Friday, November 28, 2014

Be Thankful for "Bugs"

A couple days ago the following post crossed my Facebook newsfeed, and it is an excellent reminder of why insects and other arthropods are so important to us as human beings, and to the planet Earth as well.

Honeybee pollinating flower in Arizona
"Thanksgiving is tomorrow …and we all have much to be thankful for. But don’t forget to thank our pollinating friends (bees, beetles and a host of other critters) that provide 1 out of every 3 mouthfuls of food and drink we consume. Without them, and the invaluable service they provide, our lives and our world would be drastically different. Happy Thanksgiving!"

Ecosystem Services

Beyond pollination, insects and related invertebrates furnish many other "ecosystem services" that we can't easily put an economic price on. They are responsible for seed dispersal in many plants. They are at the front lines in the decomposition process for all organic matter be it animal or vegetable. Their activities aerate and mix the soil. They serve as the basis of the food chain, feeding other invertebrates and many vertebrates from fish to birds to bats to aardvarks and anteaters.

Dung beetle pair rolling dung ball in Kansas

A scientific article was published in 2006 in the journal Bioscience that attempted to quantify just four of these ecosystem services: pollination, pest control in croplands, waste (dung) removal on rangeland, and food for wildlife (recreational hunting, fishing, birdwatching, etc). The carefully calculated estimate of the value insects thus provide, in the United States alone, was a staggering sixty billion dollars ($60,000,000,000).

Golden-winged Skimmer dragonfly in Georgia
Watchable Wildlife

Insects are quickly becoming "watchable wildlife" in their own right. Countless field guides and online resources cater to those who enjoy observing butterflies, dragonflies, moths, tiger beetles, and nocturnal "singing insects" like katydids and crickets. What will the next craze be? It is clear that these communal passions are not only sustaining themselves, but actually growing in popularity, as witnessed by the explosion of National Moth Week, for example. There are festivals for everything from butterflies to bees, even mosquitoes (in Paisley, Oregon).

Drosophila "fruit fly" in Colorado
Research and Medicine

Insects and other arthropods are also used extensively in scientific research and medicine. We owe much of our knowledge of genetics to research conducted on "fruit flies" (Drosophila spp.) and flour beetles (Tribolium spp.). Fly larvae are used to clean wounds because they carefully avoid living tissue while secreting fluids with antibiotic properties. Many patients with joint inflammation and diseases swear by "bee venom therapy," even though it may be relegated to the category of alternative medicine by the healthcare establishment. Spider, scorpion, and insect venoms continue to yield promising derivative compounds. Some fireflies produce chemicals that show promise in fighting herpes.

Paper wasp nest in Cape May, New Jersey
Art, science, and inspiration

Many people find inspiration in the world of insects. We owe the invention of paper to ancient peoples in Asia who observed paper wasps constructing their nests of chewed wood and plant fibers. We continue to refine the performance of our aircraft thanks to experiments on, and observation of, insect flight. Insects are being enlisted in the fight against terrorism because of their acute chemo-tactile senses that far exceed our own abilities to detect harmful substances and agents; and their small size that allows them access to the most remote cracks, crevices, and other cavities. Artists are endlessly inspired by the beauty, colors, and patterns of insects.

Cochineal scale insects on cactus, Colorado
Raw Materials

Lastly, insects and their kin provide us with many invaluable raw materials and products. Silkworms and spiders produce silk with different properties of strength, durability, and elasticity, often exceeding the quality of synthetic fabrics. Honeybees produce honey, and beeswax. Cochineal scale insects produce organic scarlet dye, and the lac scale insect yields shellac. Many cultures also consider insects themselves as a staple food source, a practice known as "entomophagy" that is steadily gaining favor in modern western cultures.

Tiny gall wasp (Cynipidae) I found yesterday, Colorado
Personally....

Personally, I value insects and arachnids as an endless source of fascination. Their physical diversity is mind-boggling. The behaviors they engage in are amazing. You can find them anywhere and everywhere, even inside your own home in the middle of a cold winter. Their stories demand telling, and I feel honored and privileged to have a modicum of ability to bring them to life for others.

What is it about "bugs" that you are thankful for? I encourage you to share your thoughts and feelings here.

