Female Wasp Larvae Eat Brothers for the Good of Their Genes

Bear with us on this one…it might get a little complicated:

Wasps from the genus Copidosoma lay two eggs into a host egg (for example a moth or butterfly egg). One of these two eggs is male and one is female. The male and female larvae then begin multiplying–much like single celled organisms–into a thousand copies of themselves inside the egg. Thus the female “sisters” are more closely related to each other than they are to their brothers, and vice versa. The host egg, however, can only accommodate about half of the thousands of larvae now writhing around within it.

Congratulations! It’s a girl. Female wasp larva (right) feasting on its brother (bundle of cells in the middle)

Some of the sister larvae are sterile, and though they cannot reproduce to pass along their genetic material, they CAN stop their brothers from doing so. How? You don’t know? By transforming into a serpintine shape with over-sized jaws and eating their brothers alive while they’re still just a bundle of cells. Duh.

Evolutionary biologist Andy Gardner of Oxford University explains, “Although the genes for this spiteful behavior find themselves at an evolutionary dead-end in the sterile larvae, copies of these genes are passed onto future generations because they are also present in the clonal sisters, who do survive and reproduce.”

“Madeline J. Stingerstein, you stop ravenously feasting on your embryonic brother this instant or you will go to bed without supper this evening, young lady!” Encrytid wasp, Comperia merceti


By Orac

Orac is the nom de blog of a humble surgeon/scientist who has an ego just big enough to delude himself that someone, somewhere might actually give a rodent's posterior about his copious verbal meanderings, but just barely small enough to admit to himself that few probably will. That surgeon is otherwise known as David Gorski.

That this particular surgeon has chosen his nom de blog based on a rather cranky and arrogant computer shaped like a clear box of blinking lights that he originally encountered when he became a fan of a 35 year old British SF television show whose special effects were renowned for their BBC/Doctor Who-style low budget look, but whose stories nonetheless resulted in some of the best, most innovative science fiction ever televised, should tell you nearly all that you need to know about Orac. (That, and the length of the preceding sentence.)

DISCLAIMER:: The various written meanderings here are the opinions of Orac and Orac alone, written on his own time. They should never be construed as representing the opinions of any other person or entity, especially Orac's cancer center, department of surgery, medical school, or university. Also note that Orac is nonpartisan; he is more than willing to criticize the statements of anyone, regardless of of political leanings, if that anyone advocates pseudoscience or quackery. Finally, medical commentary is not to be construed in any way as medical advice.

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