Whether we are talking about "hornpipes, jigs, strathspeys or reels" (as Robert Burns lists them in his epic poem Tam O'Shanter) Scottish Country Dances are usually based on music with 8-bar phrases played 4 times to give a unit of 32 bars. Most commonly, a dance involves 4 couples in a set with a single repetition of the dance being performed by three of the couples, and requiring 32 bars, which are repeated 8 times. so that each of the couples performs the basic repetition twice as the lead dancers, giving an 8 x 32 bar dance. But there are many different patterns for other sets (of 3, 4, 5 or occasionally 6 couples) and with 40 or 48 bars per repetition. Usually, each repetition is a different tune, most commonly for 32-bar dances, the tunes consist of two parts, each of 8 bars and each played twice. In order to provide the music for a complete 8 x 32 bar dance, a band could play 8 different 32-bar tunes but this is exceedingly rare. Instead, it is normal for 4 tunes to be played with one (termed the dance's original tune) being played first and last and the other three being played twice giving a tune pattern such as ABCDBCDA. But there are many variations, eg, when the original tune has more than 2 parts.
Time Signatures and Tempi
Highland and SCD authorities
bagpipes vs dancing tempi
Reels (and hornpipes): 2/2 vs 2/4 and 4/4 (Advice from the Pont Street dem team piper: use 2/4 marches!)
Jigs 6/8 and very occasionally 9/8. Fewer notes per bar than reels so can be played faster.
Dances and Tunes
In compiling the following list, I am surprised about how many of the dances I know are associated with pipe tunes that I play. On the other hand there are many, many dances, that I either dance regularly or occasionally, which are not.
One of the most popular Scottish Country dances, the 8 x 32 bar Reel of the 51st Division, is danced to the tune The Drunken Piper. This is a very famous dance.
The Australian Ladies, a rarely played and somewhat unusual, 4-part competition march (unusual in that it is written in the key of D) is played as a reel for the 8 x 32 bar dance of the same name.
The Earl of Mansfield a 3-parted 2/4 march is used for the 8 x 48 bar reel of the same name.
The Meeting of the Waters
Mairi's Wedding, Brown-haired Maiden, one of the most popular dances (an 8 x 40 bar reel) using a very easy-to-play tune derived from the song of the same name.
Mrs MacPherson of Inveran, a a classic and challenging 6-parted bagpipe reel, often played by pipe bands as part of their competition March, Strathspey and Reel sets, is used for the 8 x 32 bar reel of the same name.
Interestingly, and surprisingly given that strathspeys are a form of dance unique to Scotland, very few strathspey tunes used in country dancing can be played on the pipes as they usually require a greater tonal range than the pipes can manage (an octave plus one note). The only dance I know is with an original tune that can be played on the pipes is the 8 x 32 bar Monymusk.
The 6/8 march, The Atholl Highlnders (either 4- or 6-parted) is played at jig tempo for the dance The Duke of Atholl's Reel (which is a jig!).
The Glendaruel Highlanders a 4-parted 6/8 march is used for the now rarely attempted dance, Bonnie Anne, a very complicated, once-through, 96-bar jig. The four parts of the tune provide 64 bars of music, followed by a repeat of the first two parts giving a further 32 bars. Easy for the piper but not for the dancers!
The De'il Amang the Tailors, a traditional 2-parted bagpipe reel, is the original tune for the 8 x 32 bar reel of the same name. I do not rate this nominally 3-couple dance highly (because the third couple just stands there for three-quarters of the dance. Mind you at the end of an evening of dancing it can be rather nice to just stand there. Perhaps more famously, this pipe tune is used for the first and last 40 bars of the Eightsome Reel (which also requires another eight 2-parted reels, each part being played three times) giving a total bar count of 40 + 8x48 + 40. 464 bars lasting just over 8 minutes. Some of the tunes played by some bands may also be pipe tunes, eg Muriel Johnstone includes The Fairy Dance, The Mason's Apron and Mrs Macleod of Raasay, all of which I used to play. But playing the pipes for a full dance of the Eightsome Reel is something I have never tried. The tempo and stamina required are too much for me.
The Blue Bonnets, a rather boring jig, IMHO, is danced to the 6/8 march of the same name.
The 5-couple jig Airie Bennan normally uses the 4-parted 6/8 march The Cock of the North as its original tune. The tune was popular amongst Glasgow children in my day due to the lyric used there: "Auntie Mary had a canary, up the leg of her drawers..."