Table 1.
Experimental conditions of the six study species.
| Rosmarinus officinalisa,b | Asphodelus ramosusc | Lavandula stoechas | Echium plantagineumb,d | Ballota acetabulosae | Teucrium divaricatume | |
|---|---|---|---|---|---|---|
| EXPERIMENTAL GROUP | ||||||
| Flowering time (month of peak flowering) | October–April (midpoint January) | March | April | May | June | June |
| Date | 06.−29.01.2015 | 12.03.−28.03. 2014 | 30.03.−19.04.2014 | 05.05.−25.05. 2015 | 24.05.−17.06. 2014 | 24.05.−17.06.2014 |
| Day temperatures (°C) | 7–34 | 12–22 | 16–28 | 14.5–38.5 | 20–41 | 20–41 |
| 24 h average temperatures (°C) | 3.5–30.5 | 8.8–18.8 | 12.8–24.8 | 12–36 | 17.5–38.5 | 17.5–38.5 |
| Temperature increments (°C) | 4 | 2 | 2 | 4 | 3 | 3 |
| Number of steps | 8 | 6 | 7 | 7 | 8 | 8 |
| Light/dark (h) | 10/14 | 11/13 | 11/13 | 14/10 | 14/10 | 14/10 |
| Number of plants | 19 | 12 | 20 | 15 | 15 + 1 | 15 + 11 |
| CONTROL GROUP | ||||||
| Placement | Outdoors | Climate chamber | – | Outdoors | Outdoors | Outdoors |
| Date | 06.−29.01.2015 | 03.−24.03. 2015 | 05.05.−25.05. 2015 | 24.05.−08.07.2014 | 24.05.−08.07.2014 | |
| Day temperature (°C) | Failed (see text for details) | 15 | – | – | – | |
| 24 h average temperature (°C) | 11.8 | – | – | – | ||
| Number of steps | 6 | 7 | 15 | 15 | ||
| Light/dark (h) | 11/13 | – | – | – | ||
| Number of plants | 9 | 11 | 6 | 6 | 6 + 6 | |
First increment was 3°C due to technical limitations of the climate chamber.
Plants were treated twice during the experiment with the solution of Caster 20SL insecticide to treat a minor parasite infestation.
Due to two general power cuts (lasting several hours but with a prior notice given) the control group experiment had to be stopped twice and the plants were taken outdoors for the time of the blackout to maintain the dark/light regime. The temperature outdoors at the time was similar to that in the chamber. After resuming the experiment, the plants were again given time to adjust to the chamber to ensure equal sampling conditions. As a result, in two cases the time between two measurements was 5 days instead of the usual three. The interruptions did not have any detectable influence on the patterns of flowering and nectar production.
Plants were additionally watered, if necessary, on Day 3 after nectar sampling to retain soil moisture under extremely high temperatures.
Some of the original plants of were replaced when they reached the end of their flowering period, in order to have an equal number of test plants at each temperature step. e.g., one plant was replaced in the case of B. acetabulosa, so that each step would have 15 plants (number of plants: 15 + 1).