By Yetta Jager, Green Sanctuary Committee
For everything, turn, turn, turn.
There is a season, turn, turn, turn.
And a time for every purpose under heaven.
A time to be born, a time to die,
A time to plant, a time to reap…
– Pete Seeger (based on Ecclesiastes 3: 1-8)
Spring is here. It's time to think about preparing Westside for growth. Turn, turn, turning the soil so that we can plant flowers to feed pollinators, including not just butterflies, but also bats, birds and other critters. Insects have declined significantly due to agricultural use of pesticides by industrial farms. One reason that these declines make me sad is that insects have interesting life histories. For example, the tight coevolved relationships between some flowering plants and their pollinators are fascinating.
Charles Darwin was interested in coevolution and wrote the book, ‘Fertilisation of Orchids’. When a colleague in Madagascar sent him seeds of an orchid with a nectary one and a half feet long, Darwin exclaimed, ‘Good Heavens, what insect can suck it?!’. He hypothesized that there must be a pollinator moth with a long-enough proboscis to reach the nectar at the end of the spur. A few years later, the explorer and naturalist Alfred Russel Wallace suggested that it might be a Sphinx moth, possibly related to one he’d found in South Africa (see drawing). Sure enough, a Madagascan subspecies was later found to pollinate the orchid. The Sphinx moth first does a ‘fly-over’ to locate the correct orchid species by smell. Then it backs up, unrolls its proboscis, and flies forward to extract nectar (and pollen) from the orchid. There’s a similar case closer to home. The Mexican long-tongued bat has a tongue that rolls up and extends to pollinate night-blooming cacti and agave.
Why do these pollinator-plant relationships evolve? Well, orchids benefit because they can ensure that their pollen is efficiently transferred to flowers of the same species (so they are not waste pollen on other flowers). Moths benefit too because the orchid produces nectar resources that other insects can’t get to. This creates a positive feedback loop causing both populations to grow faster where they co-occur. That is, unless some change or disturbance causes one of the pair to go extinct. Which is why very specialized and/or interdependent species tend to be more vulnerable to extinction (for example, under climate change).
At Westside, we can enhance biodiversity by planting native perennials that native pollinators are adapted to, supplemented by well-behaved annuals to extend blooming to late fall. In April, let’s start a mutualistic relationship with pollinators by planting flowers for all of us to enjoy.