nature

Born of glaciers

/ Ted C. MacRae / 11 Comments

Three months of camp life on Lake Tahoe would restore an Egyptian mummy to his pristine vigor, and give him an appetite like an alligator.–Mark Twain, Roughing It (1872)

p1020578_2 When Mark Twain first laid eyes upon Lake Tahoe in 1861, he thought it “must surely be the fairest picture the whole earth affords.” More than a century and a half later, that opinion is still shared by another Missouri boy, and though I would gladly welcome three months of camp life over one week at a ski resort, I nevertheless remain confident that my vigor will be fully restored by the time I return to work next Monday. The journey that began some days ago in the foothills of my beloved, ancient Ozark Highlands has today taken me to one of the youngest of landscapes to grace Lake Tahoe – Emerald Bay. I have written previously about Lake Tahoe (one year ago almost to the day) in a post that also featured photos of Emerald Bay and its only island, the iconic Fannette Island. p1020596_2 The Tahoe Basin itself is a relatively young landscape, forming within the last 5-10 million years as the basin floor dropped between two uplifted blocks. Volcanic flows in the valley on the north side of the present lake dammed the valley to form the lake, whose level has fluctuated drastically over time during the past 2 million years as Pleistocene glaciations have repeatedly damned the Truckee River that drains the lake into the lowlands of Nevada. At maximum, the level of the lake approached 7,000 feet in elevation – nearly 800 feet higher than today. p1020577_2 It was the last of these glacial events – near the end of the Pleistocene just 10,000 years ago – that gave birth to Emerald Bay. Unlike the “ice sheets” that spread out across much of the continent, the ice age here manifested itself as individual glaciers that formed at the highest elevations and carved out individual valleys as their crushing weight ground them inexorably downward. The elongated shape characteristic of such glacial valleys is seen not only in Emerald Bay, but in the adjacent Fallen Leaf Lake and Donner Lake in the north as well. John Muir alludes to this glacial birth in a description of Emerald Bay that he wrote in his private journal in 1888:

Emerald Bay is about two miles long. Its mouth is nearly closed by a terminal moraine; the sides are formed by lateral moraines. The left lateral is very striking, well formed, three or four hundred feet high where it joins the shoulder of the mountain, timbered with pine and spruce¹ sparsely on the grayish slopes.

¹ Actually firs, of the genus Abies.

Upper Eagle Falls from Eagle Lake - part of a ''glacial staircase'' above Emerald Bay

Upper Eagle Falls from Eagle Lake - part of a

Unfortunately, the very existence of Lake Tahoe is under threat. While the mountain building processes that created the Sierra Nevada have ceased for now, the erosive forces caused by weathering continue unabated. The Sierra Nevada range is being gradually worn down, and Lake Tahoe is filling with sediment at an average rate of about 1/10th of a millimeter per year. At this rate, Lake Tahoe will become a meadow in just over 3 million years.[/humor]

Lake Tahoe facts:

  • It is 22 miles long, 12 miles wide, and holds about 40 trillion gallons of water – enough to cover the entire state of California to a depth of 14.5 inches!
  • Maximum elevation of the lake surface is about 6,229 feet above sea level.
  • The lake is drained by the Truckee River, one of a few rivers that run inland to the desert rather than towards the ocean.
  • It is the third deepest lake in North America, with an average depth of 989 feet. However, the deepest point is about 1,645 feet.  It is the largest lake in North America above 600 feet elevation.
  • Surface temperatures can reach as high as 75°F in summer, but at depths below 600 feet the water remains a constant 40°F.
  • Lake Tahoe does not freeze over, although Emerald Bay has formed complete ice cover at least three times during the 20th Century and partial cover in more years.

More Lake Tahoe facts can be found at the U.S.D.A. Forest Service, Lake Tahoe Basin Management Unit FAQ site and at Tahoe Topics and FAQ’s, by David C. Antonucci (2004).

