Appreciation for Different Pollinators

 

When I first entered the world of growing professionally, it was tempting to assume that any new insect was intent on destroying my crops.  The acts of placing seeds in the ground and nurturing plants for food are not effortless, nor is the process worry-free – a lot can happen between germination and harvest.  So, it makes sense that growers risk falling into the trap of focusing on the pests.

However, it is equally important for farmers to learn about invertebrates that work with us – as well as those that are steadfastly neutral with respect to our crops – to successfully steward our land.  Many of the crops on our diversified farm rely on pollination services to produce the food we hope to make available to others.  Last year, for Pollinator Week,  I spent some time learning more about wasps and their role as pollinators.  This year, I wanted to explore some other, less well known invertebrates and their powers of pollination.

Hoverflies – they’re everywhere

I will readily admit that I have not given much thought to hoverflies (also known as flower flies or syrphid flies) until I started a project four or five years ago to take photos of the insects that we could find around our farm.  As I began the work of identifying the insects in these images, I was surprised to find many in the family Syrphidae.

Hoverflies can be found on every continent except Antarctica and there are approximately 6,000 known species.  Hoverfly populations are often greater than wild bee species, so even if they are less efficient than bees, they can make up for that with their relative abundance.  On our farm, we have noticed Oblique Stripetail Hoverflies more often than any other hoverfly.  It turns out that these insects are good pollinators and their larva will predate on aphids, one of the pests we want to control on our farm.

Research on hoverflies has been sparse, but one study suggests that true flies (Diptera) are the second most important order of pollinating insects after Hymenoptera (bees, wasps and ants).  Hoverflies are generalists, visiting a wide range of plants looking for nectar as a food source.  Unlike most bees, they are not restricted to a limited home range and they can carry pollen over longer distances while foraging or during migration.

Green Bees – showy and shy

Another insect that has had my attention for a while is the Green Bee or Green Sweat Bee.  We can’t help but notice them because their sparkling green color is almost startling.  The problem for me is that they are a bit shy, preferring not to pose for the camera.  And that’s why I am pleased to offer up this cropped photo that provides evidence that I finally succeeded in capturing an image of one.

Green Bees will visit a wide range of flowers, though they favor asters, goldenrods and coreopsis in late summer and fall on our farm.  Once they emerge in the spring, they will forage until the fall, so they have to adjust their food sources as the year progresses.  I have observed them visiting the small flowers on maple trees in the early spring and squash flowers in the summer.

Green Bees are typically ground nesting, though some will use hollow twigs and logs.  The parent Green Bee will mix pollen and nectar with their own saliva to leave as a food source once the larva hatches.  It has been suggested by some scientists that the saliva keeps the food fresh and helps to protect the eggs in their sealed chamber.

Simply knowing a few facts about Green Bees has encouraged me to continue our farm’s program to leave areas of the ground undisturbed, rather than tilling everything.  It also solidifies our desire to leave leaf litter and brush piles as natural areas.

Soldier Beetle – they eat, you harvest

The Soldier Beetle is another frequent visitor to our growing areas at the farm.  When I first became aware of them, I mistook them as a pale-colored lightning bug.  But, once I started farming in earnest, it didn’t take me long to identify who they really were.

My opinion of the Soldier Beetle became much more favorable the moment I learned that they are great predators of caterpillars, aphids and other soft-bodied insects that find our vegetable plants attractive.  These beetles have one generation of young each year, while some types of aphids can have eight or more generations of young.  If you ever need an example to explain why broad-spectrum insecticides are a bad idea, here it is!  The pest can rapidly repopulate while the predator cannot.

While Soldier Beetles might supplement their diet with pollen and nectar, they particularly like to visit flowers where they can lie in wait for their prey.   We see them most frequently around our farm in August and September.  They are frequent guests on some of the flowers we intercrop with our melons and squash.  As a result, they appear on the vine plants as well.

Hawkmoth – long tongue, will pollinate

It’s hard not to be fascinated by the Hummingbird Moth or Hawkmoth as it hovers over flowers seeking nectar.  Their flight patterns are similar to a hummingbird and we typically see them around our farm in the evenings, though we might also see them earlier in the morning.

I wanted to include the Hawkmoth to remind all of us that pollinators are not dedicated to servicing the food crops farms like mine grow.  As a matter of fact, some hawkmoth larva can cause problems for our crops.  I’m looking at you, Tomato Hornworm (Five-Spotted Hawkmoth)!  But it is important to recognize that this is just one type of hawkmoth and there are ways to deal with the Tomato Hornworm naturally.  At my own farm, we’ve simply recognized that their population isn’t too large and the small amount of damage they might create isn’t a problem.  As long as our natural system is balanced, they don’t qualify as a pest – especially when you consider their value as pollinators.

Hawkmoths have a long proboscis that enables them to reach into flowers that keep pollen and nectar deep within them.  Many plant and hawkmoth pairings have evolved over time.  The hawkmoth receives food and the plant gets pollinator services.  If either the plants or the hawkmoths are removed from the natural system, the other will die off.

Hawkmoths can carry pollen as much as fifteen to twenty miles from the source, unlike honeybees that typically go no further than three to five miles from their hive.  As humans continue to develop land areas, wild plant populations become more fragmented.  The hawkmoth’s sturdy build and ability to fly longer distances makes it possible for pollination to occur even when plants are not nearby.

If it’s on a flower and it moves…

The process of learning more about different kinds of pollinators has increased the depth of my appreciation for the incredible diversity in the natural world that surrounds us.  I am coming to understand that I won’t always see the value any given organism brings to the world until I explore more.  And even if I don’t discover a redeeming feature, that doesn’t mean there isn’t one.

But I think I have discovered one thing that seems certain.  If it’s an insect on a flower and that insect can move to another flower, it has a chance to carry pollen and support the next generation of plant life.

-------

For those who are interested, this is my latest blog for Pesticide Action Network that is intended to draw attention to pollinators during Pollinator Week.  One of our efforts at PAN is to fight against the overuse of pesticides that harm our pollinators.  Part of my job is to remind everyone that pollinators are important, interesting and worthy of protection.  I hope you will take some time to consider this issue.