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Can’t Touch This

by Andrea Kautz

From the name of them, you may guess “blister beetles” are insects you might not want to handle. However, they sure are beautiful to look at! We’ve been noticing blister beetles out and about at Powdermill over the last week or so. Some fly around clumsily, while other flightless species scurry among the leaf litter. Beetles in this family (Meloidae) secrete a defensive substance called cantharidin, a skin irritant that can cause blistering. They are also very toxic when consumed, and can be fatal for livestock if present in the hay supply.

Multi-colored blister beetle on a rock.
Shiny blue blister beetle on a rock.
Two different genera of blister beetles that are common in SW Pennsylvania: Lytta (top) and Meloe (bottom). Top image credit: Shaun Pogacnik. Bottom image credit: Christian Grenier.

Blister beetles are parasites, mostly in the nests of ground-nesting bees and wasps. Watch this short video clip to learn more about their life cycle. Spoiler alert: In this species, the newly hatched beetle larvae clump together and attract a male bee using a fragrance, and then transfer to the female he mates with, ultimately gaining access to her nest, where they feed on both the pollen provisions and the bee larvae themselves!

Whether larvae or adults, these striking beetles certainly have a fascinating dark side. There is always more than meets the eye when it comes to entomology!

Andrea Kautz is a Research Entomologist at Carnegie Museum of Natural History’s Powdermill Nature Reserve. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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Carnegie Museum of Natural History Blog Citation Information

Blog author: Kautz, Andrea
Publication date: May 26, 2021

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Armored Advantage

A folded hindwing of this lightning bug is visible beneath a raised forewing.

As adaptations go, the hardened forewings of beetles have a long track record of success. The paired structures, known as elytra (or singularly as elytron), don’t contribute significant aerodynamic advantage to beetle flight. Because they protect the delicate hindwings under all other circumstances, however, elytra help to ensure the capability of flight whenever it’s necessary.

Evidence for the survival advantages conveyed by the wing covers is impressive. The order Coleoptera, the scientific category of beetles, contains more than 380,000 named and described species, a figure that represents nearly a quarter of currently known animal species.

In Dinosaur Armor, the world premiere exhibition occupying the R. P. Simmons Family Gallery for the next 10 months, a colorful array of preserved beetles illustrates the insects’ built-in shield adaptation.

wall of beetle specimens

Visitors interested in elytra can visually study a far larger and more diverse beetle display just outside the Dinosaur Armor exit. Here hundreds of curated specimens from the scientific collection have been arranged in a wall-sized display.

detail of beetle specimens on display

Collectively and individually, this mass of pinned beetles serves to reinforce an unstated theme of Dinosaur Armor: functional exterior armor does not necessarily preclude natural beauty.

Patrick McShea works in the Education and Visitor Experience department of Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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An Annual Return to My Bug-loving Roots

black and beetle on goldenrod
Image used by permission of Stuart Tingley, Cormierville, New Brunswick, Canada. Megacyllene robiniae (Forster), female on bloom of goldenrod

It’s that time of year again when one of my favorite beetles, Megacyllene robiniae (Forster), is starting to appear. Called the “locust borer” due to its larva’s habit of feeding in the living wood of black locust trees, it is one of the last species of long-horned beetle (family Cerambycidae) to emerge in late summer. Adults can be found feeding on the flowers of goldenrod, starting around late August and persisting in the field well into October. The beautiful yellow and black patterned beetles are strikingly colored, but can be quite cryptic when resting on the flowers of goldenrod, which shares the same shade of yellow as the beetle. As long as a larval host source is nearby, a stroll in a field of goldenrod is sure to produce a few adults, boldly feeding on pollen in broad daylight, yet still difficult to visually sort out from the background of the flowers which they visit.

