Posts Tagged ‘insects’

My Dirt is your Disguise – Insects

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Friday, August 10th, 2012

My Dirt is your Disguise – Insects by Julie Craves

Okay, so domestic chores are not one of my strong points. Yet it was alarming to see a dirty bit of crud in the foyer begin to move under its own power across the entryway. Had I neglected housecleaning for so long that dust bunnies were becoming living organisms, like some Far Side cartoon?

A closer look revealed the animated detritus was an immature Masked Hunter (Reduvius personatus), a true bug inadvertently introduced from Europe sometime before 1900. They are now found over much of the U.S., most frequently being found in the central and northeastern states. They prefer dry conditions, so they are often found indoors. We have found them near doorways and on the front porch, where they hang out to feed on the insects attracted to the lights.

As do other members of the genus, the immature stages of the Masked Hunter look like smaller versions of the adults, except they are covered with fine hair-like structures which collect dust, dirt, and lint (adults are sleek and black). This camouflage perhaps helps the youngsters sneak up on their prey.

Like other assassin bugs, Masked Hunters stab their insect prey with beak-like mouth parts, then inject chemicals that both subdue the victim and liquefy their innards for easy slurping. While small – under an inch – Masked Hunters can nonetheless inflict a painful poke to humans if they are mishandled. They’re benign, though, and don’t transmit any diseases. In fact, they are often considered pretty good housemates. Masked Hunters are mainly nocturnal, and bed bugs are a favorite food, accounting for their alternative name “masked bed bug hunter.”

Bed Bugs Insects

Bed Bug © Will Ferguson

I’m happy to report we don’t have bed bugs, and I’m okay with allowing these little predators to keep the foyer and porch free of other insect invaders. Since covering themselves with debris only improves their hunting prowess, I’ve decided to put off the dusting for just a little while longer…

Surprise, I Smell

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Thursday, June 14th, 2012

Roundneck Sexton Beetle (Nicrophorus orbicollis) photographed at night in my backyard. I later noticed in the photo a tiny mite clinging to its neck. These beetles have a close relationship with these mites (Poecilochirus sp.). The larval mites apparently do not harm the beetle, but use it like a taxi ride to a carcass. The carcass furnishes the mites with fly eggs for food. by Kent McFarland

It’s moth watching time and bugs of all sorts arrive from the darkness to whirl and whiz around the black light in my backyard. Something lands on my hand and I shake it off without much notice. It’s not unusual to have a variety of insects landing on me when I’m near the light. On the ground below me in the beam of my headlamp lies a small Burying Beetle that was just tossed from my hand. These beetles are true to their name. They bury carcasses of small animals as a food source for their larvae. This beetle had left a rather pungent and peculiar smell on my hand.

With nearly 70 species worldwide and only about 8 species here in New England, these red and black beetles are unmistakable. My beetle turned out to be a Burying Beetle or Roundneck Sexton Beetle (Nicrophorus orbicollis), apparently one of the most common species in this area. Lots of them are colored red and black, but only this one has a round pronotum, the plate of armor between its head and abdomen.

My hand didn’t smell gruesome at all. It was a sweet smell that resembled horse manure, but much more pungent. I actually kind of liked the smell. But what exactly caused it? Was it residue on the beetle from rotting flesh? Was it emitting a chemical of some sort? Either way, I first went inside and washed my hands before exploring for an answer. My mother would be proud.

Carrion beetles are chemical wizards. Using their clubbed antennae, each with three orange segments on the end, males can detect a dead carcass over a mile away. When a carcass is secured he emits a pheromone to attract a female. Perhaps my hand was sprayed with his pheromone?

I once had an instructor for a hazardous materials course for my firefighting certificate. He liked to call everything “methyl-ethyl bad stuff” with his tongue firmly in his cheek. It turns out that carrion beetles actually make it. A close relative of this beetle emits a pheromone comprised of ethyl 4-methyl heptanoate, which apparently has a strong fruity smell. Not a very good descriptor of the smell on my hand.

Once the male secures the carcass and attracts a female, both bury the carcass. They produce oral and anal secretions that help reduce decay by inhibiting bacteria. The female lays eggs in the soil near the carcass rather than right on it. They are unusual among insects in that both the male and female parents tend to the brood. The adults eat the carrion and regurgitate the food for the larva. After about a week the parents leave the brood and the larvae pupate in the soil.

Whether from the residue of a rotting carcass, mate attracting pheromones, or anal secretions able to stave off bacteria, the burying beetle left me with more than a smelly hand. He left me with yet more wonder for the ecological workings of my backyard.

