Bodyguard

Over the past couple of days I've begun to feel that the sciatica's improving a little, so I agreed to drive Pete out to a meadow in King's Cliffe, where he's doing an entomological survey. We left fairly early, as heavy showers were predicted for the afternoon.

The drive wasn't too painful, and once we arrived I was able to walk slowly around the meadow and take some photographs, although standing to take macros is still surprisingly uncomfortable, because trying to be very still tends to incite a muscle spasm. After a while my leg began to get a bit tired, so I lay down in the grass in a sheltered corner, and let the sun warm my back. It was amazing how many tiny insects I observed while doing this, and I managed to ge some good photographs of tiny leaf-hoppers only a couple of millimetres long.

I was also fascinated to watch this red ant Myrmica ruginodis gathering nectar from the extra-floral nectary on the stipules of common vetch. Most people know that many plants produce nectar within their flowers to attract insect pollinators. However, some plants have extra-floral nectaries which are situated in parts of the plant outside the calyx. These are glands that produce water and sugars but they are not designed to attract and reward pollinators. The nectar produced is sweeter than phloem and is made up of a mixture of glucose, fructose, sucrose and some protein, amino acids and organic acids.

Extra-flora nectaries may be found on leaf margins, leaf axils, petioles, stipules, flower bracts, sepals and flower stalks. They may be conspicuous as raised glands or recessed basins and are sometimes coloured differently than the surrounding plant material, as here. Ants are often attracted to these to feed, as are occasionally other insects. The presence of the ants helps to protect the plant from browsing and from insects laying eggs on the foliage, and experiments have shown that plants with ants do better than plants without. Ants at nectaries on buds can also protect the flower from nectar robbing. So this little creature is effectively acting as the plant's bodyguard!