Wednesday, June 17, 2015

In search of the Arizona Oak Borer, Megapurpuricenus magnificus (LeConte), (Cerambycidae: Cerambycinae: Trachyderini) using *fermenting bait traps*

Part 1. Introduction

Last update: Thursday, August 6, 2015

Of all the species of longhorn beetles (Cerambycidae) in Arizona, the Oak Borer, Megapurpuricenus magnificus (LeConte) (formerly the genus Crioprosopus), is surely one of the most spectacular - “magnificent” as John LeConte aptly named it - thus making it highly prized and greatly coveted by students and collectors of all entomo-categories. Accordingly, various aspects of its life history (emergence, habitat preference, distribution, and abundance or lack there of) are distorted by considerable folklore, fish stories, and other dubious anecdotal information.

Megapurpuricenus magnificus (LeConte) 
Image from Eya (2015. Figs. 148 & 150)
Not being a stalwart cerambycid-ophile, a perusal of relevant literature was in order to distinguish Megapurpuricenus fact from fiction. An internet search returned three papers emphasizing biology and adult behavior:

 Hovore, F. T. 1983. Taxonomic and biological observations on southwestern Cerambycidae (Coleoptera). The Coleopterists Bulletin 37: 379-387.

Sanchez Mártinez, G., O. Moreno Rico, and M. E. Siqueiros Delgado 2010. Crioprosopus magnificus LeConte (Coleoptera:Cerambycidae) in Aguascalientes, Mexico: Biological observations and geographic distribution. The Coleopterists Bulletin 64: 319-328. 

Sanchez Mártinez, G., O. Moreno Rico, J. F. Reséndiz Martinez, V. J. Arriola Padilla, y E. González Gaona. 2014. El barrenador de encinos Crioprosopus magnificus: bases para su diagnóstico y control [The Oak Borer Crioprosopus magnificus: bases for diagnosis and control]. Centro de Investigación Regional Norte Centro Campo Experimental. Pabellón de Arteaga, Aguascalientes, México Folleto Técnico. Núm. 57. [includes color photos of adults, larvae, and oak damage]

A fourth taxonomic paper was obtained directly from the author: 

Eya, B. K. 2015. Revision of the genus Crioprosopus Audinet-Serville, and description of three new genera of Trachyderini (Coleoptera:Cerambycidae: Cerambycinae). Zootaxa 3914(4): 351-405. 

A collective synopsis of those papers provided the following baseline information:
  • Megapurpuricenus magnificus is a Mexican species which reaches its northern distributional limits in southeast Arizona.
  • Distribution: southeast Arizona (Cochise, Pima Counties) (Hovore 1983); north and central Mexico (Aguascalientes (Sanchez-Mártinez et al. 2010), Chihuahua (Eya 2015)). I was unable to verify the reference to “Sonora” attributed to Hovore (1983) cited on the website, BugGuide. Hovore’s paper makes no reference to the distributional extent of M. magnificus which deals solely with Arizona populations in Miller and Carr Canyons, Huachuca Mountains, Cochise County; Texas Canyon, at the northern end of the Dragoon Mountains, also Cochise County; and briefly mentions Kitt Peak, in the Quinlan Mountains, Pima County. Other reported localities in the Huachuca Mountains include Garden and Huachuca Canyons.
  •  Host restricted to Quercus spp.: Q. arizonicaQ. emoryi, Q. hypoleucoides (Hovore 1983); Q. potosina, Q. grisea, Q. eduardii, Q. aff. obtusata  (Sánchez-Martínez et al. 2010, 2014).  
  • Temporal data: approximately mid-June to early August with most collections in mid-July (Hovore 1983). 
  •  Adult emergence occurs during the early monsoon season once the average relative humidity reaches 50% or greater (Sanchez-Mártinez et al. 2010).
  • The largest flights are on warm sunny mornings following periods of rain with activity decreasing over subsequent dry days (Hovore 1983). In a vintage dog-eared field notebook I found where I had scrawled: "Crioprosopus Carr Cyn. (Huachuca Mtns) rainy a.m. VI-27-00" [sic] - evidently the data of a specimen I'd seen.
  •  Males fly swiftly over tree tops or slowly circle the outer canopy in search of females. Occasionally, males may also be encountered on the ground. Females are usually observed resting on the outer foliage of oaks (Hovore 1983).
  •  Adult activity is restricted to an approximate two to three hour period in the morning. A few were found as early as 0730h, with the greatest activity concentrated between 0930h and 1130h (Hovore 1983). 
  • In central Mexico, adult emergence is linked to new leaf growth on host plants. At this time of the year the foliage is orange to reddish, closely resembling the elytral color of M. magnificus (Sanchez-Mártinez et al. 2010).
  •  Although somewhat circumstantial, both Hovore (1983) and Sanchez-Mártinez et al. (2010) suggested years of local mass emergence with intervening years showing little to no adult activity. Hence, the “every three years” emergence theorem which also coincides with the three-year life cycle of M. magnificus reported by Sánchez-Martínez et al. (2010, 2014).
  • Signs of larval activity and adult emergence of M. magnificus on Quercus spp. consist of two types of wood boring evidence (Sánchez-Martínez et al. 2010):
1) Entrance holes on the main trunk with a profuse dark brown exudation and abundant frass accumulation at the base of the trunk.

