Evolution has yielded many interesting creatures on this planet. Through evolution creatures slowly change. With each new change the creature either survives to pass on its new trait or does not. Through this amazing process creatures adapt to where they live, to better their likelihood of survive. It is all about passing on genes to the next generation. Those who pass on their traits are typically considered to be successful. It is all about finding a mate and passing on genes.
Beetles of the genus Pleocoma or more commonly known as Rain Beetles are experts on passing their genes. in fact this is pretty much all they do. Their entire lives are dedicated to finding a mate successfully. Through evolution they have mastered this.
These beetles start out like many other things as eggs underground. When they hatch as larvae they look “grub-like with a curved, whitish body and pale yellow-brown head.” During this stage they live soley underground feeding on nearby tree roots which typically are pear or apple trees. This is all they do, eat, eat, eat. They continue munching away on the roots for anywhere between 9 and 13 years. The reason they spend so much time eating is because they are storing as much energy as possible for later as fat. Eventually their whole chance of mating relies on how much they eat at this stage.
Once they have eaten their “fill” of roots they enter the pupal stage and mature to their adult form which is about a month before the first real rain falls over California. “The adult is similar in appearance to scarab beetles, with strong legs for digging. It is dark or reddish brown and hairy”. When they emerge as adults they don’t have any form of working mouthparts and do not have a digestive system so they never eat as an adult. It is at this time that the beetles put use to the energy they have been storing up for all their lives this is the energy they live on during their whole period as an adult. The males and females will dig themselves out of the ground that they have been living in all their life. The males will fly and use their specialized antenna to pick up on the pheromones of the females and seek out a female. Males will typically fly after the first rain of the season hence the name Rain Beetle. The females will surface from the ground for a short period of time wait for a male to mate with her. Females do not have the ability to fly. There is evidence that they may have at some point because they do have “wings” that are just little nubs.
The males need to act quickly because they only have enough energy to fly for around two hours. They use their antennae to pick up a female pheromone. Once they find the female they may have to fight off other males who also found her. Once the male is the victor he mates with the female. Shortly after mating the male will die because it has expended most of the energy it had. The female uses the energy she stored all her life to mate and then to dig a deep tunnel around 10 feet underground to lay the eggs around the roots of a tree to give the future larvae the all so important food source it needs. In most cases the female can live for a few months on it’s reserve of energy before dying.
Thus a new life cycle will begin with a male successfully finding a female and mating with her. This is the entire life goal for the Rain Beetle. They have evolved in such a way to focus solely on mating and passing on genes. The adults don’t have a digestive tract so that it can speed up the mating process by not expelling energy and time to develop and utilize a digestive tract. instead it uses this energy to find a mate and pass on genes. Although many people will look at the Rain Beetle and think that it is a useless creature (or a nuisance if you own an orchid). But this is in actuality an amazing creature. Evolution has slowly molded this insect so that it is a master of passing on genes to the next generation taking millions of years to reach this mastery. This is what is truly remarkable about the Rain Beetle.