Rooibos Bushes Keep Turning Up Insects Without Names

In the space of two years, three insects nobody had ever named were collected off cultivated rooibos bushes and described as new to science. Two of them arrived in the same paper. None of the three does the plant any harm, and almost nobody outside a small circle of taxonomists has heard of any of them.

The Ministry finds this rather comforting, and would like to explain why at some length, because there is no hurry.

Three species, two papers, one plant

The first arrived in June 2020, in a paper describing a new leafhopper genus, Geelus, and twelve new species at once¹. Its author is Michael Stiller of the Agricultural Research Council's Biosystematics Division, working from the National Collection of Insects in Pretoria. It ran to forty-four pages in the journal Zootaxa, and is indexed in the usual places² for anyone minded to check the Ministry's homework. Ten of the twelve species came from confined areas of northern and southwestern South Africa. The other two came from Namibia. One of them, Geelus dundraad, was collected on cultivated rooibos, and is smaller than a grain of rice.

The other two arrived in October 2022, in a seventy-nine-page survey of the leafhoppers of the Fynbos Biome⁴ by Stiller and Michael D. Webb, covering the low, hard-leaved scrub rooibos itself grows in. That paper describes eight new species and one new genus: three species of Colistra, one Proekoides, three Proekes, and a genus called Xhoreus with a single species in it. Its abstract contains one flat sentence the Ministry read twice. "Two species, C. acapitatus and C. bucapitatus, were collected on Rooibos tea."

So: Geelus dundraad in 2020, Colistra acapitatus and Colistra bucapitatus in 2022. Three animals, one plant, under three years. All of them were lifted off a crop grown commercially since the 1930s, in a district that has been farmed, walked over and driven through for a century, and none of them carried a name until the decade we are standing in.

Every one of the twelve was an Afrikaans word

Here is the part the Ministry would like framed and hung in the corridor.

Scientific names are conventionally built out of Latin or Greek. Geelus itself follows that habit loosely enough. The twelve species names in the 2020 paper do not follow it at all. They are ordinary Afrikaans words, used in the taxonomic convention called nouns in apposition, which permits a describing author to set a word beside the genus name and let it stand:

Geelus driehoekdraad. G. drietanddraad. G. dundraad. G. haakdraad. G. kinkeldraad. G. lemdraad. G. nektanddraad. G. platdraad. G. slangdraad. G. stompdraad. G. viertanddraad. G. vurkdraad.

Read down the list and the pattern arrives on its own. Every one of them ends in draad, the Afrikaans word for wire: triangle-wire, three-tooth-wire, thin-wire, hook-wire, kink-wire, blade-wire, flat-wire, snake-wire, blunt-wire, fork-wire.

The wire is not a description of the insect you would see. It is a description of something inside it.

Leafhoppers are a taxonomist's difficulty, because a great many of them look like one another: small, wedge-shaped, and inclined to leave before you have finished looking. The reliable differences are internal, in the fine architecture of the male reproductive anatomy, examined under magnification, which varies between species in ways the outside of the animal does not. In Geelus, the distinguishing structures are ridges and blade-like projections on a part called the aedeagal shaft, and they are thin, curved, hooked, forked and flattened in twelve consistently different ways.

So Stiller named each species for the shape of its own wire. The published etymology for Geelus lemdraad, recorded in the taxonomic literature³, reads: "Named in the Afrikaans language, nouns in apposition, lem, blade, and draad, wire, for the ridges or blade-like structures on the aedeagal shaft. Gender masculine." That single sentence lays bare the entire naming scheme.

Which tells you, by the same pattern, roughly what dundraad is saying. Dun is Afrikaans for thin. The name reads as thin-wire, almost certainly for a slender version of the same structure. The Ministry has read the etymology note for lemdraad in full and is inferring dundraad from the scheme rather than quoting a line it has seen, and would rather be dull about that than confident about it.

There is something quietly lovely in the choice all the same. A South African entomologist, describing South African insects from South African fields, reached for the language actually spoken in those fields and used farm words. Draad is the word for fence wire. It is what the Cederberg is strung with. Twelve insects nobody had ever named now carry a vocabulary you could hear at a farm gate.

The convention did not carry over to the 2022 paper, which builds its names the ordinary way, out of Latin. Acapitatus, bucapitatus, semialius: no farm gates there. The Afrikaans scheme belongs to the Geelus paper alone, which is part of why it is worth pointing at.

What "collected on rooibos" does and does not mean

Now the deflation, which the Ministry insists on delivering itself rather than leaving to a sceptical reader.

Being collected on a plant is not the same as living on it, and neither is the same as damaging it. Both papers are taxonomic descriptions. Their business is establishing what these animals are and how to tell them apart, not measuring what they do to a crop. Neither reports any damage to rooibos, because neither went looking for damage. And the 2020 paper is explicit that the genus is not fussy: between them, the twelve Geelus species were found on 35 plant species across 18 plant families. Whatever these insects want, a great many South African plants apparently provide it.

So none of the three is a pest of rooibos. Not a new threat, not an emerging concern, and not something any grower needs to do anything about. Rooibos does have real insect problems, three of them worth a farmer's attention, a leafhopper, a looper caterpillar and a moth whose larva bores into the root, and the Ministry has filed that story separately. This is not that story. This is a stranger and gentler one: animals that have been sitting on the crop all along, in plain sight, wanting nothing from anybody, and that simply did not have names.

The field has a longer history of this than you might expect. An even older Agricultural Research Council survey of cultivated rooibos, Riaan Stals's unpublished 1997 report⁸, had already counted well over a hundred insect species living on the bush, of which only a fraction were doing it any harm (the numbers are in the pests file). Even in the 1990s, on a crop somebody was studying carefully, the bushes were carrying more kinds of insect than anybody had names for.

There is one further detail in the 2022 paper worth having. All the species it treats are similar in appearance and size, and all of them have reduced hind wings, which is to say they are not built for going far. The distribution models in the paper show ranges confined to the Fynbos Biome and largely to the Western Cape. A rooibos field, then, sits inside the range of insects found in this one corner of the country and essentially nowhere outside it, and two of them were not on any list until 2022.

The drawers behind all three

None of this happened in a burst. It is a career. Michael Stiller has spent his working life describing southern African leafhoppers, one genus at a time: the year before Geelus, a new genus called Discolopeus with nine new species⁶, associated with shrubs, trees and poisonous plants in South Africa; in 2023, a revision of the genus Hadroca⁷ that described five more new species, a genus found only in South Africa and mostly in the Fynbos Biome, same as the rest.

That is what taxonomy looks like from the inside, and it does not look like discovery in the adventurous sense. It looks like drawers. Specimens come in from decades of fieldwork, are pinned, labelled, sorted, dissected, drawn, and compared against everything already described, and eventually a paper says: these eleven are one thing, this one is not, and here are the names. The fieldwork may be thirty years old. The animal may be common. The work is deciding, carefully and permanently, what to call it.

Almost nobody will read either of these papers. Very few rooibos farmers will ever hear the word dundraad, and no part of their season would change if they did. The Ministry is not going to pretend otherwise.

But it does mean something that the record is still open. A plant this thoroughly farmed, in a landscape this thoroughly mapped, handed over three animals new to science in under three years, and somebody in Pretoria sat down and gave them names.

Next time you are near a rooibos bush, know that there is a fair chance of something small and wedge-shaped somewhere on it, sitting still, harming nothing, carrying a name it did not have when you first started drinking the stuff.