Source: I wish to thank the Missoula Butterfly House and Insectarium for sharing the quote at the top of this post. Please visit their website, donate if you are able, and "like" them on Facebook. Thank you.

Monday, November 24, 2014

Springtails

Imagine animated flecks of salt and pepper running, even jumping, all over the bathtub, shower stall, wash basin, or window sill. Maybe you don't have to imagine, maybe you have actually experienced this and thought you were seeing things. Welcome to the world of springtails, tiny invertebrates that are among the most plentiful of organisms, both indoors and out.

Classification

So primitive, in the evolutionary sense, are springtails that scientists cannot even agree whether they are insects. They used to be, as members of the order Collembola. These days they are more likely to literally be placed in a class by themselves: the class Collembola; and treated as "non-insect hexapods." Regardless, there is no denying their importance as members of the soil fauna, and instrumental in the recycling of nutrients there.

Size and Abundance

Springtails are very small. Most are 1-3 millimeters. A "giant" sprigtail may measure 6 millimeters. The largest known species reaches a maximum of 17 millimeters. What they lack in size they more than make up for in sheer numbers. Estimates of the number of springtails per cubic decimeter of (forest) soil vary from 200 to 1,800, probably according to soil texture, composition, and fertility. A decimeter, by the way, is one-tenth of a meter (Bellinger, et al., 2014).

Many springtails active at night on a porch

Habitat

The Collembola are not always restricted to soil and leaf litter. Some species inhabit caves, others inside rodent burrows, still others occupying intertidal zones. Some species live in ant or termite nests, still others on the surface of still waters, even the surface of the snow, hence the common name of "snow fleas" for Hypogastrura nivicola and its relatives. You probably have springtails in the potting soil of your houseplants, and around the drains of sinks, tubs, and basins. The one overriding prerequisite for the presence of springtails is the presence of moisture.

Food

Springtails feed on all manner of organic matter, but the majority seem to eat rotting plants, insect frass (poop), fungal hyphae and/or spores, pollen grains, or dead invertebrates. A few are predatory on soil micro-organisms like rotifers and tardigrades ("water bears"), while fewer still are predatory on other springtails and tiny insects. They cannot be considered pests, but could, in rare instances, be indicative of mold or fungal issues when found indoors.

Look closely: Many springtails from under a board in a field

Anatomy

Not all springtails....spring. Still, they get their common name from two peculiar appendages that most springtails possess. A forked, tail-like appendage called the furcula on the ventral (underside) of the abdomen projects forward from near the tip of the abdomen on its fourth or fifth segment. When "cocked," the fercula (aka furca or furculum) hooks into a latch-like organ called the tentaculum (or "retinaculum"), located on the third abdominal segment. When the tentaculum releases, the furcula is driven downward against the substrate (surface on which the animal is resting), catapulting the springtail up and away, often several times the creature's body length. This bouncing locomotion is certainly observable by the naked eye.

All springtails feature a "ventral tube" or collophore, on the underside of the first abdominal segment. It's function is poorly understood, but it has been suggested that it may act as an extra leg, helping the creature navigate slick surfaces by means of adhesion; it may also function as a grooming organ, and/or as an intake for liquid water.

Lastly, springtails can be identified by having the tibia and tarsus fused into a "tibio-tarsus;" by the simple eyes composed of up to eight ocelli; four- to six-segmented antennae; and mouthparts concealed by folds in the cuticle of the animal's face.

A large and ornate springtail from beside a stream

Life Cycle

The sex life of springtails is not terribly intimate. Males produce packets called spermatophores that contain sperm. He may make a direct deposit to the female's genital opening, but most species deposit spermatophores one at a time on the surface of the substrate. Sometimes the spermatophore is on a hair-like stalk. There are apparently a variety of strategies for improving the odds that a female will find and pick up the species-appropriate spermatophore in a timely fashion. Males will actively consume old spermatophores, so time is of the essence.

A mated female will lay eggs individually or in small clusters in the soil. The babies that hatch resemble miniature versions of the adults, and thus go through "simple" or "incomplete" metamorphosis, molting several times after emerging from the egg.

Interestingly, the adults continue molting, up to fifty times during their mature lifespan. This may be due to the fact that springtails absorb oxygen directly through their soft exoskeleton. Chinks in the armor may not facilitate proper metabolic processes.

