Brood X encore, billions of cicadas? Not this time – Straggling cicadas of Brood X, Magicicada spp.

 

Guess who you might see in the next few weeks in your neighborhood, Brood X stragglers!

 

Last May in 2021 cicada lovers exulted in the arrival of billions of periodical cicadas in the eastern United States. By mid-June as the party wound down, they bemoaned the fact that in most of the DMV these strange and magnificent creatures would not return until the spring of 2038. But guess what, last week on an early morning walk on a trail in Columbia, MD, I was surprised and delighted to encounter a freshly molted male pharaoh periodical cicada, Magicicada septendecim, scaling a gnarly ancient red maple tree. Nearby beneath the same tree, a second male dodged running shoes and bicycle tires roaring down the asphalt. My sightings mirrored reports of cicada sightings in more than a dozen states in the eastern half of the US. These off-cycle sightings of a few periodical cicadas are part of the ongoing mystery surrounding one of Nature’s most magical creatures. Before local cicadaphiles get their hopes up too high and cicadaphobes start packing to leave town, please know that this is not the full-blown cicadapalooza of 2021. Brood X cicadas will be seen throughout the land but at densities many orders of magnitude less than those seen last year.

Against the background calls of Canadian geese and mallard ducks, a male Brood X cicada scales an ancient maple tree in the early morning light. Watch as this lonesome bachelor avoids entanglement in a spider’s web. Instinct drives his quest to find a mate. Little does he know that his chances of passing along his genes to the next generation are between slim and none.

In several states in the eastern half of the US, shed skins appearing on plants in your landscape during the next several weeks are likely those of straggling Brood X cicadas.

Cicada experts call sightings of a few cicadas in “off” years, cicada “stragglers.” Stragglers are periodical cicadas that emerge in years prior to or after the year that massive numbers of their broodmates are expected to emerge. Often, 17-year cicada stragglers emerge four years prior to their expected emergence date; however, it is possible for periodical cicadas to emerge between 8 years earlier or 4 years later than expected. Based on historical data, researchers can associate stragglers with their massive parent brood. The map accompanying this episode provides scientifically vetted accounts of actual sightings of periodical cicadas in our region this spring. This wonderful event has entomologists eager to add new information to our knowledge of these inimitable creatures. Experts believe that part of the straggling phenomenon is genetic while environmental factors, such as the quality of the host tree immature cicadas dine on while underground, contribute to the appearance of stragglers. Sadly, densities of stragglers in an area rarely achieve a quorum great enough to overwhelm hungry predators and other foes, and their unfortunate off-cycle appearance leads to oblivion for their progeny.

This recent map compiled from data sent to iNaturalist and Cicada Safari apps shows locations where Brood X cicada stragglers are likely to be seen this spring. Credit: Gene Kritsky, Mount St. Joseph University

Cicadaphiles, don’t despair, as this spring provides one more chance to enjoy cicadas and to help scientists learn more about these creatures. You can participate in the highly successful community science project that resulted in hundreds of thousands of data points last year by joining the Cicada Safari. To be part of the action, go to the app store on your cellular phone and download the Cicada Safari app. It is free and very easy to use. Download, register, and start snapping pictures of cicadas. Easy as pie. Cicada geniuses will vet your images and add them to a growing data base designed to demystify the seasonal phenology and distribution of these charismatic creatures. On this Memorial Day Holiday and over the next several weeks as you enjoy parades, cookouts, and adventures in the great outdoors, keep your cell phones handy, eyes open and ears on the ready, and snap some shots of straggling Brood X cicadas.

Acknowledgements

We thank Dr. Gene Kritsky of Mount St. Joseph University for providing the nice map of recent cicada sightings and for providing inspiration for this episode. To learn more about magical periodical cicadas, please visit the fabulous repository for all things cicada at Cicada Mania and search the archives at Bug of the Week for “cicada.” To read John Kelly’s take on tardy cicadas here in the DMV in the Washington Post, please click on this link:  https://www.washingtonpost.com/dc-md-va/2022/05/22/cicadas-emerging-broodx/. The wonderful fact-filled review of cicada biology and ecology, “Advances in the Evolution and Ecology of 13- and 17-Year Periodical Cicadas” by Chris Simon, John R. Cooley, Richard Karban, and Teiji Sota was consulted for this episode.

