A: When it’s a longhorned beetle!
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.
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.
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 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!
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