Controlling indoor springtails

At worst, springtails should be considered a cosmetic nuisance, and certainly not worthy of chemical assaults. They are not considered a risk to human health, the health of pets, or destructive to property. If you must, here are some steps you can take to literally dry them to death, the only sure-fire "cure."

  • Do not overwater houseplants. Should you find springtails in houseplants, take the plants outside and allow the soil to dry out for several days.
  • Consider using a dehumidifier in the room where you are seeing springtail activity. Lowering the atmospheric moisture level is always helpful in minimizing or eliminating springtail populations.
  • Spread a very thin layer of diatomaceous earth (DE) where you are seeing springtails, such as on a window sill. Reconsider this if you have curious pets or toddlers, as DE is essentially pulverized glass. Diatomaceous earth etches the cuticle of insects, causing them to dehydrate and die.
  • Repair worn weatherstripping on doors, and seal cracks and crevices that springtails (and other arthropods) could crawl through to get indoors.
  • Inspect firewood, toys, and any other objects brought indoors from outside. This is essential for preventing all potential pests from entering the home.

Sources: Bellinger, P.E., Christiansen, K.A., and Janssens, F. 1996-2014. Checklist of the Collembola of the World.
Berenbaum, May R. 1989. Ninety-nine Gnats, Nits, and Nibblers. Urbana: University of Illinois Press. 263 pp.
Hopkin, Steve. 2014. Collembola Photo Gallery.
Hopkin, Stephen. "The Biology of the Collembola (Springtails): The Most Abundant Insects in the World," The Natural History Museum (UK).

Thursday, November 20, 2014

Lakin Grasshopper

Grasshopper species diversity in the southwest U.S. presents enough of a challenge for the amateur naturalist, but then you have the Lakin Grasshopper, Melanoplus lakinus, that can apparently pass for several hundred species all by itself. That's an exaggeration, of course, but there is such great variability in the color, pattern, and wing length of this species that it is mind-boggling.

Lakin Grasshopper male

Lakin Grasshopper is often overwhelmingly abundant in disturbed habitats such as vacant lots and weedy fields and rangeland filled with its favorite host plants, members of the goosefoot family Chenopodiaceae. This includes Russianthistle ("tumbleweed"), kochia, and native saltbush (Atriplex spp.). It will also feed on various forbs and grasses such as lambsquarters, western wheatgrass, and downy brome. Despite high population densities in some years, it is seldom a crop pest.

Lakin Grasshopper female

This is a grasshopper of the Rockies and Great Plains, ranging from South Dakota and southern Minnesota south through western Iowa, most of Kansas, western Oklahoma, the west half of Texas, plus Nebraska, Colorado, New Mexico, and the eastern two-thirds of Wyoming, Utah, and Arizona. It also occurs deep into central Mexico.

Red form female from New Mexico

Melanoplus lakinus is a pretty "average" grasshopper. Adult males measure about 22 millimeters in body length, females 30 millimeters. Most specimens are short-winged as adults, but some are fully-winged. The overall color varies greatly from brownish or gray to green or even red. The tibia ("shin") segment of the hind leg is usually blue, armed with spines that are black or at least black-tipped. The inner surface of the hind femur ("thigh") is often reddish in part, especially along the bottom edge where the tibia folds into it. The top surface of the femur is most often marked with pronounced dark bands.

Green form female from Colorado

Dark bands on the abdomen, especially near the base, are helpful in recognizing the species in the field, but ultimately one has to examine the external genitalia of the male to confirm identification.

Ok, so how do you even tell apart the different genders? Below is an image that shows the male and female side-by-side, from the rear. The male is on the right. The female is on the left, but her abdomen is twisted to repel his advances, or accept his overtures, I'm honestly not sure which because I did not stick around long enough to see the outcome.

Male on right, female on left, rear view

The male's parts are pretty complicated, but you want to look at the shape of each "cercus," paired tail-like appendages. In the example below, we see that the cercus of M. lakinus is shaped something like a Hershey's candy kiss: broad at the base and tapered toward the tip. Next, take a look at the shape of the subgenital plate. It is best to view it directly from the rear, like in the image above. We can see it has a low, blunt tooth right in the middle. The supra-anal plate also offers species-specific details, but they are more difficult to discern, especially in images.

