Thursday, February 27, 2014

Red-headed Bush Cricket

When you think of a cricket, a robust blackish or brownish insect probably comes to mind. Maybe you imagine the classic “cricket on the hearth,” cheerfully “chirp-chirp-chirping” from some concealed location indoors or outside. You might be surprised to learn that crickets in the family Gryllidae come in a variety of forms, with a corresponding diversity in song. The Red-headed Bush Cricket, Phyllopalpus pulchellus, is a delicate, diminutive, and colorful creature with a trilling song.

Male

This species is active both day and night, and at first glance may be mistaken for some other kind of insect. Adults are only 7-9 millimeters in body length, and they crawl over foliage well off the ground in contrast to the more lumbering, ground-dwelling field crickets that are more familiar.

Females have unmodified front wings, and a sickle-like ovipositor jutting from the rear of the abdomen. Males have the front wings modified for producing a shockingly loud, high-pitched calling song. His wings are asymmetrical in venation, and the left one with a clear spot in the middle.

Female

He elevates his front wings to a nearly vertical position, and often selects a “stage” where two leaves come close together. This configuration helps amplify and project his song.

Phyllopalpus pulchellus is also known as the Handsome Trig, and indeed it is sharply-dressed. Both genders are easily recognized by their bright red, black, and yellow color pattern. Their mouthparts include palps, like most other insects with chewing mouthparts, but the terminal segment is conspicuously broadened. It gives them the appearance of having “boxing gloves” that are in constant motion as the insect senses the chemical properties of the surfaces they roam across.

This is a common insect that ranges from southern New England to northern Florida and west to the eastern borders of Kansas, Oklahoma, and Texas. Look for the adults in July, August, and September in low shrubs and bushes.

I have had success finding the Red-headed Bush Cricket simply by scanning various plants, whether the creature is singing or not. It does helps to know what they sound like, though, so take a listen to the digital recording on the ”Singing Insects of North America” website. In my experience, the song is even more shrill than it comes across in the recording.

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.
Elliott, Lang and Wil Hershberger. 2006. The Songs of Insects. Boston: Houghton Mifflin Company. 228 pp.

Tuesday, February 25, 2014

Striped Pine Scale

Scale insects are abundant true bugs, but they may be the most overlooked of all insects. Quite frankly, they don’t look anything like insects. The females are nearly or entirely sedentary, and usually covered by a waxy shell or coating secreted by the insect. The overall impression is one of an aberration in the growth of the host plant, or perhaps an insect gall, or a snail or other mollusk. Such is the case with the Striped Pine Scale, Toumeyella pini.

I found the immature female specimens shown here on an ornamental pine in my Colorado Springs neighborhood on November 1, 2011. It is these females that overwinter, their shell-like dorsal surface protecting them from the elements. This was actually one of two species of scales attacking the tree. The much smaller, silky white ovals are pine needle scales in the genus Chionaspis (family Diaspididae).

The Striped Pine Scale is one of eighteen known species in the genus Toumeyella. It is native to the U.S. and Canada where it is considered a pest species. The hosts are pines, mostly two- and three-needle species (needles bundled in twos or threes).

Like other scale insects, aphids, and many other sap-sucking bugs, T. pini secretes copious amounts of a liquid waste product called “honeydew.” This sweet, sticky substance is highly attractive to ants, wasps, bees, and flies. In fact, the presence of a scale insect infestation may first be betrayed by large numbers of yellowjackets swarming over an affected pine tree.

Excessive honeydew deposits also breed sooty mold, which can turn needles and branches black, inhibiting photosynthesis and further weakening a tree.

The active stage in the life cycle of the Striped Pine Scale is the youngest nymph stage, known as a “crawler.” Crawlers are very tiny, emerging from the eggs in late May or early June. They may hitchhike to new host trees via insects, birds, mammals, people, or gardening tools and machinery.

Crawlers gravitate toward new growth on a tree, settling in after only a day or two. They molt (shed their exoskeleton), losing their legs and acquiring longer mouthparts. Female crawlers attach to the twigs, while male crawlers settle on the needles. The male scales are much smaller, and more elongate in shape, than the females shown in these images.

After that first molt, the female insects will not move again. Males mature in late summer, sprouting wings and flying to females. They mate with immature females, and those females overwinter in diapauses (not feeding). There can be more than one generation in the southern reaches of their range, up to three generations per year in Georgia.

In the crawler stage, the Striped Pine Scale is preyed upon by lacewing larvae and lady beetles. The adult female scales are eaten by the moth caterpillar Laetilia coccidivora (family Pyralidae), and both male and female scales are parasitized by the tiny chalcid wasp Coccophagus lycimnia (family Aphelinidae), at least on Loblolly Pine in Georgia (Clarke, et al., 1989). House Finches, Yellow-rumped Warblers, and other birds also feed on these scale insects.