Copyright © Ted C. MacRae

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A journey through time

/ Ted C. MacRae / 6 Comments
hole_in_the_mountain

East Humbolt Range, northeastern Nevada

During the past two days, my family and I made the long drive from St. Louis, Missouri to Lake Tahoe, California to enjoy a week of skiing (both alpine and cross-country), snow-shoeing, hiking (at lower elevations), and decompression.  At 1,990 miles, it’s not a drive for the pampered or easily bored (and for those with children, thank goodness for in-car DVD players). Yet, for those willing to explore the little seen wonders of a landscape that most people see only from 30,000 feet, driving cross-country can be a richly rewarding experience.  I have traveled through many parts of the U.S., but this was my first time experiencing the “northern route” between Missouri and California along I-80.  Along the way, I saw:

  • Massive flocks of snow geese roosting in wetlands along the Platte River Valley, rising up at morning’s light in swirling clouds and stringing across the sky in vast, intersecting “V”s as they begin another day on their journey northward.
  • Sandhill cranes in the Nebraska Sand Hills, dropping down from the sky like miniature parachutes as they congregated in fallow corn fields to feed amongst the stubble.
  • The vast, high, arid, lonely expanses of the Wyoming Basin, transitioning from mixed-grass prairie in the east to sagebrush steppe in the west.
  • The stunningly spectacular descent down the western escarpment of the Wasatch Range, where the eastern edge of the Great Basin laps against the western edge of the Rocky Mountains.  (Nightfall unfortunately deprived me of my chance to see the vast Great Salt Lake and the even more expansive stretches of its associated salt flats.)
  • The magnificent Great Basin landscape and its alternating basin and range theme – its broad basins of salt lakes, marshes and mud flats interrupted at regular intervals by craggy, north to south mountain ranges formed as a result of strike-slip faulting during the past 30-50 million years as the thin Basin crust continues to crack and stretch even thinner.
  • The dramatic eastern face of the Sierra Nevada Range, its snow-capped peaks rising massively as a single granite block at the western edge of the Great Basin, and the equally dramatic, tortuous climb up to Spooner Pass at 7,200′ elevation before the 1,000′ drop down into the majestic Lake Tahoe Basin.

Driving across such a vast expanse of North America, especially in the west with its endless vistas and majestic landscapes, invites contemplation about earth and time.  Starting out in the foothills of my beloved Ozark Highlands – born before life itself and weathered for a billion and a half years, driving through the upstart Rocky Mountains – mere babies at only 50-100 million years of age, and finally arriving at the truly young Lake Tahoe – whose mere few million years of age make it a mere infant in geological time, I realized that the vastness of these landscapes, and of the countless tectonic, erosional and sedimentary episodes that shaped them, is surpassed only by the vastness of the time it took to create them.  For those willing to make the investment, driving through these landscapes is more than a trip across the country – it is a journey through time.

Copyright © Ted C. MacRae 2009

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Answers to “Winter botany quiz #2”

/ Ted C. MacRae / 3 Comments

Finally, I present to you the answers to “Winter botany quiz #2 “. The delay in providing these answers was two-fold. Firstly, I knew this would be a hard test, so I wanted to give people plenty of time to figure out the answers. Secondly, the answers were delayed an extra day due because of some debate that arose among the experts I consulted about #3 – more on that below. I thank all those who participated, and while there was no clear-cut “winner”, several honorable mentions are deserved:

  • Doug Taron, who was the first to properly deduce the South African nature of these plants.
  • James C. Trager, a myrmecologist (yet still my friend!) who correctly identified the genus of #1.
  • Everyone, for guessing that #2 was “an orchid” – although Tom @ Ohio Nature was the only one to use the formal scientific name for the family, and Doug Taron was the only one to attempt a generic identification (and came close – Oncidium and Ansellia are both assigned to the tribe Cymbidieae in the subfamily Epidendroideae).

