New research indicates that bees and moths have secret senses that allow them to “feel” nearby flowers. These senses also help them to navigate long distances.
Bees are sophisticated flying insects with a fine set of senses that act as useful tools when it comes to seeking out pollen and nectar as they buzz from one flower to another.
They have wide-angled compound eyes and sensitive antennae. But recent research reveals that bumble bees have another hidden sense that lets them detect if another bee has already visited the flower before them. Fine hairs on their bodies can sense changes in electrostatic fields.
Here is an unrelated 3:58-minute video by Science Editor about this subject:
Professor Daniel Robert is an expert in animal senses and behavior at the University of Bristol in the UK. His findings show that bumble bees can sense weak electrostatic fields that form when they fly close to a flower. This can be discerned without the insect landing, and measuring the electric field surrounding the flower reveals whether the flower has been visited in the past minutes or seconds.
Such a sense has long been known in sharks and ray, which detect weak electrical fields created by other fish in water. Even water-based mammals like dolphins and the platypus use electric fields to help them hunt for prey.
This, however, is one of the first examples of electroreception in the air. Bees do not hunt other airborne insects with this ability. They use electrical fields to find nectar and pollen-rich flowers.
Opposite charges attract, so negatively charged pollen will stick to positively charged bees.
Bees develop a positive electric charge as they fly, because as they fly, they lose electrons due to the air rubbing against their bodies. This causes a small positive electric charge that helps bees collect pollen more easily from negatively charged flowers. Flowers are connected to the earth, which is a rich source of electrons, so they are negatively charged.
Imagine the static that is created if you rub a balloon on your hair or sweater. This is like the charge the bees collect, except the bee charge is about 10,000 times weaker.
Once the pollen sticks to the bee, it transforms to be more positively charged during flight. This makes it more likely to stick to the negatively charged stigma, or female part of a flower.
Professor Robert and his colleagues decided to explore further by putting an electrode in a flower to detect a current flowing through the plant whenever a bumble bee approached in the air. This study revealed that an electrostatic field is generated between them that exerts a tiny attractive force.
Were the bees aware of this electrostatic field? They decided to offer bumblebees discs with or without sugar rewards. The ones with sugar had 30 volts of electricity flow through them to create an electrical field. It was determined that the bees could sense electrical fields and learned that they were associated with rewards. Bees couldn’t identify the sugary disk without the charge.
Another group researched and published that honeybees were able to detect electrical fields after Professor Robert’s work.
How insects could do this remained a mystery, so Professor Robert established the ElectroBee project. He discovered that bees have fine hairs on their bodies that move in the presence of weak electrical fields. Each hair has such sensitive nerves at its base that they can detect minor movements of as little as seven nanometers, caused by the electrical field.
Professor Robert believes that when a bee visits a flower, it may cancel out some of the negative charge to reduce the electrostatic field that forms when bees approach. By changing the strength of the electrostatic field, it may allow other bees flying past to figure out if a flower is worth visiting before landing, which saves them time and energy.
A change of electrical potential happens in seconds, whereas other signals like the color or smell of a flower can take minutes or hours.
In summer of 2020 Professor Robert and his team planned to test their theory in a meadow that the electric field helps bees know which flowers to visit by counting bumblebee visits to flowers and measuring electric fields around the flowers.
Their findings could help scientists understand the relationship between plants and pollinating insects, which is crucial for improving the production of many vital fruit crops that rely upon bees for pollination.
Professor Robert is also investigating whether bumblebees use their electrostatic charge to let their nest sisters know about where the best places are to fly to for pollen.