Anatomy of male M. lakinus

When two grasshoppers do get together, it looks like this:

Mating pair, male on top

Pretty kinky, almost literally! Mated females deposit clusters of eggs ("pods") in the soil by telescoping their abdomen as deep as it can reach. The eggs are held together by a kind of foamy secretion that hardens to protect the mass from environmental extremes. The eggs hatch in late May or early June, on average, the following year. In Arizona, where summer monsoons trigger hatching, emergence is usually in early July. The nymphs pass through five instars (an instar is the interval between molts), reaching adulthood in about a month.

Long-winged female from New Mexico

This year was a good one for the Lakin Grasshopper here in Colorado, and also in New Mexico, as heavy spring rains provided the nymphs with plenty of food after years of draught. The adults have hung around a long time, too. Just yesterday I spotted one basking on the sunny side of a building in our townhouse complex.

Sources: Capinera, John L. , Ralph D. Scott, and Thomas J. Walker. 2004. Field Guide to Grasshoppers, Katydids, and Crickets of the United States. Ithaca, NY: Comstock Publishing Associates (Cornell University Press). 249 pp.
Branson, David H. and Bethany Redlin (eds.). 2004. Grasshoppers: Their Biology, Identification and Management. 2nd Edition. US Department of Agriculture, Agricultural Research Service.
Grasshoppers of Colorado

Sunday, November 16, 2014

Ballooning Spiders

Do you remember that meme that went around on Facebook expressing gratitude that spiders can't fly? Here it is:

Well, not so fast my friends. Spiders actually can get aloft, thanks to the phenomenon of "ballooning."

Ballooning is the number one way that spiders disperse themselves across the landscape. It is practiced mostly by immature spiders that do not weigh much and are easily blown away; but many spiders are quite small as adults, too, and they can balloon as well. It is a way spiders avoid competition with each other for prey and "web sites."

This technique is brilliantly simple. The spider simply climbs to the top of a vertical object like a plant stalk, fencepost, or mailbox, and issues threads of silk from its spinnerets. When the spider detects a breeze, it stands on "tiptoe," facing the wind, and tilts its abdomen toward the sky. With any luck, the air currents whisk the spider off its perch and up, up, and away it goes.

Ballooning wolf spider, Blue Stem Prairie Open Space

Recent investigations also suggest that spiders can harness electrostatic forces in the atmosphere to balloon on calm days and/or achieve greater success than they might from the wind alone. This is beyond both my grasp of physics and the scope of this post, but you are welcome to read more here.

The spider families that utilize ballooning the most include the crab spiders (Thomisidae), orbweavers (Araneidae), long-jawed orbweavers (Tetragnathidae), and dwarf spiders (subfamily Erigoninae of the Linyphiidae). Personally, I have also seen wolf spiders (Lycosidae) ballooning, like this one at Bluestem Prairie Open Space along the edge of Johnson Reservoir near Colorado Springs, on March 10, 2014.

Alex Harman also documented a ballooning event of immature Six-spotted Fishing Spiders, Dolomedes triton, at Horicon Marsh in Wisconsin on October 26 of this year.

© Alex Harman

Ballooning is most often performed in spring and late fall by spiderlings, but adult dwarf spiders balloon during the winter, too. The most favorable conditions for a "launch" are when the weather changes to warm days after a prolonged period of cold. This creates updrafts as the ground temperature heats rapidly. Here on the Front Range of Colorado, gusts can be strong and spiders are no doubt carried a long distance.

Darwin, during his voyage on the H.M.S. Beagle, noted large numbers of ballooning spiders coming to rest on the ship's rigging. At the time, the vessel was approximately 100 kilometers off the eastern coast of South America, and Darwin suspected the spiders had drifted at least that distance, if not farther.

Not only are ballooning spiders transported horizontally, they can be blown to high altitudes as well. At least one spider has been collected by airplane at 15,000 feet over Tallulah, Louisiana during a study that lasted from 1926-1931 (Glick, 1939). The greatest number of specimens was still taken at well under 1,000 feet, however.

