Table 1. Sharing coefficients for competing species used in the different scenarios.

	Signal			Public goods		Nutrients1
	S1		S2	F1	F2	N1	N2
Scenario 1: Symmetric sharing
Species A	1	a		1	b	(1−c)/2	c/2
Species B	a	1		b	1	c/2	(1−c)/2
Scenario 2: Exploitation
Species A	1	0		1	0	1	0
Species B	a	1		b	1	c/2	(1−c)/2

¹Note that the multiplier of 1/2 in the definition of c follows from the condition of constant nutrient intake. This multiplier is not necessary in the case of signals (a) and public goods (b).