Blue Flower Wasps: From late January to March our garden becomes the home to a large number of steely-blue wasps which zoom around feeding on flowering native plants and flying close to the ground. These striking insects play an important role in the control of one of Australia’s problem insects, scarab beetles commonly known as Christmas Beetles. These beetles appear in summer and feed on eucalypt foliage. When they occur in large numbers they will defoliate eucalypts. They are one of a number of factors, which contribute to the death of mature eucalypts. The larvae of scarabs live underground and feed on roots. Blue Flower Wasps parasitise the larvae and that helps to reduces scarab numbers. The flower wasps zooming around our garden are all males. Females are wingless and their front legs are developed for digging. After mating, the females burrow into the ground, paralyse and lay their eggs on the scarab larvae . When the eggs hatch, breakfast, lunch and dinner are there for the taking. We have seen male Blue Flower Wasps feed on the nectar of Backeas, Leptospermums (Tea trees) and Bursaria spinosa (Blackthorn). They are also reputed to feed on the sugar solutions secreted by aphids and scale insects. There are some questions to be answered about these fascinating insects. What do the females feed on? Do they climb into plants to feed? How do the females detect scarab larvae, which may be at least 15 centimetres (6 inches) underground? All ideas and theories will be gratefully received.