My, what busy palps you have!

In mid- to late summer, the swamps of southeast Missouri and adjacent areas along the Mississippi River become awash in color as stands of hairy rose mallow (Hibiscus lasiocarpus) put forth their conspicuous, white and pink blooms. I’ve been waiting for the mallows to bloom this year, as there is one particular beetle associated with plants in this genus that I have been keen to photograph since I first picked up a real camera a few years ago, to this point without success. My first attempt this year came in early August as I noted the tell-tale blooms while passing through extreme western Kentucky. I was foiled again (but would succeed the next day—more on this in a future post), but as I tiptoed over the soggy ground searching through the lush foliage, I saw a small, brightly colored cricket with curiously enlarged mouthparts. Even more interesting was the constant, almost frenetic manner in which the insect was moving these mouthparts. My first attempts to detach the leaf on which it was moving spooked it, and it jumped to another leaf, but I persisted and finally succeeded in detaching the leaf with the critter still upon it and maneuvering it up towards the sky for a few photographs.

Phyllopalpus pulchellus (red-headed bush cricket) | Hickman Co., Kentucky

Phyllopalpus pulchellus (red-headed bush cricket or “handsome trig”) | Hickman Co., Kentucky

It didn’t take long to identify the cricket as Phyllopalpus pulchellus, or “red-headed bush cricket” (family Gryllidae). This species, also known as the “handsome trig” on account of its stunning appearance and membership in the subfamily Trigonidiinae, is distinctive among all North American orthopterans by its red head and thorax, pale legs, dark wings, and—as already noted—highly modified maxillary palpi with the greatly expanded and paddle-like terminal segment. According to Capinera et al. (2004), adults appear during mid- to late summer near streams and marshes on vegetation about one meter above the ground—precisely as this individual was found. Surely it represents one of our most photographed cricket species (208 BugGuide photos and counting).

The greatly expanded palps are thought to mimic beetle mandibles or spider pedipalps.

The greatly expanded palps are said to mimic beetle mandibles or spider pedipalps.

The obvious question to anyone who sees this species is, “Why the curiously enlarged palps?” Both males and females exhibit this character (even as juveniles), so it seems clear that there is no special sexual or hypersensory function. One idea mentioned on BugGuide (perhaps originating from this EOL post by Patrick Coin) suggests that the crickets are Batesian mimics of chemically-defended ground beetles (family Carabidae) such as bombardier beetles (genus Brachinus). This thought is based on their similar coloration, the convex and shiny (and, thus, beetle-like) forewings of the females, and some resemblance of the enlarged palpi to the mandibles of the beetles. I am not completely satisfied with this idea, since bombardier beetles are generally found on the ground rather than foliage. Moreover, males lack the convex, shiny forewings exhibited by females, and resemblance of the palps to beetle mandibles doesn’t explain their curiously constant movement (ground beetles don’t constantly move their mandibles). Another idea suggested by orthopterist (and insect macrophotographer extraordinaire!) Piotr Naskrecki is a mimetic association with another group of arthropods, noting that the busy movements of the palps is very similar to the way jumping spiders (family Salticidae) move their pedipalps. This suggestion also is not completely satisfying, as it leaves one wondering why the crickets are so boldly and conspicuously colored. While some jumping spiders are brightly colored, I’m not aware of any in eastern North America with similar coloration (indeed, many jumping spiders can be considered ‘drab’). Perhaps the crickets have adopted mimetic strategies using multiple models in their efforts to avoid predation?

The brown wings and long, sickle-shaped ovipositor identify this individual as a female.

The brown wings and sickle-shaped ovipositor identify this individual as a female.

The individual in these photos can be identified as a female due to the presence of the sickle-shaped ovipositor and, as mentioned above, the convex, shiny forewings. Males possess more typically cricket-like forewings, perhaps constrained to such shape by the sound producing function they must serve. The males do, however, exhibit an interesting dimorphism of the forewings, with one wing being clear and the other one black. Fellow St. Louisan and singing insect enthusiast James C. Trager notes this dimorphism has been mentioned in the literature but not explained and suggests it may have something to do with the adaptive physics of sound production.

