Mounting behavior of female Trichogramma wasp on a mated Pieris brassicae female

Trichogramma wasp mounts a mated female of the large cabbage white butterfly Pieris brassicae to hitch a ride to the butterfly’s oviposition sites where they parasitize the freshly laid eggs. In case wasps try to climb onto the butterfly’s leg, they can be kicked off. Therefore wasps mostly climb onto the butterfly’s wings after which they tend to move towards the thorax just behind the butterfly’s head.