It's Always Something....

To quote the lovely Ms. Rosanne Roseannadanna, "It just goes to show you, it's always something." It may take months, even years, to learn that something you observed and recorded is noteworthy, or potentially so. Such was a recent case in which an image I posted on Bugguide.net was finally identified, more or less, leaving still more questions than answers.

November 27, 2014, Thanksgiving Day in the U.S., I was at the Cheyenne Mountain Zoo where my wife works as a primate keeper. The zoo restaurant staff caters a holiday lunch, and employees bring potluck dishes to supplement. Before and after the feast, I was out looking for insects, as the weather was reasonably conducive to finding late autumn macro-fauna.

On a wooden fence railing I spotted what at first I thought might be an aphid. Upon closer inspection, it was an aphid relative known as a "jumping plant louse" or psyllid. This is a tiny insect. Total body length is only 2.6 millimeters, or 4-4.5 mm if you measure from head to wingtip. It varies from light green to greenish gray.

Psyllids were once lumped into a single family, but research has shown that there are several families. A few species are very abundant and conspicuous, like hackberry psyllids. A few others are economically impactful, especially in orchard crops. The remaining majority are poorly known, keeping a very low profile on native plants.

The image I uploaded to Bugguide understandably floundered in obscurity until February 2 of this year when I received notification that someone had left comments and even moved the image into genus-level classification. I was grateful, but also surprised by the comments left by Chris Mallory:

"Bactericera nr. arbolensis
In nearly every regard it is consistent with this Shepherdia-associated species originally described from Arboles, CO. However, the medial cell of the forewing is much smaller than described and illustrated, and in this aspect it does not agree with any known described species.
There could be several reasons for this. First, the size of the medial cell of B. arbolensis may be more variable than the literature suggests. Alternatively, this may be an undescribed but related species. In either situation it is a very interesting find. I'd love to see more of them."

Wow. Chris Mallory is an expert on the superfamily Psylloidea; and is also one of the individuals behind the comprehensive online guide SoCalFauna.net, a photographic gallery of most of the animals one is likely to encounter in southern California.

Thanks to the in-depth profile page at Chris's Psyllids.info website, I learned that the species he thinks it might be is known from Silver Buffaloberry, Shepherdia argentea and Canadian Buffaloberry, Shepherdia canadensis. Neither of those plants is very common, if found at all, along the Front Range of Colorado. It is, however, conceivable that the zoo landscapes with one or both of them, so I will have to check out that possibility. Meanwhile, there are few literature records of the psyllid itself: MONTANA: Roosevelt County; WYOMING: Sweetwater County: Green River; COLORADO: Montrose County: Cimarron; LaPlata County: Durango; Archuleta County: Arboles. All but the Montana record are from west of the Continental Divide. The type specimens, those from which the insect was described and named, were 3 males and 4 females collected by C.F. Baker in Arboles.

There are 24 known species of Bactericera found in North America north of Mexico, and mine is potentially a twenty-fifth. This just goes to show you, you never know what you might turn up if you point your gaze, and camera or phone, at a yittle, teeny-tiny bug.

Sources: Crawford, D.L. 1914. A Monograph of the Jumping Plant-lice or Psyllidae of the New World. 85: 186 pp. Government Printing Office, Washington, DC.
Tuthill, L.D. 1943. "The Psyllids of America North of Mexico: (Psyllidae: Homoptera)," Iowa State College Journal of Science. 218 pp.

In Praise of Aphids and Scales

When the flowers of autumn are gone, when even the asters are fading fast, where is a wasp or bee or butterfly to go for sustenance? The answer may surprise you, and turn your concept of what is a "pest" on its head.

Highly active, flying insects like bees, wasps, flies, moths, and butterflies rely on high carbohydrate resources like flower nectar to fuel their vigorous lifestyle. When those normal floral resources are no longer available, the insects must travel down other avenues. Fallen, fermenting fruits are one solution. The high sugar content of an apple, pear, or peach beginning to rot does not go overlooked by yellowjackets and paper wasps in particular.

Western Yellowjacket with conifer aphid at center left and Pine Needle Scale at center right

Pomes and other fruits are not, however, the answer to autumn insect nutrition. The overwhelming majority of sweet, sugary carbs are provided by other insects, namely aphids and scales. At this time of year, aphids in particular are feeding on plant sap in earnest, and excreting copious amounts of liquid waste called "honeydew." Infested trees are literally dripping with honeydew, and a great diversity of other insects are drawn to this equivalent of the corner bar.

Conifer aphids and their shocking large eggs

Many aphid species are also transitioning to alternate host plants for the coming winter. This is why you see so many aphids on the wing, landing on your plate at the tailgate party, and otherwise providing a tiny but prolific nuisance to outdoor activities. The aphids thus need their own fuel, and it takes a ridiculous amount of plant sap to yield that result. Xylem and phloem are notorious for being nutrition-poor, so sap-sucking insects cycle those products rapidly through their digestive systems. Liquid honeydew comes out as fast as sap is going in.

Even this Painted Lady butterfly is enjoying aphid honeydew

Social wasps tend to dominate the scene at fall aphid colonies. Because the wasp colonies are winding down, if not finished altogether, their paper palaces have emptied totally and there are now vastly more individual wasps out in the field than there were earlier in the year when many workers were inside the nest feeding the larvae, building new cells in the comb, and engaging in other housekeeping chores. With no purpose left to serve except their own individual survival, worker yellowjackets might qualify as unstable or mentally-ill were they human beings.