#1.  Ornithogalum seineri (family Hyacinthaceae)
Ornithogalum is a large genus occurring mostly in the drier habitats of southern Africa and around the Mediterranean.  The genus and its relatives were formerly included in the Liliaceae (as many of the participants guessed), but the group is now given familial status as the Hyacinthaceae.  This genus contains numerous species of horticultural note.  One is (as James noted) O. umbellatum, or  “star of Bethlehem”, which in North America has escaped cultivation as a garden ornamental and gained status as an invasive weed.  Another is O. longibracteatum (syn. caudatum), a popular houseplant with the common name “pregnant onion”.  This species, native to the Cape and Natal Provinces of South Africa, is easily recognized by its bulb that “gives birth” to tiny replicas of itself just beneath a thin, transparent ‘onion’ skin (as shown in the photo at right from Trans-Pacific Nursery).  At flowering, a long spike grows from the center of the green strap leaves, eventually giving rise to a spearhead of tiny white flowers situated at the end.

While I couldn’t find much information about O. seineri, I did find this spectacular photo of numerous blooming plants in bushveld habitat amongst grazing zebra (photo by ingrid1968 in this post at SANParks.org Forum).  My view of this species was not quite so spectacular, as I saw only the lone plant in the photographs posted earlier.

#2.  Ansellia africana (family Orchidaceae)
Ansellia is an African genus of orchid commonly called Leopard Orchid or African Ansellia.  There is some degree of morphological, geographical and ecological variation in Ansellia populations, with the result that several species, subspecies and varieties have been described.  Flower color varies from pure yellow to variably splotched with brown to almost completely black with finely indicated yellow divisions.  Recent taxonomic work has concluded that there are no discontinuities within the spectra of variations exhibited and the populations are thus attributable to the single, polytopic species, A. africana (Khayota 1999).

Ansellia africana is a large, perennial, epiphytic species that usually grows attached to the branches of tall trees but is sometimes found growing on rocks.  This genus is immediately recognizable by its large, cane-like pseudobulbs that arise from a basal rhizome and is notable for the white, needle-like, upward pointing aerial roots that form a sort of “trash basket” around the clump.  The term is surprisingly appropriate, since the root basket seems to function in catching dropping leaves, flowers and detritus which provide nutrients for the plant as they decay.  This species can grow to enormous size and often forms spectacular clumps, some of which have an estimated weight of more than one ton.

Of the three plants featured in the quiz, this was the one I expected someone would guess, since the species is popularly cultivated by orchid enthusiasts.  Unfortunately, the pressures of wild collection for commercial purposes has caused declines in its population.  The problem is exacerbated by the unsustainable methods use to harvest, transport, and cultivate wild-born plants.  Host trees are usually cut down and sections with the orchid removed, resulting in wholesale destruction of both orchids and hosts. After harvesting, plants are cut up and transported slowly in open handcarts, to be sold along roadsides where they may sit exposed to full sun for days or weeks.  Cutting the clumps damages the roots, and exposure results in dessication, making it difficult for harvested plants to recover once in cultivation.  Plants that do survive harvest and transplant suffer high mortality rates in cultivation due to improper attention to light and moisture regimes.

#3. Adenia sp., poss. glauca (family Passifloraceae)
To be completely honest, not only did I not expect anyone to guess this one, I didn’t think I was even going to be able to provide an answer. I sent the photos to my friend and colleague, George Yatskievych, director of the Flora of Missouri Project (and author of the recently published Steyermark’s Flora of Missouri, 1999 and 2006), who forwarded the photographs to several more colleagues, and at the same time I posted the photos on SANParks.org Forum (a fantastic resource, which I just recently discovered myself, for those interested in South Africa National Parks and their natural history). It took some time for these sources to weigh in with their opinion, which in the end were in agreement that it represented a species of African passion flower in the genus Adenia of the family Passifloraceae (not to be confused with Adenium, a genus of flowering plants in the family Apocynaceae – also occurring in Africa). As for which species, the choices had been narrowed down to either A. glauca or A. fruticosa. According to Imberbe, a photo of the leaves would have been diagnostic, and the flowers are also different (A. glauca has yellow flowers while those of A. fruticosa are green). Fred Dortort, in an article on the University of California at Berkely Botanical Garden website titled, “Passion and Poison“, notes that A. fruticosa has a tall, spindle-shaped caudex topped with a few thin, sparsely-leafed, arching branches, while in A. glauca the caudex is roughly globose and can become quite large. This description seems to favor A. glauca, which Imberbe also noted was known to occur in the area where I took the photographs.

