It was just another day. My friends and I went outside for lunch again. Every time we ate outside, we would walk around Scarsdale's ecosystem just to observe the scenery. Usually, we would just come by the customary wildlife such as frogs and birds.
However, today was something special. Two of my friends and I were sitting by the pond when the fourth one shouted at us to run over to him. The three of us got up and sprinted to him, amazed at what we saw.
It was a hatching mantis egg! I was amazed. We were incredibly fortunate to come at the exact time the egg was hatching! We found them all over the egg, on the branches, and even under the leaves!
Introduction
The scientific name for a mantis is mantodea, and they are from the Mantidae family! They are characterized by front legs with enlarged femurs that have a groove lined with spines into which the tibia presses. Using their spined front legs, mantises, which feed exclusively on living insects, seize prey in a viselike grip. When alarmed the mantid assumes a “threatening” attitude by raising and rustling its wings (if it is a winged species) and often displays bright warning coloration.
Furthermore, female and male mantises display very different phenotypes/characteristics. Female's are usually larger and are green, while the males are smaller and brown.
Habitat
Mantises are usually found among the green vegetation. Thus, mantises may be disguised to resemble green or brown foliage, a dried leaf, or a thin twig.
This camouflage helps it hide from predators, and also makes it unnoticeable as it stalks and prowls its victims.
Mating
The mating relationships between mantises are definitely the most interesting part of them.
As context, the female lays about 200 eggs in a large cocoon like capsule. This is called the ootheca which is pictured here.
This ootheca serves to protect the eggs and developing mantises from adverse weather conditions and enemies.
Interestingly, during mating, the female mantis will sometimes eat the males head! Scientists call this sexual cannibalism. Despite the gruesomeness of this act, it may benefit the species in the end.
Research has found that, in an evolutionary sense, sexual cannibalism can lead to more eggs laid, which increases the chance for a higher number of offspring to survive.
This is because the male praying mantis brain controls the inhibitions to mating, and a ganglion in the abdomen controls the motions of copulation (sexual intercourse). Without his head, the male praying mantis will lose his inhibitions and thus continue mating, which means he can fertilize more of the female's eggs.
Paradoxically then, the female praying mantis's sexual cannibalism may have an evolutionary advantage for both the female and the male. The male will have more of his genes passed on to the next generation if he fertilizes more eggs, and more eggs are laid by females who eat their mates, allowing for more offspring.
This is shown, as in a research study published in 2016, scientists fed crickets armed with radioactive labels to a group of praying mantises, in order to make each insect individually traceable.
Males and females were then paired off for mating. After mating, half the pairs were allowed to progress to sexual cannibalism, while the rest were interrupted.
According to the findings, published in Proceedings of the Royal Society B, females that ate their mates produced an average of 51 more eggs than their non-cannibalising counterparts.
Thanks to the radio-labels, the team was able to trace how much of each mantis’s biology was passed on to the eggs. Interestingly, the eggs of females that ate their mates contained significantly more male-derived amino acids, and more biological material from the male mantis.
“When a female ate a male after a mating event, she was found to have around 17.7% more of his biological material in her reproductive tissues, including her eggs and ovaries, than a female who only mated and did not cannibalise her mate,” explained lead researcher Kate Barry, a biologist at Macquarie University in Sydney.
Thus, what this shows is an evolutionary advantage to the male and female mantises. The male can fertilize more eggs and spread his genes to more offspring, while the female can PRODUCE more offspring. This results in an advantage for the mantis species as a whole due to a larger population.
However, there is a separate reason behind sexual cannibalism in mantises. In fact, female mantises often eat their mates just for nutrition! The females may be unable to resist a male meal that's so tempting and so vulnerable. And sure enough, researchers have shown that well-nourished female mantids refrained from cannibalism, while those deprived of food ate any male in sight, whether or not mating was involved.
This is incredibly interesting, as research posted in Proceedings of the Royal Society B has even found that a female mantis may even fake fertility in order to have a male meal!
Conclusion
In the end, the message is that in evolution, there is a reason to everything. All species live to produce the next generation, and every little behavior contributes to that one goal, even if it includes decapitating your mate.
Commentaires