Borges da Silva, E., Franco, J.C., & Mendel, Z. 2008 Can facultative parthenogenesis occur in biparental mealybug species?. Proceedings of the XI International Symposium on Scale Insect Studies, Oeiras, Portugal, 24-27 September 2007. ISA Press Lisbon, Portugal 322 pp.
Notes: Facultative parthenogenesis (facultative haplodiploidy-thelytoky), in which reproduction is usually typically amphimictic, but where unmated females may produce viable offspring by thelytoky, is known in Hymenoptera and Hemiptera. The existence of facultative parthenogenesis in mealybugs has been reported by different authors and questioned by others in relation to certain species. In order to test the hypothesis of facultative parthenogenesis in Planococcus citri (Risso), Pseudococcus calceolariae (Maskell) and Pseudococcus viburni (Signoret) (Hemiptera, Pseudococddae), second-instar mealybugs were removed and placed singly in plastic vials with a potato sprout, to obtain isolated individual virgin females. After 65 days each female that did not oviposit viable eggs was exposed to adult males. It was found that none of the three tested mealybug species was able to produce offspring without mating. However, in the case of P. viburni and P. calceolariae, 54% and 72% of the virgin females formed ovisacs and 15% and 16% laid a few (1-8) unfertile eggs, respectively. The results suggest that the three studied mealybug species are obligate amphimictic.