Species identification aside, the genus Adenia is notable for its bizarre adaptations for water storage. Most of the 100 or so species in this Afrotropical and Indomalaysian genus have underground tubers. Those of species adapted to drier environments have grown proportionately larger, with some turning into above ground caudices that can take several different forms and that, in some species, may reach up to eight feet in diameter and height. Even more notable than these succulent adaptations are the poisonous properties that many plants in the genus possess. Not all species have been analyzed (and I found little or conflicting information about A. glauca and A. fruticosa), but one species in the genus – A. digitata – has gained notoriety as perhaps the most poisonous plant in the world. Two different toxins are found within its tuber, one a cyanogenic glycoside, the other a particularly potent toxin called modeccin. The latter is a 57kD protein that resembles ricin and acts a powerful inhibitor of protein synthesis by binding to ribosomes (Gasperi-Campani et al. 1978). Imberbe, in her comments about the photos I posted on SANParks.org Forum, noted the following about plants in this group:

…take heed of the Afrikaans name “Bobbejaangif” (Baboon poison)… It has been used as a fish poison, as well as in suicide and murder. It causes nausea, fits and liver and kidney damage.

REFERENCES:

Gasperi-Campani, A., L. Barbieri, E. Lorenzoni, L. Montanaro, S. Sperti, E. Bonetti, & F. Stirpe. 1978. Modeccin, the toxin of Adenia digitata. Biochemistry Journal 174:491-496.

Khayota, B. N. 1999. Notes on systematics, ecology and conservation of Ansellia (Orchidaceae), pp. 423-425. In: J. Timberlake & S. Kativu (eds.), African Plants: Biodiversity, Taxonomy and Uses, Royal Botanic Gardens, Kew.

Copyright © Ted C. MacRae 2009

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Expanding blogroll

/ Ted C. MacRae / 9 Comments

I’m still looking for the correct answers to Winter botany quiz #2.  Several commentors have correctly identified the plant family for one of the three plants and gotten close with the second (it’s not a true Liliaceae), and Doug properly surmised that the photos were indeed taken in South Africa (specifically, in Limpopo Province near the Matlaba River in the vicinity of the Waterberg Range).  With the additional clues I’ve given in the comments to that post, I still think generic and even specific identifications are possible for #1 and #2, while for #3 an ID at any level may prove to be quite a challenge.

While we wait for those answers, I thought I would feature some of the recent additions to my ever-expanding blogroll.  Some of these blogs seem to be already well-known, but only recently have I stumbled onto them myself.  Others I think may not be so widely known, but should be.  All struck a chord with me for some reason, whether it be their entomology-related subject matter, focus on life or nature in my beloved Ozarks, or the brilliance of their writing or photography.  I encourage you to pay them a visit and see what they have to offer.

Botany
Several new links in this section are worth mention. A Neotropical Savanna is an excellent weblog by Mary Farmer about her experiences with plants in Panama (and occasionally their insect associates). Closer to home, Get Your Botany On! features contributions by a consortium of astute botanists, one of which is Missouri-based Justin Thomas.  Justin also writes his own blog – The Vasculum – his exquisite and informative writings are reminiscent of those found on my long-time personal favorite, Ozark Highlands of Missouri (by the ever-eloquent Allison Vaughn).

Insects & Invertebrates
The number of links in this section has grown tremendously in recent weeks.  Bug Eric is one of the newest of these on my list, but its author – Eric Eaton, of Kaufman Field Guide to Insects of North America fame, has been around the bug scene for a long time.  Bug Shutterbug! is the work of Kolby Kirk, whose just published book, Insects & Spiders of Nicaragua, showcases some of his extraordinary photography. Coleop-Terra is written in German, but author Robert Perger’s beautiful beetle photographs can be understood in any language. For regular lessons about the insects around us and their impact on humankind, visit Debbie’s Insects Blog by Debbie Hadley, and orthopteroid specialist Ed Baker keeps us updated on activities from “across the pond” at Invertebrate Diaries (Ed also recently hosted Circus of the Spineless Issue 36). Shelly Cox has joined our growing ranks of Missouri entomologists, posting insect photos on MObugs while she prepares a field guide to the common insects of my beloved home state. Sections, a relatively new blog by British entomologist Laurence Livermore, contains enough information in each post to satisfy even the most erudite among us, and some spectacular captive insects can be seen at SIAM Insect-Zoo & Museum. Rounding out this section, weirdbuglady gives a refreshing view of entomology from an unconventional (and sometimes delightfully immature) perspective.

