In reality, the aerodynamics of many insect wings, including those of bumblebees, have more in common with helicopter blades than with the fixed wings of conventional aircraft. Two pairs of wings attach to the thorax of the bee, but the wings on each side are joined with hooks, so that they act as one. Even so, the surface area is quite small, and the wings must beat at about 200 beats per second to keep the bee aloft. This is 10 to 20 times faster than nerve impulses can travel from brain to muscle, so, unlike vertebrate muscles, where each contraction is the result of a separate nerve impulse, bumblebee muscles are asynchronous. This means that the contraction of one pair of muscles stretches the opposing set, and the stretching is sufficient stimulus to initiate contraction of the stretched muscles, and so forth. Occasional nerve impulses serve simply to indicate that flight is still required.

The lift produced by this system is sufficient to hoist at least twice the bumblebee’s body weight—an important consideration, since a full load of nectar and pollen can weigh nearly as much as the worker bee carrying it. Furthermore, a bumblebee can still fly when half the wings have worn away. Far from being an aerodynamic non sequitur, these creatures could teach us a thing or two about staying aloft.

The same wing muscles which power flight are also used to produce the characteristic bumblebee buzz. In Christchurch, a visit was made to Industrial Research, where a small team of people investigates vibrations of economic significance—including, surprisingly, the buzzings of bees. Industrial Research invented the rubber shock absorbers which are now being used internationally to protect buildings and bridges from earthquake damage, and the company’s interests also include reducing vibrations in band saws to reduce wood wastage and monitoring vibrations in the Hamilton jet engine to make it more efficient. One of the group, mechanical engineer Marcus King, has been investigating the effect of buzzing on the anthers of various flowers.

Of particular interest has been kiwifruit, for which bumblebees are excellent pollinators. Kiwifruit anthers look rather like the rockets in early cartoon strips. Vibrations of the right frequency cause the “booster region” of the rocket to twist and warp, splitting the “fuselage” and hurling the pollen out into space. Kiwifruit anthers require vibrations of 6930 Hz before they spontaneously explode, but the bumblebee buzz ranges from 300-400 Hz (a frequency close to the G above middle C on a piano). How then do bumblebees get the pollen off the anther?

The secret, Marcus found, was in the loudness of the buzz and the way in which the bee collects the pollen. If you watch a bumblebee on a poppy (or some varieties of rose), you’ll quickly notice that it uses its legs to rake up a bunch of anthers and hold them against its body, then “buzzes” them before moving on to the next group of anthers. The buzz causes the hard plates that make up the exoskeleton of the bumblebee to vibrate, and the amount of energy that can be transferred from the buzzing bee to the anthers is so great that the pollen literally explodes outwards. It is not just the thorax, where the muscles are situated, which vibrates, but the whole body, head included. It is this powerful buzz that makes the bee such a good pollinator. If you hold the stem of the flower while the bee is buzzing, you can feel the strong vibrations through your hands.

As well as using the buzz to dislodge pollen from anthers, bumblebees produce it during nest building (to compact soil), when threatened by a predator (to scare it away) and when “angry” such as on a windowpane.

By recording the bumblebee buzz and then slowing it down, it has been shown that the bee does not emit a constant sound, but a series of short (less than a tenth of a second) buzz pulses. Nearly everything that a bumblebee does is geared towards obtaining food for the hive (as pollen or nectar), and a series of short pulses requires less energy to produce than a continuous bombardment of single-pitched sound.”

Science Advances ran a recent report on the lift- ing capacity of bumble bees.

“They can carry 60, 70 or 80 percent of their body weight flying, which would be a huge load for us just walking around,” said researcher Susan Gagliardi, a research associate in the College of  Biological Sciences at the University of California, Davis. “We were curious to see how they do it and how much it costs them to carry food and supplies back to the hive.”

Gagliardi and Stacey Combes, Associate Professor in the Department of Neurobiology, Physiology and Behaviour, measured the energy expended by bumblebees flying in a specially designed chamber (an emptied snow globe). They attached small pieces of solder wire to the bees to adjust their weight.

“We have the bees in a little chamber and we measure the carbon dioxide they produce. They are mostly burning sugar so you can tell directly how much sugar they are using as they are flying,” Gagliardi said.

They also used high-speed video to examine wing beats and movements.

Two modes of flight

Because bumblebees fuel flight from the nectar they are carrying, they should get lighter as they fly and use less energy. To their surprise, Combes and Gagliardi found that the bees could actually use less energy per unit load when they were more heavily laden.

“They get more economical in flying the more heavily loaded they are, which doesn’t make any sense in terms of energetics,” Combes said.

Looking closely, the researchers found that bumblebees have two different ways to cope with increasing loads. They always increase stroke amplitude (how far the wings flap) when they are more heavily loaded, but this isn’t enough to support the extra weight on its own. To make up the difference, bees can increase wingbeat frequency, which generates more lift and increases energetic cost.

But bees also have an alternative, subtly different flying mode that allows them to carry heavier loads while expending less energy than when they increase flapping frequency.

“It’s not yet clear exactly what this ‘economy mode’ involves,” Combes said, “although it may involve a change in how the wing rotates to reverse direction between strokes. But it is something the bees can choose to do, or not.”

“It turns out to be a behavioural choice they are making in terms of how they support the load,”Combes said.“When bees are lightly loaded or rested, they are more likely to increase wingbeat frequency. When they are more heavily loaded, they switch to the mysterious economy mode, producing enough force to support the load with only a small increase, or even a decrease, in flapping frequency.”

In summary then, we have an insect that can create mental imagery, possess complex navigational skills, use tools, solve complex problems, detect floral cues such as colour, shape, pattern and even electric fields. They are able to warm up cold muscles simply by shivering. They are able to maintain a nearly constant thoracic temperature on both hot and cold days, can conserve energy when carrying heavy payloads and use their special buzzing frequencies to dislodge nectar that other insects are unable to. Without the bumblebee, some plants would not be able to be pollinated.

According to evolutionary scientists, the evolution of bees coincided with the evolution of flowering plants because they both needed each other to survive. But beyond that generalised statement, there is a gaping hole in their description as to how bees arrived with complex pollination skills just at the right time for flowers to provide equally complex, chemically based, nectar and pollen. It makes far more sense to accept the creation record as it stands with God creating fully developed plants on day 3 and the fully functioning insects on day 6.