Cornicle length in Macrosiphini aphids: a comparison of ecological traits
1. Aphids often emit cornicle droplets when attacked by predators. While the function of cornicle droplets has long been debated (i.e. mechanical protection vs. chemical signalling), it is not understood why aphid species have cornicles of different lengths. 2. It was hypothesised that aphids living...
Saved in:
Published in | Ecological entomology Vol. 27; no. 6; pp. 758 - 762 |
---|---|
Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Oxford, UK
Blackwell Science Ltd
01.12.2002
Blackwell Science |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | 1. Aphids often emit cornicle droplets when attacked by predators. While the function of cornicle droplets has long been debated (i.e. mechanical protection vs. chemical signalling), it is not understood why aphid species have cornicles of different lengths.
2. It was hypothesised that aphids living in more scattered colonies have longer cornicles to scent‐mark predators with cornicle droplets containing alarm pheromone, so that clone‐mates are provided with advanced warning of a threat, even if not at the predation site. To test this hypothesis, multiple regression analyses were used, due to a lack of phylogenetic information on these taxa, to address which ecological traits (amount of wax on an aphid, degree of colony aggregation, feeding shelter, ant attendance) are correlated with cornicle length.
3. Aphids living in dense colonies tended to have shorter cornicles than aphids living in more scattered colonies. Also, aphids with more protection (i.e. wax) on their bodies had shorter cornicles. Aphids also tended to have shorter cornicles when tended by ants. The presence of a feeding shelter was not a good predictor of cornicle length.
4. It is suggested that longer cornicles function to scent‐mark predators with alarm pheromone to increase the inclusive fitness of a clone; however the negative correlation between the amount of individual protection, and also ant attendance, and cornicle length argues for a trade‐off between different forms of defence. |
---|---|
Bibliography: | ark:/67375/WNG-P6PMJ9R9-K istex:628D448CE42CAFF1BA24B09A8F7D95C1A6ABFB01 ArticleID:EEN470 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0307-6946 1365-2311 |
DOI: | 10.1046/j.1365-2311.2002.00470.x |