TABLE 1.

Formation of labeled acetate and CH₄ from ¹⁴CO₂ in gut homogenates of Cubitermes spp. in the presence and absence of external electron donors.

Termite species	Electron donor	Formation rate (nmol gut−1 h−1)a
		Acetateb	CH4
C. umbratus	Nonec	0.016	1.60
	H2d	0.27	3.21
C. orthognathus	Nonec	0.037	1.03
	H2d	0.23	2.66
	Formatec	0.12	1.70

^aRates were calculated by linear regression by using the data points of two replicate assays (r² ≥ 0.95). 

^bCalculated assuming that both C atoms of acetate stem from CO₂. 

^cIncubation atmosphere: N₂-CO₂ (80/20 [vol/vol]). 

^dIncubation atmosphere: H₂-CO₂ (80/20 [vol/vol]).