Table 2.

Measurements (mean ± s.e.) (µm) in non-drinking, transition and drinking regions (1, 2 and 3, respectively) of butterfly proboscises (figure 5). Means in columns within species followed by the same letter are not significantly different (p > 0.05; Tukey-HSD)

Species	n	feeding guild	region	dorsal legulae width (upper branch only)	single galea width
Danaus plexippus	7	nectar	1	21.5 ± 1.0c	124.1 ± 1.4a
			2	31.7 ± 1.5b	117.3 ± 1.6b
			3	42.4 ± 1.3a	107.6 ± 0.7c
Papilio glaucus	4	nectar	1	39.7 ± 1.5c	167.3 ± 3.5a
			2	50.5 ± 1.6b	156.2 ± 3.1b
			3	57.9 ± 1.7a	133.6 ± 3.0c
Vanessa cardui	4	nectar	1	12.3 ± 0.6c	109.3 ± 3.3a
			2	19.2 ± 1.6b	101.9 ± 2.6a
			3	33.0 ± 1.7a	92.6 ± 1.5b
Polygonia interrogationis	6	sap	1	13.9 ± 0.4c	148.7 ± 2.8a
			2	34.1 ± 2.3b	125.5 ± 1.5b
			3	56.9 ± 0.6a	105.2 ± 1.1c
Limenitis arthemis astyanax	4	sap	1	18.2 ± 2.6c	261.1 ± 2.6a
			2	68.0 ± 4.8b	237.3 ± 3.0b
			3	92.4 ± 1.3a	188.7 ± 3.3c