Eggs! Eggs! Unfortunately, Eggs.

Sometime during last night, Darwin laid her first oothecae, which is Praying Mantis for “egg sack.” It’s about three and a half inches long, pastel green, and a few millimeters thick. Although you can’t see each individual egg, there are ripples on the surface of the ootheca that indicate where some of the ~three dozen eggs are located.

So this is an interesting occurrence. Darwin is unfertilized; as in, she has not mated with a male of the same specie. Yet, she clearly just laid eggs, and is likely poised to do so again. Since Darwin never mated, common knowledge might find this event slightly preposterous. After all, a zebra or a pigeon or a human female certainly cannot reproduce without a mate.

It appears that Darwin has conducted parthenogenesis, which derives its roots from the greek parthenos, meaning ”virgin”, and genesis-birth,” is a form of self-fertilization. Without any genetic input from a mate, Darwin has laid eggs that will eventually hatch as almost exact identical copies of herself. However, these offspring will be sterile, and will be exclusively female. In nature, parthenogenesis is a remarkable technique for quickly colonizing an area, bypassing the complications of sexual reproduction. Mantids in the wild can thus survive in areas of low population density where other animal species might not.

However, there is the issue of having absolutely no genetic variation among a population. If some exogenous factor emerges within a habitat— a disease, or a decrease in temperature, or a volcanic eruption or other natural disaster— since there is no variation at all within the population, the entire colony is more likely to collapse than evolve.

I wanted Uroborus to reach adulthood before Darwin conducted parthenogenesis. Borus is a male Ghost mantis with a brown coloration and an expectedly different genetic makeup. However, Borus only recently had his 6th molt, which leaves him one short of adulthood (wing buds have formed, so within a month, he will molt into adulthood).  Hopefully, Darwin will still be receptive to Borus, though I’m not sure if sexual reproduction is possible at this point after parthenogenesis has taken place.

All this being said, Darwin is a captive mantis, as will be her progeny, and is unlikely to be exposed to a  selecting force such as widespread disease, drought or predation. So it’s really not a big deal, and I look forward to more pastel green oothecae appearing over the next few months.

Here’s a few pictures of the egg sack and of Borus molting.

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