First case of parthenogenesis in Cryptolaemus montrouzieri (Mulsant) (Coccinellidae: Scymninae) under laboratory conditions in Morocco

Although Cryptolaemus montrouzieri (Mulsant) (Coccinellidae: Scymninae) has been widely used in biological control against a wide range of pests, no studies have been reported regarding asexual reproduction of this important predator. Our study was carried out under controlled temperature (27 °C) and photoperiod (12 H) conditions. A cohort of 250 C. montrouzieri 4th instar (late preimaginal stage) larvae was collected from the rearing cages and placed in Petri dishes (14.5 cm diameter) containing different developmental stages of Dactylopius opuntiae (Hemiptera: Dactylopiidae) as food. After the emergence of C. montrouzieri young adults (24 h old), they were taken individually and introduced into new Petri dishes where different developmental stages of the mealybug were maintained under the same temperature and photoperiod conditions. Twenty days after emergence, it was observed that a small portion of C. montrouzieri unmated females laid eggs, and 100 % of the adults that emerged from these virgin females were males. Our results show, on one hand, that several C. montrouzieri populations can reproduce by arrhenotokous parthenogenesis, and on the other hand, it seems that the waxy cotton produced by the scale insect females stimulates C. montrouzieri females to reproduce by parthenogenesis.