Williamsita | Catalogue of Organisms

A while back, I wrote a post about the crabronid wasp genus Podagritus. This time, I'm going to cover another crabronid genus found here in Australia: Williamsita.

Williamsita sp., copyright David Francis.

Like Podagritus, Williamsita species are boldly coloured wasps, typically mostly black with contrasting yellow or orange markings. They differ from Podagritus species in being more robust with the base of the gaster not notably pedunculate. Other distinguishing features include the presence of distinct foveae (pits) against the margins of the eyes (occasionally less distinct in males), thirteen-segmented antennae in males, and a pygidial plate in both sexes that is narrowed and concave in females, quadrate in males. Williamsita species also do not have the palps reduced as in Podagritus, instead having the more typical arrangement of six segments in the maxillary palps and four segments in the labial palps (Bohart & Menke 1976).

To date, eleven species have been recognised in the genus Williamsita (Leclercq 2006). Most are found in Australia with a single species each known from New Caledonia and Vanuatu. Leclercq (1950) suggested dividing the genus between two subgenera with all species except the New Caledonian type species W. novocaledonica forming a subgenus Androcrabro. Features supporting the latter taxon included the presence of ventral notches on one or more segments of the antennae in males. However, Leclercq later suggested abandoning such a formal division, questioning its significance (Leclercq 2006). The Australian species of Williamsita are, nevertheless, distinct from the two insular species in being marked with much stronger punctation over the body.

Most Williamsita species remain little seen and poorly known. However, breeding habits have been recorded for two Australian species, W. bivittata and W. tasmanica (Maynard & Fearn 2021; McCorquodale et al. 1989). Both these species nest in branching holes in rotting wood, either commandeering burrows left by wood-boring insects or excavating their own. Prey consists of larger flies such as blow flies or soldier flies which were carried back to the nest by the wasp running with the fly carried below the body. Up to six paralysed flies might be placed lying on their backs in a nest cell with an egg laid across the 'throat' (i.e. at the joint between head and thorax) of one of the flies. The cell would then be closed with a plug of woody frass. McCorquodale et al. (1989) recorded W. bivittata constructing several such cells in a series along a single tunnel, whereas Maynard & Fearn (2021) found W. tasmanica more likely to place a single cell in a side-branch. As both observations were limited to a single location in a single season, though, one might reasonably question whether these represent true differences in species behaviour or were determined by available conditions. There's a limit to how deep a Williamsita can burrow.

REFERENCES

Bohart, R. M., & A. S. Menke. 1976. Sphecid Wasps of the World. University of California Press: Berkeley.

Leclercq, J. 1950. Sur les crabroniens orientaux et australiens rangés par R. E. Turner (1912–1915) dans le genre Crabro (subgenus Solenius). Bulletin et Annales de la Société Entomologique de Belgique 86 (7–8): 191–198.

Leclercq, J. 2006. Hyménoptères crabroniens d'Australie du genre Williamsita Pate, 1947 (Hymenoptera: Crabronidae). Notes Fauniques de Gembloux 59 (2): 115–119.

Maynard, D., & S. Fearn. 2021. Ecological and behavioural observations of a nesting aggregation of the endemic Tasmanian digger wasp Williamsita tasmanica (Smith, 1856) (Hymenoptera: Crabronidae: Crabroninae). Papers and Proceedings of the Royal Society of Tasmania 155 (1): 43–50.

McCorquodale, D. B., C. E. Thomson & V. Elder. 1989. Nest and prey of Williamsita bivittata (Turner) (Hymenoptera: Sphecidae: Crabroninae). Australian Entomological Magazine 16 (1): 5–8.

A surprisingly early visit by a royal: Monarch butterflies and their caterpillars, Danaus plexippus

 

This pretty monarch arrived early to the milkweed patch this year.

 

Zinnias are dynamite attractors for many butterflies, including male monarchs.

