Tempting tok-tokkies

In the 19th and early 20th centuries, some of the America’s greatest entomologists were coleopterists.  Army surgeons John L. LeConte and his protégé George W. Horn, California’s Henry C. Fall, Col. Thomas L. Casey (much maligned for his mihi itch¹ affliction, although in recent years regaining due respect for his insight on generic relationships), and “the Professor” Josef N. Knull, just to name a few.  What did these fine men have in common?  They studied beetles – not just tiger beetles or jewel beetles, but the entire order!  The world was much smaller then, and new information was generated at a much more leisurely pace.  Today such an approach is impossible.  With 300,000 described species in the order (conservatively) and growing, today’s students of Coleoptera must narrow their focus in one way or another – either by concentrating on one family or ecological guild, or by restricting their studies to a small geographic region.  I’ve tried, more or less successfully, to follow suite – jewel beetles are my primary focus, and I restrict my work with the ecologically similar longhorned beetles only to North American species.  Well, and I’m also working on tiger beetles, but only in Missouri… although I have begun taking fall tiger beetle trips to neighboring states.  Hmm, on second thought, I guess I haven’t been that successful at focusing (sigh! – and a likely explanation for my perpetual backlog of specimens unprocessed and papers unwritten).

¹In taxonomy, a term usually cast towards those who have a combination of disregard for quality over quantity when describing new taxa and a demonstrably high ego (Evenhuis 2008).

Whatever focus I do manage, it all goes out the window when I have the chance to collect in another country – especially someplace as exotic as Africa.  This is not a huge problem, as I can at least stay pretty much focused on just beetles.  Moths and butterflies are pretty, but it just takes too much effort to keep each specimen in good shape.  Bees and wasps also capture my interest, but I never know for sure whether I’ll get stung, and the extra precautions required to avoid such possibility are enough to make me pass on them.  Orthopterans don’t generally excite me unless they’re big and gaudy – in which case just one or two for the collection is fine.   And flies? Well, they’re flies! About the only non-coleopterans that regularly distract me are treehoppers – running into a mess of them, with their bizarre, fantastical shapes will always stop me in my tracks.  Fortunately, they’re not so abundant that they are constantly grabbing my attention.

Beetles, though – that’s a different story.  While I can resist the temptation to collect many of the groups outside of my sphere of interest, there are others that are consistently too tempting for me to pass up.  One of these is the Tenebrionidae, or darkling beetles.  With some 20,000 described species worldwide, it is among the most speciose of beetle families (larger than my beloved Buprestidae), and this diversity combines with difficult taxonomy to make them truly challenging for even the most serious students of the family.  For hacks like me, they’re impossible.  Moreover, they’re not even especialy pretty – usually just black.  Why do I collect them? Mostly because of their (in many cases) large size, comically awkward shuffling gait, and often exaggerated surface sculpturing.  Especialy diverse in more xeric habitats, I’ve collected quite a few in my frequent trips through the southwestern U.S. and even managed to get many of them identified by tenebrionid icon Charles A. Triplehorn.  Southern Africa is a true center of diversity for this group, with some 3,500 species recorded from the area – nearly 20% of the global diversity!  A number of particularly large species that go by the common name “tok-tokkies” make their homes in the dry Namib desert and surrounding bushveld.  Along with dungers and chafers and tyrant ground beetles, tok-tokkies would prove to be one more distraction in my nevertheless successful quest for African jewel beetles.

Psammodes hirtipes

Psammodes hirtipes

“Tok-tokkie” refers not to a particular genus or tribe of tenebrionids, but rather a number of flightless species that have developed a unique “tapping” method of communication between males and females.  The name “tok-tokkie” is onomatopoeic, referring to the sound these beetles make when they tap their abdomen on the ground.  In the same way that fireflies have species-specific patterns of flashes, different species of tok-tokkies tap with differing frequencies.  The beetle makes the noise by raising its abdomen and then bringing it down on the surface of the ground several times in quick succession.  Males initiate the tapping and await a response from a receptive female.  Signals are exchanged back and forth until, eventually, the two locate each other and mate.  Females lay eggs in shallow excavations in the dry, sandy soil, and the larvae that hatch feed within the soil on the roots of small plants. The dry Namib Desert has some of the most astounding species of tok-tokkies. Some – called “fog tok-tokkies” – have developed specially modified grooves to trap moisture from fog banks rolling onto the Atlantic coast. Others drink by doing a “head-stand” to allow condensed dew to trickle down to their mouths. Heat avoidance is another challenge in the Namib. Some species extrude dots of white wax from small pores on their elytra in response to increasing sunlight intensity, eventually appearing white-spotted or striped. The wax reflects the sun’s rays and helps keep the beetle cool. Other species beats the heat by running – in fact, the fastest running beetle in the world is one of the Namib tok-tokkies (and not, as I would have suspected, a tiger beetle). Unlike its mostly clumsy brethren around the rest of the world, this beetle blasts across the scorching sand at lighting speeds. A related species boasts the longest relative leg length of any beetle in the world.

Psammodes virago

Psammodes virago

I knew none of this in 1999 when I was in South Africa’s Northern (now Limpopo) Province, and while the tok-tokkies we encountered in the bushveld habitat below the Waterberg Range were not quite as marvelous as those of the nearby Namib Desert, they were still irresistible to this indefatigable beetle collector. Not knowing their names, we came up with our own names for them based on their appearance. Psammodes hirtipes was “wrinkle butt” due to the numerous prominent tubercles at the sides and rear of its otherwise smooth elytra. Psammodes virago, was “helmet beetle” because of its smoothly domed “army helmet” shape. Our designation of “armoured tank beetle” for Anomalipus elephas (photo credit) was amazingly close to its actual common name of “large armoured darkling beetle” (Picker et al. (2002), as was “white legs” for Dichtha incantatoris (photo credit), which Picker et al. (2002) call the “white-legged tok-tokkie”. In all, I collected some dozen species of tenebrionids during my stay at Geelhoutbos farm. Most of the smaller ones are still unidentified, but hopefully someday they will prove useful to some tenebrionid specialist.