Gossamer, © Fairyist.com

"Gossamer" is the term for the silk lines spiders create when ballooning, and the cumulative effect can literally shroud the landscape in a blanket of gossamer as the spiders come to rest. Considering that there are easily dozens upon dozens of spiderlings per egg sac, multiplied by dozens of egg sacs, multiplied yet again by however many species exist in a given area, it is no wonder that ballooning individuals can create such a spectacle of spent silk.

Not every attempt at aerial navigation is a success, of course. I personally witnessed a small crab spider take off from a utility box in my neighborhood, only to land unceremoniously about three feet away in the street.

Ballooning crab spider, Xysticus sp., Colorado Springs

Still, spiders are able to achieve amazing feats this way. They are often among the first animals to colonize islands, and habitats destroyed by storms, volcanoes, and other natural disasters. Re-colonization of the island of Krakatau, and the blast zone around Mount St. Helens, are two of many well-documented instances of ballooning spiders conquering new territories.

Sources: Brunetta, Leslie, and Catherine L. Craig. 2010. Spider Silk. New Haven, Connecticut: Yale University Press. 229 pp.
Foelix, Rainer. 2011. Biology of Spiders (Third Ed.). Oxford: Oxford University Press. 419 pp.
Glick, P.A. 1939. The Distribution of Insects, Spiders, and Mites in the Air. Washington, DC: United States Department of Agriculture Technical Bulletin No. 673. 151 pp.

Friday, November 14, 2014

Thank you, followers!

I can think of no better way to use my 500th post than to thank the many people who read this blog faithfully. Without followers like you, I never would have reached this milestone. Many days I have wondered why I bother posting, but then I look at the growing number of icons under "members" in the right sidebar, and remember who is waiting for the next story.

We ♡ our followers!

Friends who are more tech-savvy than myself also remind me that there are hundreds of other people looking in that don't show as members. Every month or so I also get a report from Google that surprises me with how many "hits" this page receives daily, and where those hits are coming from. Sure, most of my audience is from the U.S. and Canada, but I also have visitors from the United Kingdom, Australia, and South Africa. I may need to make some field trips abroad so I can talk about arthropods from those places, too.

Last month I had over 9,000 new visitors, 274 returning visitors. Facebook and Blogger are my top "social sources" by far, with WordPress, reddit, and Twitter bringing up the rear. That surprises me because I get re-tweeted all the time (and thank you for that!).

My overall goal is to reach an audience unfamiliar with insects and arachnids, providing the most accurate and relevant information I can. I also want to encourage other naturalists to keep on finding and observing invertebrates, reporting their own sightings, images, videos, and audio recordings to appropriate archives. I welcome suggestions for how to improve on that.

It is important to note that many of my posts could not be possible without input from entomologists and arachnologists far more expert than myself. I frequently need to have specimens identified before I can write about the species, genus, or family, and were it not for specialists willing to share their knowledge, I would be nowhere.

Lastly, if you have an enterprise that has anything to do with a positive approach to natural history, have written a book, or do public programs, I would be willing to put up an advertisement for you, as I have done with BioQuip. Don't be shy, I am always delighted to reward good work, and would happily devote a blog post to your business, achievements, or observations, especially if you do not have a blog of your own.

Thank you again for making "Bug Eric" a successful venture. I look forward to continuing to produce it for as long as I can. There is certainly no shortage of subject matter, even if I had started several lifetimes ago. Oh, wait, the internet has not even existed for that long.

Tuesday, November 11, 2014

Little Bugs with a Big Bite: Minute Pirate Bugs

Sometimes it seems the tiniest of insects is the biggest nuisance. Mosquitoes come to mind, as well as black flies, and "no-see-ums" or "punkies" (biting midges in the family Ceratopogonidae). One other insect often responsible for surprisingly painful bites is the aptly-named "minute pirate bug." There are about 90 species in the family Anthocoridae found in North America, in 22 genera, but only a few cause us grief.

Insidious Flower Bug biting me in Colorado

The Insidious Flower Bug, Orius insidiosus is, appropriately, the species most likely to get under your skin. Well, on your arm, hand, or neck, where it will likely probe you painfully. At only 2-2.5 millimeters, it is possible to overlook it entirely when trying to pinpoint the source of your irritation. In the right light, however, the little bug appears bright white and black.