In a previous episode of Bug of the Week back way back in 2011, we visited monarch butterflies that debuted in my flower garden in mid-June.  Fast forward to 2022 when a Bug of the Week enthusiast announced the arrival of a monarch in her yard the second week of April. Thinking this early appearance was somewhat anomalous, I congratulated her on her good fortune and wondered what meteorological mystery might have promoted such early arrival of this voyager from down south. Problem was milkweeds here in the DMV were not even close to providing food for monarch caterpillars in early April. No telling what happened to that premature wanderer. 

Well, almost two weeks ago in early May, a beautiful female monarch discovered my small patch of butterfly weed and bestowed more than a dozen eggs to several sprouts over a few days. At last count, fourteen small caterpillars were enjoying milkweed leaves to get nutrients and hopefully a sufficient dose of cardiac glycosides to thwart predators. In previous episodes we delved into clever defenses of monarch caterpillars and butterflies acquired from noxious chemicals found in leaves of milkweeds on which they dine. My observation of a female monarch and her caterpillars is not the first report of this iconic butterfly moving up the East Coast this spring. Journey North, a really cool migrant-tracking website, recently reported monarch adults in New Jersey and caterpillars in other locations in Maryland and Pennsylvania. What surprises me is how early monarch caterpillars arrived in my garden. Historically, eggs and larvae don’t usually appear at my home until June or July. Perhaps this is just another indication of how our ever-warming world affects the plants and animals. 

Friday May 13th was a lucky day when this pretty monarch female stopped by my small patch of butterfly weed. Watch as she curls her abdomen and deposits an egg. Within days the egg hatched and a very tiny caterpillar just a few millimeters long began to dine on milkweed leaves. As the caterpillar grows, it eats more each day. One week after hatching the half-grown caterpillars make leaves disappear very fast. At last count, more than a dozen caterpillars of various sizes are dining on milkweeds in the milkweed patch.

While western populations of migratory monarchs enjoyed an unexpected, remarkable rebound last winter, in January Monarch Watch provided a rather gloomy projection of the population size of eastern migratory monarchs overwintering in Mexico. Continued exceptional drought west of the Mississippi and extreme heat in other parts of our land could spell trouble for milkweeds that monarchs depend on for food. Trouble, too, for adult butterflies and their young, which are imperiled by high temperatures. In the short run, we can do our part for monarchs by providing appropriate food for adults and their young by planting regionally native milkweeds for caterpillars and nutritious nectar sources for adults. Studies by Adam Baker and Daniel Potter discovered that garden design can play an important role in monarch conservation. Milkweeds with adult nectar sources nearby, planted along perimeters of gardens or relatively isolated from other non-host plants, were those most likely to have monarch eggs and caterpillars compared to milkweeds mixed with or hidden by other vegetation. In the long run, not only for monarchs but for all living things, we better find ways to cool this planet down.

Will exceptional drought and extreme heat imperil milkweeds and monarchs as they continue their annual migrations? Graph credit: Richard Heim, NCEI/NOAA

Acknowledgements 

Bug of the Week thanks Aimee for sharing her monarch sighting that served as the inspiration for this episode. Paula Shrewsbury provided video content. The fascinating article “Configuration and Location of Small Urban Gardens Affect Colonization by Monarch Butterflies” by Adam Baker and Daniel Potter provided several cool insights into monarch behavior. The following article from the University of Maryland IPM newsletter provides more detail on monarch conservation methods in the “Beneficial of the Week” article on page 8: https://extension.umd.edu/sites/extension.umd.edu/files/2021-09/21Sep03L.pdf

Opening Dors | Catalogue of Organisms

My current dayjob mostly revolves around identifying and counting dung beetles. When Europeans settled Australia, they brought their farm animals with them. Unfortunately, the large piles of dung produced by cattle and horses proved rather daunting to native scavengers used to the more compact droppings of kangaroos and possums. And if you've ever experienced an Australian summer, you'll know that flies are definitely a thing. To help with this situation, Australia has had a long-running programme introducing exotic dung beetles that are better able to clean up after livestock. Most of these are members of the typical dung beetle family Scarabaeidae but one species, Geotrupes spiniger, represents a different subgroup of the superfamily Scarabaeoidea. These are the earth-boring dung beetles or dor beetles of the Geotrupidae.

