Fig. 2

Experimental set -up used for testing ballooning activity in Argiope bruennichi spiderlings. Each spiderling was placed individually on a ballooning unit (b). Behind the six ballooning units PC ventilators (a) were installed on a wooden beam to direct the silk threats. Under the ballooning unit a larger ventilator (c) was fixed to generate upward wind velocities. Grey arrows represent the direction of the airflow