Trillions of Cicadas Sing of Intelligent Design
Love them or hate them, the cicadas are coming — trillions of them. Maybe quadrillions. Having lived underground for years, they’re all coming up for a brief frolic of food, song, and dance. After a few weeks of play, their newborn larvae will crawl back into the soil till next time their internal clocks strike all at once.
Scientists are intrigued by the coordinated emergence of these insects in prime numbers of years: 13 and 17. This year is special for having two broods emerge at the same time: Brood XIII (17 year cycle) and Brood XIX (13 year cycle). This particular convergence only occurs every 221 years. The last time it happened, in 1803, Thomas Jefferson was President. Most easterners will see one brood or the other, but in the overlapping region around the Great Lakes, residents will get the double show. Scientists will be taking advantage of this rare convergence to learn more about cicadas.
There are 15 species of periodic cicadas, each with their own prime number and cycle. Their territories span 29 states from New York to eastern Texas. Often confused with locusts, cicadas are basically harmless to humans and plants, although their sheer numbers can seem overwhelming and their collective noise deafening. Mostly heard and not as often seen, they make some of the loudest sounds of any insect. The males make the sound using a flexible membrane on the torso that they can flex with their abdominal muscles. Cicadas also emit a collective mist of urine that is also harmless, consisting almost entirely of water. For those that can’t take the noise or mist in the overlapping region, give them a couple of weeks to do their thing and it will be over till 2037. In the meantime, birds will have a feast day, and consider, if you can bear it, that the bugs are edible for humans. Any confectioners in the crowd? Free ingredients for the taking! Probably best covered in chocolate.
Cicadas, Darwin, and Design
When I last wrote about cicadas in 2016, a different brood was emerging in the northeast, a 17-year brood. In that article, we considered questions about whether the Darwinian explanation for the prime-number synchronization was satisfactory, and we considered some of the design features of these insects.
If predation is a problem, why the billions at once? With so many, they could come up every year and do just fine. Why wait? And if selection pressure helps the cicadas, can’t it help the predators the same way? Where are the 17-year predators? Besides, you wonder what the predators are eating outside the two-to-six-week window the cicadas are active.
Like the peppered moths and the Galápagos finches, the evolutionary story of cicadas offers a certain intuitive satisfaction, until you start asking questions. Worse, it distracts from the really interesting aspects that really need explaining.
Now that eight years have passed, more information has been published that should increase our awe of this phenomenon. In 2022, Günter Bechly showed a photo of a fossil cicada in Cretaceous amber that has essentially the same body plan as modern cicadas. Any evolution in 115 million years has been mostly cosmetic.
The Aesthetics of Cicadas
AP reporters Seth Borenstein and Carolyn Kaster did their best to make the cicadas look pretty, with photographs and prose exalting their “rich reds, gentle greens and basic blacks” as an example of “Nature’s artwork” (in the eyes of “some beholders” at least). They can seem overpowering in numbers and might strike some as strange — even alien.
But individually, up close and personal, a cicada has splashes of color, subtle shapes and that special something that some scientists and artists say translate to beauty. Even if to the average person it’s just a bug… To artists and scientists, cicadas are more awe-inspiring than awful.
Another scientist expresses his appreciation for these wonders of nature.
“There’s a lot of things in the world today to get freaked out about. Cicadas aren’t one of them,” said Mount St. Joseph University biologist Gene Kritsky, who wrote a book on this year’s dual emergence. “They’re beautiful insects. They’ve got these red eyes, black bodies, orange-colored veins on these membranous wings. I love the way they come up in these big numbers. I like that I can predict when they come out. It’s a scientific experiment every time
Perhaps this is excusable praise from a scientist who earned tenure from his research on cicadas.
Cicada Superlatives
Now that you know not to be creeped out by the bugs, you can tolerate a short animated photo of one coming out of the ground like a boxer ready to fight. It’s in Seth Borenstein’s earlier AP story of the coming “Cicada-geddon” arriving in May and June. Nice buggy!
“We’ve got trillions of these amazing living organisms come out of the Earth, climb up on trees and it’s just a unique experience, a sight to behold,” [Saad] Bhamla said. “It’s like an entire alien species living underneath our feet and then some prime number years they come out to say hello.”
The emerging cicadas climb up trees to make noise and mate. After the eggs are laid in the tree, the nymphs fall to the ground and dig down to the roots where they will live and feed on water and nutrients in xylem, using specialized pumps in their heads.
The cicada gets so much fluid that it has a lot of liquid waste to get rid of. It does so thanks to a special muscle that creates a jet of urine that flows faster than in most any other animal, said Georgia Tech’s Bhamla.
There they will live in hiding till the prime clock strikes again. At New Scientist, Corryn Wetzel explained that double emergences are not that rare, since there are 15 species, three on the 13-year cycle and twelve on the 17-year cycle.
It isn’t so much the number of cicadas but the area these red-eyed insects will invade. “It’s not unheard of to have dual brood emergences, but this one is notable for the geographic range it covers,” says Jonathan Larson at the University of Kentucky. “It’ll be a spectacular force of nature.”
Can Cicadas Be Darwinized
The above articles all assume evolution. Can research scientists publishing in peer-reviewed journals justify the Darwinian origin story? Chinese Academy scientist Hui Jiang and 12 other international colleagues tried to. In Nature Communications, the team wrote about a “Mesozoic evolution of cicadas and their origins of vocalization and root feeding.” They spoke of evolution 30 times and origin 3 times, but never mentioned mutations or natural selection — a major omission if these “beautiful” bugs diverged from ancestral insects by Darwin’s celebrated mechanism. Their explanation consists primarily of possibilities, perhapses, and maybes.