Missouri & My Beloved Ozarks
This section features a second blog by Shelly Cox – Explore Missouri, which features non-insect nature photos from our beautiful state, while Beau thoughtfully chronicles life in rural Missouri with Fox Haven Journal.

Nature & Conservation
I added Brewster’s linnet . com because of a series of posts about a recent trip to the lower Rio Grande Valley of south Texas. Lindsay and Scott bill Through Handlens and Binoculars as a blog about “Botany… Birds… Butterflies…”, but its subject matter is, in reality, even more diverse (including this recent, informative post about gray tree frogs). I suspect Tom Arbour’s Ohio Nature Blog needs no introduction, considering his current post contains 30 comments as of the time of this writing!

Nature Photography
Some strong photography blogs are joined by Voyages Around My Camera, which features stunning photography by Adrian Thysse (who also authors Evolving Complexity).

Uncategoricalizable
Finally, I’ve added this completely new section specifically for Maggie’s quirky, vexing, and truly unique giroofasaurus-vexed. Nuff said!

Copyright © Ted C. MacRae 2009

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Winter botany quiz #2

/ Ted C. MacRae / 10 Comments

In the first winter botany quiz, I learned that I have some rather astute botanists amongst my readership. They were not only able to quickly identify to species every plant I had pictured but also identify their commonality, sometimes from quite afar. As a result, this one is harder.  I use the term “winter botany quiz” in the broadest possible sense – just because it’s winter here doesn’t mean it’s cold everywhere! All of the photos were taken in the same general (for now unspecified) locality during late November and early December (this paragraph simply reeks of clues!).

To give everyone a fair chance, I’ve turned on comment moderation so people can submit their answers without seeing what has already been submitted.  I’ll remove moderation after a couple days or so.  First one with all the right answers wins the admiration and jealousy of their peers!

424046-r1-e018_018_21

#1A

424046-r1-e019_019_21

#1B - closeup of flowers in #1A

424046-r1-e020_020_2

#2A

424046-r1-e021_021_2

#2B - closeup of flowers of #2A

424046-r1-e022_022_2

#3A - the vine, not the trees

424046-r1-e023_023_2

#3B - closeup of vine base

Copyright © Ted C. MacRae 2009

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Magodo – giant twig wilter

/ Ted C. MacRae / 16 Comments

petascelis-remipes

In previous posts, I have highlighted some of the insects I observed on a trip to South Africa in November-December 1999.  All of the photos I have shown to this point were taken at Borakalalo National Park in North West Province or at the Geelhoutbos farm of Susan Strauss below the Waterberg Range in the formerly Northern, now Limpopo Province.  Both of these locations are deep inside the bushveld, providing ample opportunity to observe an incredible diversity of insect life.  This is not to say that insects, even spectacular ones, cannot be found in more urban areas.  During the weekend between those two mini-expeditions, I stayed with my friend and colleague, Chuck Bellamy, at his home in Pretoria, a beautiful city with lovely architecture, elegant gardens… and some very impressive bugs!  The bug in this photo was found on a tree in a shrubby enclave, and at well over 35 mm in length it is easily the largest leaf-footed bug (order Hemiptera, family Coreidae) that I have ever seen.  Its chunky build, velvety black coloration with thin yellow lines along the sides and down the center of the thorax, and greatly enlarged hind femora quickly led me to a provisional identification of a male Petascelis remipes, or giant twig wilter.  This ID was confirmed by my friend and colleague Harry Brailovsky, an entomologist at UNAM (Universidad Nacional Autónoma de México) and world expert on Coreidae (and who, incidentally, just recently published a review of this Afrotropical genus – Brailovsky 2008).