Image from Sánchez-Martínez et al. (2010. Fig. 5)

2) Clean, round, or slightly elongated, exit holes about 1/2-inch (12mm) diameter on the main trunk, approximately 14-inches to 15-feet above ground level.

(Left) Emergence hole on Q. emoryi, Miller Canyon, Huachuca Mountains. (Right) Terminal leaf cluster of Q. emoryi.
The latter type perfectly describes the emergence hole I photographed on 23.VI.2015 (above), situated about four feet from ground level on the main trunk (± 20-inch dia.) of Q. emoryi, a recorded host of M. magnificus, in Miller Canyon, Huachuca Mountains. The exit hole and other older, sealed holes of similar diameter were on the west-facing side of the tree (shaded during morning hours). Sunlight not striking this side until late afternoon, at a waning angle, notably after the greatest period of adult activity (0930h-1130h) as reported by Hovore (1983).

In examining the exit hole, the recently exposed bark is clearly visible, in contrast to the weathered gray of the surrounding trunk. This strongly suggests a recent emergence of M. magnificus or, of course, another large species of coleoptera (Cerambycidae, Buprestidae?) that utilizes Quercus as a host. On 08-09.VI.2015, weather stations in the Huachuca Mountains reported from 0.30-inches (Ramsey Cyn.) to 0.47-inches (12 mi. SW of Sierra Vista, 5400 ft. elev.) of early seasonal rainfall. Based on the fresh, pristine condition of the exit hole, and if it is, in fact, that of M. magnificus, this moisture was apparently sufficient to stimulate, albeit limited, adult emergence.

From this information I was able to speculate what areas would provide the greatest possibility of bagging “The Red Beast.” Since Trachyderini and Purpuricenini are strongly attracted to fermenting baits (MacRae 2000), this type of trap was the obvious and most practical method to use. 

Trapping sites included three aforementioned areas with verified M. magnificus occurrence, all in Cochise County: Carr Canyon and Miller Canyon, on the east slope of the Huachuca Mountains, and Texas Canyon, at the north end of the Dragoon Mountains. A fourth intermediate locality with extensive oak woodlands on the east slope of the Dragoons, Cochise Stronghold, was also baited.
In earlier posts, I chronicled my efforts using “fermenting bait traps” (FBTs) to survey for and collect adults of Megacyllene robusta Linsley and Chemsak and other collateral coleoptera in southeast Arizona. For the neophyte and uninitiated, I have repeated my methods and bait ingredients from those posts with some minor editing and additions. The only variation worth mentioning is several puréed over-ripe bananas to the bait mixture: 

"Fermenting bait traps" have long been used to collect a wide variety of insects, especially coleoptera, that are often difficult to acquire by other means. They function by passively collecting the many insects that are attracted to the aroma of fermentation.

Essentially, about 1-qt of bait mixture is poured into a plastic container, typically a 1-gal juice or water jug, modified by cutting large openings on the sides for the insects to enter. The tall 2-liter soft drink bottles have been used with great success. There are probably as many bait variations as there are insects attracted to them and there is'nt a "perfect" bait recipe. A veritable smorgasbord of ingredients and combinations have been used including stale wine, flat beer, vinegar, canned juices, brown sugar, molasses, honey, palm sugar, golden cane syrup, malt extract, tannic acid, over-ripe or rotting fruit*, and denatured alcohol. There are many others. 

