Posts Tagged ‘bugs’

Jumping Oak Galls

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Wednesday, December 19th, 2012
Jumping Oak Galls

Jumping Oak Galls © Julie Craves

Jumping Oak Galls by Julie Craves

A move to a new house has been responsible for my lack of productivity here the last few months. Now that we are settled in, we are anxious to get to know our large property. We have eight acres of wet woods, and while my bark identification skills are serviceable, I’ve been spending more time looking down at the ground to unlock some of the secrets of the forest we will now stewards.

Many of the mature trees are Black Cherry, Bur Oak, and Swamp White Oak. I noticed that many of the fallen oak leaves were pocked with dozens, if not hundreds, of round lesions, each the size of a pinhead. On the uppersides of the leaves, they looked just like pimples. On the underside, each lesion was a shallow pit that was either empty or had a tiny nodule nestled in it.

Those nodules are galls, created by very minute wasps in the genus Neurotarus. They’re known as jumping oak galls, because when the galls detach from the leaf and fall to the ground, the wasp larva inside will sometimes wiggle around and cause the gall to move. The fully developed wasp larvae will overwinter in their galls on the ground. Galls that remain on the leaves are probably doomed – they’ll either dry up and die, will expire because they have been parasitized or their galls have been invaded by insect inquilines, interlopers that feed on the gall tissue.

If all goes well, these galls will produce the all-female generation. Neurotarus wasps, like many of the others in their family, have elaborate life cycles that include alternating asexual and sexual generations.

Members of this family of wasps are quite host-specific, usually attacking only one or a few species of oaks; none use hosts in both the red and white oak groups. All the gall-bearing leaves I found were white oaks, with none on the plentiful red oaks present on the upland parts of the property.

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…

Grasshopper the Jumping Gluttons

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Friday, July 6th, 2012

Two-striped Grasshoppers by Kent McFarland

Grasshoppers are known for jumping and eating. Their strong hind legs and specialized elastic fibers in their knees allow them to jump twenty times their body length. Pound for pound, a grasshopper can eat up to 20 times as much vegetation as a steer, according to the Oklahoma Cooperative Extension Service.

Unlike many herbivorous insects, most grasshoppers will eat many different species of plant. Some can wipe out crops. Others, like the Two-striped Grasshopper (Melanoplus bivittatus), eat plants that are toxic to grazing cattle. When the going gets tough, grasshoppers may even eat dry plants on the ground or even scavenge weak or dead grasshoppers.

Video of a Two-striped Grasshopper eating by Kent McFarland

The Creosote Bush Grasshopper (Bootettix argentatus), found in the southwest, is the only grasshopper among the more than 660 species known in North America that feeds on only one plant, its namesake the Creosote Bush. The leaves have a resinous coating that makes them indigestible to most herbivores. There’s more resin in the buds and young leaves compared to the mature leaves. To combat the resin the grasshopper adds more oxygen in the digestive process that helps to make the resin more digestible. The resin content throughout the plant lowers during the evening hours for some reason. Of course the grasshoppers feed mostly during these hours.

Grasshoppers have powerful mandibles to rip plants into tiny pieces. Salivary glands in the mouth begin to digest the food chemically. The food passes from the mouth through the muscular pharynx down the esophagus to and to the crop. Like a bird’s crop, this organ can hold food until later. From the crop it enters the gizzard where the food is ground. Sliding down to the stomach, it is attacked by enzymes that break the food down even further. Nutrients are absorbed and the waste products are converted into dry pellets called frass and dropped to the ground.

Rocky Mountain Locust (Melanoplus spretus) ranged through the western half of the the U.S and Canada. Early European settlers described massive swarms. One famous sighting of a swarm was estimated to cover 198,000 square miles, weighed 27.5 million tons, and had about 12.5 trillion grasshoppers in it. Thirty years later they were extinct. The last one was found in Canada in 1902. It is thought that plowing and irrigation somehow disrupted the natural cycle of this grasshopper dooming it to extinction. Imagine the amount of vegetation that these swarms must have eaten.

Recently, for the first time that I can ever recall, I lay down and very closely watched the grasshoppers feeding in my garden. I was reminded of the old television series “Kung Fu” when the master questioned the student.

Master Po: Close your eyes. What do you hear?
Young Caine: I hear the water, I hear the birds.
Po: Do you hear your own heartbeat?
Caine: No.
Po: Do you hear the grasshopper which is at your feet?
Caine: Old man, how is it that you hear these things?
Po: Young man, how is it that you do not?

Buzzing Bumblebees

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Tuesday, June 26th, 2012

Bumblebee by Jack Ballard

Diverse in size and feeding habits, bees exhibit a wide range of social structures. Most people have some elementary understanding of the complex relationships of bees in a honey-producing hive. A hive of honey bees may contain up to 40,000 bees, with the queen producing 1,000 to 2,000 eggs per day to replace worker bees lost to predators while foraging and those dying of old age. However, there are many forms of bees who exist in colonies containing a few dozen to a few hundred individuals. Bumblebee colonies typical contain around 50 to 200 bees in August or early September when their population is at its highest.

Bumblebees are among the bulkiest bees in America. Important pollinators, bumblebees are often seen buzzing around suburban vegetable and flower gardens. Their flight has been characterized in song, and also described as defying the laws of flight. While bumblebees’ aerial antics are certainly worthy of a melody, the supposed theoretical prohibitions on their flight are in error. The idea that bumblebees are theoretically incapable of flight probably stems from a book by French scientists published in the 1930s where the authors applied principles of fixed-wing flight to the bees. More recent analysis shows that bumblebees use exceedingly fast, irregular and rotational wing movements which generate sufficient lift and propulsion for their buzzing, erratic patterns of flight.

