"Computational Aspects of the Murder Hornet"
An Engineering Overview
by Fred Reed
"I have long been a partisan of insects in general, and hornets in particular, as exemplars of the most varied, imaginative and sometimes, in a correct use of an overused word, weird design and engineering in the live world. There is more of the unlikely, preposterous, and inexplicable in our six-footed cocitizens than in all the vertebrates combine. By comparison, we humans are a mundane and unimaginative lot.
None of this leaps immediately to consciousness. Think of hornets in terms of IT and mechanical engineering, optics, and aerodynamics, and they will concentrate the attention. A complete description of a murder hornet would be sufficient to allow an engineer of enough ability to construct one from the description alone. The description would consist of layer upon layer of great complexity, biochemical, molecular biological, cellular, and, subsuming all, genomic. We will today consider only the anatomical, physiological, and IT aspects.
The murder hornet represents a very high degree of precision, miniaturized, optimized, multidisciplinary integrated engineering with a autonomous maintenance and energy management. Human endeavor has produced nothing resembling the hornet’s elegance of design. Consider some of its systems individually:
First, the hornet perfectly controls six multi-jointed legs, allowing it easily to walk over uneven surfaces, even while hanging upside down. This requires coordination and sensory feedback. Any robotics engineer will attest to the difficulty of doing this.
Second, its flight system allows it to hover, engage in aerobatics, and fly at forty miles an hour. This requires adjusting the rate of wing beat and angle of attack of the wings. This is not simple. It also requires precisely located muscles anchored to the body and attached to the wings. These latter are seen to consist of a thin flight membrane reinforced by a network of supporting elements. The design produces a wing both strong but light.
Third, the sting. This consists of a biochemical mechanism to produce the venom, a sac to hold it, muscles to express the venom through the stinger, muscles to force the stinger into the victim, and the stinger itself. These must exist simultaneously and function in coordination in order to work. Absent any one, the system is useless
Fourth, the digestive system with its components and its complex biochemistry.
Fifth, vision. We tend to think of eyes as being of little interest since we all have them and most of us have a very simple idea of their function and complexity. This is illusory. The hornet’s compound eyes consist of large numbers of intricately designed ommatidia, I don’t know how many the hornet has—quite a few as its eyes are large–but the dragon fly has thirty thousand.
Here a point that could be made of any of the insect’s systems. On examination, the hornet’s eyes are complicated and exquisitely engineered. The description below largely is from the Wikipedia and heavily edited to remove technical details, which makes it a bit awkward. Follow the link for the whole thing.
“The compound eyes of… insects are composed of units called ommatidia (singular: ommatidium). An ommatidium contains a cluster of photoreceptor cells surrounded by support cells and pigment cells. The outer part of the ommatidium is overlaid with a transparent cornea. Each ommatidium is innervated by one axon bundle (usually consisting of 6–9 axons, depending on the number of rhabdomeres) and provides the brain with one picture element. The brain forms an image from these independent units…
Ommatidia are typically hexagonal in cross-section… At the outer surface, there is a cornea, below which is a pseudocone that acts to further focus the light. … Each ommatidium consists of nine photoreceptor cells (primary and secondary pigment cells and organized into a different tier. These “R cells” tightly pack the ommatidium. The portion of the R cells at the central axis of the ommatidium collectively form a light guide, a transparent tube, called the rhabdom. A hexagonal lattice of pigment cells insulates the ommatidial core from neighboring ommatidia to optimize coverage of the visual field…affecting the acuity."
The “…advantage of this arrangement is that the same visual axis is sampled from a larger area of the eye, thereby increasing sensitivity by a factor of seven, without increasing the size of the eye or reducing its acuity. Achieving this has also required the rewiring of the eye such that the axon bundles are twisted through 180 degrees (re-inverted), and each rhabdomere is united with those from the six adjacent ommatidia that share the same visual axis. Thus, at the level of the lamina – the first optical processing center of the insect brain – the signals are input in exactly the same manner as in the case of a normal apposition compound eye, but the image is enhanced…..”
Again, complex, miniaturized, optimized, integrated, elegant.
Sixth, the respiratory system consisting of spiracles, openings along the body, through which air enters and is pumped in and out by muscular contractions under control of timing and coordinating circuitry.
Seventh, the circulatory system, simple but requiring muscular contractions to pump hemolymph , as well as control circuitry.
Eighth, other sensory systems such as the antennae and auditory receptors, nerves detecting touch, three simple eyes (ocelli), etc.
Fitting all of these systems into an insect two inches long is a feat of engineering compaction orders of magnitude beyond current human possibility. Yet more astonishing, and hard to explain, is the IT aspect, the system integration and control to allow them to function seamlessly together.
To begin, the brain (for so we will call it) receives tens of thousands of what amount to pixels from two eyes and melds them to form an image. The brain must map this two-dimensional retinal information onto a three-dimensional world in real time since hornets do not characteristically run into things. This is not mathematically trivial. Then the brain must interpret this information to decide what is going on in its environment, decide what to do about it, coordinate the action of legs, wings, perhaps stinger, mouth parts, housekeeping tasks such as respiration and digestion, on and on. This is a lot of computation.
How hard is a hornet’s information processing? Programmers working in assembly language think of processing in terms of lines of code. How many assembly language instructions would be needed to control the six legs, wings, armament, respiration, etc., and the integration of all of these to adapt to differing circumstances? While a hornet doesn’t use assembly language, the question points to the level of computation needed.
Finally, information storage. These insects come out of the egg knowing a great many things: How to build a fairly complex nest in cooperation with others, to include knowing how to make wood paste and how to place it. How to care for young and the queen, quite complicated. How to hunt and what to hunt (honey bees, for example). When and how to react to perceived threats to the nest. Each of these breaks down into further complexity. The phrase, “Caring for the young and the queen” consists of seven words, but in practice involves many sub-tasks. Mating, done while flying (Think airline pilots and stewardesses) requires both agility and knowing how to do it. Further, the brain allows considerable learning. Hornets fly far from the nest, often through forests, and return, necessarily having learned the way.
In IT terms, how many bits would be required to hold this information? Note that much of it must be graphic. Hornets know what honey bees look like, for example, and what other hornets look like and many other things. The brain and nervous system must be a quite good graphics processing unit. How is this storage accomplished? Note that this information is not learned, though they can learn things, but inborn. Stored how?
We have all heard the expression, “He can’t walk and chew gum at the same time.” The hornet can fly complexly, walk, process visual inputs, control its respiratory rhythm, envenom enemies, process other sensory inputs, all effortlessly and in coordination to manage housekeeping. They clearly have something paralleling the human autonomic nervous system. Does it break, as ours does, into sympathetic and parasympathetic branches? The hornet clearly has a voluntary system, being able to decide what to do according to environmental inputs.
Now, hardware. A hornet’s brain, somewhat distributed, consists of very little tissue. Wikipedia: A hornet’s brain “may contain fewer than one million brain cells, compared with the 86,000 million that make up a human brain.”
Nerve impulses in any organism travel at speeds orders of magnitude lower than those found in computers. The insect has slow wiring and little of it. How does such a minor brain manage to manage a highly complex hornet? This is engineering way above our pay grade."
