Pollinating insects

The bee is arguably the best-known pollinator, but it is important not to forget about other pollinator species.

 

It is not always easy to determine whether an insect sitting on a flower will play a role in pollination. A distinction is made between floricultural insects and pollinating insects. All the insects that frequent flowers to feed on nectar or pollen are said to be floricultural. In doing so, by passing from one flower to another, some insects involuntarily carry pollen and thus ensure pollination. We can then qualify them as pollinators.

 

The same insect can pollinate one species of plant and flower for another. This is the case, for example, of the ground bumblebee (Bombus terrestris).

As its tongue is short, it cannot access the nectar of some flowers that are too deep. It therefore happens to "cheat" by making a hole at the base of the flower to collect the nectar. In this case, it no longer ensures pollination since it is not in contact with the stamens and the pistil! He is no more than a floricultural.

Diptera are presented by the fact that the second pair of wings is presented by balancers, organs that begin as stabilizers of flight. We know about 140,000 species of it worldwide, including more than 8,500 in mainland France.

 

Among the species of floricultural diptera, we find hoverflies which are flies that look for some to small wasps and are able to fly on the spot. They feed on pollen or nectar with a proboscis adapted to their diet.

One of the ways to recognize the hoverfly is its way of flying: it is both extremely fast to scamper and disappear from your sight, while being able to hover as if it were 'an observation flight, before rushing for a flower.

 

Diptera play an important role in the pollination of small flowers, unattractive to large pollinators.

Part of the wasps, mostly males, are responsible for collecting flower nectar. But that does not mean that they are classified as pollinating insects. Nevertheless, some species of wasps ensure the transport of pollen grains from the male organs to the female organs of plants very efficiently.

 

Wasps are essential for fig trees. The fig tree wasp, called agaonidae wasp, plays the role of pollen deliverer. It thus allows the tree to complete its reproductive cycle in full. In biology, this exclusive mutual relationship is called mutualism: the insect and the plant rely on each other for survival.

Beetles are insects that are distinguished by their hard and rigid fore wings called elytra. They form a shell that protects the abdomen and the membranous hind wings. Among the 300,000 species in the world, including nearly 11,000 in mainland France, there are many floricultural species, such as the golden whale, the common trichia or the noble edemera (in the photo).

Beetles often consume stamens and pollen: they are generally poor pollinators compared to other groups of flower insects. It should be noted, however, that the first known pollinating insects, 200 million years ago, were small beetles that frequented cycads.

More than 160,000 species of butterflies or lepidoptera are known in the world, including more than 5,500 in mainland France. The best known are the so-called "day" butterflies which only include 250 species in mainland France. The other species, often more discreet, are said to be “at night” even if some live during the day. Most species of butterflies frequent the flowers from which they collect the nectar with their long proboscis which is coiled in a spiral at rest.

Insects are drawn to the colors of flowers, for the shape and information carried by the carving and ornamentation of the petals. In general, we distinguish radially symmetrical flowers (e.g. borage), which allow various positions and attract many insects, and bilaterally symmetrical flowers (e.g. sage) which carry more information for the positioning of the insect and are generally associated with a smaller number of floricultural insects.

The petals are also adorned with lines, spots, dots that serve to guide the insect to the nectar; we are talking about nectariferous guides. Finally, insects are attracted to the scent of flowers, which can be pleasant or unpleasant to our senses. It is the combination of these factors that attracts a particular pollinator.

 

To learn more about the pollination process please see our article Understanding bee pollination.