Our results suggest that Cicadidae and Tettigarctidae might have diverged at or by the Middle Jurassic, with morphological evolution possibly shaped by host plant changes. The discovery of tymbal structures and anatomical analysis of adult fossils indicate that mid-Cretaceous cicadas were silent as modern Tettigarctidae or could have produced faint tymbal-related sounds. The discovery of final-instar nymphal and exuviae cicadoid fossils with fossorial forelegs and piercing-sucking mouthparts indicates that they had most likely adopted a subterranean lifestyle by the mid-Cretaceous, occupying the ecological niche of underground feeding on root.
Even granting those possibilities, the major questions remain unanswered: without begging the question of evolution, what mutations were selected in a Darwinian manner?
Here, we report newly described adults, a final-instar nymph, and exuviae of Cicadoidea from mid-Cretaceous (~99 Ma) Kachin amber that originated in northern Myanmar (Fig. 1). We use morphological data from fossil and extant Cicadoidea to conduct phylogenetic and morphological disparity analyses, trying to clarify the phylogenetic relationships between Mesozoic fossil and extant cicadoids and to illuminate macroevolutionary changes in their body structure adaptations. We discover the membranous tymbal and tymbal muscles associated with cicadoid sound production in the fossil record, and report fossil final-instar nymphs with specialised forelegs and long piercing-sucking mouthparts, indicative of both fossorial and root-feeding behaviours. In sum, we provide a more comprehensive picture of the relationships, and ecological and evolutionary history of early Cicadoidea.
Given the diversity of insects worldwide, how can the fossils in Myanmar explain cicadas halfway around the world in Michigan? If some cicadas today don’t make noise, and don’t live underground, why assume that extant cicadas evolved from silent ones in different niches?
One can look through the open-access paper and find little more than suggestions that various cosmetic features, such as the shapes of sclerites on this or that body part, are “stem” (primitive) or “crown” (fully evolved) features between the fossils and living cicadas.
As the forewings are connected to the mesothorax, the enlargement of the exposed mesonotum may suggest enhancement of the thoracic flight muscles, which appears also to indicate a transformation in wing morphology and flight capabilities. This trend also reveals the obvious difference in the appearance of the thoracic notum of extant tettigarctids and cicadids from an evolutionary perspective.
If the two groups are extant, why appeal to neo-Darwinism at all? Did evolution leave the tettigarctids behind? Each insect in each group is adapted to its niche. One cannot claim that one evolved from the other without begging the question of common ancestry by mutation and selection. But just keep waiting: someday the evolutionary biologist may reach the nirvana of understanding. For now, they can only visualize evolutionary transitions as possibilities.
Our research demonstrates that highly specialised, homologous body structures in insect fossils may contain identifiable transitional variants previously have been overlooked. Meticulous investigation of these continuous morphological transformations may allow for a more precise understanding of the influence of temporal and spatial changes on morphological evolution and further assist in elucidating the patterns of macroevolution.
Unscientific Explanations
A common defect in explanations like this is assuming that environments have causal power over body plans. In this case, the rise of angiosperms gave the primitive cicadas an opportunity to evolve to feed on them — that is, if you are willing to leave science behind and trust your imagination.
We consider that there might be a broad host shift or tendency in the evolution of Cicadoidea to feed on angiosperms when this newly emerged plant group diversified during the Early Cretaceous.
Bechly had something to say about the “newly emerged” angiosperms, Darwin’s “abominable mystery.”
Ascribing power to the environment commits two logical blunders: (1) inadequate causation and (2) special pleading. If angiosperms somehow caused cicadas to develop specialized mouthparts, head pumps, urine muscles, and underground lifestyles, why didn’t it do the same for all other insects similar to cicadas? One would think a law of nature (like natural selection is purported to be) would result in similar effects. To say it only drove cicadas underground to live on root xylem and then emerge every 17 years leaves all the other insects in the same environment unexplained.
The evidence for root-feeding is the most poorly documented herbivore functional feeding group in the fossil record… Root feeding undoubtedly provides advantages for cicada nymphs to migrate to and to inhabit for extended time underground, apparently representing a successful and highly specialised survival strategy.
If it is such a great strategy, why didn’t it drive grasshoppers and locusts underground? Strategy, furthermore, sounds like a word of intent. Whose intent? Nature’s? Scientific explanations were supposed to get away from personification.
Having used possibility words dozens of times (may have, possibly, likely, suggests), these scientists should admit they do not have answers, and should open themselves to other possibilities, like design. If their favored Darwinian toolkit cannot explain with any certainty the slight rearrangements of existing body parts like sclerites, how can it begin to approach the far more difficult challenges of body systems (e.g., flight, muscles, jointed limbs, sensory organs, digestive systems, reproduction, nervous systems, instincts) and their coordination into functionally complete organisms?
Open the Discussion
Surely a “fair result can be obtained only by fully stating and balancing the facts and arguments on both sides of each question,” as Darwin said, to which he added about his “mere abstract” in The Origin, “and this cannot possibly be here done.” Okay, well; his disciples now have had 165 more years to do it. Let them produce the goods instead of making promises that more research “may allow for a more precise understanding” someday.
Incidentally, the research team never did explain the prime number cycles of periodic cicadas. And I’d like to ask how the bugs’ beautiful red compound eyes can remain functional for 17 years underground in the dark to work just fine the day they’re needed. Surely there is plenty of research left for scientists who view design and beauty in nature with knowledge of engineering requirements for functional coherence.
No comments:
Post a Comment