Saturday, May 12, 2018

Bugs, Biodiversity, and Bad Guys

We're seeing more insects this year.  Better still, we're seeing a greater variety of insects at Sage Garden than we saw last year.  One of the things I liked about Arizona when I first decided to move here was that there weren't as many insects here as I was used to.  So why would I be happy to see more insects?

In a word, biodiversity.

Biodiversity leads to resilience, and resilience leads to stability and efficiency (more yield for less input).  Every natural "problem" has a natural solution.  Sometimes the problem is its own solution.  Here's an example.  Problem: mockingbirds eat figs from our trees, leaving fewer figs for us to eat.  Solution: for a modest fee of a few figs, these same birds defend our fig trees from beetles and other birds (mockingbirds are territorial).  Every year the trees grow more productive, and now there are so many figs that the mockingbirds only take a tiny fraction of them.  Besides tending our figs, they also sing for us.  Here's a similar example.  Problem: grackles and doves eat tomatoes, leaving fewer for us to eat.  Solution: these same birds drop tomato seeds throughout the yard which grow into more plants, providing more tomatoes for us to eat.  All of the tomato plants growing here were planted by birds.  Thanks, birds.  Have some more tomatoes, please.  Plus they provide fertilizer, and they keep the insects in check.  All this goodness comes free of charge, with zero human effort.

Wait a minute.  Didn't I start by saying I was happy to see more insects?  Then why would I be happy that the birds are eating them?  Who are the good guys here, and who are the bad guys?  Maybe the good guy is a natural, effortless balance.  And maybe the bad guy is the good/evil dichotomy, which leads to a monoculture approach where we pamper a single protagonist species and eradicate all competition.

I have to admit there are a few species we have eliminated completely from this place.  We chose to uproot all the foxtails, goat heads, and fiddlenecks in order to avoid injuries to people and pets.

Getting back to the insects, some old favorites have returned this year, including honeybees, ants, grasshoppers, and butterflies.  We also have some newcomers.

I didn't know what a hoverfly was before this year, when we noticed two of their hangout spots: one by a mesquite tree, and another by a dill plant (left).  This year we're seeing these predators and pollinators in large numbers.  In retrospect, I'm not surprised.  If I were a hoverfly, this dill plant and its neighborhood look like a place I'd want to be.

In smaller numbers (so far) we're seeing lacewings and damselflies here for the first time.  Despite their delicate appearance, these are both effective predators, keeping other insects in balance.

We installed a bee block for mason bees this spring, and it's getting used.  (When I took the picture below, I didn't see the photobombing bee in the red circle.) And we're seeing many mason bees at work - especially on our basil, wolfberry, sage, and brittlebush.  Maybe the mason bees are newcomers this year, or maybe we're just starting to see them because we're looking for them.  In any case, I'm glad they're here to pollinate our plants.

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