A blow fly literally getting its licks in

Meanwhile, flies, the normal prey of many social wasps, are free of worry from the purposeless wasps and fearlessly rub shoulders (humeri?) with them at the aphid honeydew banquet. The aphids themselves are still vulnerable to flower flies (family Syrphidae) that lay their eggs in the colonies. The fly larvae that hatch eagerly feast on the aphids, along with lady beetle larvae and lacewing larvae.

Larva of a syrphid fly that preys on aphids

Here in my Colorado Springs, Colorado neighborhood, ornamental conifers seem to be real aphid magnets. The trees are no doubt at least a little weakened by their circumstances of planting, isolated from other trees in soils that are not always compatible; and maybe (probably?) minus the symbiotic fungi they need to help them get their own complete nutritional requirements.

Striped Pine Scale on ornamental pine

Scale insects, too, afflict these pines, firs, and spruces. Scale insects are relatives of aphids, but are even more sessile, often covered in a hard, waxy shell secreted by the insect. The "lump" is thus a living lid over the insect that created it. Like aphids, scales secrete honeydew as a waste product. If you are unaccustomed to recognizing scale insects, it is easy to be perplexed by the wasp and fly activity. Even butterflies and moths will be flitting around inexplicably.

A tiny ichneumon wasp visits the honeydew saloon

So, the aphid colony is a bustling place at this time of year, the last epicenter of "bug" action before the leaves finally fall and the killing frosts finish off those insects still commanding our attention. They still survive, of course, hidden from view, often in life cycle stages we would not recognize as insects until spring returns them as such.

The yellowjacket trap at bottom right was not nearly as attractive as the "aphid tree" next to it

Enjoy this last hurrah of bugdom. You can easily approach the buzzing horde without fear, so intent are they on feeding. Worry not of stings, though be careful where you reach and step. This is no season to be barefoot to be sure.

Hackberry Psyllids: A Fixture of Fall

Sometimes, it is easier to identify an insect by the evidence it creates than by seeing the bug itself. Such is the case with the abundant, but tiny, hackberry psyllids, genus Pachypsylla in the family Psyllidae and true bug order Hemiptera. Psyllids are also known as "jumping plant lice" for their resemblance to aphids and ability to vault themselves away from danger.

Along one of the streets that borders our townhouse complex in Colorado Springs are a pair of hackberry trees, among the few planted ornamentals that are not oak, maple, or elm. They are invariably exploited every summer by Pachypsylla celtidismama, which produces "nipple galls" on the underside of hackberry leaves. The small, tumor-like growths do not seem to affect the health of the tree in the least, but provide housing and food for the tiny insect within each one. Up to 52 galls have been found on a single leaf (Caldwell, 1938), and they vary from smooth in texture to rather hairy. Double and triple galls are not unheard of, but it is rare to find more than one nymph occupying each gall.

The adult stage of hackberry psyllids will start appearing shortly, if they are not emerging already. Adults of P. celtidismama are only 3.5-4.5 millimeters in length from "nose" to the tips of the folded wings. They resemble tiny cicadas, but can also be confused with barklice, order Psocodea. Barklice have chewing mouthparts, though, while psyllids in general have beak-like piercing-sucking mouthparts they use to tap plant sap.

Hackberry psyllids make themselves a real nuisance when they start seeking nooks and crannies in which to hibernate. They can gather by the dozens, if not hundreds, on the exterior of doors, window screens, and the siding of homes. They pose no threat, of course, and simply hosing down the masses with water will solve the problem. The appearance of these insects en masse is a brief affair anyway.

A different Pachypsylla species

Next spring, female psyllids will deposit eggs on the leaves of hackberries at the precise time when the leaves begin unfolding from the bud. Should a psyllid deposit her eggs too early, or too late, and the chances of successful development of her offspring plunges dramatically.

The formation of the bulging gall is the tree's response to the feeding of the nymph that hatches from the egg. The little dome-like pocket insulates the nymph from hostile abiotic environmental factors, and protects it from at least some predators and parasites. The nymph goes through five stages, the last instar illustrated in the images below. Note the two pairs of developing wing pads. The spike-like projections on the rear of the insect will help it to cut an exit in the gall before it emerges as an adult.

Nymph of P. celtidismama © Hannah Nendick-Mason via Bugguide.net

Nymph of P. celtidismama © Hannah Nendick-Mason via Bugguide.net

Despite their seemingly impenetrable fortress, the nymphs are still vulnerable to tiny parasitic wasps, including Psyllaephagus spp. (family Encyrtidae), and Torymus spp. (family Torymidae). The larval wasps feed as parasites on the nymphs and then chew their way out of the gall once they complete development.

Psyllaephagus sp. © John Rosenfeld via Bugguide.net

This, and the other six species of hackberry psyllids, range pretty much wherever hackberry occurs naturally, and increasingly where it is used as an ornamental tree. The different species of psyllids make correspondingly different styles of galls, so it is easiest to assess the gall shape, size, and location to determine which psyllid is responsible. Keep in mind that gall midges (family Cecidomyiidae) can also create galls on hackberry.

You might try rearing a few galls to see what parasites emerge along with the adult psyllids. It is entirely possible you could record a new host record in the process.

Sources: Berenbaum, May R. 1989. Ninety-nine Gnats, Nits, and Nibblers. Urbana: University of Illinois Press. 263 pp.
Caldwell, John S. 1938. "The Jumping Plant-lice of Ohio," Ohio Biological Survey Bulletin 34, vol. VI, No. 5: 229-281.
Winterringer, Glen S. 1961. "Some Plant Galls of Illilnois," Story of Illinois Series No. 12. Urbana: Illinois State Museum. 51 pp.

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.