ants, n. — Green’s Dictionary of Slang

ants n.

[phr. below prob. predates n.]

1. (US) restlessness, anxiety.

1935		E. Anderson Hungry Men 17: I sure get ants when I have to stay in a spot long.
1946		J. Evans Halo in Blood (1988) 85: The papers play it up and the mayor starts getting ants about the third day and lights a fire under the commissioner.

2. (UK black) a parasite [SE ant, spoken as ants in Carib. E].

1956

S. Selvon Lonely Londoners 26: And also you have to look for work. I not saying you is a ants, but it have enough ants already in London.

In phrases

ants in one’s pants (also ants in one’s britches, ...in one’s slacks, ...up one’s ass)

(orig. US) a feeling of restlessness, being nervous, twitchy or (sexually) excited; thus extrapolation in cit. 1976.

[1918		Goodwin’s Wkly (Salt Lake City, UT) 30 Nov. 5/2: The ants have got into my pants / And are laying eggs as big as big Berthas].
1930		E. Glyn Flirt and Flapper 93: Flapper: I don’t know what I want —sometimes it’s Bruce and a baby, and sometimes it’s to [...] run wild all night — Oh, I get ants in my pants .
1931		Bo Carter ‘Ants in My Pants’ 🎵 I’m gonna hug you baby good and tight, / now love me baby like you done last night, / cause I got ants in my pants, baby for you.
1940		F.S. Fitzgerald ‘A Patriotic Short’ in Pat Hobby Stories (1967) 130: He’s got all the Spanish officers with ants in their pants.
1949		J. Archibald ‘State Penmanship’ Popular Detective Jan. 🌐 Mr. Buford Hake began to display ants in his slacks, but he said: [...] ‘Are you absolutely nuts?’.
1953		Kramer & Karr Teen-Age Gangs 24: You got too many ants in your pants tonight.
1955		T. Williams Cat on a Hot Tin Roof Act II: What makes you so restless? Have you got ants in your britches?
1963		A.E. Farrell Vengeance 76: It’s Alec all right [...] and it looks as if he’s got ants in his pants to frive like that.
1969		M. Puzo Godfather 103: He’d be as skittish as a donkey with ants up his ass.
1976		H. Selby Jr Demon (1979) 7: Knocking on his door when those ants invaded their pants.
1987		P. Robinson Gallows View (2002) 206: ‘Oh, don’t go on about it, Trev,’ Mick grumbled, shifting from one foot to the other as if he had ants in his pants.
2001		C. Brookmyre A Big Boy Did It And Ran Away 67: Ants in their pants because someone mentioned the Bogeyman.
2011		S. Kelman Pigeon English 60: The smell of beer [...] gave Dean ants in his pant [...] We had to stop ourselves from running away.