles.

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How do plants grow in inhospitable places?

A plant pushing its way up through sand. — Photo by Danielle Zerbonne

The great outdoors can produce baffling mysteries. MV Times Wild Side columnist Matt Pelikan tries his best to solve them. Got a question for the Wild Side? Send it to onisland@mvtimes.com.

I don’t get this: plants that grow in seemingly inhospitable places… saltwater, sand, sidewalk cracks…

How does this happen? How do they survive?

The whole answer:

Plants have evolved a huge arsenal of methods to allow to them to inhabit inhospitable spots. But the first question is, why do they want to live in inhospitable spots in the first place? The answer to that one is, simply put, to avoid competition. If you can grow under conditions that would kill most other plants, then you don’t have to worry so much about being shaded out by a taller plant, or having one with a bigger root system suck up all the water and nutrients.

I could go on for weeks about the various approaches plants take to make adversity less adverse. Here are just a few examples to illustrate how creative evolution has been.

Taproots. A long, thick central root plunging deep into the ground takes a lot of resources to grow. But once you’ve got one, you can reach moisture in the soil that is too deep for other plants to reach. You’re resistant to being pulled out by an animal that wants to eat you. And if a grazing animal does bite off your leaves, you have enough energy stored in your tap root to begin resprouting instantly. The ubiquitous dandelion is a great example, so successful largely because it produces a hefty tap root.

Thick skin. Many plants that grow in harsh environments have developed a thick skin, called a cuticle, on their leaves and stems. This tissue, usually waxy and impermeable, helps prevent unnecessary water loss that could kill the plant. In addition to keeping water in, a thick cuticle can help keep harmful substances out. Many plants adapted for life by the sea, for example, are resistant to the toxic effects of salt spray by virtue of a thick skin. And a thick cuticle can also help protect more delicate internal cells from damage from relentless sunlight.

Seasonality. In most places, conditions vary widely during the course of the year. And it’s not just the physical surroundings — the weather, amount of wind, or day length — that change: the amount of vegetation varies, too. So many plants have simply evolved a life cycle centered early or late in the season, when temperatures are moderate and when few other plants are active competitors. A great example would be the wood anemone, a little white wildflower of our woodlands that puts up leaves and blooms early in spring, before the trees have leafed out. In this way, the anemone gets the energy-intensive part of its life cycle over with before trees start hogging all the incoming sunlight.

You get the point: in the natural world, adversity represents opportunity for organisms that can find a way deal with the situation better than most competitors do. It isn’t that the well-adapted plants don’t suffer in inhospitable settings. It’s just that they suffer less than their competitors do, and that works out to be an advantage.

Seven-spotted Ladybug on beach plum.

These colorful but homely creatures are the larvae, or immature stage, of a ladybug. As most gardeners are aware, ladybugs are highly beneficial insects (at least from the human perspective) because both adults and larvae eat a wide range of insects that are harmful to plants. They specialize in preying on soft-bodied insects such as aphids, scale insects, and mites, which suck vital juices from plants and can also carry disease. Most ladybugs pass through four distinct larval stages as they develop, before morphing into an adult, and the energy source that powers all that growing and molting is the caloric content of a ladybug’s prey.

There are somewhere around 500 species of ladybugs in North America and, to make a rough guess, perhaps 20 species on Martha’s Vineyard. These particular larvae appear to be those of the seven-spotted ladybug, which is a Eurasian species that has been introduced widely in the U.S. to help control agricultural pests. It is now widely established — so widely, in fact, that it may be out-competing many of our native ladybugs, such as the two-spotted ladybug that is the official state insect of Massachusetts. (I bet you didn’t even know we had a state insect!) Many, perhaps most ladybug species are mildly toxic, producing chemicals that give them a foul smell and taste. The bold, distinctive patterns these beetles show — black spots on a red or orange background, or in some cases black spots on red — serve to warn away would-be predators that have had first-hand experience trying to eat a ladybug.

The plant the larvae are on happens to be a beach plum, but this is not just coincidence. Beach plum, like its close relatives the shadbushes and wild cherries, is notorious for attracting sucking and leaf-eating insects of a wide variety. The plants of this family, in other words, furnish a prey-rich environment for ladybugs, and as a result are good places to look for these most excellent beetles.

Luna moth attracted by light.

You think a porch light is attractive to moths? Try putting out an ultraviolet “black light” sometime! Many kinds of moths just can’t resist black light; in fact, biologists studying moths routinely use ultraviolet light sources to attract moths for collection or observation. But while the tendency of moths to fly toward light, and toward ultraviolet light in particular, is well known, nobody has come up with a fully satisfactory explanation. Most likely several factors play a role, and it’s also probably that different moth species respond to light for different reasons. And it’s worth keeping in mind that, for most of the evolutionary history of moths, all or most of the light at night came from the moon, stars, or the sky glow before sunrise and after sunset. So today’s situation, with artificial light sources popping up everywhere in moth habitat, is not what moths evolved to experience.

