Hymenoptera - The Ants, Bees, Wasps and Sawflies
The order Hymenoptera includes the familiar bees and wasps as well as the ants and sawflies. Ants evolved from prehistoric wasps, yet many people are unaware of the close kinship that ants share with their winged cousins. It is not known when the the two groups diverged but recent genetic evidence indicates it was at least 100 million years ago. The word "Hymenoptera" comes from the Greek words for "membrane-wing", referring to the transparent, sparsely veined wings. Hymenopterans have two pairs of these wings (wings are present in ants but only in the reproductive castes) and mouthparts designed for cutting and chewing. All Hymenopterans begin life as grub-like larvae (in social species, they are helpless and must be cared for and fed by the adults), later pupating into their adult forms. Social behavior evolved 11 times within the Hymenoptera while it occurred only once in all the other insects (termites). Among these social species, there is a tendency towards female-dominated societies, with males used only for procreation. Hymenopterans have developed not only some of the most complicated animal societies but also many of the most intricate life-cycles known in the insect kingdom. Tens of thousands of species of wasps live solitary existences of complex parasitism. Some of these parasites can parasitize other parasites within the bodies of the doomed host (talk about evolution)! The Hymenopterans are considered major benefactors of humankind: pollinating hundreds of crops, controlling numerous insect pest species through parasitism, and creating the unique delicacy that humans call honey. The oldest fossil Hymenopteran, a sawfly, dates back to the Triassic period, 225-195 million years ago. It is believed that the Hymenoptera evolved from the scorpionflies (Mecoptera), somewhere back in the mists of time. There are at least 280,000 known species of Hymenopterans.