This unusual situation may explain why eusociality evolved several times in the haplodiploid group Hymenoptera — ants, bees and wasps. As of 2009, 11 separate cases are known. However, Hymenoptera is a large group and the majority of its species are not social. Furthermore, highly developed eusociality also exists in non-hymenopterans, perhaps most obviously in termites. Most such cases involve organisms that display high levels of inbreeding, so that colony members share more than half of their genes. Therefore the same model is considered to apply to these species.