Dor beetle Geotrupes spiniger, copyright Udo Schmidt.

The geotrupids are medium-sized to very large beetles, ranging in size from half a centimetre to 4.5 cm in length (Jameson 2002). Like many other members of the Scarabaeoidea, they have broad fore legs used for digging. Their short, eleven-segmented antennae end in the asymmetrical club typical of scarabaeoids but they may be distinguished from other families in that the basal segment of the three-segmented club is expanded to form a 'cup' against which the other segments may be tightly closed. The body of geotrupids is strongly convex, and is smooth and shiny dorsally but hairy underneath. In many species, the males may bear elaborate horns and/or processes on the head and pronotum.

Male Taurocerastes patagonicus, copyright Nicolás Lavandero.

Despite their size, geotrupids are secretive animals, spending most of their time in burrows underground (which may be up to three metres in depth) and usually only emerging at night. Various species feed on animal dung or decaying matter; some feed on subterranean fungi. In at least some species, eggs are laid in brood chambers within the parent's home burrow and multiple life stages may share a single burrow. Burrows may also be shared between multiple adults when conditions demand. Though adults do not directly tend to larvae, they may stock brood chambers with food supplies. In some Australian species of the subfamily Bolboceratinae, females lay a single gigantic egg at a time that may be up to 56% the size of its layer (Houston 2011). Larvae hatching from such an egg are able to develop right through to maturity without feeding.

Adult geotrupids produce a stridulating noise when disturbed which is the origin of the alternate vernacular name of "dor beetle" ("dor" being an old word for a buzzing insect). Larvae may or may not be capable of stridulation, depending on the species.

Male Blackburnium rhinoceros, copyright Edward Bell.

The classification of geotrupids is the subject of ongoing investigation. A recent classification divides the family between three subfamilies, the widespread Geotrupinae and Bolboceratinae and the South American Taurocerastinae. Morphological differences between these subfamilies, particularly at the larval stage, have lead some researchers to question whether the Geotrupidae in the broad sense represents a monophyletic group. Molecular analyses thus far seem ambiguous; an analysis by McKenna et al. (2015) placed geotrupids as part of a polytomy near the base of the scarabaeoids. As an aside, my supervisor recently asked myself and a retired colleague whether Geotrupes spiniger was the only species of geotrupid found in Australia. I replied "yes", our colleague responded "no". Our conflict, of course, was based on whether Australia's wide diversity of Bolboceratinae contributed to the count.

REFERENCES

Houston, T. F. 2011. Egg gigantism in some Australian earth-borer beetles (Coleoptera: Geotrupidae: Bolboceratinae) and its apparent association with reduction or elimination of larval feeding. Australian Journal of Entomology 50: 164–173.

Jameson, M. L. 2002. Geotrupidae Latreille 1802. In: Arnett, R. H., Jr, M. C. Thomas, P. E. Skelley & J. H. Frank (eds) American Beetles vol. 2. Polyphaga: Scarabaeoidea through Curculionoidea pp. 23–27. CRC Press.

McKenna, D. D., B. D. Farrell, M. S. Caterino, C. W. Farnum, D. C. Hawks, D. R. Maddison, A. E. Seago, A. E. Z. Short, A. F. Newton & M. K. Thayer. 2015. Phylogeny and evolution of Staphyliniformia and Scarabaeiformia: forest litter as a stepping stone for diversification of nonphytophagous beetles. Systematic Entomology 40: 35–60.

Platybunus: the Wide-Eyed Harvestmen of Europe | Catalogue of Organisms

The western Palaearctic region (that is, Europe and the immediately adjacent parts of Asia and northern Africa) is home to a diverse and distinctive fauna of harvestmen. Among the various genera unique to this part of the world are the forest- and mountain-dwellers of the genus Platybunus.

Platybunus pinetorum, copyright Donald Hobern.

