Comparisons of termites and termite-eating animals in Africa and Australia, part 1

Africa and Australia are comparable in their climates and geological substrates. How different are the termites (Isoptera) inhabiting these continents?

The answer is: different enough to explain categorical differences between Africa and Australia in the mammals, birds, reptiles, amphibians and invertebrates (e.g. see https://www.researchgate.net/publication/271689805_Why_Are_Termite-_and_Ant-Eating_Mammals_Smaller_in_Australia_Than_in_Southern_Africa_History_or_Ecology)?

The typical diet of termites is dead plant matter mixed with the fungal matter involved in decay. Many termites on both continents continue to function as detritivores, and the animals eating these may be discussed in a later Post.

However, the most important difference between the continents is that, in Africa but not in Australia, termites have adopted major categories of foraging not typically associated with them on a global basis.

The first and most significant of these is fungus-culturing, which is restricted to the subfamily Macrotermitinae of the family Termitidae. Macrotermitines (https://en.wikipedia.org/wiki/Macrotermitinae), particularly Macrotermes and Odontotermes, culture basidiomycetes in a way analogous to farming, making them the most productive termites on Earth.

The second category is grazing. In Africa but not Australia, termites are specialised to extend beyond the scope of detritivory, by cutting leaves and shoots in the living condition and transporting them to the hive/termitarium to be eaten in a non-decayed condition (https://www.inaturalist.org/observations/28225853).

These termites are partly in competition with herbivorous large mammals for food (https://web.archive.org/web/20110110065254/http://agriculture.kzntl.gov.za/publications/production_guidelines/veld_in_natal/veld_11.1.htm). Because green matter is more nutritious than litter, these termites too tend to be more productive than detritivorous termites.

And the third category is humus-eating. Certain tropical termites (e.g. Cubitermes, see https://www.alamy.com/termite-mound-cubitermes-sp-shape-thought-to-be-adapted-to-very-high-rainfall-highland-woodland-of-guinea-western-africa-image181667275.html) in Africa, living mainly in vegetation protected from wildfire, specialise in eating the organic matter component of soil - a role typically associated with earthworms.

In Australia, termites in these three categories of foraging (fungivores, herbivores and humivores) are either absent or so scarce and small-bodied that they are relatively unimportant in the diets of animals.

The productivity of fungus-culturing termites allows them to build massive mounds of earth (https://blog.longnow.org/02015/08/28/2000-year-old-termite-mounds-found-in-central-africa/), and to dig as deep as 40 m for nutrients (https://www.researchgate.net/publication/259094145_Do_the_large_termite_mounds_of_Macrotermes_concentrate_micronutrients_in_addition_to_macronutrients_in_nutrient-poor_African_savannas and https://www.cambridge.org/core/journals/journal-of-tropical-ecology/article/abs/nutrient-enrichment-of-ecosystems-by-fungusgrowing-versus-nonfungusgrowing-termites/96BD5D0590FB7961502B0BD23026D8E1 and https://zslpublications.onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.2008.00544.x). It also allows them to support termite-eating animals - ranging from the aardvark (https://en.wikipedia.org/wiki/Aardvark) to the ant Megaponera analis (https://en.wikipedia.org/wiki/Megaponera) - with no counterparts in Australia.

The two types of termites (Hodotermitidae https://www.youtube.com/watch?v=yGBJJNVxVy0 and some Nasutitermitinae https://en.wikipedia.org/wiki/Trinervitermes_trinervoides) in Africa that harvest and eat green matter likewise support various animals, ranging from the aardwolf (https://archive.md/20130415013011/http://www.hyaenidae.org/the-hyaenidae/aardwolf-proteles-cristatus/cristatus-diet-and-foraging.html) to the double-banded courser (https://en.wikipedia.org/wiki/Double-banded_courser), with no counterparts in the Australian fauna.

Humus-eating termites include remarkably large-bodied species in Africa (https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/cubitermes), and are an important part of the diet of the giant pangolin (https://onlinelibrary.wiley.com/doi/abs/10.1111/aje.12829 and https://en.wikipedia.org/wiki/Giant_pangolin).

The result:

The aardvark is the most massive myrmecophage (https://en.wikipedia.org/wiki/Myrmecophagy) on Earth. The aardwolf is the member of the Carnivora most specialised on Earth for a diet of termites. And the giant pangolin, although only about half the body mass of the aardvark, is at least fivefold heavier than the most massive myrmecophage in Australia, namely the short-beaked echidna (https://en.wikipedia.org/wiki/Short-beaked_echidna).

Posted on October 23, 2021 05:31 AM by milewski milewski

Comments

Come on!!
If you are going to compare Australia and Africa, then you deserve to include South America.
After all South America was part of Australia until it connected up with North America.

So where do the Edendates fit into all this? What do Amazonian and other S Am termites do?
Is Australia oddball, or is Africa?

You do it far more elegantly than I could.

Waiting on tenterhooks!

Posted by tonyrebelo over 2 years ago

@tonyrebelo South America is different again, but in some ways intermediate. There are no fungus-culturing termites, but on the other hand there are fungus-culturing ants - and these too have no counterparts in Australia. Despite not culturing fungus, Syntermes does build large mounds of earth (https://www.theatlantic.com/science/archive/2018/11/brazil-termite-murundus-mounds-space-4000-years-old/576160/), in some ways emulating the mounds of African macrotermitines in shaping the vegetation. There are, as far as I know, no termites in South America similar to Hodotermitidae, but Syntermes does extend to eating living herbaceous plants (e.g. see https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1439-0418.2002.00670.x), and the fungus-culturing ants perform a related function because they harvest green matter as well as collecting litter. So, the whole ecological organisation of the termite and ant communities is different from either Africa or Australia, but the productivity for myrmecophages is far greater than in Australia. As a result we have Myrmecophaga tridactyla, which is about the body size of the giant pangolin of Africa but with a far greater range of habitats. We also have the giant armadillo (https://en.wikipedia.org/wiki/Giant_armadillo), which falls somewhat short of the aardvark in both body mass and degree of specialisation on termites and ants, but is nonetheless far more massive than any comparable animal in Australia. The South American counterpart of the smaller pangolins is the edentate Tamandua (https://en.wikipedia.org/wiki/Tamandua). One genus of small armadillos is myrmecophagous or nearly so (https://en.wikipedia.org/wiki/Southern_three-banded_armadillo). However, South America lacks counterparts for not only the aardwolf but also the various Carnivora (e.g. Otocyon, Rhynchogale, Cynictis) which semi-specialise on termites in Africa.

Posted by milewski over 2 years ago

Fascinating! Thank you for your posts!

Posted by karoopixie over 2 years ago

@karoopixie You're most welcome and I'm glad you're enjoying the content.

Posted by milewski over 2 years ago

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