Lady beetle

Cryptolaemus montrouzieri

Cryptolaemus montrouzieri is native to sub-tropical regions of Australia and the South Pacific, but has been distributed throughout the world to control various species of mealybugs and scale insects. Its host range includes 18 species of soft scales and at least 23 species of mealybugs (including citrus mealybug (Planococcus citri), long-tailed mealybug (Pseudococcus longispinus) and pink hibiscus mealybug (Maconellicoccus hirsutus).

The adult beetles are approx. 4 mm long, With an orange head and thorax; the dark wing cases (elytra) also have orange tips at the rear end. The larval stages look completely different, being covered in fluffy white waxy filaments, at first glance, they can look similar to their mealybug prey.

Both adults and larvae are predatory, with the adults and young larvae preferring mealybug eggs and small nymphs, while older larvae will generally consume all mealybug life stages. This species is a voracious predator that is particularly effective when prey densities are high.

Adult females mate soon after emerging from the pupa, and start to lay eggs several days later, either in mealybug egg masses, or close to colonies of suitable scale insects. Depending on prey availability. each female may lay approax. 200-500 eggs, ceasing production if insufficient prey are available. Under such conditions, the adults may be able to sustain themselves on less preferred prey (including some aphid species), or can be maintained by supplemental feeding with commercially available Ephestia eggs.

The optimum temperatures for development are in the range of 25-30°C (77-86°F), and a minimum temperature of 21°C (70°F) is needed for feeding and egg-laying. Temperatures above 30°C (86°F) reduce feeding and survival. Adult longevity is influenced by both prey and temperature, ranging from approx. 110 days at 25°C ( 77°F) to 50 days at 33°C (86°F); at these temperatures, the life cycle (egg to adult) takes approx. 30 days. At favorable temperatures, C.montrouzieri appears to tolerate a wide range of hurnidity levels  (50-80%RH). This species is not cold-hardy: development cannot be completed at temperatures consistently below 17°C(63°F) and it is killed by approx. 2 weeks of exposure to 5°C (41°F).