Congratulations to Ben Coulter, who wins Super Crop Challenge #16, which featured a cropped close-up of the enlarged maxillary palpi of this insect. His 12 pts increase his lead in the overall standings for BitB Challenge Session #7 to an almost insurmountable 59 pts. Morgan Jackson and Troy Bartlett round out the podium with 10 and 9 pts, respectively—Troy’s points being enough to move him into 2nd place in the overalls with 23 pts. Third place in the overalls is still up for grabs, since none of the people occupying the 3rd through 6th places has played for awhile—realistically any number of people behind them could jump onto the podium (or even grab 2nd place!) in the next (and probably last) Session #7 challenge.

REFERENCE:

Capinera, J. L., R. D. Scott & T. J. Walker. 2004. Field Guide To Grasshoppers, Katydids, And Crickets Of The United States. Cornell University Press, Ithaca, New York, 249 pp. [Amazon].

© Ted C. MacRae 2014

Super Crop Challenge #16

Who am I?

Who am I?

Can you identify the structures in the photo above (2 pts), their significance (2 pts), and the organism to which it belongs (order, family, genus, and species—2 pts each)? Comments will be held in moderation so everybody has a chance to participate, but there are early-bird bonus points on offer for those who get their answers in quickest. You’ve got the weekend to think about it. 🙂

p.s. Read the full rules for details on how (and how not) to earn points. Good luck!

© Ted C. MacRae 2014

When is a stag beetle not a stag beetle?

A: When it’s a longhorned beetle!

Parandra (Tavandra) polita

Parandra (Tavandra) polita | Alexander Co., Illinois

Last week I traveled to northwestern Tennessee to visit research plots, and on the way back I took the opportunity to stop by Fort Defiance Park near Cairo, Illinois. Fort Defiance represents the southernmost tip of Illinois, lying at the confluence of the Ohio and Mississippi Rivers, and on previous visits I had thought that the wet bottomland forest remnants present there looked like promising habitat for the ant-like tiger beetle (Cylindera cursitans). The type locality of a synonym (Cicindela alata) is in northern Illinois, but the type specimens are considered to have been introduced and, to my knowledge, no bona fide records of the species are known from the southern part of the state. I have taken the species nearby on the Missouri side of the Mississippi River (MacRae et al. 2011), so I thought the chances were good of finding it here as well. And find it I did—in good numbers! Success already in hand, I decided to stick around for nightfall and set up some blacklights to see what other beetles might be attracted from the surrounding forests.

Parandra (Tavandra) polita

The color and shape of the body and prominent jaws give the appearance of a small stag beetle.

Sadly, not much of interest was coming to the lights. Temperatures and humidity were good, but a waxing moon with clear skies didn’t help. Worse, the sheets were inundated with caddisflies—always a predictable consequence when blacklighting near large rivers but especially annoying because of their habit of flying into your face (and up nostrils, down shirts, in ears…) when checking the sheet for other insects. A few longhorned beetles did show up, as did some male and female reddish-brown stag beetles (Lucanus capreolus), and later a single coppery tiger beetle (Ellipsoptera cuprascens) also made an appearance. By 10 pm, however, I had decided enough was enough and went to one of the sheets to begin taking it down. As I did, I noticed a reddish-brown, large-mandibled beetle sitting on the sheet that, for all intents and purposes, looked like a small stag beetle. I wasn’t fooled, however, as I knew exactly what this beetle was—I had previously seen this species in the form of two individuals at a blacklight in southern Missouri very near to my current location (although it was 28 years ago!). It was Parandra polita, an usual longhorned beetle belonging to the archaic subfamily Parandrinae, and those specimens (MacRae 1994) plus another collected more recently a few miles north—also at a blacklight in wet bottomland forest along the Mississippi River (McDowell & MacRae 2009)—to date represent the only known occurrences of this uncommon species in Missouri.