This species ranges widely east of the Rocky Mountains, and is generally more abundant in the northern tier of states. It has only recently reached a problematic status along the Front Range here in Colorado. Infestations of bark-infesting woolly aphids (Pineus spp.) appear to be associated with Striped Pine Scale infestations, perhaps making trees more susceptible to attack.

Scotch Pine and Lodgepole Pine appear to be the most favored hosts for T. pini, but many other pines are subject to infestation as well. Look for the female scales, highly convex and about 6 millimeters across, on the terminal twigs of the host trees.

Sources: Clarke, Stephen R., Gary L. DeBarr, and C. Wayne Berisford. 1989. “The Life History of Toumeyella pini (King) (Homoptera: Coccidae) in Loblolly Pine Seed Orchards in Georgia,” Can. Entomol. 121(10): 853-860.
Cranshaw, W.S. 2013. “Scale Insects Affecting Conifers,” Colorado State University Extension Fact Sheet No. 5.514.
Cranshaw, Whitney. 2004. Garden Insects of North America. Princeton, NJ: Princeton University Press. 656 pp.
Williams, M.L. and T. Kondo. 2009. “Status and current composition of the soft scale insect genus Toumeyella (Hemiptera: Coccidae),” Proc. Of the XI International Symposium on Scale Insect Studies. 29-32.

Saturday, February 22, 2014

Review: Pollinators of Native Plants

Newly-minted U.S. citizen Heather Holm didn’t wait for official government recognition before delivering a gift to her fellow Americans. Seriously, she became a citizen just last Tuesday. Earlier in the month her self-published book Pollinators of Native Plants rolled off the printer at Hillcrest Media Group in Minneapolis, Minnesota. The title does not do the book justice, as this is a comprehensive primer on garden ecosystems and how to create them.

Heather’s background in graphic design serves her well in the unique organization and layout of the book. When I hear “self-published” I often expect poor paper and image quality, and an overall substandard product. That is most definitely not the case here. Images are sharp, the paper durable, and the cover is glossy and professional. There is no obvious compromise for cost-savings and the retail price of $29.95 is perfectly reasonable.

Beyond production values, this book is a labor of love for native plants and the insects and other arthropods that thrive in a well-designed and nurtured garden. Heather observed, documented, and photographed her own garden for a decade before fusing her findings with other researched information to yield the book.

Not only is the text accurate, the information is communicated in a user-friendly manner that does not talk down to a novice, or disrespect the experience and knowledge of an entomologist or botanist. This is a fine line to walk and Holm does it beautifully. Scientific terms are defined when they are first introduced, but there is also a glossary in the back. All the organisms imaged, as near as I can tell, are identified accurately, even if that means only to genus, tribe, or family. This is important because not every creature can be identified to species from a photo.

What I find truly unique about this book is that the author recognizes that a garden is an ecosystem. The gardener is a steward who works best when he or she understands how nature is working. So, Holm makes it known that not all pollinators are created equal. Most, in fact, are “flower visitors” in search of nectar. Those insects play other important roles, however, as predators, parasites, and parasitoids of pest and nuisance insects. The inclusion of those “other” bugs makes the book an invaluable resource all by itself.

Taking those complex relationships and making them understandable is a gift, but making them relevant to a gardener and homeowner is even more challenging. Again, the author succeeds. She goes on to furnish concrete action plans that can be used to enhance pollinator conservation, increase the value of the garden to surrounding wild ecosystems, and making the garden blend seamlessly with those natural areas.

The bulk of the book explores native plant and insect interactions for three basic landscapes: prairie, woodland edge, and wetland edge. It should be noted that the regional focus of the book is the upper Midwest (Great Lakes, plus Iowa, Minnesota). A typical two-page spread looks like this:

One page discusses the plant, while the opposite page explores the range of pollinators, flower-visitors, and/or predators and parasites, even herbivores, that one is likely to encounter on the plant. Additional, following pages may also be devoted to those relationships. Most of the insects have their own “pollinator profile” or similar biography in the far-right column on the appropriate page.

References, charts, and a visual index of the insects are located in the back of the book, along with examples of native plant garden diagrams, and the glossary and traditional index.

It is a joy to be able to recommend a book like this that embraces more than just plants and their pollinators; and that empowers the gardener to work with nature rather than in spite of Her.


Please see more about this book at its dedicated website, and make your purchase there, too. Authors are notorious for investing any extra income in their next project, and I certainly hope Heather Holm will continue to produce such valuable literature far into the future. Meanwhile, you will want to follow her blog, Restoring the Landscape With Native Plants.