As a base of reference, use 1-lb dark brown sugar to 1-gal water (optional: one packet active dry baker‘s yeast to jump-start the fermentation process). It may take a few days for fermentation to produce a pungent effluvium.

An assortment of suitable bait containers.
*A little-known paper (see below) describes the serendipitous discovery of many Trachyderes (Dendrobius) mandibularis (Dupont) (also Trachyderini) attracted to watermelon rinds discarded in a trash can at a roadside picnic area in southeast Arizona.

Hang traps along the edge of the forest or dense areas of shrubbery. Traps placed inside forests or stands of vegetation may yield smaller amounts of beetles but possibly different species. From my observations baiting for Megacyllene, it appeared that traps placed in areas that received several hours of direct sunlight collected more individuals - perhaps passive solar heat gain of the bait made it more aromatic and attractive - at least to insects.

Check traps every 3-5 days by pouring the bait through a fine kitchen strainer. If the trap is hung more or less at eye level, you can make a visual inspection of the contents to determine whether thorough straining is necessary. If not, I suggest using a small kitchen strainer to remove the surface debris that accumulates. Reuse and/or refill the bait to a suitable level.

Collected specimens should be rinsed in clean water to remove bait residue.

Huachuca Mountains, Carr Canyon, Forest Road 368, 1715m

Huachuca Mountains, Carr Canyon, Forest Road 368, 1520m
At a few locations where I intended to deploy traps, for a variety of reasons, it wouldn’t be convenient to check and service the traps on a frequent basis - possibly every few weeks or more rather than every few days. My solution to this predicament was to use 5-gallon polyethylene fry oil containers. Free for the asking from your local corner cafe, greasy spoon or watering hole. Nothing says “Welcome to Arizona” quite like a tall schooner of your favorite micro-brew accompanied by deep-fried gastronomic treats like a platter of pig's ears - cut to look like curly fries of course - or a bowl of crispy rooster combs - don‘t forget the jalapeño queso and salsa
Considering, 1) the fry oil container can hold significantly more bait mixture compared to a 1-gallon milk or water jug; 2) the volume of the container to open area for the effluvium to escape and beetles to enter; and 3) the moderate micro-climate beneath the oak canopy, I speculated, loss of bait through evaporation would be negligible and the need for frequent servicing alleviated. I also wondered if the residue of fry oil in the container (in this case, soy bean oil) might also contribute residual olfactory properties attractive to coleoptera and other insects.

Huachuca Mountains, Miller Canyon, Miller Peak, Forest Road 367
 Huachuca Mountains, Miller Canyon, Forest Road 367
Hypothesized biogeography. The northern dispersal of proto-Megapurpuricenus into Arizona from Mexico may have been possible during the Pleistocene by the temperate corridor of the Sierra Madre Occidental orogenic belt of western Mexico. At that time, an extensive pine-oak savanna existed in what is now northern Mexico and adjacent southern Arizona (Galloway 1970, Messing 1986, and references therein). With ensuing climate change and the formation and expansion of desert ecosystems, the distribution of Megapurpuricenus was presumably fragmented and subsequently isolated to the “sky island” mountain ranges where pine-oak woodlands retreated to suitable mesic habitats. Some of these mountain ranges, namely the Huachucas, Dragoons, and Quinlans, are where M. magnificus occurs today. It must be emphasized, however, lacking fossil evidence, the paleo-dispersal of Megapurpuricenus is at best speculative reasoning and conjecture.
Dragoon Mountains, Texas Canyon
Dragoon Mountains, Texas Canyon

Thursday, July 09, 2015

All FBTs (16) were checked and serviced on Tuesday, July 07. In addition to the recycled bait, I topped-off the traps with fresh liquid to which, this time, I added 40-ozs of cheap malt liquor (the type that is typically consumed while wrapped in a brown paper sack). No M. magnificus were in any of the traps - as yet anyway. Hovore (1983) stated that most collections were in mid-July as are the dates on all of the 39 specimens examined by Eya (2015). So, in theory, it is still early for, but approaching, peak activity of adult M. magnificus.

