Table 1. Number of insect species per plant species for various regions (i.e. the Cape Floristic Region, temperate zones, tropical zones).

The number of insect species per plant species is significantly higher in the tropics than the CFR, although this is entirely confounded by plant growth form. The CFR does not have significantly more insect species per plant species than other temperate zones, suggesting regional plant richness and growth form are better predictors of regional insect richness than environmental variables.

Insect:Plant ratio	Growth from	Region	Study
5.82	grass	CFR	This study
1.45	shrub	CFR	Prochess et al. (2009) [28]
2.06	shrub	CFR	Pryke & Samways (2008) [43]
4.34	grass	temperate	Zhu et al. (2012) [51]
3.24	grass	temperate	Collinge (2000) [52]
13.21	tree	temperate	Novotný et al. (2006) [20]
21.60	tree	temperate	Marques et al. (2006) [53]
1.24	shrub	temperate	Frenzel & Brandl (2003) [54]
2.18	shrub	temperate	Schaffers et al. (2008) [55]
23.27	tree	tropical	Basset & Novotný (1999) [56]
39.86	tree	tropical	Novotný et al. (2006) [20]
22.76	tree	tropical	Novotný et al. (2012) [50]
20.20	tree	tropical	Leps et al. (2001) [57]
35.00	tree	tropical	Novotný & Basset (2000)[58]