Pollinators, the night shift

 We are familiar with day-blooming flowers and day-visiting insects, bees, butterflies, flies and a few others. These insects usually prefer nice, warm, sunny days to visit flowers. In fact, their muscles need a certain critical temperature to begin functioning. It is possible to see some of these pollinators sitting still during chilly mornings, waiting for the sun to warm them up sufficiently so they can take to the air.

Nocturnal moths are another story. Some are well adapted to colder temperatures; they also have eyes that allow them to fly at night. Fortunately for them there are flowers that bloom at this time. Such flowers are likely to produce more nectar at night; they also release aromas that the moths are well attuned to and that enable them to find the flowers.

So when the day pollinators complete their 9-5 schedule, the night shift takes over. Let us clarify that many of these night fliers are more active at dawn or dusk than in the dead of the night. They are called crepuscular pollinators.

You may be fortunate enough to have one of those visitors to your garden if you have moonflowers, evening primroses, Nicotiana or morning glories. It can be quite a treat to see hawk moths in a regular basis visiting your garden; some seem to have a fixed schedule and show up almost daily at their appointed time. They are large, fly silently and unfurl their straw-like tongues in front of long-tubed flowers like the ones mentioned. They look like hummingbirds drinking nectar while suspended in the air. They have handsome patterns on their wings, not as striking as those of butterflies, but very beautiful in a sedate way.

Other dawn or dusk pollinators are less familiar to most of us. The squash bee is an early riser, following the schedule of squash blossoms and finishing her daily chores just after dawn or at mid-morning when blossoms begin to wilt. They are said to be up before sunrise; however, I have never seen them so early. Maybe I should spend more time in the pumpkin patch and I may catch some of them.

Worth mentioning are truly nocturnal pollinators of a different stripe, bats. Most cactus bloom at night, they are strongly scented and produce big flowers with abundant nectar, just right for such large fliers. In the absence of bats, the landscapes of the West would be profoundly different, without the rich flora of saguaros, barrel cacti and prickly pears.

Night Blooms and their Pollinators
Moths as Pollinators
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Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2011

Pollinators in winter

Wintering pollinators

Pollinators need habitat in winter. There are a few ways of providing shelter for them in our own backyards.

Hollow twigs provide refuge for many bees and wasps

Bee blocks are a very good substitute for the tree holes where many hibernating bees spend the winter

A halictid bee, Augochlora pura hibernating under the bark of a dead log

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Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2012

Bees and Vitamins

We need the vitamins provided by fruits

It is said that bees and other pollinators are responsible for one third of all our food. Whether this is exactly right I do not know; but a trip to the grocery store confirms that a substantial part of our food comes from plants that have been pollinated by insects rather than by the wind: most vegetables and fruits, drinks such as coffee and tea. We even have to include in this list beef, poultry and dairy products because farm animals feed partly on alfalfa or clover which have been pollinated by insects. Without pollinators we would be reduced to eating grains or cereals, potatoes, sea food and fish and very little else (and undernourished beef and poultry).

Tomato flowers

What is never mentioned but I find perhaps even more important than food quantity is quality. Many of our essential vitamins and antioxidants come to us courtesy of pollinators. Vegetables and fruits are loaded with vitamins such as beta carotene, vitamin C and a few others.

So, in summary, if it wasn’t for pollinators we wouldn’t be one third hungrier. Instead we would be one hundred per cent dead.

Vegetables are indispensable because of their vitamins

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© Beatriz Moisset. 2012

Sunnyside Dru: Bee Barracks update

Sunnyside Dru: Bee Barracks update: "Earlier this year we posted a picture of this bee block. There are many variations to this all over the farm..small, not really noticeable, ..."

Mountain laurels instead of rose bushes?

Last year I was traveling along the Blue Ridge in May and was pleasantly surprised by the beauty of the blooming mountain laurels. I had to look again and again to convince myself that what I was looking at wasn’t a rose garden but just a natural grove of mountain laurels.

I want that look in my garden. I have two rose bushes which I inherited from the previous owner of the property and I want to replace them. The advantages are obvious to me. Roses are not native; they provide no food for pollinators. Mountain laurel, on the other hand, is pollinated primarily by native bumble bees.

It has a peculiar system of pollination. The unopened blossoms present little knobs which give them a funny look. When the flowers open, the function of these little knobs become apparent. They are pockets that hold the anthers (the pollen carrying part of the flower) trapped. It still doesn’t explain why this is so; in most flowers the anthers are free and exposed, better to spread their pollen at the slightest touch of a flower visitor.

The mountain laurel has a different strategy. The pollen is well protected against rain and wind; but when a pollinator lands on the flower searching for nectar, the weight acts as a trigger, causing the taut stem of the anther to spring. The anther hits the pollinator gently on the back and gives it a dusting of pollen.

