We had an unexpected visitor last night. Well, I should say that it was not expected by Heidi. Heidi is from Colorado, so she is often surprised to find bugs in our house. I have been living in Tennessee for long enough that I am more surprised when there are not bugs in our house.
We were on our way to bed after putting James down for the night, and found a large beetle flying around in our room. It was a pretty large beetle to be airborne, and demonstrated very accurate navigation, even in the dark. When it landed on the floor I noticed something very strange about it – it seemed to carrying a colony of tiny spiders that were swarming all over its head and body.
Because I am not an entomologist, I was just slightly grossed out. Also, when I pointed a flashlight at the beetle it flipped itself onto its back, and I noticed that its abdomen was emitting what real entomologists call “a foul-smelling fluid.” I quickly used a piece of paper to flick the dying beetle out our bedroom door, assuming that he had been unfortunate enough to be killed by a bloodthirsty mob of baby spiders… but that made no sense.
How could so many spiders have jumped a big, fast-moving beetle, and how could they have gotten through his thick plate armor so quickly? He seemed to have gone from precision flying to apparent death very suddenly, even suspiciously suddenly. It slowly dawned on me that I had just been outwitted by a bug playing possum, so I Googled “mites on beetle” and discovered something fascinating.
Our visitor had been a shiny black Sexton or Burying beetle; there are lots of similar-looking carrion beetles, but its bright orange markings indicated that its genus was Nicrophorus. These helpful little Coleopterans are not only carrion-eaters but carrion-buriers, digging under and then covering over small rodents and birds. And not only do they lay their eggs there so their young can have a nice snack upon hatching, but both parents actually hang around to care for them. That is where the mites come in.
Phoretic mites ride around on the exploring Nicrophorinae, waiting for them to land on a likely looking carcass. The mites don’t eat carrion; they eat the eggs and larvae of other carrion eaters, thus destroying the competition and protecting the food source for their hosts. Somehow their simple little spider brains know that Sexton beetles are flying troop transports that will take them to food, and the Sexton beetles know that a small battalion of mites will help them to protect their resources.
Nature is full of symbiotic relationships, like those between cleaner fish and larger predators, or honeyguide birds and their hired muscle. Evolutionary scientists are very optimistic about how symbiosis must support Darwinism and promote the survival and fitness needed for advancing biological complexity. However, if the idea that every indescribably complex part of these tiny mites’ biology resulted from random genetic mutations is hard to swallow, how about the idea that every “fittest” chance mutation through millions of generations of mite development was consistently compatible and dependent on every “fittest” chance mutation of beetle development?
Even more complicated, how do we account for instinct? Neither of these insects has the intellect to observe the other’s habits and figure out that they can be mutually beneficial to one another, or even the brain power to notice that they are accidentally benefiting one another. And while Darwin’s Descent of Man tries to explain how actions become habits and habits might become instincts, even modern scientists can’t explain the mechanism by which habits (or memories of habits) would get into genes to be passed on to offspring.
And yet, every freshly-hatched mite knows to climb aboard departing beetles (and to not to eat their hosts’ eggs or larvae), and every freshly-hatched beetle knows to gather the mites under its wings (and to not scrape them off, even though carrying them looks… awful). This is a great wonder, and as horrible and gross as carrion-eating bugs airlifting maggot-eating spiders might sound, this teamwork represents an amazing blessing from God.
Not only does God feed the birds of the air and notice when a single sparrow falls, but he has created a creature to carefully bury that sparrow. And not only does God use the fallen sparrow to nourish the beetle and the grass, but He has created little helpers for this beetle. If God has created friends and allies even for lowly scavenger beetles, how much more will He sustain us?
And so that is what we were pondering last night as we went to sleep. Well, I should say that I was pondering it. I think Heidi kept thinking about the other ramifications of insects and arachnids joining forces to invade our house.