Despite dispensing unprovoked bites, Orius insidiosus is actually a highly beneficial bug. It is a predator of many crop pests like very young caterpillars of the corn earworm, plus insect eggs, aphids, whiteflies, thrips, and mites. Consequently, this minute pirate bug is reared commercially and sold to farmers as a biocontrol agent.

It takes only twenty days, on average, for O. insidiosus to go from egg to adult. Females lay two eggs per day, and about thirty during their lifetime. Each ovum is deposited in foliage such that the top of the capsule protrudes above the leaf surface. In about four or five days, the first instar nymph emerges from the egg. During the next two or three weeks, the nymph goes through a total of four more instars before transforming into a fully-winged adult bug. The adults live an additional three or four weeks.

Insidious Flower Bug biting me in Kansas

Adult Insidious Flower Bugs overwinter in leaf litter and probably other debris on the ground. Several generations can be produced annually over the insect's wide geographic range. It occurs east of the Rocky Mountains, plus parts of California, and has been introduced to British Columbia. Because it is available commercially, it has likely spread elsewhere, too.

Adult Anthocoris musculus, Colorado

Another species I have found commonly here in Colorado Springs is Anthocoris musculus. It is a real giant by pirate bug standards, measuring 3.4-4.0 millimeters as an adult. I have found it associated with cottonwood trees, and it is well-known from willows and other deciduous trees and shrubs as well as herbaceous plants.

Nymph of Anthocoris musculus, Colorado

It is potentially an important predator in orchards, and has been observed eating red mites and "eye spotted bud moth" in Nova Scotia (Kelton, 1978). This species ranges throughout most of North America including Alaska and northern Canada.

The next time the pirate bug bites, simply utter "Ar-r-r-r!" and remember their beneficial qualities. After all, they are probably keeping your garden free of other tiny pests.

Adult A. musculus feeding on unknown object, Colorado

Sources: "Minute Pirate Bug aka. Orious insidiosus," Evergreen Growers Supply.
Gibb, Tim. 2006. "Have a thick skin when it comes to Insidious Flower Bugs," Purdue Plant & Pest Diagnostic Laboratory, Purdue University Extension
Hull, L.A. and R.L. Horsburgh. "Minute Pirate Bug, Orius insidiosus (Say)," Mid-Atlantic Orchard Monitoring Guide.
Kelton, Leonard K. 1978. The Anthocoridae of Canada and Alaska. Ottawa: Canada Department of Agriculture. Publication 1639. 106 pp. (PDF).
Slater, J.A. and R.M. Baranowski. 1978. How to Know the True Bugs. Dubuque, Iowa: Wm. C. Brown Company Publishers. 256 pp.

Sunday, November 9, 2014

ArachNovember?

Last month we celebrated "Arachtober" over on the Flickr photo-sharing website, but with the unseasonably warm weather we have had here at home along the Front Range in Colorado, we're still seeing plenty of spiders this first week of November. Ok, we also cheated a little and took a trip into the heart of New Mexico, but it all goes to reveal how surprisingly long-lived some arachnids can be, and their different strategies for surviving the winter.

Male platform spider, Microlinyphia sp.

Fall is the time when the males of many a spider species go wandering in search of mates. So, it was not surprising to find a male "platform spider," genus Microlinyphia, in a restroom on the Bosque del Apache National Wildlife Refuge in New Mexico last Monday. I found out that the genus is easily recognized by the circular filament seen in the image above that issues from the male's pedipalp. This hair-like structure is called the "embolus," and it is the channel through which sperm travels during mating.

another view of the Microlinyphia platform spider

Female and immature male platform spiders live on flat, sheet-like webs built close to the ground amid grasses and low plants. The spider clings upside down to the underside of the web. Morning dew can make the webs much more obvious than they normally are.

Once mated, a female spider usually produces one or more egg sacs, as this labyrinth spider, Metepeira sp., has done. She has two egg sacs behind her in the image below, inside the tubular retreat she is at the mouth of. We found her near the platform spider, but outside along a railing around the "Flight Deck" at the refuge. Labyrinth spiders build a combination orb web and tangled snare.

Labyrinth spider with egg sacs behind her

The egg stage is a great way for an embryo or spiderling to spend the cold months, insulated within layers of silk spun by their mother. The eggs often hatch within the package, the spiderlings biding their time until the weather becomes favorable for their emergence.

