Life cycle shifts in Baetis rhodani (Ephemeroptera) in the Norwegian mountains

Figures & data

Figure 1. Water temperatures at station 1 (outflow of Øvre Heimdalsvatn) and station 2 (inflow of Øvre Heimdalsvatn) from 1 June 1995 to 19 September 1996.

Figure 2. Life cycle of B. rhodani at stations 1–4 in Øvre Heimdalen.

Table 1. Growth data for B. rhodani in relation to water temperature at station in the inflow and outflow of Øvre Heimdalsvatn. All dates are in 1995 except for those marked with * which are in 1996. Temperatures are in °C and n is the number of individuals used in the calculations.

Sampling station	Period	Days	Length in mm with 95% CL	Weight in mg	Mean temperature	Temperature range	n	% Growth mm/day	r^2	Level of significance	% Growth mg/day
1	18 Jun–2 Jul	14	4.12(±0.43)–5.62(±0.60)	0.311–0.758	8.2	3.8–11.9	137	2.30	0.125	p > 0.05	6.6
1	30 Aug–3 Oct	34	1.84(±0.16)–3.52(±0.31)	0.031–0.198	8.3	3.2–11.2	238	2.04	0.421	p < 0.001	5.6
1	3 Oct–14 Jun*	254	3.51(±0.31)–5.69(±0.38)	0.196–0.786	1.1	0.1–5.0	148	0.20	0.3439	p < 0.001	0.5
2	18 Jun–12 Jul	24	1.70(±0.08)–2.15(±0.09)	0.024–0.048	6.8	3.3–11.7	366	0.99	0.1231	p < 0.05	2.9
2	12 Jul–16 Aug	35	2.15(±0.09)–3.24(±0.09)	0.048–0.156	11.5	8.1–15.6	457	1.31	0.3897	p < 0.001	3.4
2	30 Aug–3 Oct	34	3.57(±0.16)–4.96(±0.14)	0.206–0.529	5.0	0.1–8.9	145	0.99	0.53	p < 0.001	2.8
2	16 Aug–3 Oct	48	1.04(±0.11)–2.43(±0.17)	0.006–0.068	6.3	0.1–13.0	158	1.86	0.6886	p < 0.001	5.2
2	18 Jun–3 Oct	107	1.70(±0.08)–4.96(±0.14)	0.024–0.529	8.1	0.1–15.6	831	1.07	0.6847	p < 0.001	2.9
3	18 Jun–12 Jul	24	1.58(±0.16)–2.33(±0.15)	0.020–0.060	6.8	3.0–12.3	88	1.66	0.3695	p < 0.001	4.8
3	12 Jul–16 Aug	35	2.33(±0.15)–4.00(±0.09)	0.060–0.285	11.9	8.2–16.1	291	1.55	0.5031	p < 0.001	4.5
3	30 Aug–3 Oct	34	4.40(±0.15)–5.63(±0.12)	0.375–0.762	5.1	0.1–9.2	141	0.70	0.51	p < 0.001	2.1
3	16 Aug–3 Oct	48	1.13(±0.12)–4.14(±0.09)	0.008–0.315	6.3	0.1–13.3	143	2.67	0.8963	p < 0.001	8.1
3	18 Jun–3 Oct	107	1.58(±0.16)–5.63(±0.12)	0.020–0.762	8.3	0.1–16.1	476	1.14	0.7825	p < 0.001	3.5
3	3 Oct–14 Jun*	254	1.96(±0.09)–2.93(±0.48)	0.037–0.117	0.5	0.1–4.4	534	0.18	0.0348	p > 0.05	0.5
3	3 Oct–14 Jun*	254	5.63(±0.12)–7.55(±6.19)	0.762–1.772	0.5	0.1–4.4	68	0.12	0.2476	p < 0.05	0.3
4	18 Jun–12 Jul	24	2.15(±0.42)–2.69(±0.15)	0.048–0.091	6.0	1.6–12.7	166	0.99	0.0538	p > 0.05	2.7
4	12 Jul–16 Aug	35	2.69(±0.15)–3.93(±0.15)	0.091–0.271	13.2	10.5–15.8	305	1.10	0.2825	p < 0.001	3.2
4	30 Aug–19 Sep	20	4.53(±0.16)–5.50(±0.14)	0.408–0.713	7.9	1.0–9.5	108	0.99	0.4225	p < 0.001	2.8
4	16 Aug–3 Oct	48	1.18(±0.18)–3.20(±0.24)	0.009–0.150	7.7	1.0–14.5	133	1.85	0.6798	p < 0.001	6.2
4	18 Jun–19 Sep	93	2.15(±0.42)–5.50(±0.14)	0.048–0.713	9.9	1.0–15.8	504	1.09	0.6128	p < 0.001	2.9
4	3 Oct–14 Jun*	254	1.99(±0.15)–2.95(±0.25)	0.038–0.119	0.6	0.1–3.6	250	0.15	0.1625	p < 0.001	0.4