Thursday, December 4, 2014

Family Emergency

Posts to this blog will not be happening for awhile. Back in late June, my mother was diagnosed with lung cancer at age 84. Within the last two weeks, the illness has become drastically worse. I am going to have to take leave to go help take care of her for an indeterminate period of time.

My parents divorced, not amicably, when I was about ten years old. I am an only child. Consequently, all matters like this fall upon me. Mom still lives in Portland, Oregon, where I grew up. I now live in Colorado Springs. My best friend from high school has, amazingly, taken it upon himself to help her in my absence, taking her to various appointments, keeping her company socially, and all the things I probably should be doing myself. I will be forever grateful to him for being there.

What scares me the most right now are the expenses that will be associated with any care (though she qualifies for most government aid), my meals, transportation, and other expenses while away from home, plus final expenses for mom, the shipping and storing of her household, etc. I honestly have no idea how I'm going to cover it all.

My mother does not have the internet, and I do not have a "smart phone," so I politely ask that you do *not* leave comments on this post. I will not be able to moderate and approve them in a timely manner. Thank you for your understanding and patience.

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