Contents of FBT in lower Miller Canyon, Huachuca Mountains.
The majority of traps in Miller and Carr Canyons were more of less similar. However, it was clear that traps at lower-to-mid elevations (1600-1700m) attracted a greater quantity and diversity than those at higher locations (>1700m). The latter consisting mostly of moths.

Texas Canyon has yet to receive adequate rainfall. Only a handful of Anomala spp. and one Euphoria leucographa (Gory & Percheron) were in FBTs there.

The large kitchen strainer is actually a splatter shield placed over frying foods. The plastic colander probably isn’t necessary but I prefer the raised sides surrounding the inner strainer when emptying trap contents. Everything, except the coffee can, was purchased at a local thrift store for less than $1.50 USD.
Older emergence hole (arrow) and exudate stain on Quercus emoryi, lower Miller Canyon, Huachuca Mountains.
Suggestive of the wood boring evidence of M. magnificus reported by Sánchez-Martínez et al. (2010 Fig. 5).

Saturday, July 11, 2015

FBTs in Carr and Miller Canyons were checked and serviced. No M. magnificus were in any of the traps. Near one of the traps in lower Miller Canyon (1650m elevation) I found a right elytron from a male M. magnificus and also saw another flying >20-feet above the ground around a large oak. Rain frequency has decreased within the last week which has significantly curtailed trap contents except for Cotinus.

On July 12, fellow FBT enthusiast, Paul Kaufman, commented: "... I saw 3 males flying in lower Miller Canyon on the 10th and 11th - caught one [photo below]. I understand they are flying in Ramsey Canyon." [read complete comment below]

Paul's reference to "Ramsey Canyon" confirms and fills an intermediate distributional gap between Carr and Miller Canyons and other reported localities in Garden and Huachuca Canyons.

Saturday, July 18, 2015

Since my last update, the monsoons have resumed in regularity. While my primary objective is M. magnificus, the FBTs are attracting a variety of other macro- and microcoleoptera representing Scarabaeidae, Cerambycidae, Elateridae, Nitidulidae, and Staphylinidae as well as Neuroptera (Chrysopidae, Mantispidae, Myrmeleontidae), and Lepidoptera.

For general curiosity, I hung two traps baited with red wine vinegar and water (3:1) in lower (>1600m) Miller Canyon.

Thursday, August 06, 2015 

Here is the citation and paper regarding Trachyderes (Dendrobius) mandibularis attracted to watermelon rinds mentioned above:

Chemsak, J. A. 1958. An attractant for two species of Cerambycidae (Coleoptera). The Pan-Pacific Entomologist 34(1):42.

 I doff my hat to Brady Richards, Aquatic Bioassessment Laboratory, California State University, Chico, for contributing a .pdf of this paper.

Other literature cited:

Galloway, R. W. 1970. The full glacial climate in the southwestern United States. Annals of the American Association of Geographers 60: 245-256. 
 “The gods play no favorites.”
 ~ Charles Bukowski

MacRae, T. C. 2000. Review of the genus Purpuricenus Dejean (Coleoptera: Cerambycidae) in North America. The Pan-Pacific Entomologist 76: 137-169.

Messing, H. J. 1986. A late Pleistocene-Holocene fauna from Chihuahua, Mexico. Southwestern Naturalist 31: 277-288. 

Part 2.: Fortune favors the prepared mind (in preparation).

For the temporary use of the Megapurpuricenus magnificus photos from their publications, I gratefully acknowledge G. Sánchez-Martínez, O. Moreno-Rico, and M. E. Siqueiros-Delgado (2010), and B.K. Eya (2015). Thanks also to B.K. Eya for a .pdf of his excellent paper cited herein, and Paul Kaufman for submitting the photo of M. magnificus he collected.

Additional contributions, observations, information and/or corrections requested.

If you free yourself from the conventional reaction to a quantity like a million years, you free yourself a bit from the boundaries of human time. And then in a way you do not live at all, but in another way you live forever.” ~ John McPhee, Basin and Range
Many thanks to Paul Kaufman for submitting this photo of M. magnificus he collected in lower Miller Canyon.

© Delbert La Rue 2015. All Rights Reserved.