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Host–Plant Relations of Gall-Inducing Insects
Galls are modified, invariably symmetrical, naturally developing plant structures that arise because of messages from certain specialist insects, mostly from the Thysanoptera, Hemiptera, Diptera, and Hymenoptera, and in a lesser frequency from the Lepidoptera and Coleoptera. Several species of the E...
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Published in: | Annals of the Entomological Society of America 2019-01, Vol.112 (1), p.1-19 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Galls are modified, invariably symmetrical, naturally developing plant structures that arise because of messages from certain specialist insects, mostly from the Thysanoptera, Hemiptera, Diptera, and Hymenoptera, and in a lesser frequency from the Lepidoptera and Coleoptera. Several species of the Eriophyoidea (Acari) induce galls and wherever appropriate, we have considered examples from the Eriophyoidea as well, generically referred under the term “insects”. The insects live within them, deriving nourishment and shelter. When these insects attack plant tissues, osmotic-change–related stress increases, thus stimulating alterations in gas exchange and subcellular metabolic functions. The osmotic stress alters the electrical properties of the plant-cell plasma membranes and impacts on indole-acetic acid synthesis and activity, which, in turn, affects the H+-transport. Insect action stimulates parts of host-cell wall to break down and the degenerated wall materials in the cytoplasm act as elicitors. In such contexts the susceptible plants use flexible strategies to mitigate stress, which generally manifest as galls. Inherited traits also play a role in providing specific shapes to the gall, which is coordinated by the innate correlating morphogenetic factors that operate normally in the plant. The gall-inducing Diptera (Cecidomyiidae), Hemiptera (Sternorrhyncha), and Hymenoptera (Cynipidae) induce galls of highly defined and exquisite shapes. Almost all of these insects are known for their specificity to plants. The gall-inducing insects, unlike many of their free-living relatives, discriminate between plants and choose from them. Selection of a particular plant by a gall-inducing insect is not a matter of chance, given that the insect encounters varied plant taxa in the natural environment. The gall-inducing insects preferentially feed on specific plant organs, or parts of these, and on specific plant species. One recent explanation is that the gall-inducing insects prefer certain plants or parts of those plants, because they need the lipidic materials, e.g., sterols, available in those plant parts, which the insects utilize for building hormones critically necessary for their metamorphosis. Because of the sedentary nature of the juvenile stages of the inducing insect, the gravid females endowed with specialized sensory structures play a key role in selecting the site precisely for oviposition and thus for the progeny. Although a majority of gall-inducing i |
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ISSN: | 0013-8746 1938-2901 |
DOI: | 10.1093/aesa/say034 |