Ghost spider female

At the bed-and-breakfast inn where we stayed in New Mexico, I found what must be a very pregnant female ghost spider, family Anyphaenidae, prowling the exterior of the house at night. Back home in Colorado Springs, before we left on vacation, I spotted a similarly bloated female jumping spider, Phidippus asotus on the downspout right outside our townhouse.

Female Phidippus asotus jumping spider

Inside the bed-and-breakfast, a pair of male cellar spiders in the genus Physocyclus were hanging around the web of a female in a corner of the ceiling. Below is one of the males approaching the female. Physocyclus seems to replace the Long-bodied Cellar Spider (Pholcus phalangioides) as the usual "indoor" cellar spider in the southwest U.S.

Male (left) and female cellar spiders, Physocyclus sp.

It is not only spiders that are out and about, but also harvestmen, appropriately-named arachnids for their season of abundance. You may know them as "daddy long-legs," but that name is widely applied to cellar spiders, even crane flies (in England at least). The one shown below is likely Phalangium opilio, a much-studied species native to Europe but now found all over the globe. They can survive the winter as eggs, adults, or immature specimens.

Harvestman: not a spider but still an arachnid

Fall is apparently also a time when young spiders disperse through "ballooning." I will eventually devote an entire post to this phenomenon, but it involves the spiders climbing up vertical objects. Consequently, you can reliably find spiders atop fence posts, mailboxes, utility boxes (for cables, electrical, phone), as they try and catch the wind and literally fly off to greener pastures. Crab spiders and wolf spiders in particular seem to be doing this right now. The little wolf spider below parachuted onto our car at Bosque del Apache in New Mexico.

Little wolf spider on our car roof

Just the other day (Friday), I found a young running crab spider, Thanatus sp., on a utility box here in Colorado Springs.....

Running crab spider, Thanatus sp.

followed by a ground crab spider, Xysticus sp., on top of a "stucco" mailbox post. Both seemed intent on ballooning, especially the Xysticus, which stood on tiptoe (tip-tarsus?) every time a slight breeze came up.

Xysticus crab spider

Finally, inside our very townhouse, Heidi discovered a female funnelweb weaver, Hololena sp., in her web atop our fireplace mantle.

Funnelweb weaver, Hololena sp.

We welcome our arachnid friends, even indoors, to help dispatch pesky flies and other insects that we don't appreciate nearly as much. We hope that your own holiday spirit of friendliness likewise extends to spiders, harvestmen, and related critters, even if it means you gently "relocate" them back outdoors.

Thursday, November 6, 2014

Large-headed Grasshopper

I am fortunate to be surrounded by a community of entomologists with a collectively vast knowledge of insects and arachnids, and I meet more of these scholars seemingly every week, at least in the digital world of listservs and social media. I owe it to one such expert, Dr. Charles Bomar, for the identification of the fortieth (40th) species of grasshopper that I have now seen in Colorado Springs alone: the Large-headed Grasshopper, Phoetaliotes nebrascensis.

I encountered the critter on the Rock Island Trail, a concrete bike path through residential and commercial areas in eastern Colorado Springs, on October 26 as my wife and I were walking our dog. I snapped only two images, figuring this was something already familiar, in the genus Melanoplus.

Consulting book and online resources at home I was surprised I couldn't find an immediate match. So, I posted the image shown above to the Orthopterist's Society group page on Facebook. Almost immediately I received an answer from Dr. Bomar. He went on to suggest even more important references that I should have, including a link to one of them.

This is the kind of "above and beyond the call of duty" that is typical of most professional entomologists who consider it an obligation to interact with amateurs and the general public. I, for one, am eternally grateful, and could not produce this blog without their help.

Back to the grasshopper. Phoetaliotes nebrascensis is found in places other than Nebraska, ranging widely from southern Alberta, Saskatchewan, and Manitoba to extreme northern Mexico; and from eastern Washington and Oregon, the northeast corner of California, east to the northern half of Texas, Missouri, and Illinois to southwest Michigan, southern Wisconsin and Minnesota.

Adult specimens are most often found from late July through October, at least here in Colorado.

The mature insect measures 21-25 millimeters (males) or 23-33 millimeters (females), and typically has only very short front wings, missing the hind pair of wings entirely. They are therefore frequently confused with subadult specimens of other species. Occasionally there are fully-winged males of the Large-headed Grasshopper, but it is unusual to find them.

