The egg-burster in the Asian planthopper Ricania speculum (Walker) (Hemiptera Ricaniidae).
The exotic planthopper, Ricania speculum (Walker), was detected in 2014 in Liguria, Northern Italy, and recorded as first alert for Europe. This highly polyphagous species lays eggs on a wide range of host plants, including economically important crops. In this paper, we provide details on the egg-burster morphology and on the role it plays in the hatching process. Eggs are laid inside the tissues of young twigs or in the leaf midrib, leaving the anterior half and the micropylar area partially exposed. At hatching time, the mature embryo pierces through the eggshell with an egg-burster located on the mid-frontal region of the embryonic cuticle, never described so far in this species and in other Ricaniids. During the process of hatching, the embryonic cuticle splits over the head, progressively slipping downwards, and is finally released over the empty eggshell, with the egg-burster.