Dear Sir,
A confession: I cheated a little. I assumed the Telugu member of your trio to be interchangeably Telugu and Kannadiga. That is of course something that will bring down every 'diga on my neck, and I will in all probability have to settle down away from Bangalore.
During our history course, when studying ancient India, we came across a curious period in Indian history called the Tripartite Struggle. During this period, which strictly speaking isn't ancient India, but really early mediaeval India, there were three dynasties in three corners of India struggling for power, and with sequential victories. Surprisingly, the majority of the victories were won by the southern power, the Rashtrakuta dynasty, against the north-western Rajput Pratihara, or Gurjara Pratihara, and the eastern Palas of Bengal.
This period of two hundred years saw almost cyclical swings in fortune, all marked by conquest of Kannauj, the golden apple of those times. There is no point in going into the intricate detail of campaign after campaign, except to observe certain things in the military historical and ethnic contexts.
In terms of military history, the significance of the Pratiharas and the different ways of war-making of the Pratihara and Rashtrakuta armies is worth mentioning.
The Pratihara were almost certainly a cavalry army, and used that arm extensively. They bottled up the Arab rulers of Sindh, and defeated their efforts to penetrate further in two different battles, which led to the loss of the left bank of the Indus, and the consolidation of Arab power in Mansurah, on the right bank. Subsequently, they found themselves constantly at war with Turkic invaders for nearly a century more, before they finally crumbled into their constituent feudatories, the Chauhans, of whom Prithviraj must be the best remembered, and the Guhilots took Chitorgarh. Three other clans, the Kalachuris, the Chandelas and the Paramars, broke off three other bits of the empire. Their rule over Kannauj lasted the longest, until Mahmud of Ghazni defeated them and sacked the city.
In sharp contrast, Rashtrakuta armies were largely infantry, although there were cavalry and elephant sections as well. It was with this infantry army that they flung back the cavalry armies of the west, and what seems to have been cavalry armies in the east as well. One historian of this period (I forget who, after 40 years of lack of access to the text books) called them the Assyrians of India, in tems of professional conduct of war.
In terms of ethnic observance, it makes nonsense of the British claim of martial races, since it was essentially the Kannadigas winning most battles, and the Bengalis and Rajputs being equally poised.
Considering that the battle for South India and East India, to quite an extent, the battles against the Marathas, including the future Duke of Wellington's signature battle, Assaye, were won by local recruits, it is clear that the martial races was an invention of the British.
I hope you found this curiousity of Indian history interesting: South Indian better than North, East Indian = Bengali and Rajput equally matched. But - alas - somebody sharp will ask me about Kambhoj horsemen riding for the Palas, and my whole pack of cards will come tumbling down!
Sincerely,