Parandra (Tavandra) polita

The entire rather than emarginate eyes distinguish this species from Neandra brunnea,

Linsley (1962) noted the tenebrionid (darkling beetle)-like appearance of beetles in this genus. Perhaps the glabrous, parallel-sided body recalls the appearance of some darkling beetles, but I have always thought these beetles looked more like stag beetles because of the reddish-brown coloration and, notably, fairly large, forward-projecting mandibles that even show the same type of size dimorphism as stag beetles—larger in “major” males, smaller in females and “minor” males. Parandrines differ from most other subfamilies of longhorned beetles by having the antennae short and equal-segmented and the tarsi distinctly pentamerous with slender, padless segments. Another small subfamily of longhorned beetles, the Spondylidinae, shares these characters, but parandrines are easily distinguished from them by several characters including the margined pronotum—also a most lucanid-like character.

Parandra (Tavandra) polita

Parandra polita also has the mandibles contiguous at the base and a narrower, more flattened body.

Although Parandrines are reasonably diverse in South America and Africa, North America boasts only four taxa, with P. polita and Neandra brunnea being the only two occurring in the eastern part of the continent. Annoyingly, I have collected just as few specimens of the latter as the former, despite the fact that N. brunnea is considered to be the most commonly encountered of all four North American taxa. The specimens were all taken in Japanese beetle traps that I ran while working for the Missouri Department of Agriculture in the 1980s, so I have never actually seen a live individual of that species. Parandra polita and N. brunnea are, however, fairly easy to distinguish, as the former has the mandibles triangular and contiguous at the base while in the latter they are sickle-shaped and well separated at the base. The former also has the eyes entire on the inner margin while the latter has them distinctly emarginate, and in basic gestalt P. polita has a narrower, more flattened body than N. brunnea.

A frontal portrait of this beetle was featured a few days ago in ID Challenge #23. A few people were fooled by its lucanid- and even cucujid-like appearance, but Stephen, Harry Zirlin, Nikola Rahme, Jon Quist, and Ben Coulter all correctly guessed this species. By virtue of being first, Stephen rises above the 5-way tie to get the win. However, I should note that Harry was the first to actually provide names for each of the four requested taxa (as did Jon and Ben subsequently), so he could make a valid claim for the win. Also, nfldkings and froglady made really nice comments about my blog and the featured photo, so I award them with honorable mentions!

REFERENCES:

Linsley, E. G. 1962. The Cerambycidae of North America. Part II. Taxonomy and classification of the Parandrinae, Prioninae, Spndylinae, and Aseminae. University of California Publications in Entomology 19:1–102, 1 plate [OCLC WorldCat].

MacRae, T. C. 1994. Annotated checklist of the longhorned beetles (Coleoptera: Cerambycidae and Disteniidae) known to occur in Missouri. Insecta Mundi 7(4) (1993):223–252 [pdf].

MacRae, T. C., C. R. Brown & K. Fothergill. 2011. Distribution, seasonal occurrence and conservation status of Cylindera (s. str.) cursitans (LeConte) (Coleoptera: Cicindelidae) in Missouri.  CICINDELA 43(3):59–74 [pdf].

McDowell, W. T. & T. C. MacRae. 2009. First record of Typocerus deceptus Knull, 1929 (Coleoptera: Cerambycidae) in Missouri, with notes on additional species from the state. The Pan-Pacific Entomologist 84(4) (2008):341-343 [pdf].

© Ted C. MacRae 2014

ID Challenge #22

For this ID Challenge, please identify the objects/structure in the photos below and discuss how they are related to each other. I’ll give 5 pts to anybody who correctly identifies the object/structure in each photo and another 5 pts to anyone who correctly elucidates their connection. Go!

Edit: I am looking for a family-level ID for the objects in the first photo and a genus-level ID for the plant bearing the structure in the second photo to get full credit. Answers will be held in moderation until the answers are revealed to give all a chance to play.

