The larval habitat ofMonodiamesa ekmaniBrundin in Lough Neagh. Northern Ireland is shallow water. ≤5m depth, on a sandy substrate. Within that habitat, larval distribution is affected by the degree of disturbance of the sediment due to wave action. Larvae are most abundant generally at 4m depth, where disturbance is low throughout the year. In an area of sand bars, larvae are more abundant in the bar troughs than on the crests at times of high disturbance, but they are more evenly spread through the area in the summer when disturbance is less frequent. The life cycle appears to be of one year's duration, with emergence in May-June.