The online magazine Travel Africa offers an informative article about the Namib tok-tokkies and this humerous video from National Geographic:

more about “Namib beetles – Travel Africa Magazine“, posted with vodpod

REFERENCES:

Evenhuis, N. L. 2008. The “Mihi itch”—a brief history. Zootaxa, 1890:59-68.

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

Copyright © Ted C. MacRae 2009

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About Ted C. MacRae

Ted C. MacRae is a research entomologist by vocation and beetle taxonomist by avocation. Areas of expertise in the latter include worldwide jewel beetles (Buprestidae) and North American longhorned beetles (Cerambycidae). More recent work has focused on North American tiger beetles (Cicindelidae) and their distribution, ecology, and conservation.
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12 Responses to Tempting tok-tokkies

  1. Embarrassingly enough, I don’ t remember coming across these during my stay in SA. I believe my first knowledge of the tok-tokkie was through the Jamie Uys’ film, ‘Animals Are Beautiful People’ from 1974. A humorous film well worth seeing.

  2. weirdbuglady says:

    It really is amazing how a few people were able to collect and name and study so many species – I’m doing a small beetle database project for a certain locality in Montreal, and going through the Lyman collection of beetles… it seems like LeConte named almost everything!

    Still being an undergrad student I don’t even know what order of insects I want to study, let alone able to pick a family. That’s the trouble with insects, they’re all fabulous.

  3. Adrian – I’ve never seen ‘Beautiful People’, but I just watched the drunk animal seen on YouTube – hilarious!

    weirdbuglady – yes, LeConte left a nice legacy. As for picking a group to study, I started my studies 30 years ago and am still having trouble deciding!

  4. Another fascinating article Ted. I love these beetles and when I find one, I cannot help but tap on the ground to see its response. There are so many of the species here, I always end up taking pics of them. You have almost got me to the point where I want to start a collection for myself.

  5. Nice blog! Brought back a flood of memories from my days in the RSA (1985-1988 ) and I spent the rest of the evening thumbing through my Field Guide to Insects of South Africa by Pickering et al. It was like visiting with old friends I had not seen in a long, long time. I would love to return there someday just to photograph every arthropod that I encounter!!

    I had my first in encounter with tok-tokkies in Namaqualand. We were collecting in a narrow, rocky kloof when I heard a clicking sound coming from one direction that seemed to be “answered” from another spot. Fortunately, I was with someone who explained to me what was going on. We had apparently stumbled upon an “amorous conversation” between a pair of lusty tenebs!

    Keep up the good work!

  6. Thanks, Joan and Art. Those were some fun beetles.

    Joan – give insect collecting a try and see what you think. If you don’t like it after all, I know someone who would be willing to provide a good home for your collection ;-)

    Art – I figured you’d like this one. Even with all the photographs I did take, I wish I’d put even more effort into photographing the many things that I experienced. I’ve got a few more things in the works from that trip that I’ll post over the coming weeks.

    p.s. – I still can’t believe we both used the word ‘indefatigable’ in our posts on the same day!

  7. :) Especially if it containes a lot of Buprestidae. This summer has been really bad. I have seen very few insects of any kind around. Even our trees are blooming 2 months later than usual, so I am not holding out for finding anything interesting this winter, although that does not stop me looking. :)

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  9. Just asking says:

    Hi guys.I live in the Eastern Cape Province of South Africa where we’ve been experiencing a drought for a long time.So Monday morning it started to rain and within 5 minutes it seemed as if our lawn was invaded with toktokkies and pretty soon there were happy couples going at it all over the place.Question 1)Why have I never seen them there before?Where would they most probably hide in your garden? 2)Why do they start mating in such a frenzy just as it started to rain?3)I am rather passionate about all things organical so why would these be good to keep around in the garden?Thanks…I’ll see if I can send you some photos tomorrow(Apparently it’s going to rain again)Ps: We also used to play a game in SA as kids where we knock on somebody’s frontdoor and hide away as soon they open the door!!!Even now the kids would ask if they may go toktokking!

  10. Just asking – thanks for your story about “toktokking” as a kid. I had read about tok-tokkies inspiring that children’s game, but it’s nice to hear from someone who actually did it.

    Regarding the sudden mating swarms in your yard, I don’t know about tok-tokkies specifically, but my experience in arid landscapes in many areas is that rains often prompt sudden bursts of insect activity to take advantage of the momentary resource in completing their life cycles. I would image the adults beetles are hiding under stones or debris – perhaps another person more familiar with the South African fauna can comment on this case in particular. They have probably always been around but you never noticed them because of timing, combination of drought length and rain intensity, etc.

    Tok-tokkie larvae feed in the soil on roots of small plants. I am not aware of them ever being considered garden pests. Adults are not only harmless, feeding on dead and decaying plant and animal matter, but also add a charming element of nature’s diversity to your garden. They should be welcomed and allowed to flourish.

    best regards–ted

    p.s. thanks for reading!

  11. Pingback: Darkling Beetle from South Africa is White-Legged Tok-Tokkie | What's That Bug?

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