Table 2.

Comparison of functional response parameter estimates for three amphipod size groups (intermediate D. villosus, large D. villosus and large G. pulex) feeding upon invasive X. laevis embryos and native R. temporaria larvae as prey.

Prey treatment	Base group	Comparator group	Parameter	Estimate (± SE) of difference ($\mathit{Da}$ or $\mathit{Dh}$)	z	P
X. laevis embryos	Large D. villosus	Intermediate D. villosus	$a$	0.233 (0.262)	0.890	0.373
			$h$	− 0.202 (0.067)	− 3.016	0.003
R. temporaria larvae	Large D. villosus	Large G. pulex	$a$	0.272 (0.205)	1.328	0.184
			$h$	− 5.606 (2.726)	− 2.056	0.040
	Intermediate D. villosus	Large G. pulex	$a$	0.477 (0.731)	0.652	0.515
			$h$	− 3.795 (2.811)	− 1.350	0.177
	Large D. villosus	Intermediate D. villosus	$a$	− 0.204 (0.735)	− 0.278	0.781
			$h$	− 1.814 (0.740)	− 2.451	0.014

Comparisons based on analyse conducted using ‘indicator’ variables in the frair package⁹⁷.

$a$ – attack coefficient, $h$—handling time (days prey item⁻¹), SE – Standard Error.

Significant differences are indicated in bold.