Misconceptions

I picked the chapter, The Mate-eating Mantis, from the book, "The Earwig's Tail" by Berenbaum. I remember as a little girl being told something about the mating ritual of preying mantises. When I started reading this chapter, the familiar memory of female preying mantises eating their spouse resurfaced in my mind. I am also very excited about my preying mantises' cocoon. I have been doing research on these insects since I found this cocoon and so decided to chose this chapter as my blog post. 

The misconcention in this chapter is the female praying mantis kills and eats her partner usually devouring the head first. However, Berenbaum states that this isn't true, at least in the vast majority of cases. There are 2,000 species of mantids in the world and the phenomenon has been reported in only a tiny handful of them. And of the most reported cases, the sexual cannibalism has been observed in captive specimens and was likely a laboratory artifact. Berenbaum suggests that these mantids that exacuted cannibalism were most likely chronically hungry or malnourished. 

Berenbaum thinks this myth was started because it was documented by extremely eloquent writers in high-profile places. It was also published in Science, the premier scientific journal of the era and was written by Leland Ossian Howard, the future chief entomologist of the U.S.  Department of Agriculture. He had broughten a male mantis to a female mantis of his friends and observed the female bit off how left tarsus, consumed the tibia and femur, and then his left eye. The male continued to try to mate through this action and finally did the deed but after his leg and thorax was eaten as well. 

There is a common act of head removal in male mantis that leads to genitalic torsion on both sexes mantis. Reflexive erections can be induced in human patients subjected to spinal block or some kinds of brain lesions. Roeder does seem to think that removal of the head may free up inhibitions from the principle nerve bundle in the head that inhibit signals to the abdomen and thus, the twisted genitalia during decapitation can be filliped around and engaged into the female. There are also studies that suggest a male seeing a female eating her fill is a "turn on" and a male will move six times faster toward such female. Also males of Tenodera ardifolia are significantly less likely to court hungry females. 

What I gathered from this chapter is preying mantises do sometimes eat the head of their mate; however, this happens in captivity more than in their natural environment. And this behavior may help benefit the males reproductive rate by promoting intact genitalia. 

Other female insects indulge on their mates as well. We read in the other book about the male speckled cockroach (shown below). This male roach produces a phermomone called "seducin"in the glands on his back that the female licks while he plans his approach. 

photo cred by wiki

We also read about sagebrush crickets. These females eat the hind wings of their mates and lick the blood that flows from the wounds they inflict. 

Fun facts:

These majestic insects are sometimes difficult to locate because of the awesome camouflaging technique they have. They make use of their coloration to blend in perfectly with leaves and stems, even swaying their bodies in the wind like the leaves.http://www.factzoo.com/insects/praying-mantis-devout-stealth-fearsome-hunter.html

The mating season in temperate climates typically begins in autumn. The female then lays between 10 and 400 eggs, depending on the species. s in related insect groups, mantises go through three stages of metamorphosis: egg, nymph, and adult. The nymph and adult insect are structurally quite similar, except that the nymph is smaller and has no wings or functional genitalia.In tropical species, the natural lifespan of a mantis in the wild is about 10–12 months, but some species kept in captivity have been sustained for 14 months. In colder areas, females die during the winter. http://en.wikipedia.org/wiki/Mantis