Moths are simple animals, and their needs in life boil to the usual basics. They need food, they need a mate, and it’s helpful to have some way of finding their way around. Explanations have been offered that relate to all three of these needs. For example, many adult moths feed on nectar from flowers. And many flowers glow under the ultraviolet let that makes up part of incoming sunlight (it’s the flower’s way of advertising for pollinators to come visit). So there may be some primitive tendency in moths to fly toward ultraviolet light in expectation of a meal. This tendency, then, would bring moths in to human light sources, at least ones that emit part of their energy in the ultraviolet range.

Many kinds of moths may also patrol large areas to find mates, and in order to be efficient about it, they would want to avoid going over the same area repeatedly. One way to do this is simply to fly in a straight line, and some moths may use the moon or bright starts to help this. If you head towards the moon, or keep it on, say, your starboard beam, you’ll keep moving in a roughly straight direction. But if you try this with a light source that is much closer than the moon, you either arrive there and then don’t know what to do next, or you end up circling the light in an effort to keep it at the same angle. Both mechanisms could bring moths to light.

Finally — and I get in over my head on this one — some biologists noted a similarity between the frequency of ultraviolet light and the resonant frequency of some of the chemicals, called pheromones, that moths produce to lure in potential mates. In other words, ultraviolet light somehow reminds moths of the irresistible smell of a mate, even though one stimulus is a visual one and the other is a scent.

So take your pick: any, or all, or none of the above. Many kinds of moths are attracted to light, and that’s really all anybody knows for sure. But there is also agreement that in today’s environment, moths are paying a price for their fondness for light. The moths around your porch light are essentially wasting their time, hanging around in a sterile habitat that is unsuitable for them to live or reproduce in. Disruption of moth life cycles by artificial lighting is a real problem, and it’s one you can help with by turning outside lights off unless you are actively using them.

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Major players in our ecosystem, bees and wasps are highly evolved, highly diverse, and endlessly interesting to watch.

An unidentified bee, on coneflower, well covered with pollen. — Photo by Matt Pelikan

Midsummer is peak season for most types of insects, but especially evident right now are the panoply of bees and wasps that live here. While it’s usually clear if an insect is a bee or a wasp, the distinction actually seems somewhat arbitrary to my inexpert eyes. Bees, in general, are plump and fuzzy; wasps are lanky and while they may have spines or hairs, they generally don’t look furry. In any case, one peculiarity marks this entire group of insects: while they have two wings on each side, the hind wing is much smaller than the front wing, and the two are locked together into a single unit, which looks and functions like a single wing, by a row of special anatomical hooks.

One of our less common bumblebees, probably Bombus perplexus, on lavender.
One of our less common bumblebees, probably Bombus perplexus, on lavender.

As a group, the bees and wasps are unfairly maligned. With the current concern over declines in pollinator populations, pretty much everyone understands that bees and wasps of beneficial because of their role in transporting pollen from plant to plant. But these insects are still stigmatized as aggressive and feared because they can sting.

To be sure, there are a few species of each that are irritable enough to make awkward neighbors. The so-called social bees and wasps, that is, the species that live in large colonies and build elaborate nests, certainly will sting in defense of their homes. (Wouldn’t you?) Honeybees, yellow-jackets, and paper wasps all fall into this class. But the vast majority of our bees and wasps nest alone or in small groups and invest relatively little effort in their nests (which may be underground or in dead vegetation). While capable of stinging, most of these species are docile, and some, quite literally, won’t sting even if you try to make them (yes, people have experimented!). And even the social bees and wasps are generally quite amiable when they are out foraging, away from their nests.

The self-defense capability of bees and wasps does give these insects a degree of immunity from attack. Accordingly, they’ve evolved striking color schemes, usually involving black and yellow stripes, as a warning to would-be predators. It doesn’t always work; many species of birds, for example, snag wasps with impunity, often rubbing the stingers off on a branch before swallowing them. But the cautionary markings are effective enough so that other insects have evolved patterns that mimic those of bees and wasps: some hover-flies and bee-flies, for instance, look enough like bees that it takes a careful look and a knowledgeable eye to spot the difference. (Handy short-cut: flies almost invariably have short, stubby antennae, while antennae on bees and wasps are longer and often sharply bent.)

Solitary bees and wasps share a fondness for visiting flowers, and they are equipped with long tongues with which they extract pollen or nectar from blossoms. A great way, therefore, to get acquainted with these insects is to keep an eye on the same flowers that butterflies like to visit: milkweed, goldenrod, or garden plants like blazing star, butterfly-bush, or lavender, for instance. In good habitat, it’s not uncommon to find five or six species of bees and wasps feeding on the same cluster of flowers.

