The Elaborate Plans of the Capricorn Beetle

Originally published in Disciple, January 10, 2011.

The larva of the European Capricorn beetle (Cerambyx cerdo) is a tough little grub. It can and does tunnel through the heart of oak trees, and fattens on the sparse nourishment it finds in the fibers and juices of the living oak.

For three years this grub bores its way deep within its hardwood home, safe from hungry predators. But at the end of its appointed time, some trigger causes the larva to end its random foraging and tunnel its way out to the bark-to, but not through the bark, for it is not yet ready to emerge.

Having left but a thin veneer of concealment, the grub retreats to the interior and there prepares a sumptuous bedroom for its pupa stage. It hollows out a chamber three to four inches long, and lines it with raveled woody fibers fluffed soft as velvet.

The Capricorn grub also fixes an inner barrier to protect the helpless pupa. This barrier is composed of wood chips from its tunneling, plus a hatch made of a substance resembling limestone. It has carried the ingredients for this hard plug in its stomach throughout its years in the larval stage.

Its preparations complete, the grub retires to its bedchamber, turns to face the exit tunnel, and commences the slow transformation into an adult beetle. When the metamorphosis is complete, the beetle will push its way through the protective barrier and the final bark obstruction, ready to fulfill its adult destiny.

But several details of the grub's preparations call for further reflection: First, some sort of internal clock or time-sense tells it when its three years as a grub are nearly finished. Second, the larva knows, somehow, just the right amount of outer bark to leave undisturbed. Had it left less, unwelcome intruders would be more likely to discover the entrance. Had it left more, the adult beetle would not be able to escape, as it is not equipped with the powerful digging jaws of the grub. Third, the grub always enters the pupa stage with its head toward the exit. This is essential, because the adult beetle, with its hard external skeleton, is incapable of turning around in the bedchamber. It would die where it was born, if it were headed in the wrong direction. Fourth, the larva knows how soft and vulnerable the pupa's flesh will be, and upholsters its chamber accordingly. Fifth, it creates a wall to protect the immobile pupa, utilizing a calcium "cud" it has brought along for the purpose.

There is, of course, no way for the larva to learn about these things. It goes through its life cycle totally alone. So the question must be asked: "How does the grub come by all this knowledge?" Obviously, it must be instinctive knowledge. The Capricorn larva is "programmed" with implanted directives, just as surely as a modern computer is programmed by its operator.

But the "Operator" in this case has a mind infinitely beyond man's. While we grope and fumble to comprehend such mysteries of life, the all-wise Creator goes on sustaining the universe, as He has done through long ages. Truly, it is as God said through the prophet Isaiah: "‘My thoughts are not your thoughts, neither are your ways my ways,' saith the Lord. ‘For as the heavens are higher than the earth, so are my ways higher than your ways, and my thoughts than your thoughts'" (Isa. 55:8-9).

Surely a God who fashioned such an intricate world-whose living parts are woven together by divinely given instinct-is worthy of all praise and reverence. Let us indeed praise our Father God, and set our hearts to know Him better!

The Old Scot (Ted Kyle) served as managing editor for Pulpit Helps magazine (Disciple's predecessor publication) from 1993-2008. He was always fascinated by the natural world, and readily saw God's hand in every detail. Ted went to be with His Creator and Savior in April 2013

Source: The Wonders of Instinct. Jean Henri Fabre, The Century Co., New York, 1918, pp. 55-58.

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