The Design Packed Into a Fruit Fly

The most amazing animals of all may be the tiniest. Consider how much bio-technology has to fit into the head of a fruit fly.

How Fruit Flies Navigate for Miles Over the Desert

It’s been awhile since we heard about the latest research in the Dickinson Lab at Caltech. In 2003, Michael Dickinson dazzled us with descriptions of the navigation abilities of the tiny fruit fly, Drosophila (8 Dec 2003). The lab is still in operation, ready to dazzle us with another feat of the minuscule flyers: celestial navigation. A press release from Caltech says,

What do ancient seafaring explorers and fruit flies have in common? Caltech researchers have discovered that, similar to nautical navigators of old, fruit flies use celestial cues like the sun to navigate in straight lines.

The research is described in a paper appearing online on August 30 in the journal Current Biology. The work was done in the laboratory of Michael Dickinson, Esther M. and Abe M. Zarem Professor of Bioengineering and Aeronautics.

The article asks us to ponder the challenge of walking in a trackless desert, with no landmarks, yet needing to keep in a straight line.

This is the conundrum of Drosophila, the common fruit fly, in the desert. Almost 40 years ago, a study found that fruit flies can fly up to nine miles in one night in search of food and water. How are these tiny insects able to navigate such long distances?

“For flies crossing inhospitable territory, flying around in circles would be really dangerous—they’re less likely to find any food or water,” says postdoctoral scholar Ysabel Giraldo, the study’s first author. “Surprisingly, fruit flies are seasonally found in environments like the Mojave Desert. They must get there from somewhere, and once there, they must figure out how to get around.“

Using Dickinson’s ingenious flight simulator, researchers found, to their astonishment, that the little flies can use the sun as a marker. They will fix a bright spot in one position in their visual field and stick with it for long distances. “It was a bit surprising to find that the same pesky little flies that flit around fruit bowls and wine glasses have the capacity to navigate for many miles using the sun,” Dickinson said. The flies come equipped with “compass neurons” to do this. Researchers used genetically modified neurons to watch active neurons light up, using a powerful microscope to peer through tiny holes in the fly’s head while it was on the flight simulator. To work, the compass neurons must be able to integrate their information and then signal the muscles of the wings to stay on course.

Most likely, well-known migrating insects like Monarch butterflies also come equipped with specialized neurons for their multi-thousand-mile migrations. Fruit flies, however, are much smaller, so their equipment represents micro-miniaturization of the bio-technology. Information on the Dickinson paper can be found at Caltech Coda.

Evolutionists believe that fruit flies have been navigating like this for many millions of years, but they didn’t say how the ability emerged by chance mutations and natural selection.

How Sustained Flight Is Mediated

They have fruit flies in India, too, and researchers there found one component of a system that allows for sustained flight. So what’s all the excitement about flight? A press release from the National Centre for Biological Sciences (NCBS) at the Tata Institute of Fundamental Research (TIFR) asks that question, and describes what they found.

Have you ever wondered how tirelessly the tiny fruit fly buzzes around your fruit bowl? This behavior not only demands tremendous energy but also requires highly coordinated neuronal signaling that enables continuous flight. A recent study from Prof. Gaiti Hasan’s lab has uncovered molecules required in the fruit flies brain that enables flight for long periods of time and helps them locate the fruit bowl in your pantry. One of the key proteins identified in this study is the FMRFa receptor (FMRFaR). The authors describe a role for this receptor in a specific class of neurons in the adult fly brain which helps the fly sustain flight for long periods of time.

This receptor is a member of the family of G-protein coupled receptors (GPCRs), known to convert hormonal signals into actions. The team found that mutant flies without FMRFaR could only fly about half the time.

A fruit fly body is only a few millimeters in length.

“One would expect that flying for several minutes at a stretch would require a continuous stream of sensory information for the fly to reach its destination. Here, we believe that the FMRFaR on dopaminergic neurons helps in processing such sensory information and thus enables sustained flight in the right direction”, says corresponding author, Prof. Hasan.

Many questions remain, however, such as the source of the information that triggers the protein. The FMRFaR protein has a length of 549 amino acids, according to the UniProt database. The Illustra Media film Origin showed that the probability of getting a protein less than a third that size (150 aa) would never happen by chance in the history of multiple universes.

How much design do you need to see before you give up on Darwinism absolutely and forever?