Backyard Jungle

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Tuesday, June 5th, 2012
Insects Spiders

Giant Resin Bee © Arthur V. Evans

The New York Times recently ran an article entitled, “So Much Life on a Little Patch of Earth.” It outlined the wide array of flora and fauna in the author’s small, typical suburban yard, including a moth that was the first record for North America. So many of us feel that nature is…somewhere else. We travel to find new and novel creatures, when indeed they can be found in our own backyards.

Our yard in suburban Detroit is very small, but we have provided a tiny pond; many native trees, shrubs, and plants; and lots of vegetative structure. Naturally, we’ve kept a yard list of birds, which is currently at 136 species. A couple of years ago, we decided that we’d try to identify all the Hymenoptera in the yard – bees, wasps, ants, and relatives. We are up to 89 species even though we haven’t attempted to figure out ants or the plethora of very small wasps and bees that tend to make the project more tedious than fun.

Among these is a wasp in the genus Euodynerus that has yet to be described by science. We see this species, known simply as “species F”, every year and have sent specimens to the researcher who will be writing the official description.

Two others were some of the first Michigan records for one of the grass-carrying wasps, Isodontia elegans, and the non-native Giant Resin Bee (Megachile sculpturalis). These discoveries scored me co-authorship on two papers on their distribution. Many other species were simply new and exciting to us.

The Hymenoptera were our starting point. Since so many flies are mimics of bees, we’ve started keeping track of all of them, too. And while we haven’t yet assembled lists, we are also on the lookout for beetles, bugs, and other arthropods.

While we’ve probably documented most of the common species, we still have frequent moments of triumph when we encounter something new. And we love the sense of stewardship our inventory brings us. Take a look in your yard, and see what you can discover!

Deception – Simpson’s Grass-Pink

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Monday, April 16th, 2012

Simpson's Grass Pink by Jungle Pete

Cross-pollination is most commonly achieved by wind or insect. Pollen from the male part of the flower is transferred to the female part of another flower of the same species. Insects are lured in with the promise of nectar and are the ambivalent dupes of this well orchestrated exchange of genetic material. Not all promises are what they seem.

My good friends Milla and Richard and I were wildflower hunting on the CREW lands in Collier County, Florida recently. A prescribed fire and an extended drought have made conditions optimal for an amazing diversity of wildflowers, but there was one in particular that Milla insisted we had to find. She had seen it days before and she promised it wasn’t far from the parking lot.

How far?
“Near Lettuce Lake!”
Ok, that’s not far. I had an appointment and had to be somewhere as promised.

After an hour of stopping to photograph flowers I asked again “how far?”
“Just at the bend in the trail!”

Thirty minutes later the trail bent. There amongst a myriad of wildflowers, as promised, stood tall, a lone Simpson’s Grass-Pink (Calopogon tuberosus var. simpsonii), a terrestrial orchid variety only found in seasonally wet, marly soils. The genus Calopogon translates to “beautiful beard” and refers to the unique bristles on the upper lip of the three-petaled flower. The bristles give the appearance of stamen and a false promise of nectar. While attempting to land on the upper lip, heavier insects will cause it to bend, dipping them back onto a mass of pollen grains which can then be transferred to the next flower where cross-pollination is achieved.

This variety is distinguished from the common form, Grass Pink (Calopogon tuberosus) by a narrow and elongated upper lip and is found in grassy savannahs (at the bend in the trail!)

We found several more plants nearby, which all seemed to benefit from the recent fire and open canopy. It was well worth the walk and I was thankful for trusting in Milla’s promise. It did make me wonder how many insects have been tempted by the Grass Pink’s deception and how many have learned to turn around before wasting their time. I’m glad I didn’t.

Birding Ain’t for Wusses!

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Thursday, April 12th, 2012

Summer Tanager adult male, Western © Joe Fuhrman/VIREO

I wasn’t the least bit afraid of heights when I was young. I remember standing on the third step from the top of a 30-foot extension ladder to paint the peak of a house one summer. No problem.

I guess I’ve gotten smarter. Heights now make me very nervous.

When I decided to go to Ecuador, I knew I was going to have to deal with this. Getting up into the canopy of trees or above them via birding towers is crucial.

At the Sani Lodge on the Napo River in Ecuadorian Amazonia I got my chance to test my resolve. Early one morning we hiked out to a green, steel tower about ten or twelve stories high; I deliberately didn’t calculate the height or even look up to see how tall it was.

Scarlet Tanager adult male, breeding © Rob Curtis/VIREO

To keep myself from bailing out, I deliberately went first. Wet, mesh steps and minimal rails made it an added challenge. I put a steely grip on both handrails and willed myself up.

