Scarcity of termitaria of the grass-harvesting termite Trinervitermes in Namibia, and implications for the aardwolf (Proteles cristatus)

@hamishrobertson @tonyrebelo @jeremygilmore @botswanabugs

In May 2006, a colleague and I traversed Namibia from the southern border to the eastern Caprivi Strip.

One of my search-images at the time was for the termitaria of Trinervitermes (https://www.inaturalist.org/observations?taxon_id=567388).

Trinervitermes trinervoides is widespread and common in South Africa. It is one of the main foods of Proteles cristatus, which is remarkably widespread in southern Africa (https://www.inaturalist.org/taxa/1306005-Proteles-cristatus).

There is at least one record of a termitarium of Trinervitermes in Namibia (https://www.inaturalist.org/observations/154573786). This is in the pro-Namib, viz. the eastern border of the Namib desert (https://www.landscapesnamibia.org/sossusvlei-namib/landscape-members/689 and https://www.sciencedirect.com/science/article/abs/pii/S0140196396902037 and https://www.sciencedirect.com/science/article/abs/pii/S0140196318302155).

Another record is pertinent. The incidence of termitaria of Trinervitermes in the Kgalagadi Transfrontier Park (https://www.inaturalist.org/observations/32915349) indicates that there may be a similar incidence in the adjacent part of Namibia, where the relevant environment straddles the international border.

However, in my own transect of Namibia, I did not spot even a single termitarium of this genus.

This raises a puzzle.

Proteles cristatus is widespread in Namibia (https://www.inaturalist.org/observations?place_id=7140&taxon_id=1306005).

Since its diet in southern Africa is said to consist mainly of Hodotermes and Trinervitermes (in that order of preference), three possible explanations are:

On 11 May 2006, we excavated an abandoned mound of Macrotermes michaelseni, near Okahandja (https://en.wikipedia.org/wiki/Okahandja). This fungus-culturing termite is absent from the southern half of Namibia.

Trinervitermes - and its stores of cut grass-stems - was present inside this mound. I tasted the nasutes to confirm the taste of turpentine. It seems that Trinervitermes exploits old mounds of Macrotermes, without changing their external appearance.

Elsewhere in northern Namibia, I found Hodotermes in the mounds of M. michaelseni.

This observation raises the following question:
Where Trinervitermes and Macrotermes coexist, is it true to say that the former refrains from building its own above-ground structures?

Publicado el mayo 25, 2023 12:06 MAÑANA por milewski milewski

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