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20 Aug 2018

Ants farming aphids!

Written by Stephen Reeves, Ranger at Crathes Castle
Ranger Roddy came across the amazing sight at Crathes Castle, Garden & Estate of some wood ants ‘farming’ aphids on a young spruce tree.

While out preparing for one of our Animal Tracking children’s guided walks at Crathes Castle, our seasonal ranger Roddy came across a fascinating example of animal interaction, where some wood ants were ‘farming’ some aphids. The aphids were feeding on the sap of a young spruce tree, where it had likely been damaged by a roe buck thrashing its antlers. Excess sugars from the sap are excreted by the aphid in a concentrated form called honeydew, which in turn is fed on by the ants by ‘milking’ the aphids – you may be able to catch a glimpse of this in the video. 

The ants actively farm the aphids by keeping them all together and protecting them from predators such as ladybirds, wasps and hoverfly larvae. You will also see in the video a ladybird being swarmed by a few ants and a wasp approaching, looking for a meal. Honeydew can form up to 90% of the ants’ diet, and they take it back to their nest to regurgitate in order to feed the queen and other workers in the nest. Ants are well known for some incredible behaviour but it was great to capture an example here on video at Crathes Castle and to show it to the participants on our Animal Tracking walk.