About two-thirds of the way up the tower I had to stop and catch my breath in the middle of a stairway. As I stood there looking straight ahead, neither up nor down nor sideways, our guide Domingo ducked under my arm and went ahead.

Within seconds he touched my arm. I was concentrating so hard, I almost jumped out of my skin. “Essnake,” he whispered in his version of English.

Ahead in a corner of the next landing was an eight-inch coil of lime green, diamond-headed snake. If I’d gone two steps further, I’d have been staring right into its small, beady eyes.

Continue up or head back down?

With instructions from Domingo, I turned sideways, grabbed the right handrail behind me with both hands, and cautiously inched past the snake.

Flame-colored Tanager adult male © Robert A. "Spike" Baker/VIREO

My knees were jelly when I got to the top of the tower. A 12-foot bridge was all that separated me from the wooden platform at the top of a giant kapok tree. I grabbed the rails with both hands, closed my eyes, and crossed it.

Once on the platform I opened my eyes and reached for a wooden support nailed to a tree limb. Domingo grabbed my arm. “Bullet ant,” he said, pointing to a huge ant about an inch and a half long. “Bullet ant?” “If eet bite you, it feel like you heet by bullet.”

We had a productive morning in the canopy. Lots of parrots and macaws and aracaris, an Ornate Hawk-eagle, and many kinds of brilliantly colored tanagers, to name just a few. The climb was sure worth it.

Going down was no easier. In fact, it was scarier. The snake was still there, and I couldn’t help but look down.

Back at the lodge we discovered that the snake was an Amazonian Palm Viper, sometimes called a two-striped forest pit-viper (Bothriechys bilineate). No one at the lodge had ever seen it on the tower before. It would have to pick my day on the tower as its first!

Hepatic Tanger adult male © Rick and Nora Bowers/VIREO

Ode to Migration

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Friday, March 30th, 2012

Wood Thrush, adult © Brian E. Small/VIREO

What do a Wood Thrush, a Monarch butterfly and a Common Green Darner dragonfly have in common? Each spring they all migrate great distances to the Northeast from warm southern climates to breed. We’ve known where thrushes winter in Central America. We’ve known where Monarchs winter in Mexico for nearly 40 years now. But no one knows where the darners spend their winters or how they repopulate the Northeast each spring. We cannot manage and conserve a migratory animal without knowledge of its full annual cycle.

I have joined a group of biologists that are hot on the trail of discovery. I have teamed up with the Migratory Dragonfly Partnership, a group of scientists from across the United States, Canada and Mexico, to better understand dragonfly migration. Pete Marra from the Smithsonian Conservation Biology Institute and I are leading a ground-breaking study using stable-hydrogen isotopes in the wings of dragonflies to trace spring migrants back to their natal origins, unlocking the geographic scale and connectivity of these populations.

Dragonfly migrations have been observed on every continent except Antarctica, with some species performing spectacular long- distance mass movements. The Wandering Glider dragonfly is the global insect long-distance champion; making flights across the Indian Ocean that are twice the distance of Monarch butterfly migrations. In North America, dragonfly migrations are seen annually in late summer and early fall, when thousands to millions of insects move from Canada down to Mexico and Florida and the West Indies, passing along both coasts of the United States and through the Midwest. North America may have as many as eighteen migratory dragonfly species, some engage in annual seasonal migrations, and others are more sporadic migrants.

Monarch, male © Rick Cech

Spring movements northward by dragonflies are rarely seen, presumably because it occurs over a wider front, over a longer time period, and with fewer individuals than in the fall. We know it happens because dragonflies appear early in spring in places where nymphs have not yet emerged.

The best-known migrant dragonfly in North America is the Common Green Darner. This species appears in early spring at northern latitudes, often seen flying before any local dragonflies have emerged. These are migrants from the south, returning from perhaps Florida, the Caribbean, or Mexico. These individuals breed soon after they arrive in spring, and their nymphs develop quickly in wetlands warmed by the summer sun. Many adults emerge in August, and instead of maturing and breeding at the same site, they begin a southward movement that may take over a month. Their destination is at present unknown but presumably the same areas thought to produce spring migrants. Migrating individuals may breed at their final destination or along the way.

Although migration is common, it is not obligatory for Common Green Darner. Populations in more northern areas are known to contain both resident and migratory individuals. These phenotypes overlap in space, but exhibit strikingly different annual phenologies appear to limit temporal overlap in breeding. Migrants arrive at breeding ponds in March – April and larvae develop into adults in 4-5 months. Residents begin their breeding cycle roughly one month later in June – July and larvae overwinter in ponds, finally emerging as adults in May-June in the following year.