According to Picker et al. (2002), these insects are found on plants in the genus Combretum.  Like most species in the family, they have scent (“stink”) glands that provide defensive capabilities. Adults are gregarious and bold, walking towards intruders with antennae vibrating when disturbed, and they are apparently capable of squirting their defensive secretions for some distance.  The nymphs are black as well but futher advertise their noxiousness with warning coloration of red spots on a whitish background. Interestingly, and despite their powerful chemical defenses, this species is considered a delicacy in parts of Mozambique where it is known as Magodo.  In a post called Insects for Dinner (in a blog with the eerily similar title, Beating about the Bush), Bart Wursten of Gorongosa National Park in Mozambique describes how local folk burn small patches of the grassland in which these insects are found to smoke them out and catch them.  The Magodo hunters kill the bugs by breaking off the head and removing the scent glands, which releases a very strong almond-like smell.  In doing this, the locals are able to catch considerable quantities of the bugs, which they eat with supper.

Lest you believe such practices are an anomaly, van Huis (2003) has compiled a list of about 250 insect species used as food in sub-Saharan Africa.  Lepidoptera, Orthoptera and Coleoptera represented the bulk (78%) of species eaten, with Isoptera, Hemiptera, Hymenoptera, Diptera and Odonota making up the rest.  Several examples of toxic insects and the traditional methods used to remove the poisons were given.  It was noted that whether or not insects are eaten depends not only on taste and nutritional value, but also on customs and ethnic preferences or prohibitions.  I’m not one to shy away from the thought of eating insects – after all, shrimp are just bugs that live in water, and insects rank far lower in ‘slime factor’ than many other invertebrates (e.g., oysters) that enjoy great popularity in our culture.  I’ve eaten roasted beet armyworm (Spodoptera exigua) pupae and munched on chocolate covered ants, but that’s kid stuff – the armyworms tasted like the soy sauce in which they were roasted, and the ants tasted like, well… chocolate.  I did once eat a softshelled crab (alive!), and I actually hope to one day taste the enormous grub of the giant metallic ceiba borer, Euchroma gigantea, eaten by indigenous cultures in Central and South America.   Still, I think I’d need a lot of faith in my chef’s scent gland removal prowess before I started scarfing Magodo down like popcorn.

What insects have you eaten?

REFERENCES:

Brailovsky, H.  2008. Notes on the genus Petascelis Signoret and description of one new species (Hemiptera: Heteroptera: Coreidae: Coreinae: Petascelini).  Zootaxa 1749:18–26.

Picker, M., C. Griffiths and A. Weaving. 2002. Field Guide to Insects of South Africa. Struik Publishers, Cape Town, 444 pp.

van Huis, A. 2003. Insects as food in sub-Saharan Africa. Insect Science and Its Application 23(3):163-185.

Copyright © Ted C. MacRae 2009

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Illinois Butterfly Monitoring Network

/ Ted C. MacRae / 6 Comments

For those of you who plan to be in the Chicago area on Saturday, March 7th, perhaps you’ll be interested in attending the 2009 Illinois Butterfly Monitoring Network Annual Indoor Workshop. I’ll be giving a talk entitled, “From Hilltops to Swamps: Insects in Missouri’s Rarest Prairies,” in which I’ll focus on the natural history and some associated insects in two of Missouri’s most critically imperiled natural communities – the loess hilltop prairies in the northwestern corner of the state, and the sand prairies of the southeastern lowlands. How a beetle guy ended up being invited to talk to a butterfly group is still a little confusing to me, but apparently IBMN Director, Doug Taron (author of Gossamer Tapestry) put in a good word for me.

The Illinois Butterfly Monitoring Network (IBMN) is a citizen scientist program monitoring the health of butterfly populations throughout northeastern and central Illinois.

The IBMN was initiated in 1987 by The Nature Conservancy to explore the effects of habitat management on invertebrates. From 7 sites in the Chicagoland area in its first year, the program has expanded greatly and is now monitoring more than 100 sites throughout Illinois.  Butterflies are ideal “indicator organisms” with which to monitor the effects of prescribed burning and other management techniques, since many species are restricted to intact prairie and savanna remnants by narrow habitat requirements.  The fact that they are relatively easy to identify allows them to be monitored in a cost effective manner with the help of dedicated amateurs.  Much the same can be said for tiger beetles (which will – surprise! – be featured prominently my talk).