Thursday, February 20, 2014

Fork-tailed Bush Katydid

I vividly recall an episode in my childhood that perhaps cemented my fascination with insects. I must have been somewhere between eight and eleven years old. One afternoon in late summer I heard an insect calling at regular intervals from a rhododendron bush outside the front door of our Portland, Oregon home. I finally tracked down the creature and discovered it was a male Fork-tailed Bush Katydid, Scudderia furcata. What happened next I shall relate later in this post.

I did not know at the time what kind of katydid I was observing. Years later I discovered E. O. Essig’s book Insects of Western North America in our public library and found the species there. Indeed, it was virtually the only option for western Oregon, Washington, and southern British Columbia.

Eight species of bush katydids in the genus Scudderia are now recognized in the United States and southern Canada. The Fork-tailed Bush Katydid is by far the most widespread, being transcontinental in its geographic distribution. Still, in most regions it is next to impossible to separate from other species.

The only reliable way to differentiate Scudderia species is by the shape of the “dorsal process” or “supra-anal plate” in adult male specimens. This horn-like feature juts out of the top of the abdomen at the rear. Another structure, the “sub-genital plate” curves up from below to meet the supra-anal plate. The sub-genital plate may at first be mistaken for an ovipositor, an organ found only in female katydids.

Not surprisingly, the shape of the dorsal process in the Fork-tailed Bush Katydid is, well, fork-like. It looks like a miniature tuning fork, as revealed in the image above. Images of wild, living male bush katydids are usually impossible to identify to species because the folded wings usually conceal the supra-anal plate.

Males also possess the “file and scraper” modifications on the “shoulders” of their front wings. These are the structures they rub together quickly to produce songs. Bush katydids typically rasp a short, intermittent call: s-s-s-s-s-S-S-S-T. This discontinuous song no doubt helps prevent predators from pinpointing the location of the insect.

Back to the opening story. I saw the male katydid produce its song, and in short order a female flew in to join him. Both genders, once close to each other, will talk in soft “ticks,” but I do not recall them having such a conversation. The next thing I knew, the two were in copula, “tail-to-tail.” I watched in horror as I saw a white, gelatinous mass oozing from between the two. When they finally separated, it appeared the female had been torn open and was losing her innards.

I learned much later in my life that the male was the source of this mass. Male katydids and related orthopterans transfer a protein-rich spermatophore in the process of inseminating a female. She consumes this object while the male’s sperm enter her oviduct.

Scudderia sp. female

Fertilized female bush katydids use their curved, knife-like ovipositors to insert eggs between the layers of a leaf, at the leaf’s edge. The result is a kidney bean-shaped bulge in the leaf. A female can lay up to 175 eggs, but deposits a small quantity at each location. The following spring, a tiny katydid emerges from each egg.

Scudderia sp. nymph

Nymphs go through six instars (an instar being the interval between molts), gradually accruing wing pads and both internal and external reproductive organs. They are general feeders on the foliage of shrubs. They are sometimes considered a pest in orchards and citrus groves when populations build to high levels (Bentley, 2002 and Headrick, 2000).

Adult S. furcata are 36-40 millimeters from the head to the tips of the folded wings, so they are not small insects. Still, they are incredibly well camouflaged. Most specimens are wholly green, but late-autumn specimens are correspondingly brownish, reddish, or even pink. They are most active at night, and are sometimes drawn to outdoor lights. Both sexes fly well.

Katydids in general are among my favorite insects, and I can’t help but wonder if that mating pair forever endeared them to me. Keep a listen for katydids in your own yard, garden, or neighborhood park. See if you can tell different species apart by their songs. Search with a flashlight and you will eventually find one of these amazing insects.

Sources: Bentley, Walt. 2002. “Researching Biology and Control of Forktailed Bush Katydid (Scudderia furcata Brenner) and Western Spotted Cucumber Beetle (Diabrotica undecimpunctata howardi Barber) in Stone Fruits,” California Tree Fruit Agreement Research Report 2002 .
Bland, Roger G. 2003. The Orthoptera of Michigan – Biology, Keys, and Descriptions of Grasshoppers, Katydids, and Crickets. East Lansing: Michigan State University Extension, Extension Bulletin E-2815. 220 pp.
Elliott, Lang and Wil Hershberger. 2007. The Songs of Insects. Boston: Houghton Mifflin Co. 228 pp (and a CD).
Headrick, David. 2000. “Fork-tailed Katydid Studies,” Citrus Research Board 2000 Annual Report.
Helfer, Jacques R. 1972. How to Know the Grasshoppers, Cockroaches, and Their Allies (Second Ed.). Dubuque, IA: Wm. C. Brown Company Publishers. 359 pp.