Platybunus species are moderate-sized long-legged harvestmen of the family Phalangiidae, the central body in larger individuals being about eight millimetres long (Martens 1978). Their most characteristic feature is a relatively large eye-mound, distinctly wider than long and occupying a large section of the anterior carapace. As with other European phalangiids, they eye-mound is ornamented with a row of denticles each side though the body lacks denticles over the remainder of the dorsum. The body is often comparatively slender, tapering towards the rear (particularly in males), and is marked on the dorsum by a darker median band. The pedipalps have a pair of well-developed setose apophyses on the inner distal ends of the patella and tibia, and a series of long spine-like tubercles on the underside of the femur. These tubercles presumably function in the capture of prey, forming a basket that can be closed around the harvestman's victims. External sexual dimorphism in Platybunus is fairly minimal though females are overall larger and fatter. The penis is notably long and slender with a relatively small glans, offset from the shaft by a more or less marked constriction.

Platybunus bucephalus, copyright Adrian Tync.

Martens (1978) recognises four species of Platybunus found in higher altitude regions of central Europe with the species P. bucephalus and P. pinetorum occupying much of the genus' range. Platybunus bucephalus may be distinguished from P. pinetorum by, among other features, its relatively shorter legs. Platybunus pallidus is endemic to the Carpathians, and the tiny P. alpinorelictus inhabits the Garda Mountains of northern Italy. Another species, P. anatolicus, was described from Turkey by Roewer (1956)*. In general, Platybunus species inhabit alpine and subalpine forests, being found among the herbaceous undergrowth, under bark or on rock faces. Where their ranges overlap, P. bucephalus is more accustomed to extending beyond the forest margins than P. pinetorum and may be found above the tree-line. In recent years, the range of P. pinetorum has extended northwards, being first recorded from the UK in 2010 and Sweden in 2015 (Fritzén et al. 2015). At least some populations of P. pinetorum are capable of reproducing parthenogenetically and this may have played a part in its spread.

*Platybunus mirus was described by Loman (1892) on the basis of two male specimens that supposedly came from Sumatra. Though the identity of this species has never been resolved (Loman's illustration of the penis is at least suggestive of a true Platybunus), the claimed locality seems almost certain to be an error of some kind.

The internal classification of the Phalangiidae remains in need of further investigation. Platybunus has been recognised by some authors as forming a subfamily Platybuninae with a cluster of other western Palaearctic genera bearing similar ventrally spined pedipalps (Zhang & Zhang 2012). However, other authors have not separated this group from the subfamily Phalangiinae. The platybunines may represent a phylogenetically coherent grouping, or their shared features may reflect adaptations to a similar life style. The genital morphology of Platybunus is recognisably distinct from that of other platybunines which may argue against any relationship (Martens 1978). On the other hand, platybunines might possibly be distinguished from phalangiines by the chemical composition of their repugnatorial gland secretions (Raspotnig et al. 2015). A formal analysis of the family's evolution would be a welcome advance.

REFERENCES

Fritzén, N. R., V. Rinne, M. Sunhede, A. Uddström, S. Van de Poel & P. De Smedt. 2015. Platybunus pinetorum (Arachnida, Opiliones) new to Sweden. Memoranda Soc. Fauna Flora Fennica 91: 37–40.

Loman, J. C. C. 1892. Opilioniden von Sumatra, Java und Flores. In: M. Weber (ed.) Zoologische Ergebnisse einer Reise in Niederländisch Ost-Indien vol. 3 pp. 1–26, pl. 1. E. J. Brill: Leiden.

Martens, J. 1978. Spinnentiere, Arachnida: Weberknechte, Opiliones. Gustav Fischer Verlag: Jena.

Raspotnig, G., M. Schaider, P. Föttinger, V. Leutgeb & C. Komposch. 2015. Benzoquinones from scent glands of phalangiid harvestmen (Arachnida, Opiliones, Eupnoi): a lesson from Rilaena triangularis. Chemoecology 25: 63–72.

Roewer, C. F. 1956. Über Phalangiinae (Phalangiidae, Opiliones Palpatores). (Weitere Weberknechte XIX). Senckenbergiana Biologica 37 (3–4): 247–318.

Zhang, C., & F. Zhang. 2012. On the subfamilial assignment of Platybunoides (Opiliones: Eupnoi: Phalangiidae), with the description of a new species from China. Zootaxa 3190: 47–55.