The workshop will be held Saturday, March 7, 2009, 9:30 AM until 3:00 PM at the Gail Borden Public Library, 270 North Grove Avenue, Elgin (directions).  Registration is required, contact Mel Manner at (847) 464-4426 or by email.

Copyright © Ted C. MacRae 2009

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Ship-timber beetle

/ Ted C. MacRae / 18 Comments

Atractocerus brevicornis

One of the more unusual, and enigmatic, beetles that I encountered in South Africa was this beetle in the pantropical genus Atractocerus.  Placed in the family Lymexylidae (ship-timber beetles), species in this genus look less like beetles than they do large flying ants or strange damselflies due to their highly reduced elytra that expose their greatly elongated abdomen and leave the hind wings uncovered.  The hind wings also are unusual in that they are held fan-like in repose rather than folded as in most other beetles.  Atractocerus brevicornis is the only species in the genus found in Africa (Scholtz & Holm 1985).

Adults are attracted to light at night, as was this individual that came to our ultraviolet light at Geelhoutbos farm below the Waterberg Range in Limpopo Province. Nothing is known about the biology of Atractocerus, but larvae of other genera are reported to bore into hardwoods and palm stems (Picker et al. 2002). Larvae of the genera Lymexylon and Melittomma are believed to form symbiotic associations with ambrosia fungi that grow on the walls of their galleries (Young, 2002).  Adult females deposit fungal spores in a sticky matrix when they lay their eggs, and the hatching larvae carry the spores into wood on their bodies.  The large eyes of Atractocerus, however, suggest a predatory lifestyle. The common name of the family originates from a northern European species that has in the past been a destructive pest of ship timbers.

Atractocerus species are rarely encountered and therefore, not well studied. Their evolutionary history is still unknown; however, the oldest known lymexylid fossil is a very primitive member of the genus Atractocerus preserved in 100 myo Burmese amber (Grimwold & Engel 2005). Thus, the lineage containing these beetles had already appeared by the mid-Cretaceous and may have originated as early as the Jurassic, a fact that has earned them the moniker “living fossils.” These beetles were once thought to be among the most primitive of all Coleoptera – their simple wing venation, almost undifferentiated antennae and tarsi, and naked abdomen being likened to a supposed neuropteran common ancestor. Most authors now consider the family to be most closely related to the cucujiform groups Cleroidea and Cucujoidea (Wheeler 1986, Young 2002), although some have placed it in the Elateriformia near the Lampyridae based on wing venation. Scholtz and Holm (1985) accepted a cucujiform placement but related the group to the Styopidae (twisted-winged parasites), apparently due to the similarity of their highly reduced forwings.  At the same time, they acknowledged the many morphological and behavioral differences between the two groups, the latter itself being the subject of much evolutionary debate due to disagreement about whether the reduced forwings of male stylopids are truly homologous to the elytra of Coleoptera (some have even suggested homology with the halteres of Diptera that were switched from the metathorax to the mesothorax as a result of homeotic mutation). Most authors now place this latter group in the separate order Strepsiptera.

REFERENCES:

Grimaldi, D. and M. S. Engel. 2005. Evolution of the Insects. Cambridge University Press, New York, xv + 755 pp.

Picker, M., C. Griffiths and A. Weaving. 2002. Field Guide to Insects of South Africa. Struik Publishers, Cape Town, 444 pp.

Scholtz, C. H. and E. Holm (eds.). 1985. Insects of Southern Africa. Butterworths, Durbin, South Africa, 502 pp.

Wheeler, Q. D. 1986. Revision of the genera of Lymexylidae (Coleoptera: Cucujiformia). Bulletin of the American Museum of Natural History 183:113-210.

Young, D. K.  2002. 71. Lymexylidae Fleming 1821, pp. 261-262.  In: R. H. Arnett and M. C. Thomas [eds.], American Beetles, Volume 2, Polyphaga: Scarabaeoidea Through Curculionoidea, CRC Press, Boca Raton,880 pp.

Copyright © Ted C. MacRae 2009

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