There is some evidence air temperature plays a role in the maintenance of this phenotypic variation. Final-instar larvae of migratory phenotypes reared in the laboratory required a minimum water temperature of 8.7oC to develop into adults. In Ontario, resident phenotypes required 20% more accumulated degree-days than migrants to complete development. These thresholds suggest the relative size of migratory populations could vary with latitudinal gradients and temperature.

Green Darner © E. R. Degginger, Color-Pic, Inc.

Despite the fact that it spans several countries and has been documented since at least the 1880s, North American dragonfly migration is a poorly understood phenomenon. Knowledge about migratory cues, flight pathways, population connectivity and the southern limits of overwintering grounds is still seriously lacking. This knowledge gap prevents development of international management plans and coordinated conservation actions to sustain and protect the migration. None of the dragonfly species known to be migrants in North America is currently endangered, but identifying the habitats on which migrating dragonflies rely for their transcontinental flights may help us better protect these important systems. The threats to wetland habitats, including the effects of global climate disruption, could alter environmental cues for migration, affect larval development and adult emergence times, disrupt migratory corridors, or render overwintering habitat unsuitable.

The overarching goal of this study is to understand the geographic scale and connectivity of dragonfly migration. Remarkably, we can do this by examining the chemistry locked in the dragonfly’s wings.

Stable-hydrogen isotopes are ideal for inferring natal origins dragonflies because they reflect the latitude at which body tissues were grown and because they are chemically inert once bound. Vaporizing a tiny piece of a wing in a mass spectrometer gives us the figures we need to determine the latitude of the pond where they grew up. With the help of volunteers in the field and museum collections from the past, we are sampling Common Green Darners from Mexico to Texas, over to Florida and up the eastern half of North America into Canada in a quest to better understand what might be one of North Americas most amazing animal migrations.

Small Wonder

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Friday, March 9th, 2012

Crablike Spiny Orbweaver by Rosemary Allen

A small but intriguing spider called the Spiny Orbweaver or Gasteracantha cancriformis  has woven her orb web between my bougainvillea and firebush in the pathway of what seems to me to be an insect highway complete with a steady breeze. The dorsum of this spider’s abdomen is white with black spots that resemble a smiling face and large red spines on the margin. She is about 5mm long and 10mm wide. The males are smaller and tend to hang below off of the females web but I see no sign of the male. Perhaps they have already mated and he has died, as is typical for this species.

How did she figure out this would be the best place to weave her web? She seems to catch mostly small insects like gnats and mosquitoes for which I am very grateful. I have been watching her for three days now, waiting for bigger events to photograph but the larger insects have been able to avoid her snare so far. I think it is worthy to note: a bumblebee hovered in front of her for a few seconds before buzzing off and even the Monarchs seemingly preoccupied with their mating either went under or over her web. The same was true for the Peacock, Sulphur and red admiral butterflies. I did notice thicker places in the web with white tufts of silk close to the center but the rest of the web is practically invisible. It’s a narrow chute three feet across in which she has chosen to set up camp, with her orb web no more than one foot in diameter and right at my eye level. In the past I have seen them as a nuisance but now I am intrigued at their ability to meet their needs. The spiny protrusions on her abdomen have always fascinated my young nephews and they don’t think twice about picking them up by their spines to get a closer look. Could this be her protection from predators? They don’t seem to have a bad bite and they help keep our pesky insects at bay. On the fourth day she is mysteriously gone. The web, which is usually rebuilt at night is in pieces. Did she move on? Was she eaten by the Mockingbird that patrols this area? Did she create an egg sac when I wasn’t looking and go off to die? I need to pay closer attention.

Red Admiral © Rick Cech

Ant Buffett

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Monday, February 27th, 2012

Eastern Lubber Grasshopper by Jungle Pete

For a moment the corpse moves and thinking it’s still alive, I shift backward from my seat on the ground. The insect that is being consumed by an army of ants has long since expired, but the communal efforts of the tiny insects to break the hopper into pieces have caused it to list. I, with my macabre fascination with the grisly side of nature, have spun the scene into an imaginary Zombietown of arthropods. In fact it’s a simple scavenge site and underneath the roiling cloak of ants is a spiny-legged, flightless Eastern Lubber Grasshopper (Romalea microptera). Chances are the lack of useful wings led to death by wheel, and its present state.

How the mouse met its end is a mystery, as is the curious rubble pile surrounding it. Based on the reddish pelage on top and the white below, I would say this is a Cotton Deermouse (Peromyscus gossypinus) that once lived in the swamps of the Picayune State Forest east of Naples, FL.

