The role of pollination in growing fruits and vegetables is a marvelous mystery of Nature, but a potential stumbling block, as well, for indoor farmers…

When first looking into the question, I could see myself developing virtuoso skills, swirling an artist’s brush around stamens (the male parts) standing tall in the center of my developing male flowers, sweeping up pollen dust to carry to pistils (or female parts) of same-variety female flowers…  Does that sound dicey? Well, to tell the truth, I would prefer
that flowers do their own mating… as long as, in the end, fruits and vegetables are forthcoming…

Thankfully, there are veggies and fruits to be cultivated indoors that do not require any pollination at all. These are those grown mainly for their roots and leaves (not for their flowers and seeds). In this category are carrots, lettuce, potatoes and sweet potatoes, onions, garlic, herbs, and (in the cabbage family) broccoli, cauliflower, and brussels sprouts… Not a bad list to choose from, when putting food on the table…

There are also some veggie crops that are self-pollinating, meaning they contain both the male and female elements together, and so can produce their crops without the intervention of pollinators. Falling into this group are green beans, tomatoes, sweet peas, okra, green peppers, and eggplant…  So, with such veggies at our eventual disposal, we have a wide variety of colorful, nutritious choices to accompany our grains, other staples, and protein sources.

However, there are still some veggies that do require pollinators on my list of must-haves (see here), and probably on yours, as well. Who would want to go without all the varieties of squashes, or pumpkin, or cucumber and melons, or berries (think of strawberries, blueberries, blackberries and raspberries…). While the wind does contribute to pollination, by shaking pollen dust from one flower to another (this being why indoor crops grow best near an outside window that can periodically be opened, in fine weather, for some natural sun and air flow, while attracting a bee or two, and certainly a few flies…).  You must be prepared to forgo the pleasure of home-growing these natural treasures… or, as an
indoor farmer, you will have to face the need for pollination…

And in this regard, who today has not heard of the devastation caused to our number one pollinator, bees, by certain chemicals used in modern agriculture? Although that discussion often feeds into dire warnings about the depletion of certain crops, and without minimizing either the dangers to bees (and birds, and butterflies, and even to
us…) of the implicated chemicals, or the simple pleasure that bees bring by their busy activity in our gardens (in addition to their honey and pollen), we can nevertheless take comfort in the fact that, if push comes to shove, humble, albeit pesky, flies are also buzzing around out there, and for once they are providing a real service as they make their way from flower to flower, incidentally transporting pollen as they find and suck up nectar.

These undeniably annoying insects are, and have always been, involved in agriculture… For instance, as they are the principal pollinator of cacao trees, we can thank our lucky stars for flies every time we eat a piece of chocolate…  And it is perhaps not irrelevant to mention that in Sardinia, a certain cheese is produced that requires the
‘intervention’ of flies in the aging process… This cheese was banned by the European Union for a time, but due to popular demand (yes!), it had to be reinstated, albeit under the label ‘traditional’ to circumvent EU hygiene regulations…

In ancient times, flies, along with beetles, were the primary pollinators of flowers. In contrast to bees, flies and beetles are not busy carrying pollen back to their hives, but just out grazing, flitting among the flowers in search of nectar, and only distributing pollen co-incidentally.  As well, being less sensitive to cold than bees, flies are ‘on the job’ more consistently and put in longer hours, all of which are appreciated qualities in pollinators.

Flies can, if need be, step in to replace bees as primary pollinators. While their role in pollination is only now beginning to be seriously studied, it is recognized that fly activity alone
results in yields comparable to and even better than with bees exclusively.  And when both are present and active, crop yields are typically even higher still.

Many people think of flies primarily for the role they play in ‘recycling’ in Nature, by contributing to decomposition…  Plant matter, asw ell as dead flesh, and feces, all attract flies by their associated odors. This is how flies become a source of potential contamination, most notably when they have access to our food, where fly activity (certain species intrinsically more so than others) can be a serious hazard to human (and animal) health.

Yet, with growing interest for ‘managed’ flies in agriculture, to compensate for the decreasing numbers of bees, studies are now being carried out to gather broader information than has heretofore been available…

For the record, almost everyone knows that flies can only ingest liquids, so they vomit a solution onto solid food, to break it down.  And if, just prior, they have visited something
contaminated by malevolent bacteria, they are in a good position to pass on that contamination in their vomit, or by simple contact, the same way they distribute pollen.  Also, different insects, including flies, are attracted to dead flesh. In fact, the larvae of flies (maggots) are (and have been for centuries) used in medicine to delicately eat away the dead flesh from wounds.  In forensic medicine, the arrival times to corpses of different insects, including different species (notably blue and green, to keep it simple) of flies, help to determine not only the time, but often even the place of death.

The usual lifespan of a fly is 24 to 67 days. They are present almost everywhere on the planet, and, as mentioned, still active at low temperatures, when bees are not.  And, if the presence of pollinator bees becomes more and more problematic, the different variables in the use of flies (species health, wide availability of rearing media, possibilities for management of potential sources of contamination, husbandry costs…) are becoming more and more economically feasible on an industrial scale (given high fecundity and rapid development), and so all these points are increasingly the object of serious studies.

As indoor farmers, we should give our indoor crops, at every possible opportunity, access to the warmth of sunlight (direct and day-long is ideal, second best is morning sun, then sun from behind protective glass windows.  And even so, it is possible, even likely, that we will need to compensate at some point for growing indoors with ‘grow-lights’ (a subject we will look at later…), natural, or fan-generated air currents, and the lack of contact with natural pollinators.

But, in regard to this last point, we can just toss out the Raid and the fly-swatters, reminding ourselves, once again, that humans have always ended up discovering that every living creature has a role to play, an essential role, in the balance of Nature, whether we are able to easily determine that role, or not…

So, let’s arm ourselves with artist’s brushes, while cracking off a piece of chocolate, or sweetening our tea with honey, to honor our insect allies (but don’t leave any of these out where the flies can them!)…

Cheers!