What are these?

What are these objects?

What is this, and how does it relate to the structures in the other photo?

What is this structure, and how does it relate to the objects in the first photo?

© Ted C. MacRae 2014

What was that insect?

Yesterday I posted an identification challenge of a different sort. The main subject in the photo was a jewel beetle (family Buprestidae), but there was also another insect in the photo—a small parasitic wasp sitting on the branch below the beetle. Some of you saw it—Charley Eiseman was the first and correctly guessed it was a member of the family Encyrtidae, earning 5 pts, and Wikispecies editor gets 5 pts for further identifying it as a member of the genus Metaphycus. Honestly, I took several shots of the beetle and never saw the wasp until I examined the photograph during processing. I’m not certain, but I think the small object next to the wasp could be a scale insect (family Coccidae), which are known hosts of Metaphycus spp.

Of course, there is still the jewel beetle, and it wouldn’t be fair for me to award points for the wasp but not the beetle. Heath gets 5 pts for first identifying the beetle in the genus Agrilus; however, nobody was able to identify the species as A. granulatus—commonly associated with cottonwood and poplar (Populus spp.) across North America. Since Charley was the only person to mention both the beetle and the wasp, I’m going to give him a tie-breaking bonus point and declare him the challenge winner.

Populations of A. granulatus have been assigned to several subspecies—the beetle shown here (photographed June 2013 at Beaver Dunes, Oklahoma) represents the nominate form—restricted to the U.S. east of the Rocky Mountains, where it breeds in native eastern cottonwoods (P. deltoides) and introduced Lombardy poplars (P. nigra var. ‘Italica’). Agrilus granulatus is often confused in collections with A. quadriguttatus, but that species is associated with willow (Salix spp.) and can be further distinguished by the less dense pubescence of the lower face not obscuring the surface; the pronotum with the lateral margins evenly rounded and not strongly sinuate at the base, the median channel less distinct, and the lateral depressions scarcely pubescent; and the elytra more gradually narrowed posteriorly with the tips more acutely rounded and more coarsely serrulate and the pubescent spots less distinct (Fisher 1928).

Here are a few more photographs of the jewel beetle (without the wasp):

Agrilus granulatus granulatus on Populus deltoides | Beaver Dunes, Oklahoma

Agrilus granulatus granulatus on Populus deltoides | Beaver Dunes, Oklahoma

Agrilus granulatus granulatus on Populus deltoides | Beaver Dunes, Oklahoma

Agrilus granulatus granulatus on Populus deltoides | Beaver Dunes, Oklahoma

Agrilus granulatus granulatus on Populus deltoides | Beaver Dunes, Oklahoma

Agrilus granulatus granulatus on Populus deltoides | Beaver Dunes, Oklahoma

REFERENCE:

Fisher, W. S.  1928. A revision of the North American species of buprestid beetles belonging to the genus Agrilus.  U. S. National Museum 145, 347 pp.

Copyright © Ted C. MacRae 2014

ID Challenge #22: The Bone Collector

After a long hiatus, it is time to resurrect BitB Challenge Session #7 with this very unusual ID Challenge. Some of you may know (and most probably don’t) that, among my many other hobbies, I am a bit of an armchair paleoanthropologist. Over the years I have assembled replicas of a few of the more significant fossil hominid finds that have shaped our understanding of human evolution. For this challenge, identify the fossils shown below with 1) “nickname” of the fossil (2 pts), 2) currently accepted genus (2 pts) and species (2 pts) assignment, 3) country of origin (2 pts), and 4) approximate age (2 pts). Comments will be held in moderation while the challenge is open to give all a chance to play. Answers will be revealed in the next couple of days or so.

p.s. Don’t be afraid to try—I’ll be surprised (and impressed) if anybody gets a clean sweep of the points. Good luck!

Update: Bonus question (to be used in case of a tiebreaker)—which of these is my favorite, and why (up to 5 pts)?

BitB ID Challenge #22

© Copyright Ted C. MacRae 2013