Cotton Deermouse by Jungle Pete

Considering the masses of formic foes piled upon the remains of the snake, you’d think it would be hard to identify the creature beneath. The telltale marking is a yellow band around the neck, which makes it easy to identify as a Ring-necked Snake (Diadophis punctatus). I often find this secretive snake under logs or debris on the ground. When threatened they will expose their brightly colored dorsal side to warn would be predators away.

Ringed-necked Snake by Jungle Pete

From a distance, the ant traffic was so heavy it could have been mistaken for a slender snake. The sinuous band of ants ended at a well-picked apart Pig Frog (Lithobates (Rana) grylio). Similar in size and shape to the American Bullfrog (Lithobates (Rana) catesbeiana), only the Pig Frog is found in South Florida. Both species are sought after for their edible legs. This one kept them but little good that did.

Pig Frog by Jungle Pete

Death is unkind. I certainly have sympathy for all of the creatures that meet with an untimely end, especially those that are victims of human carelessness. In the end, their deaths are not in vain. A colony of ants will feast.

My Year in Nature Part 2: Bugs and Plant Edition

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Tuesday, January 10th, 2012
Racket-tailed Emeralds

Racket-tailed Emeralds by Julie Craves

In my quest to have a more pleasant look back at 2011 than I was receiving from the news, I reviewed the surprise discoveries I made in the natural world this year. Since I am an ornithologist, many high points have to do with birds. But like anybody who spends a lot of time in the field, I find other taxa are often in the spotlight.

For instance, for the last decade my husband and I have been compiling a list of county dragonflies and damselflies for our urban southeastern Michigan home county. In the past year, we decided we had likely discovered all the species likely to regularly occur here, having added nearly 50 species to the list. I started writing up a paper. Yet right at summer’s start, we stumbled upon a thriving population of Racket-tailed Emeralds (Dorocordulia libera), many busy working on the next generation, like the pair in the photo. This is a species previously represented in the county only by a literature record from the 1870s. A month later, we were amazed to find a Dragonhunter (Hagenius brevistylus), a new county record and the largest dragonfly in the U.S. – not easily overlooked. Both of these species were in places we had searched many times over the years.

Dragonhunter

Dragonhunter © Sidney W. Dunkle

A bit more prosaic was my discovery of a population of Florida Lettuce (Lactuca floridana) along the trails at work on my urban university campus. This is a state-threatened plant in Michigan. I have walked by the plants I found thousands of times before. Although similar to other Lactucas and sort of non-descript (okay, ugly) when not in bloom, woodland lettuce is tall and easy to see. Was this a very recently established population, or had I somehow missed them on my countless walks?

Florida Lettuce

Florida Lettuce © Jessie M. Harris

Common Checkered-Skipper (Pyrgus communis) reaches its northern range limit in southern Michigan. Over the years they’d occasionally been seen locally and seemed to be becoming more common, but my searches had been fruitless. Happily, 2011 was my year to add this species to my state butterfly list with one in a neighboring county. Shortly thereafter, I got to add it to my home county list…and hometown list…and yard list. I walked outside with my morning cup of coffee to find one right in the front garden.

Common Checkered-skipper

Common Checkered-skipper, Female © Rick Cech

My 2012 bring us all the excellent experience of new discoveries in familiar places!

True Colors

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Thursday, January 5th, 2012

Pausing to take in the magnificence of the wet grass prairie, hoping for a glimpse of a deer, and hearing the cry of a Bald Eagle, I was eventually pulled in to witness the Red-shouldered Hawk making a kill. I turned toward the stand of pond cypress and focused my gaze. I heard a scuffle and time seemed to slow down as I sensed the stand of shedding cypress holding this hawk, struggling to gain his footing on a branch. Then, slowly and deliberately he peeled back from his talon full of leaves, his prize of a katydid. He ate it slowly and I wondered if the bird was actually tasting his morsel or being careful not to drop it. After the meal the bird flew to a nearby perch to bathe in the sun and look out with me and my companion over the wet prairie. As other visitors came and went along the boardwalk, they were oblivious to his presence just a few feet away from their footsteps.

This is what I love about being at Corkscrew Swamp Sanctuary here in Collier County, Florida; an opportunity to experience the daily life within this wetland wonder and use it as my own nourishment for my heart and mind. The three of us continued our meditation of sorts until my human companion and I felt the pull to enter the forest and travel down toward the bald cypress further into the swamp. Finding more moments like the one I had just had was tempting and irresistible.