Amblyseius andersoni is a predatory mite, its body is light beige or sometimes dirty milky in color and is up to 1 mm in size. The male is smaller than the female, its size is no more than 0.5 mm in length. The female lays several eggs daily under leaves, often along the veins. The adult female lays 50 eggs during its life cycle. The larvae hatch from eggs and do not feed, they have only 6 legs, in contrast to the nymphal instars.
The life span has a standard type of ontogenesis for parasitoid mites with successively changed developmental instars: egg, larva, protonymph, deutonymph, adult (female or male).
The life span at a temperature of 25 ° C: egg (3-6 days) – larva (1 day) – protonymph (3-4 days) – deutonymph (3-4 days) – imago (up to 35 days).
Eggs are oval, light white, partially transparent, their length is up to 0.25 mm, width is about 0.18 – 0.2 mm.
Larvae are matte white, inactive, have 3 pairs of legs, and don’t feed on.
Protonymphs are the 2d instar of pre-imaginal development. They are very active, mobile predators and have 4 pairs of legs. Body length is 0.3 mm. Color is milky white.
Deutonymphs are the 3d stage of pre-imaginal development. They have 4 pairs of legs, also whitish, but larger and more voracious. Body length is 0.4 mm.
Influence of temperature on beneficial insects’ development rate
|Stage of development
||Time of pre-imaginal development (days) at a constant temperature ° С
Adult predators attack all stages of the spider mite. Predator nymphs prefer to feed on eggs, they can prey on other pest development instars. Victims range includes various species of herbivorous mites: Tetranychus urticae, Tetranychus cinnabarinus, Tetranychus atlanticus, Tetranychus turkestani, Oligonychus pratensis, Oligonychus perseae, Oligonychus semen ilicis, Panyndi Four-legged ticks Eriophyidae), Phytonemus pallidus, Polyphagotarsonemus latus (family Tarsonemidae mites). In the absence of spider mites, predators can attack the larvae of thrips – Thrips tabaci, Frankliniella occidentalis (family Thysanoptera).
The predatory activity in feeding spider mite imago is approximately 5 individuals and 15-20 eggs daily. A.Andersoni can feed on pollen as an alternative food, experiments have shown that while eating pollen of Ricinus communis and Zea mays predator population continued to develop. The diet intensity depends on victim population density and the temperature and humidity of the environment.