Time for tigers in the DMV: Six-spotted green tiger beetle, Cicindela sexguttata

Poised to pounce on its next meal, the beautiful six-spotted green tiger beetle is a fierce predator in eastern forests.

Last week, I received two strangely linked inquiries, one from a concerned citizen and another from a friend. Both had stunning emerald green creatures that crossed their paths. The concerned citizen discovered a beautiful green beetle in a bowl of fruit being served at an outdoor gathering. Fruit in the bowl included grapes from Chile. Concern hinged on the possibility that this remarkable insect was the vanguard of some new and, perhaps, hostile horde of invaders ready to deliver more six-legged misery to our already beleaguered ecosystems. A few days later a friend asked about gorgeous emerald green insects she encountered “all over the place” on bike trails and hiking paths in the DMV. Well, after examining an image of the beetle in the fruit bowl and taking a stroll on the lovely Northeast Branch Trail, my conclusion was that the beetle in the fruit bowl and the trail-traveling green ghost were one and the same, six-spotted green tiger beetles. 

Lawns, gardens, sunny bike trails, and paths through the forest are great places to watch six-spotted tiger beetles. Unfortunately, fast wheels and speedy feet may spell danger for inattentive tiger beetles.

Six-spotted green tiger beetles range from southern Canada to Texas and are most commonly observed in the eastern half of the US. I saw my first one in early April on a paved trail meandering along the Little Patuxent River in Columbia, MD. Predators as both larvae and adults, the name “tiger” suits them well. They are awesome hunters. The exceptionally long legs of adults provide lots of ground clearance and enable bursts of speed as they dash across trails and forest floors. Large eyes enable them to peruse their surroundings for signs of movement and potential meals. Unlike praying mantids that are “sit and wait” predators, tiger beetles actively stalk, pursue, and capture their victims. One amusing trick to play with these hunters is to spot one at a distance and toss a pebble or a small twig near the beetle. This often triggers an inquisitive charge as the beetle scrambles to see if a potential meal has entered its ambit. 

Tommy, my resident tiger beetle, seems startled by a tent caterpillar when it ventures just a little too near. A few moments later, I discovered Tommy behaving more like his “tiger” namesake as he snacked on the rear-end of the caterpillar. Watch as sharp paired mandibles (jaws) and the second pair of mouthparts called maxillae move back and forth to ingest this tasty treat.

The strange tiger beetle larva lives in an underground lair and captures unsuspecting prey that stray too near.

Like their feline namesake, the tiger beetle has powerful jaws used to capture, subdue, and consume its victim. Each jaw is armed with several stout teeth. The jaws grasp, pierce, slice, and crush. Just behind the jaws, a second pair of mouthparts called maxillae help shove pieces of flesh into the maw of the beetle’s digestive tract. Tiger beetles are carnivores as both adults and juveniles. The female tiger beetle lays eggs singly on the ground. Upon hatching, the immature stage, the larva, constructs an underground burrow. From this lair, the larva stealthily awaits dinner. As a hapless insect or spider strolls by, the larva springs from the hole like a jack-in-the-box and impales its victim with stiletto-like jaws. The prey is drawn into the burrow and eaten. Strange hook-like structures found on its abdomen help anchor the beetle larva in its burrow. 

As generalist predators and members of Mother Nature’s hit squad, tiger beetles consume pests in our gardens and landscapes and provide the important ecological service of biological control. Tiger beetles are tough to capture without a net, but if you catch one, be careful; they have powerful jaws and can give you a little nip. These diminutive tigers will be common along sunny bike trails and paths over the next month or so. If you have some free time, take a walk in the forest or ride along one of our many beautiful bike paths to catch a glimpse of these tiny awesome predators. 

Acknowledgements 

“An Introduction to the Study of Insects” by Borrer, De Long, and Tripplehorn, and iNaturalist were used as resources for this episode. Thanks to Amy, Bruce, and Laura for inquiring about tiger beetles and inspiring this episode. Gaye Williams provided great insights on the identity of the tiger beetle found in the fruit bowl.