In an intensive study, begun in 1955, on the biological control of Pseudaulacaspis pentagona (Targ.) and Pulvinaria psidii Mask. on oleander (Nerium oleander) in Bermuda, several species of COCCINELLIDAE were successfully established, but none developed a population sufficient to control either scale. The failure of these apparently suitable species of Coccinellids was therefore investigated. It seemed possible that insectivorous lizards, which are very abundant everywhere, might be responsible.

Dissection of a number of lizards, Anolis grahami, and A. leachi, in the autumn and winter indicated that at both these times their effect on the natural enemies of scale insects in general and of Pseudaulacaspis pentagona and Pulvinaria psidii in particular, was considerable. Both Coccinellids and Hymenopterous parasites were eaten in large numbers. A surprising number of very small insects including ants, was eaten, and although a number of the insects eaten are harmful, on balance it would appear that, particularly with regard to the biological control of scale insects, the elimination from Bermuda of these lizards, which are introduced species, would be beneficial.

Experiments are being carried out to test this, and the introduction of predacious birds, particularly that of the Trinidad kiskadee, Pitangus sulphuratus, is planned.