The Hawke's Bay-Wairarapa iwi's people have a Maori MP for 79 of the past 82 years.
Mr Tomoana believed Internet Mana machinations and crossfire with the Maori Party played into Ms Whaitiri's hands.
"The name-calling and the mud-slinging, the people weren't comfortable with that, so they went back to the mothership."
Aged 49 and raised around Whakatu and Hastings, Ms Whaitiri had an election-night majority of 4279, more than three times that of her by-election win in June last year after the death of East Coaster and former boss Parekura Horomia, who had been MP for 14 years.
Mana Movement candidate Te Hamua Nikora, based in Gisborne but with some particularly active campaigning in Hawke's Bay, had to settle for second place, as he did last year in what was also his first bid for a place in Parliament.
But he wasn't about to raise the white flag, telling followers yesterday: "In three years, that's us again."
Votes in Ikaroa Rawhiti totalled 18,820, about 600 more than the 2011 election.
Ms Whaitiri polled 8614, Mr Nikora 4335, and Wairarapa-based Maori Party candidate and prospective second Maori Party List MP Marama Fox 3315.