Fig. 1.

Kairomone-sensitive stages and time lag of development of inducible defences in Daphnialongicephala. (A–E) Dependence of defence expression on the initiation of kairomone exposure (A: 1st, B: 2nd, C: 3rd, D: 4th and E: 5th instar induction). Levels of significance are shown by shades of red; grey indicates no significant differences (NS) between the kairomone treatment and the control group. Defences are significantly expressed no earlier than the 4th instar irrespective of the initiation of kairomone application, i.e. kairomone exposure in the 1st or in the 2nd instar does not elicit defences before the 4th juvenile instar and therefore kairomone sensitivity starts in the 2nd juvenile instar. From the 2nd juvenile instar, a time lag of one instar can be observed between kairomone exposure and expression of defences. This is valid for all measured kairomone-sensitive stages.