A wasp called Sanborn's bee-wolf absconding with a bumblebee.
A wasp called Sanborn’s bee-wolf absconding with a bumblebee.

The dietary preferences of bees and wasps diverge, though, when it comes to the provisions they make for their offspring. Bees typically stock their nests with pollen, which they gather industriously and transport to their nests in specially designed sacks on their legs. Pollen grains stuck to the insect’s body get transported to other flowers, and it is the very hairy bodies of bees that make them such effective pollinators. Solitary wasps, in contrast, transport pollen less effectively and generally lay in a supply of arthropod meat for their young.

The process is a bit grisly, though it works out well from the human perspective: solitary wasps are important players in controlling populations of insects that eat plants, including crops and ornamentals. Here is where solitary wasps put their stingers to use: finding a suitable prey item (and most wasps are quite specific about the kind of arthropods they prefer), the adult wasp stings its victim, paralyzing it, and then hauls it back to the nest it has prepared.

Wasp eggs are laid on or next to the immobilized prey, and upon hatching, the wasp larvae feeds on the victim. It’s a fascinating bit of biology. Species taken as prey range from spiders to cicadas to grasshoppers; there are even wasps that capture bees. Some wasps subdue and carry prey considerably larger than themselves: I’ve seen a wasp carrying a bush-katydid that must have weighed twice as much as its captor.

Major players in our ecosystem, bees and wasps are highly evolved, highly diverse, and endlessly interesting to watch (as long as you give wide berth to the nests of social species). Give them some of your attention this summer.

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Luna moth. — Photo by Danielle Zerbonne

The great outdoors can produce baffling mysteries. MVTimes Wild Side columnist Matt Pelikan tries his best to solve them. Got a question for the Wild Side? Send it to onisland@mvtimes.com

Here’s a good one –  a picture of a luna who battled his way inside my house and thrashed around until he finally settled on a jar of capers in my pantry. He was attracted to our porch light. Why is that? At one point I used to leave the porch light on overnight so I could go out in the morning and see what had gathered. But then I felt guilty watching the chickadees pick them off one by one from the screen in the morning.

The Pelikan brief:

You think a porch light is attractive to moths? Try putting out an ultraviolet “black light” sometime! Many kinds of moths just can’t resist black light; in fact, biologists studying moths routinely use ultraviolet light sources to attract moths for collection or observation. But while the tendency of moths to fly toward light, and toward ultraviolet light in particular, is well known, nobody has come up with a fully satisfactory explanation.

The rest of the answer:

Most likely several factors play a role, and it’s also probably that different moth species respond to light for different reasons. And it’s worth keeping in mind that, for most of the evolutionary history of moths, all or most of the light at night came from the moon, stars, or the sky glow before sunrise and after sunset. So today’s situation, with artificial light sources popping up everywhere in moth habitat, is not what moths evolved to experience.

Moths are simple animals, and their needs in life boil to the usual basics. They need food, they need a mate, and it’s helpful to have some way of finding their way around. Explanations have been offered that relate to all three of these needs. For example, many adult moths feed on nectar from flowers. And many flowers glow under the ultraviolet lightt that makes up part of incoming sunlight (it’s the flower’s way of advertising for pollinators to come visit). So there may be some primitive tendency in moths to fly toward ultraviolet light in expectation of a meal. This tendency, then, would bring moths in to human light sources, at least ones that emit part of their energy in the ultraviolet range.

Many kinds of moths may also patrol large areas to find mates, and in order to be efficient about it, would want to avoid going over the same area repeatedly. One way to do this is simply to fly in a straight line, and some moths may use the moon or bright starts to help this. If you head toward the moon, or keep it on, say, your starboard beam, you’ll keep moving in a roughly straight direction. But if you try this with a light source that is much closer than the moon, you either arrive there and then don’t know what to do next, or you end up circling the light in an effort to keep it at the same angle. Both mechanisms could bring moths to light.

Finally — and I get in over my head on this one — some biologists noted a similarity between the frequency of ultraviolet light and the resonant frequency of some of the chemicals, called pheromones, that moths produce to lure potential mates. In other words, ultraviolet light somehow remind moths of the irresistible smell of a mate, even though one stimulus is a visual one and the other is a scent.

So take your pick: any, or all, or none of the above. Many kinds of moths are attracted to light, and that’s really all anybody knows for sure. But there is also agreement that in today’s environment, moths are paying a price for their fondness for light. The moths around your porch light are essentially wasting their time, hanging around in a sterile habitat that is unsuitable for them to live or reproduce in. Disruption of moth life cycles by artificial lighting is a real problem, and it’s one you can help with by turning outside lights off unless you are actively using them.