Although some people believe bumblebees are incapable of stinging, both queen and worker bumblebees can sting. While camping at a lake at the base of the Beartooth Mountains, my daughter was once stung by a bumblebee. She reported, however, that the sting wasn’t nearly so painful as one delivered by a yellowjacket.

Often misunderstood, bumblebees are an integral strand in the complex web of biological interactions that maintain life on earth. Encountering a bee in the garden or camp isn’t a cause for alarm, but an opportunity to consider their critical connection to human life and our need to maintain a planet hospitable to our buzzing benefactors.

The Moth that Came from the River

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Wednesday, June 20th, 2012

Chestnut-marked Pondweed Moth by Julie Craves

One of a child’s first natural history lessons is usually that caterpillars grow up to become butterflies or moths. Eager to witness this transformation, we seek out caterpillars in yard and field to shepard through this remarkable metamorphosis. We soon learn the importance of raising the larvae on the same species of plant on which they were found. For many of us, this is our introduction into the interdependence of plants and animals, and the complex life cycles of even common organisms around us.

A couple of years ago I was doing an insect survey on a property along the Detroit River. I noted a pretty little moth which was quite common; many appeared freshly emerged, which made me curious about what the caterpillars fed on. From my photograph (above) I identified the moth as a Chestnut-marked Pondweed Moth. “Pondweed” is a pretty generic term, but I’ve generally heard it refer to submerged plants in the genus Potamogeton. Sure enough, Potamogeton is the host plant for this species…and the larvae are aquatic. I consider myself pretty well-versed in various butterfly and moth species and their host plants, but aquatic caterpillars were new to me.

This moth is not unique. In this same genus are species whose larvae feed on waterlilies, watermilfoil, and other water plants. Most feed on submerged parts. Other moths in the same family feed on algae scraped from rocks or diatoms trapped in silken sheets spun by the caterpillar. Many have gills for all or part of their larval stage. Females of some species may submerge themselves in an air pocket to lay eggs up to four meters underwater! Members of a number of other moth families are also known to have aquatic larvae.

When I think of flying insects that have an aquatic larval stage, my first thought is always dragonflies. Then many species of flies, as well as beetles, caddisflies, and some true bugs. Now I can add moths to this list, something I never imagined when I raised my first sphinx moth from a “tomato worm” as a bright-eyed child.

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!

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!

Bumble Bees

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Thursday, November 17th, 2011

American Bumble Bee

As I was sweeping my back patio this week, I found a dead and desiccated bumblebee. Since I’m no entomologist, I have no idea whether it was male or female. I hope it was a male.

Unlike honey bees – which hive together in large numbers over the winter, bumble bees rely solely on their queen bees for the propagation of their colonies. The workers and drones all die off each fall. The queen bee spends the winter alone in the ground or in some other warm place.

When I first came to Manitoba, I was delighted to find bumble bees here because I thought the winters might be too cold for their survival. But they are hardy critters; they live as far north as the Arctic Circle. They’re found on Ellesmere Island, in fact, less than 500 miles from the North Pole. They’re especially familiar on the prairies and mountain meadows.

Like most other kids, I loved finding bumble bees when I was a kid. Back in the days when yellow and black were the colors of warning signs rather than florescent lime green, bumble bees seemed to be equipped with their own furry warning coats.

With their deep, rumbling buzz, their chubby bodies, and seemingly undersized wings, they were not only noticeable, they were the easiest flying insects to catch. I regret to admit that many a bee died in a Mason jar with a nail-punctured lid while in my youthful custody.

Nowadays, they too are in serious decline. A University of Illinois researcher, Sydney Cameron, did a study of eight of the fifty species of US bumblebees a couple of years ago. Four of the eight are in serious decline. A 96% decline.

Kids and I aren’t the only ones who’ll miss them. Since they pollinate tomatoes, cranberries, blueberries, raspberries, strawberries, and apples, we all should take heed of their possible demise.

Winter Guest

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Wednesday, March 17th, 2010

There was a scream upstairs and then a yell for mom. It sounded like another teenage moment so I kept my nose in my book downstairs. A few minutes later my wife showed up at the table with a pair of underwear in her hands. “Can you tell me what this is,” she asked. I thought about telling here it was indeed a pair of dirty underwear, but her white knuckled grasp of it was an indication that this was no time to be smart-alecky. She loosened her grip a bit and there in her hand was what appeared to be a Hemiptera. The odor it was emitting was quite pungent when I grabbed it and put it to my nose. Now I was really interested.

What my girls had found crawling on the wall was a Western Conifer Seed Bug (Leptoglossus occidentalis). This bug was originally a Pacific Northwest species, but it has been moving eastward for the last 100 years. Our winter guest is in the family of squash bugs or leaf-footed bugs, named for the leaf-like flattened extensions on their hind legs. Nationwide, there are 88 species of leaf-footed bugs. All of them feed on plants. Our little friend enjoys the sap from developing pinecones.

It was very tame and easily handled. They are not poisonous and they don’t cause any damage. They’re just trying to get out of the cold. Normally, they winter under tree bark or crevice near the evergreens they feed on. There is a Red Pine tree right beside our house, so it wandered in somehow.

That scent I smelled? It was an alarm pheromone that is secreted from glands and consists mostly of hexyl acetate, which is often used in the creation of fragrances and flavor manufacturing, as well as hexanal, which is used to make fruity flavors in foods.

This bug was a lucky one. I put him outside on the pine tree and far away from the underpants monster.