Derek – Thursday 28th June

Every evening this week a few of us have come in to water the plants. Our barrels were filled by members who live nearby. Even so, we are barely keeping up; it’s so hot and dry, and we have no running water.

Water is essential for plant survival. The various chemical reactions that maintain plant cells take place in an aqueous medium. Photosynthesis cannot occur without water. Water also acts as a sort of skeleton in green plants. Water pressure in the cells keeps them stiff, collectively keeping the plant upright. Shortage causes wilting as the pressure weakens.

The plant suffering least in the garden is the buddleia. We have given it no water at all and, with its deep roots, it survives. The shrub was brought from China as recently as the 1890s. Escaping from cultivation, it is regarded by some as an invasive species. Now found on wasteland, railway cuttings and on high walls, it thumbs its nose at such critics.

There are many hollyhocks in the garden, two metres high in some places with their trumpet like flowers in yellows and pinks. There’s a white scabious, higher still, up to two and half metres, trying to compete with the buddleia jungle which is likely to be flowering next week. And hopefully attract butterflies, as we haven’t had many this summer.

The pond is eight inches down on its May level, even though we’ve added water. I see no tadpoles at all. I have accused the dragonfly nymphs of killing them, and they don’t deny it. Though it has been suggested that the water boatmen could be in on the cull. My research tells me that most are vegetarian, so I stick with dragonfly nymphs as the killers. The nymphs have a deadly weapon, called a mask, which is a hinged device beneath the head. It is flicked forward to catch prey with a pair of pincers at its tip.

I observe two dragonflies on an iris leaf in the pond. No matter what accusations I make, they don’t care. Two hours later they are still there. Can they be laying eggs? I am puzzled as they have no wings. I am able to reach one, it does not react, for it is just the husk of a dragonfly. I see a third husk. They are extremely detailed, showing the ridges on the body, the head, thorax and abdomen divisions and the six legs, which is why I was fooled into thinking it was an actual dragonfly. They are the remnants of a new adult dragonfly that has emerged and flown off.

A nymph, once mature, leaves the water, and climbs up a leaf, in this case an iris. This often happens at dawn which is why we did not see the emergence, but just the debris. The skin of the nymph splits and a crumpled dragonfly emerges. At this point it is vulnerable to an attack by a bird, as its soft body and wings must harden in the air before it can fly away. Adult dragonflies can live up to eight weeks, but two or three is more usual. More than ninety percent of their life is spent as nymphs on the floor of ponds and streams.

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