Megacyllene is a genus of Cerambycidae that elicits as much sentimental as scientific interest for me, because it was one of the first long-horned beetles I encountered as a kid. I can still remember coming home from school in the early autumn and heading out into a large field of goldenrod behind my Ohio home to look for the beetles. The only other species of Megacyllene present in Ohio and Pennsylvania is Megacyllene caryae (Gahan) – the “painted hickory borer.” Contrary to M. robiniae – it is one of the earliest cerambycids to emerge in late April to early May, the adults having eclosed in the fall and remaining in their pupal cells until spring. I vividly remember my grandfather bringing home a load of hickory firewood one January, unaware that it was infested with the beetles. Upon splitting a log, he found the adults in their pupal cells awaiting the Spring warmth to emerge. He and I together split those logs smaller and smaller looking for more specimens. We ended up with a nice series of beetles and a bunch of wood whittled down to kindling size!

Image used by permission of Shannon Schade, Elkton, MD. Megacyllene caryae (Gahan), mating pair

Monochamus notatus (Drury) is a spectacular species of long-horned beetle, common in Pennsylvania in stands of white pine. The larva feeds under the bark of dying or dead pine and its feeding can be heard as a high-pitched rasping sound as far as 20 feet from the tree. This behavior has earned the species the common name of “pine sawyer” – the noise resembling the sound of an old-fashioned two-man crosscut saw raking back and forth through a log.

Image used by permission of Carolyn Waddell, Bugguide #1184417, Creative Commons, Ottawa, Ontario, Canada. Monochamus notatus (Drury), male

When I was thirteen, while camping at Mohican State Park in north-central Ohio with my family, I was sitting at a picnic table eating lunch. Suddenly, a large male M. notatus came wafting through the campsite, its lengthy antennae trailing behind it, and looking about the size of a small bird to my young bug-enthusiast eyes. I dropped my food, jumped from the table, grabbed my net, and swept the beast out of the air – the first cerambycid beetle that I ever collected! I still have that specimen 46 years later and I attribute it with starting me on the road to specializing on the family Cerambycidae – now my strongest area of taxonomic expertise. I have seen millions of specimens of long-horned beetles from all around the globe during my career, but that one specimen generates more sentiment than the rest combined – I can still smell the pine scent in the air on that day I caught it.

Collecting insects as a kid was the gateway into an amazing world of diversity, and as it turned out, the foundation of what would become my career and lifelong passion. When I look at specimens I caught in those early years, they produce a flood of memories – of specimens caught and of those that got away; of woods where I memorized every fallen log and patch of flowers; of the copy of Josef Knull’s 1946 book “The Long-horned Beetles of Ohio,” with its pages worn and every word read over and over again a thousand times; even the long bike rides, carrying my net and jars out to areas remote from my home in search of “wild” areas in which to hunt for beetles. The specimens serve as little time machines – carrying me back to my childhood and the dawn of my interest in entomology. Going into the field now is more sophisticated, and structured, and planned – better gear, GPS units to record localities, a lifetime of experience to rely upon – not to mention a car that can take me farther afield. But those days of simple exploration, where nearly every venture outdoors uncovered some new wonder, will always be some of my most cherished memories – and those beetles on pins will always be the vehicles that carry me back to that wondrous time in my life.

Bob Androw is a Scientific Preparator in Invertebrate Zoology. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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The Manticore

manticore specimen next to a dime for scale
Figure 1.  Adult male Manticora imperator, dorsal view (photo credit: V. Verdecia).

The Manticore.  In ancient Persia, a scary, man-eating monster with the head of a man, the body of a lion, and the tail and sting of a scorpion. In nature, one of the most spectacular of God’s favorite creatures, beetles (there are more beetle species than anything else living today).  The genus Manticora (“the one who devours men”) consists of 15 known species confined to the southern portions of Africa, mostly to the oldest geologic portions of that region, and mostly to open desert and dry savannah habitats. They are relatively primitive, flightless, predatory black tiger beetles of enormous size.  The males of some species are particularly spectacular, with huge asymmetrical mandibles, reaching the extreme in Manticora imperator, with a toothed left mandible and a larger right mandible bent like a sickle (Figures 1-2).  Mandibles in both sexes are used to attack prey, and, in males, also to combat other males and to clasp the female during copulation.

Figure 2.  Close-up of mandibles and maw of male M. imperator (photo credit: V. Verdecia).

