Table 1.

Elements in a species association matrix. Interaction frequencies (a_ij) between c animal and r plant species and their respective totals (rows:A_i, columns: A_j, total elements: m).

	Animal sp.1	sp. 2	...	sp. c	Total
Plant sp. 1	a11	a12	...	a1c	$A_{i=1}={\displaystyle \sum _{j=1}^c{a}_{1j}}$
sp. 2	a21	a22	...	a2c	$A_{i=2}={\displaystyle \sum _{j=1}^c{a}_{2j}}$
...	...	...	...	...	...
sp. r	ar1	ar2	...	arc	$A_{i=r}={\displaystyle \sum _{j=1}^c{a}_{rj}}$
Total	$A_{j=1}={\displaystyle \sum _{i=1}^r{a}_{i1}}$	$A_{j=2}={\displaystyle \sum _{i=1}^r{a}_{i2}}$	...	$A_{j=c}={\displaystyle \sum _{i=1}^r{a}_{ic}}$	$m={\displaystyle \sum _{i=1}^r{\displaystyle \sum _{j=1}^c{a}_{ij}}}$