Author
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Grissell, Edward |
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HOBBS, K. - PALM DESERT, CA |
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Submitted to: Proceedings of the International Society of Hymenopterists
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/25/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Insects feeding on seeds can be a major source of crop losses, and seed-feeding wasps are important in limiting the amount of seed produced by a plant. In this paper the host range for a single species of seed-feeding wasp is shown to be broader than previously known. The range was discovered to include trees of ornamental and agricultural value as well as trees that are noxious, invasive weeds. The latter have cost as much as $60 million in one year to control mechanically. It is suggested that the wasp involved may also attack nut-producing trees of high commercial value in California and Arizona. Knowing the correct species of wasp and its host range could save millions of dollars when attempting to correlate the biological control of a noxious weed and at the same time save an agricultural crop. This information will be useful to growers and pest managers working with nut crops. Technical Abstract: Seed-feeding species of the genus Megastigmus (Hymenoptera: Torymidae) are generally specific at the generic level of host plant. An anomalous group of Megastigmus species associated with genera in the family Anacardiaceae appear to be an exception to this rule and may pose insight into factors of host-plant selection, host-plant switching, and natural and human-induced geographic distribution. Circumstantial evidence is presented that Megastigmus transvaalensis (Hussey) is an Old World species of seed-feeder that attacks Rhus spp. in South Africa, that it has host-shifted onto Schinus spp. introduced into South Africa from the New World, and then has been transported to the New World probably via infested seeds. |
