The subsocial bug Elasmucha dorsalis lays egg masses on the underside of the leaves of female plants of Aruncus dioicus. Each bug straddles her eggs and shields her offspring with her body, until they moult to the 2nd instar. Females that: attended aggregations of 2nd and later instar nymphs feeding on fruit of inflorescences often settled close to the basal part of or just below the aggregation, and faced towards the base of the inflorescence. The nymphal aggregations often Seemed to be too large for females to guard effectively. The position and orientation of females attending 2nd or later instar nymphs probably enabled them to detect predators walking towards the nymphs.