A recent donation gives Carnegie Museum of Natural History one of the best collections of these beetles in the world, nearly a thousand specimens, including all the species and subspecies.  This includes many of the types (specimens designated to represent the species when an author names a new animal or plant).  Long series of many of them (Figure 3) allows analysis of variation and distribution, addressing conservation issues, and has great potential for exhibit purposes.  Some of the species are now threatened, not by collecting, but by construction and development over their very limited habitats and ranges.

Figure 3.  Typical drawer from CMNH collection with several Manticora species (photo credit: V. Verdecia).

The larvae (Figure 4) look and behave more like tiger beetle larvae from other parts of the world, except that they are enormous.  They dig a vertical burrow up to a meter in depth, depending on substrate, which they can drop down into when disturbed.  The larval head is like a big armored plug with jaws attached.  In attack mode, they block the burrow entrance with the head (making the hole difficult to see) and wait.  There is also a large hook toward the rear on the larva’s back which makes it difficult for anything to dislodge it from the burrow. If something edible gets within striking distance, the larva throws its forebody out, grabs with its large jaws, and drags the prey into the burrow.

Figure 4.  Larva of M. mygaloides, antero-lateral view (photo credit: V. Verdecia).

Adults hibernate underground in a large chamber at the end of a tunnel that can be as much as a meter and a half in length.  Most are active from October to March after the summer rains, but they can wait a long time if necessary, until the unpredictable, erratic summer rains come. Activity is in the daytime, and they do not hesitate to attack other large armored beetles, or invertebrates that are larger than the attacker.  You have perhaps seen giant millipedes the size of a bratwurst in various insect zoos? There is a filmed instance of a Manticora finishing off and eating a 10-12 inch millipede, though the beginning of the event was missed, and it is possible the millipede was already injured. These are probably not the normal preferred prey of these aggressive beetles (the millipedes, that is, not the bratwursts, which are not known to occur in the wild).  But it still seems like quite a feat for an animal only about 20% the size of its dinner.

Bob Davidson is Collection Manager of Invertebrate Zoology at Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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The Story of a Beetle, a Dolphin, and Some Remarkable Genitalia…

By Bob Androw

In 2014, while processing a light trap sample from the Dominican Republic, I came across a series of Phyllophaga that I could not identify. At first, this wasn’t too unusual – this one genus of scarab beetles contains over 500 named species. Upon closer examination, I was thrilled to determine that I was looking at a species new to science. I specialize in Cerambycidae, the long-horned beetles, and dabble with scarab beetles on the side – so I like to refer to Phyllophaga as one of my “mistress groups.” While I already had one species named after me, Phyllophaga androw, this would become the first new Phyllophaga I had personally discovered and would have the opportunity to describe.

When describing a new species, one of the challenges, and the joys, is choosing a name. With millions of insect species known, more than a few names are already taken. There are lots of options – naming it after one of its traits – color, size, shape; after the place it was found; after some factor of its biology; after a notable person in one’s life or after a renowned colleague; or, just maybe, after the shape of its genitalia. Hmmm… let’s clarify that…

Many species of Phyllophaga are nearly inseparable by their outward appearance, but the genitalia can vary drastically between species. The male genitalia in beetles are usually strongly sclerotized, meaning that they are hard, rigid structures – hence the shape is fixed in any given species.

Phyllophaga delphinicauda, male holotype CMNH-IZ #325,315.
Phyllophaga delphinicauda, male holotype CMNH-IZ #325,315.

 

The new species was no exception – externally it closely resembled a number of other species but the genitalia were remarkable – having a delicate fluke-like structure arising from the upper surface. It so resembled a dolphin’s tail that the name was inevitable – Phyllophaga delphinicauda – the Phyllophaga with “the tail of a dolphin.” In 2016, I published the description in the Annals of Carnegie Museum, and, in doing so, reduced by one more the naming options available for species discovered in the future.

 

Phyllophaga delphinicauda, A-D, male genitalia (dorsal, lateral, ventral and posterior views, respectively). E, female genital plates.
Phyllophaga delphinicauda, A-D, male genitalia (dorsal, lateral, ventral and posterior views, respectively). E, female genital plates.

 

Access the original publication for Phyllophaga delphinicauda Androw here. 

Bob Androw is a Scientific Preparator in Invertebrate Zoology. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.