Marc T. J. Johnson and Anurag A. Agrawal. 2005. Plant genotype and environment interact to shape a diverse arthropod community on evening primrose (Oenothera biennis). Ecology 86:874–885.

Appendix A (Table A1). A test for crossover interactions for Simpson's diversity index using genetic correlations between each habitat (Thomas and Bazzaz 1993).

	Sandy	Xeric	Mowed	Disturbed
Mesic	0.47 (-0.02-0.80)	0.5 (-0.03-0.88)	0.17 (-0.4-0.71)	0.28 (-0.45-0.79)
Sandy		0.29 (-0.26-0.63)	0.08 (-0.50-0.68)	0.16 (-0.53-0.68)
Xeric			0.17 (-0.45-0.72)	0.07 (-0.55-0.60)
Mowed				0.23 (-0.30-0.67)

   Notes: Spearman's rho was calculated using rank correlations (upper number), while 95% confidence intervals (in parentheses) were estimated using 1000 bootstraps, with replacement, on the original correlation using Systat. In no case do the confidence intervals reach the null hypothesis of 1 (i.e. no crossovers), indicating significant crossover interactions between all habitats. 

LITERATURE CITED

Thomas, S. C., and F. A. Bazzaz. 1993. The genetic component in plant size hierarchies: norms of reaction to density in a Polygonum species. Ecological Monographs 63:231–249.