Table 1.

Inflorescence, flower and fruit traits of Aechmea mertensii associated with either Camponotus femoratus (C.f-bromeliads, n = 22) or Pachycondyla goeldii (P.g-bromeliads, n = 26)

	C.f-bromeliads	P.g-bromeliads	U-test	P
Inflorescence traits
Inflorescence length (cm)	18·21  ±  2·03	5·71  ±  1·08	5·92	<0·0001
No. of spikes per inflorescence	26·95  ±  4·10	10·11  ±  2·14	5·79	<0·0001
No. of flowers per inflorescence	256·61  ±  61·55	64·24  ±  17·22	5·79	<0·0001
Flower traits
Flower length (mm)	1·30  ±  0·04	0·99  ±  0·04	5·92	<0·0001
Flower width (mm)	0·36  ±  0·01	0·32  ±  0·01	5·52	<0·0001
No. of ovules per flower	12·67  ±  0·53	9·29  ±  0·43	5·91	<0·0001
No. of pollen grains per flower	5825  ±  1985·85	3238  ±  1103·41	3·42	<0·0005
P/O ratio	479·25  ±  93·71	352·02  ±  60·96	1·92	0·054
Fruit traits
No. of fruits per inflorescence	209·52  ±  45·21	56·18  ±  12·06	5·66	<0·0001
Fruit-set (%)	84·43  ±  4·84	85·32  ±  2·88	0·55	0·577
No. of seeds per fruit	10·71  ±  0·89	7·50  ±  0·93	3·99	<0·0001
Seed mass per fruit (mg)	2·67  ±  0·32	1·84  ±  0·24	3·41	<0·0001

Comparison of both A. mertensii ant-garden variables (mean  ±  s.d.) were conducted using the non-parametric Mann–Whitney U-test.