Termite mounds in tropical Asia are puzzlingly different from those in Africa

Everyone knows that the only part of the world that bears any faunistic resemblance to Africa is tropical Asia, particularly the Indian subcontinent.

However, what may be poorly appreciated by most naturalists is how this relates to the ecologically important fungus-culturing termites, Macrotermes and Odontotermes.

Both of these genera occur in both Africa and Asia. However, the main differences are that the largest above-ground structures

  • are built by Macrotermes in Africa, vs by Odontotermes in Asia, and
  • are far smaller in Asia than in Africa.

Lee and Wood (1971), on page 172, states:
"Large termite mounds (species not identified) are common on grey soils near Soekamandi (https://mapcarta.com/15598374) in Java."

Mounds, large enough to be sites for the cultivation of dryland crops, are scattered through rice paddies on the flat lowlands of Thailand.

In Sri Lanka, mounds of Odontotermes redemanni (https://en.wikipedia.org/wiki/Odontotermes_redemanni#:~:text=Odontotermes%20redemanni%2C%20is%20a%20species,of%20sugarcane%2C%20tea%20and%20coconut.) are large enough for the cultivation of crops.

In central Congo, there are large fossil mounds (now abandoned) of termites, dating from a previous dry period. These nave densities of 4-7/ha, and occupy 30% of the ground surface. The outer layer of these mounds is fairly fertile. However, the central mass consists of subsoil, which has proven to be infertile for cultivated crops when levelled. In this area, horticulture has produced large patches of sterile ground.

Hesse (1955) noted that, in many areas of East Africa, the mounds of termites are used as earth-licks (i.e. for geophagy), by Bos and wild ungulates. (My commentary: in my experience, this includes the relatively small mounds of Odontotermes.)

The chapter 'Effects on vegetation' in Lee and Wood (1971, pp. 162 ff) is a good review of the patterns of vegetation on large mounds. "In Thailand, Pendleton (1941) noted that large termite mounds (Macrotermitinae) were occupied by a dense growth of trees and shrubs which did not grow well, if at all, on the padi or forested land around them".

Posted on June 04, 2023 02:06 AM by milewski milewski

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It has been noted, in the literature, that the ability of the various spp. of Macrotermes to build mounds of characteristic types, regardless of the parent subsoil, is remarkable.

However, the mounds of Macrotermes are absent from most of the Athi-Kapiti plains (https://kwcakenya.com/regional-associations/athi-kapiti-wildlife-conservancies-association/), an area of about 3,500 square km.

However, large, low mounds of Odontotermes do occur here.

These plains are of 'black cotton soils', i.e. montmorillonite-rich vertisols. I suspect that termites cannot build large, structured mounds or termitaria on cracking clay.

Elsewhere in the vicinity of Kajiado (https://en.wikipedia.org/wiki/Kajiado), Macrotermes occurs on various substrates, other than cracking clay.

Posted by milewski over 1 year ago

A biogeographical aspect worthy of further investigation is a difference between India and Africa in ants specialising in the predation of Macrotermes and Odontotermes.

In Africa, there are at least two species of large-bodied ants (>1 cm in one species and >2 cm in the other) that specialise on eating Macrotermes, as follows.

Both are widespread in Africa south of the Sahara.

Megaponera analis (https://www.inaturalist.org/taxa/426190-Megaponera-analis) workers have body length of 5-18 mm.

Paltothyreus tarsatus (https://www.inaturalist.org/taxa/475699-Paltothyreus-tarsatus) is the largest-bodied ant in Africa; workers have body length of 4-25 cm.

In West Africa, M. analis eats exclusively Macrotermes; P. tarsatus particularly eats Macrotermes bellicosus (https://www.inaturalist.org/taxa/346641-Macrotermes-bellicosus), but is not exclusively a myrmecophage.

Which comparable spp. of ants, if any, occur in India?

Please see Roedel M-O and Braun U (1999, https://onlinelibrary.wiley.com/doi/10.1111/j.1744-7429.1999.tb00128.x and https://www.jstor.org/stable/2663971 and https://agris.fao.org/agris-search/search.do?recordID=US201302908193 and https://www.semanticscholar.org/paper/Associations-between-Anurans-and-Ants-in-a-West-and-R%C3%B6del-Braun/94c8c9578fe8d299a9181fd5dda3063dac33f456).

Posted by milewski over 1 year ago

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