July 2024

The seasons continue to progress as planet Earth causes us in temperate zones to be bathed in the warm sunshine of the long days of summer. We experienced the release of copious wind-blown pollen from trees during the spring flush of leaves and tree flowers such as hazel, oak and birch catkins. June gave us grass pollen, which I have recently watched billowing from the growing hay, like smoke in the breeze. Wind pollination is a very inefficient system and is mostly dependent on wind for transport. The flowers do not have to be attractive either to insects or humans. Very little wind-blown pollen will fertilize a seed. Insects appeared about 480 million years ago (MYA), whereas plants providing nutritious nectar appeared about 125 MYA. The most successful of these produced attractive flowers. With this, the efficiency of sex among plants was revolutionised. While some insects will harvest pollen from wind pollinated trees such as willow. But when plants started producing nectar and bright pigmented signal petals there was an explosion of beauty around the planet. From then, relationship between insects and flowering plants proliferated the diversity and success of the flowering plants that we see today. Apparently, the first flowering plants were magnolias, although there is some evidence that there may have been flowering water lilies before them. Not only did the plants start exploiting the insects (and vice versa), but they also exploited other animals as well.

About 3,630 BC, East Asian humans started exploiting silk moth caterpillars to produce the wonderful silk yarn made into some of the finest human garments. They started transporting it to the Eastern Mediterranean to sell, via the Silk Road. These traders traversed areas such as modern Kazakhstan, where there has always been a large population of Tian Shan brown bears and wild apple trees. The bears are partial to the sweetest apples which they select to eat and memorise their locations, such that the information is passed through generations of bears. The consequence is that trees producing the sweetest apples have proliferated from the seeds that passed through the bears and germinated to generate sweet apples picked by silk traders both to eat and trade with Europeans. The result is the abundant and variable apples of Europe, which in turn were taken to North America by French Jesuits in the late sixteenth century. The successful proliferation of apples in the United States was subsequently aided by the missionary Johnny Appleseed.