The color pattern of this species is so similar to other species that one cannot readily distinguish them based on those variable characters. Once again it is the shape of the male genitalia at the tip of the abdomen that is useful in identification. An overhead or rear view of the entire insect will, however, reveal the swollen head that gives this species its name. The head is noticeably wider than the thorax.

The Large-headed Grasshopper can be common in a variety of habitats, even being a dominant species, especially in tallgrass prairies. Both grasses and broadleaf herbs are on its menu, but it seems to prefer rangeland grasses. It is considered a low-grade pest at worst, but is usually inconsequential. It prospers with spring rains, populations rising dramatically under such conditions.

I can hardly wait to see what "new" grasshoppers turn up next year here in the Springs. There are some that I know occur here that I just haven't seen yet, so my bugwatching list is sure to grow.

Sources: Capinera, John L., Ralph D. Scott, and Thomas J. Walker. 2004. Field Guide to Grasshoppers, Katydids, and Crickets of the United States. Ithaca, NY: Comstock Publishing Associates (Cornell University Press). 249 pp.
Capinera, J.L. and T.S. Sechrist. 1999. Grasshoppers (Acrididae) of Colorado: Identification, Biology, and Management. Fort Collins: Colorado State University Experiment Station Bulletin 584S.
Johnson, Dan L. 2008. Grasshopper Identification and Control Methods to Protect Crops and the Environment. Ottawa: Agriculture and Agri-Food Canada.

Sunday, November 2, 2014

Black Carpet Beetles, Attagenus spp.

Among the more common household pests you are likely to encounter are the Black Carpet Beetles in the genus Attagenus, family Dermestidae. They are slightly larger, more oval, and jet black compared to the usually more abundant Anthrenus carpet beetles, but they share similar feeding habits.

Adult Black Carpet Beetle

There are nine species of Attagenus known from north of Mexico. Most are about 3-5 millimeters in length as adults. The larvae are distinctive in being tapered from front to back, with a bundle of long hairs extending from the rear end. At maturity the larva is about 9.5-12.7 millimeters, excluding the "tail" of hairs.

Larva of Black Carpet Beetle

As is the case with other carpet beetle larvae, the hairs can cause dermatitis in some people. The patient may frequently interpret the symptoms as insect "bites," resulting in misdiagnosis by physicians. It usually takes years of exposure to carpet beetle infestations to begin exhibiting reactions, but in rare instances, inflammation of the respiratory tract and eyes can also occur.

While the larvae feed mostly on dried animal products such as shed hair and skin cells from people and pets, wool garments and blankets, silks, furs, animal hides, and dead insects that collect in spider webs, light fixtures, and along window sills, they also consume dried plant matter on occasion, especially cereals and grains. So, they can be a pantry pest as well as a clothes closet pest.

Adult Attagenus feed on flower pollen

Control and prevention of a Black Carpet Beetle infestation is best achieved by thorough cleaning of one's domicile, through vacuuming up accumulated pet hair, and dust (most of which is flakes of dead skin from people and pets). Discard any infested items. Outdoors, remove abandoned mammal, bird, and wasp nests. Understand that despite all your efforts, it is next to impossible to become immune to the occasional infestation.

Insects are incredibly adept at exploiting human behavior and household ecosystems. Few are as efficient as Black Carpet Beetles when it comes to scavenging our food and clothing. They are to be despised, no doubt, but also admired for their adaptability.

Sources: Evans, Arthur V. 2014. Beetles of Eastern North America. Princeton, NJ: Princeton University Press. 560 pp.
Gahlhoff, Jerry G., Jr. 2013. "Black Carpet Beetle," Featured Creatures. Entomology and Nematology, University of Florida/Institute of Food and Agricultural Sciences. Publication Number EENY-18. Note the image of the adult beetle depicts a Dermestes species, not Attagenus.
Jacobs, Steve. 2010. "Carpet Beetle Dermatitis," Insect Advice from Extension. College of Agricultural Sciences, Pennsylvania State University.
White, Richard E. 1983. A Field Guide to the Beetles of North America (Peterson Field Guides). Boston: Houghton Mifflin Company. 368 pp.