Robin's pincushions can be seen on wild roses this month. Each one has been growing since the spring when a tiny female gall-wasp (Diplolepis rosae) laid its eggs in unopened rose buds. This caused the overgrowth of rose tissue into a ball-like mass of up to 60 chambers where the young wasps have been growing and developing. At first the pincushions appeared green, but by September they have usually become pink or crimson and so are easier to spot. The larvae will overwinter here and emerge next May as tiny wasps.
Spindle is quite common in the hedgerows and the deep pink berries with their orange seeds are very distinctive at this time of year. Spindle berries are rich in fats and proteins and although the seeds are poisonous to people, birds such as robins can sometimes be seen fiercely defending a spindle tree which they use as a food reserve. It has been observed that the highest rate of consumption of spindle berries is in December.
Darwin noticed that spindle bushes in the Cudham valley produced very variable amounts of fruit but that some bushes always produced more than others. He therefore looked in spring at the flower structure and found there to be 3 different types:
• Those with a normal stigma (female part), but smaller stamens which contained no pollen; functionally female plants which produced many berries.
• Some with a small stigma and normal stamens which produced no fruit or only a very small number (functionally male plants).
• Some which appeared hermaphrodite and produced some fruit but there were less seeds per fruit than in fruit from 'female' plants.
Birds such as the chiff-chaff are eating sugary foods like blackberries and elder berries. Some of the food is converted to fat and stored around the pectoral muscles from where it will be mobilized on long migration flights such as that of the chiff-chaff to West Africa.
Small mammals are also reaping some of the rich harvest of autumn fruits, nuts and berries, storing food as fat to help them survive the winter.
Spiders and Spiders webs
On dewy mornings the intricate and very different webs of many spider species can be seen in the Site, from the sheet-like webs built by species including the tiny money spider, to the funnel webs of spiders that hide in wait to drag prey down into their lair and the orb webs of spiders such as the familiar garden spider. As well as building webs to trap prey, some spiders, such as the nursery web spiders, build tent-like webs to protect their young.
Following wet weather, September is a good month to start looking for fungus within the Site. There are about 3000 species of larger fungi in the UK with three main ways of obtaining nutrients: some are parasites, but a great many are either decomposers, breaking down dead animal and plant material, or mycorrhizal. This last group live together with higher plants, supplying them with water, phosphates and some nitrogen while the higher plants provide the fungus with sugars.
When Darwin was in South America he remarked how a globular, bright-yellow fungus, elastic and turgid when young, but tough and deeply pitted when old, grew in vast numbers on the beech-trees. He said,
"In Tierra del Fuego the fungus in its tough and mature state is collected in large quantities by the women and children, and is eaten un-cooked. It has a mucilaginous, slightly sweet taste, with a faint smell like that of a mushroom. With the exception of a few berries, chiefly of a dwarf arbutus, the natives eat no vegetable food besides this fungus. …… at the present time, I believe, Tierra del Fuego is the only country in the world where a cryptogamic plant affords a staple article of food." He also remarked how he "found a second species on another species of beech in Chile : and Dr. Hooker informs me, that just lately a third species has been discovered on a third species of beech in Van Diernan's Land. How singular is this relationship between parasitical fungi and the trees on which they grow, in distant parts of the world!"