Native Plants

Bugs are Picky Eaters

Why do ecologists claim that native plants are better for the ecosystem? Sure, in California, most native plants use less water; but there are plenty of water-conscious plants from other dry regions around the world. You could give a vague appeal to the heritage of the land, but besides that? Any other reasons to plant native?

Last year I read Nature’s Best Hope by Doug Tallamy and he made an actually-convincing argument for native plants that centers around preserving wildlife.

There are around 1600 types of native bees in California. While common honeybees are generalists, and can survive on pollen from many different types of plants for food, about half of bee species are specialists. Specialists can survive on only one or few types of plants for food. If their particular plant goes missing, so do they. This applies to caterpillars and other bugs as well. A common example is the monarch caterpillar, which relies on milkweed to survive.

Unsurprisingly, native bee and caterpillar species have evolved to survive on native plants. Now it is clear to me; bugs are picky eaters. And since larger species such as birds and frogs rely on these bugs to survive, native plants support the entire food web, all the way up.

Not all native plants are equal. Supporting a diverse ecosystem provokes the following framework: select native species that support the largest number of caterpillar and bee species (turns out, caterpillars are a good proxy for other wildlife). In my zip code, for example, willow trees support 328 different caterpillar species. Oaks come in at 275, while maple trees only support 120. To determine this, I’m using this native plant finder tool.