You are not currently logged in.
Access JSTOR through your library or other institution:
If You Use a Screen ReaderThis content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Capitula on Stick Insect Eggs and Elaiosomes on Seeds: Convergent Adaptations for Burial by Ants
Vol. 6, No. 6 (1992), pp. 642-648
Published by: British Ecological Society
Stable URL: http://www.jstor.org/stable/2389958
Page Count: 7
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Preview not available
1. The eggs of many stick insect species (Order Phasmatodea) bear a striking resemblance to seeds. These eggs are not only similar in size, shape, colour and texture to seeds, but in many species bear a knob-like structure known as a capitulum. This structure resembles an elaiosome, a lipid-rich appendage on some seeds known to be an adaptation for burial by ants. 2. We present observations and experiments demonstrating that capitula and elaiosomes are convergent in function as well as in appearance. 3. Capitula, like elaiosomes, promote removal of eggs to ant nests and buried eggs suffer reduced rates of parasitism by wasps. 4. Phasmatid nymphs are capable of emerging from eggs buried under 6 cm of soil. 5. Capitula are found only in those phasmatid species which drop eggs freely on to litter and not in species which bury eggs or glue them to vegetation. 6. Elaiosomes and capitula are both adaptations to use ant mutualists for burial, a striking example of evolutionary convergence between the plant and animal kingdoms.
Functional Ecology © 1992 British Ecological Society