Adaptive radiation of gall-inducing insects

• Published in: Basic and applied ecology 2005-10, Vol.6 (5), p.413-421
• Main Author: Price, Peter W.
• Format: Article
• Language: English
• Subjects: Adaptive zones on host plants; Aphididae; Aphids (Homoptera: Aphididae); Cecidomyiidae; Cynipidae; Diptera; Gall midges (Diptera: Cecidomyiidae); Gall wasps (Hymenoptera: Cynipidae); Homoptera; Host-genus resources; Hymenoptera; Opportunistic host shifts; Phylogenetic hypotheses; Pistacia; Salix; Sawflies (Hymenoptera: Tenthredinidae); Sibling species; Tenthredinidae
• ISSN: 1439-1791
• DOI: 10.1016/j.baae.2005.07.002

The adaptive radiation of four taxa of gall-inducing insects is compared: sawflies (Hymenoptera: Tenthredinidae), oak gall wasps (Hymenoptera: Cynipidae), aphids (Homoptera: Aphididae), and gall midges (Diptera: Cecidomyiidae). The sawflies, with only three genera but many species per genus, colonized many adaptive zones. Many sibling species have been recently recognized. Such characteristics suggest a dynamic evolutionary state of radiation. Innovations in the substrates used for oviposition by sawflies, probably involving ovipositional accidents, have enabled evolution from free-feeding ancestors into diverse gall types and galling sites – from leaf edge to leaf lamina, leaf midrib, petiole, bud, and stem. Host shifting among species of willows ( Salix) has been extensive and opportunistic. The oak gall wasps, like the sawflies, colonized many adaptive zones, in terms of galling sites on the plant and diverse gall types. The gall wasps include large genera, and use a geographically widespread host-plant genus rich in species, with largely opportunistic colonization of new hosts. The gall-inducing aphids on Pistacia in Israel show radiation into many adaptive zones, with different gall types and galling sites on the host plant, even though the radiation is much less extensive than in sawflies and gall wasps. A major limiting factor in this smaller radiation appears to be the low richness of Pistacia species and the host specificity of the galling aphids to this plant genus. The gall midges are similar to the sawflies and gall wasps with many large genera. Their radiation is much greater than in the related fungus-feeding midges, indicating the importance of a rich host flora for insect radiation. The study of adaptive radiation in gall-inducing insect taxa offers many opportunities for comparative studies in evolutionary biology. Es wird die adaptive Radiation bei vier Taxa von gallbildenden Insekten verglichen: Blattwespen (Hymenoptera: Tenthredinidae), Gallwespen (Hymenoptera: Cypnipidae), Blattläuse (Homoptera: Aphididae) und Gallmücken (Diptera: Cecidomyiidae). Die Blattwespen mit nur drei Gattungen aber vielen Arten pro Gattung besiedeln viele adaptive Zonen. Viele nah verwandte Arten wurden in letzter Zeit erkannt. Solche Charakterisika lassen eine dynamische Phase der Radiation vermuten. Innovationen bei den Substraten, die für die Eiablage bei den Blattwespen genutzt werden, möglicherweise unter Einbeziehung von Eiablagefehlern, ermöglichten eine