Table 1.

Results of randomization tests on phylogenetic and chemical overdispersion of Bursera communities

Area	Localization	Elevation, m	Phylogenetic distance					Chemical distance
			Observed, mean	Random, mean	Z score	P	No. of species sampled	Observed, mean	Random, mean	Z score	P	No. of species sampled	% species attacked by monophagous or oligophagous Blepharida
Chilpancingo	lat 17–18°, long 99–100°	400–650	40.530	38.795	0.473	0.338	12	0.909	0.815	1.548	0.031**	13	92
		400–1,000	38.614	38.705	−0.034	0.548	18	0.879	0.815	1.404	0.058*	19	78
		400–2,200	37.020	38.735	−0.993	0.847	29	0.814	0.814	−0.009	0.500	28	65
	lat 16–19°, long 98–101°	400–2,200	36.674	38.726	−1.428	0.913	34	0.817	0.815	0.066	0.435	36	61
Cañón del Zopilote	lat 18–19°, long 99–100°	400–500	40.800	38.700	0.288	0.355	5	0.960	0.184	1.280	0.060*	5	89
		400–750	40.056	38.796	0.276	0.424	9	0.904	0.815	1.321	0.064*	11	80
		400–1,000	39.181	38.714	0.151	0.469	15	0.896	0.815	1.480	0.044 **	15	79
		400–2,200	38.537	38.785	−0.110	0.577	22	0.812	0.815	−0.073	0.562	23	72
	lat 17–20°, long 98–101°	400–2,200	39.389	38.717	0.636	0.275	42	0.817	0.815	0.076	0.489	39	69
Tehuacán	lat 18–19°, long 97–98°	550–800	37.000	38.788	−0.393	0.696	9	0.935	0.815	1.413	0.036**	9	86
		550–2,200	36.894	38.687	−0.487	0.726	12	0.884	0.815	1.08	0.125	12	80
	lat 17–20°, long 96–99°	550–2,200	39.330	38.719	0.282	0.415	24	0.849	0.815	0.749	0.236	19	82
Infiernillo	lat 18–19°, long 101–102°	200–500	43.267	38.588	0.734	0.234	6	0.957	0.816	1.709	0.007**	8	86
		200–1,000	44.278	38.690	1.222	0.084*	9	0.927	0.816	1.776	0.011**	12	64
		200–2,200	40.627	38.710	0.719	0.223	18	0.876	0.815	1.328	0.075*	19	71
	lat 17–20°, long 100–103°	200–2,200	37.403	38.723	−0.757	0.784	29	0.843	0.815	0.835	0.209	27	68
Aguililla	lat 18–19°, long 102–103°	150–300	43.867	38.888	0.781	0.221	6	0.981	0.813	1.445	0.028**	5	80
		150–600	42.607	38.636	0.788	0.204	8	0.954	0.816	1.659	0.015**	8	89
		150–1,000	43.033	38.685	1.350	0.073*	14	0.888	0.814	1.204	0.094*	13	58
		150–2,000	43.331	38.755	1.879	0.017**	20	0.818	0.814	0.087	0.506	17	69
	lat 17–20°, long 101–104°	150–2,000	39.786	38.714	0.685	0.254	32	0.821	0.815	0.200	0.444	30	59
Zihuatanejo	lat 17–18°, long 101–102°	0–1,000	38.611	38.682	−0.014	0.547	9	0.786	0.815	−0.369	0.699	9	22
		0–2,000	39.439	38.767	0.186	0.461	12	0.778	0.813	−0.570	0.745	12	33
	lat 17–18°, long 101–102°	0–2,000	42.053	38.739	1.851	0.018**	28	0.806	0.814	−0.213	0.612	26	53
Aquila	lat 18–19°, long 103–104°	0–1,000	40.717	38.682	0.693	0.245	16	0.837	0.815	0.373	0.415	15	43
		0–2,000	41.987	38.704	0.466	0.054*	22	0.826	0.815	0.256	0.433	19	50
	lat 17–20°, long 102–105°	0–2,000	39.468	38.711	0.431	0.349	29	0.806	0.814	−0.237	0.620	26	52

For each community examined, the observed average chemical or phylogenetic distance between species was compared to a distribution of average chemical or phylogenetic distances of an equal number of randomly selected species (the null model). P values are reported for one-tailed tests, i.e., the observed chemical distance was greater than all but the proportion P of 1,000 null communities. ∗, P < 0.1; ∗∗, P < 0.05.