Tag Archives: nectar

Back Door Thieves

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I took a quick walk through one of our restored wetlands last week.  Most plants had finished blooming for the year, but in some recently-mowed patches, there were some scattered flowers of beggarticks (Bidens sp) and blue lobelia (Lobelia siphilitica). I knelt down to look more closely at some small bees I spotted crawling around on the lobelia flowers.

I saw one bee crawl in and out of one of the flowers, but for the most part, the bees (and a few flies) were all hanging around at the base of the flowers.  As I watched, I saw one slide its long tongue into the flower.  I couldn’t tell if it opened up a hole or just took advantage of one that was already there.  Either way, it was apparently “stealing” nectar from the flower through a back window rather than entering politely through the front door.

A bee inserts its tongue into the base of a lobelia flower while two flies loiter nearby.

Another bee stealing nectar.

I sent photos and questions to both Jennifer Hopwood and Mike Arduser, who are always generous about sharing their expertise with me.  They both agreed with my interpretation, and Mike added some additional information.  He said that blue lobelia flowers have slits in them that make this kind of nectar robbing pretty easy for bees.

It seems an odd strategy for a flower to make it easy for bees to steal nectar without providing any pollination services in return.  Maybe the slits serve another purpose and the benefits outweigh the costs.  Or maybe it’s just a random loophole that natural selection hasn’t yet closed.  Regardless, blue lobelia plants tend to produce copious amounts of seed, so the flowers must get enough front door visitors to do the job.

In addition to the bees, there were a lot of flies hanging around the flowers too.  Flies have pretty short tongues, and it didn’t look like any of them were sticking those tongues into the flower slits.  Instead, they seemed to be feeding on the outside surface of the flower.  Maybe nectar was seeping through those flower slits?  Or maybe the bees were a little sloppy with their drinking and the bees were cleaning up after them?  Whatever the reason, I saw at least as many flies as bees on the flowers, so there must have been some attraction.

Flies were crawling around the bases of the flowers too, apparently feeding on the leftovers.

I wish now that I’d spent more time examining the flowers, and that I’d brought one home with me so I could look at the slits under a scope.  However, I hadn’t really planned to stop at the wetland, let alone to kneel down in the mud to look at bees stealing nectar from hapless flowers.  Also, my neck was starting to throb a little from holding my head at an uncomfortable angle necessary to photograph the bees.  Instead of sticking around to learn more, I took my camera, my muddy jeans, and my sore neck back to the truck and headed home.

Little cheater…

Photo of the Week – May 19, 2017

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Over the last five years or so, I’ve been learning a lot more about pollinators, and that has changed the way I look at prairies.  As I walk around our prairies, I often think about how I would see the site if I was a bee trying to find enough nectar and pollen to both survive and provision my eggs.  Often, our prairies are full of flowers, but April and May can be pretty tough months.  The flowers that are blooming tend to be small and scattered, and I can walk a lot of steps without finding anything.

Prairie ragwort (Packera plattensis) was a welcome sight for this orange sulphur butterfly after its northward migration this spring.

The lack of available flowers in the spring is not necessarily a new thing.  Spring weather is unpredictable, and investing resources in blooming early means risking a late freeze or (in some cases) flooding rains that can scuttle the whole process.  However, many prairies today have fewer spring flowers than they used to, and restored prairies (crop fields converted back to prairie vegetation) are often low on spring flowers because finding seed for those species is difficult.  Flowering shrubs can help make up for a scarcity of spring wildflowers, but they are also less common these days than they used to be.

Shrubs like this wild plum (Prunus americana) can provide critically important pollinator resources when few wildflowers are blooming. This photo was taken back in mid-April.

Prairie managers and gardeners can both play important roles in helping to provide spring flowers for pollinators.  In prairies, allowing shrubs to grow in some areas of the landscape can benefit pollinators in the spring, but also help out increasingly rare shrub-nesting birds during the summer.  Thinking about spring flower availability might also help inform prairie management plans, and enhancing restored, or even remnant prairies, to add missing spring wildflowers might be beneficial as well.  For gardeners, adding native spring wildflowers can be both aesthetically pleasing and extremely important for the bees and other pollinators in your neighborhood.

By the time this monarch emerges as an adult in a few weeks, there should be plenty of wildflowers available for it. Hopefully, it will be competing for nectar against a number of bees and other pollinators that made it through a tough spring season.