Mountain laurel flowers produce a moderate amount of pollen; but most of it ends up where it is intended, on the body of a pollinator, rather than being wasted in other ways. It seems like a highly economic method to spread the pollen.

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Rain and Pollinators

Where do pollinators go when it rains? You certainly don't see many of them around when it is pouring. They may be sturdy little fellows but they have some limitations. Wind or rain (or even cloudiness) can be too much for most of them. Cold weather also makes them think twice before going outside.

Gathering of male Andrena bees early in the morning

There are many different kinds of pollinators: bees, flies, butterflies, moths, and a few other insects; not to mention a few non insect ones such as many kinds of birds, bats and even a few other mammals. Let us look at one group in particular, bees. Bees probably do about 90% of all pollination so they deserve our attention. Bad weather is too much for most of them, but some fare better than others. A few bumblebees tolerate the cold of the Arctic Circle. Some bees fly at dawn or dusk or in the very early spring, although the majority prefers the daytime, sunny weather and warm temperatures. Wind is harder to overcome than chilly weather. There are physical limitations to flight, so when the wind reaches certain speed all flying insects find themselves grounded. That is why a steady breeze brings welcome relief from mosquitoes and gnats.

Rain is a serious problem to insects; a mere drop of rain is the equivalent of a big bucket to us; it would knock them down harshly. The weight of the moisture clinging to their bodies proportional to their own body weight would also be a major problem.

Insects are sensible enough to lay low when conditions are severe. Females return to their nests and stay there. Males, on the other hand, do not have nests to return to; they are not homemakers and know nothing about nests so they resort to a different kind of shelter. The males of many species seek each other company. They may stay in groups on flowers or leaves, or hanging from twigs. They clamp their strong jaws onto a twig and go to sleep this way. There are times in the early morning in which you can find one of these roosts. The insects may be dew covered and very sluggish and will need some sunshine before they can start moving around. Others cluster inside large flowers such as squash. These places offer some protection from the weather.

Carpenter bees spending the night clinging to a Passionaria flower

Probably these roosting places are not as secure as the nests where the females stay and this may very well be one of the reasons why male lives are shorter than female's. Males only mission in life is to mate; after that they are dispensable. Females, on the other hand, need to live a little longer in order to build nests, gather food, lay eggs and seal the entrance to their nests.

Sometimes, after a particularly rainy spring, trees produce very little fruit and one wonders about the connection between the abundant rain and poor crop. What happens is that the pollinators didn’t have enough opportunity to visit flowers because of the weather.

It is interesting that many native bees can face these hardships better than honey bees and turn out to be better pollinators under certain circumstances. Honey bees are very quick to return to their hives when weather conditions are poor. They also work shorter hours, starting later in the morning and quitting earlier in the afternoon. Some bee specialists say that native bees and bumblebees are not unionized and find themselves forced to work longer hours and under poorer conditions.

Roosting male bees

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Magnolias and Beetle Pollination

Magnolias were among the earliest flowering plants, which evolved many million years ago, long before there were any bees. Butterflies and moths were also absent in those days. The only pollinators available were probably beetles and flies, the so-called “dumb pollinators”. This term refers to the fact that the late-comers to the world of pollination, particularly bees, can perform remarkable feats of memory and skillful manipulation of flowers.

When bees entered the scene, perhaps twenty or thirty million years later (give or take a handful of millions), they took to the pollinating job with gusto. They became real pros which adapted to the ever growing variety of flowers and developed skills par with the complexity of these newly evolved plants. The same can be said of many butterflies and moths and also some wasps. That is how they earned the name of "smart pollinators".

Neither magnolias nor beetles are very specialized to pollination by insects. The flowers, though lovely have a very simple structure; for instance, there is no distinction between petals and sepals as in most other flowers. In turn their pollinators, beetles, are very clumsy at their task; sometimes they get carried away and eat parts of the flowers along with the pollen they find there. Their mouth parts are made for chewing, rather than for gathering nectar and pollen, so they can’t be blamed for their sloppiness. The flowers, in turn, are adapted to this rough treatment; that is why magnolia petals tend to be rather leathery; and, most importantly, the seeds are well protected.


You develop a new respect for the pollinating responsibility of beetles when you take a look at the many families of these insects that visit magnolia flowers: sap-feeding beetles, tumbling flower beetles, leaf beetles and weevils, among others (or if you prefer their technical names: Nitidulidae, Mordellidae, Chrysomelidae and Curculionidae).



Bees, bumblebees, flower flies, a few types of stink bugs, leafhoppers and several other types of insects are also found visiting magnolia flowers attracted by their nutritious pollen and nectar.

But most of them arrive at the flowers too late, after the blooms are past their prime and are not receptive for pollination. So it is the beetles that carry the lion's share of the responsibility for perpetuating these plants.

Beginners Guide to Pollinators and Other Flower Visitors

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© Beatriz Moisset. 2012