Cutting a bugs' penis shorter found to reduce reproduction chances

May 13, 2015 by Bob Yirka, report
SEMs showing (a,b) the normal tip of the processus and (c) the intact lumen after experimental manipulation. Credit: Proceedings of the Royal Society B , DOI: 10.1098/rspb.2015.0724

(—A small team of researchers from the University of St Andrews and one from the University of Bristol, both in the UK has found, not surprisingly, that snipping a certain bugs' penis caused it to have less success in producing offspring. In their paper published in Proceedings of the Royal Society B, Liam Dougherty, Imran Rahman, Emily Burdfield-Steel, E. V. Greenway and David Shuker describe their experiments with Lygaeus simulans bugs and what they learned through their efforts.

Lopping off sections of a , for most species would involve serious injury and trauma (for some the mere thought of it might be enough)—but not so, apparently, for L. simulans. The males of these little , which are typically just 11 millimeters or so in length, come equipped with a penis that is very nearly comical in its length, on average 7 mm, which for those keeping track, is in the neighborhood of two thirds of its body length (it drags the thing around beneath itself). Even more odd is that most of the penis, aka its intromittent organ, is bereft of nerves, muscles or even blood vessels. And even odder than that is the fact that the female organ into which the male places its appendage is much too short to accommodate such length. Thus, the researchers sought out to discover the reason for such a mismatch.

To find out if the male could survive and mate if its penis was cut shorter, the team took scissors in hand and set to work snipping off differing lengths from a host of "volunteers." They then watched to see how well the bugs copulated and then measured their reproductive success. As it turned out, the shortened organs did not appear to cause undue hardship to the male, or the females for that matter. The bugs copulated as normal—it was only when counting offspring that a change was noted. The more they cut off, the less reproductively successful the males were. Cutting off 5 percent of the penis, for example, resulted in a big drop-off, and cutting off thirty percent cut both the rate of copulation and the rate of insemination.

The team also took micro-CT scans of the bugs in mid-copulation and discovered that in order for the male organ to fit inside the female parts, a lot of coiling occurred. With bits cut off, there was less to coil, and that, the team surmises, is likely the answer to why the males have such a long organ.

Explore further: In sex-reversed cave insects, females have the penises

More information: Experimental reduction of intromittent organ length reduces male reproductive success in a bug, Proceedings of the Royal Society B, Published 13 May 2015, DOI: 10.1098/rspb.2015.0724

It is now clear in many species that male and female genital evolution has been shaped by sexual selection. However, it has historically been difficult to confirm correlations between morphology and fitness, as genital traits are complex and manipulation tends to impair function significantly. In this study, we investigate the functional morphology of the elongate male intromittent organ (or processus) of the seed bug Lygaeus simulans, in two ways. We first use micro-computed tomography (micro-CT) and flash-freezing to reconstruct in high resolution the interaction between the male intromittent organ and the female internal reproductive anatomy during mating. We successfully trace the path of the male processus inside the female reproductive tract. We then confirm that male processus length influences sperm transfer by experimental ablation and show that males with shortened processi have significantly reduced post-copulatory reproductive success. Importantly, male insemination function is not affected by this manipulation per se. We thus present rare, direct experimental evidence that an internal genital trait functions to increase reproductive success and show that, with appropriate staining, micro-CT is an excellent tool for investigating the functional morphology of insect genitalia during copulation.

Related Stories

In sex-reversed cave insects, females have the penises

April 17, 2014

Researchers reporting in the Cell Press journal Current Biology on April 17 have discovered little-known cave insects with rather novel sex lives. The Brazilian insects, which represent four distinct but related species in ...

Penis size: Researchers provide the long and short of it

March 3, 2015

What is an "average" size for a penis? The enduring question now has a scientific answer: 13.12 centimetres (5.16 inches) in length when erect, and 11.66 cm around, according to an analysis of more than 15,000 appendages ...

Sea animal has grow-again penis

February 13, 2013

Scientists reported Wednesday on the bizarre sex life of a sea slug that discards its penis after copulation. Then grows a new one.

Ancient European bear had unusually large penis bone

September 26, 2013

( —Researchers working at Spain's Batallones-3 dig site in the area of Cerro de los Batallones have unearthed five baculum (os penis) that once belonged to five now extinct examples of a species of bear classified ...

Penis size does matter if you are a bank vole

October 5, 2011

( -- While size may not matter when it comes to humans, a new study published in Behavioural Ecology and Sociobiology found that the width of the male bank vole’s penis plays a role in social dominance.

Recommended for you

Termite queen, king recognition pheromone identified

March 19, 2018

Researchers at North Carolina State University have for the first time identified a specific chemical used by the higher termite castes—the queens and the kings—to communicate their royal status with worker termites. ...

New life form answers question about evolution of cells

March 19, 2018

Bacteria and Archaea are two of the three domains of life. Both must have evolved from the putative last universal common ancestor (LUCA). One hypothesis is that this happened because the cell membrane in LUCA was an unstable ...

A reference catalog for the rumen microbiome

March 19, 2018

The digestive tracts of ruminant (cud-chewing) animals such as cattle, sheep, and goats convert lignocellulosic plant matter to short-chain fatty acids used for nourishment with unparalleled efficiency, thanks to the activity ...


Adjust slider to filter visible comments by rank

Display comments: newest first

5 / 5 (3) May 13, 2015
The sign should read "Dr. Mohel - Entomologist."
4.7 / 5 (6) May 13, 2015
So if you cut its dick off, it's less likely to reproduce. Talk about a brilliant bit of deduction.
4.2 / 5 (5) May 13, 2015
Who pays these people?
5 / 5 (2) May 13, 2015
Well, this is an important discovery... NOT!
not rated yet May 13, 2015
Some researchers are bugged by penis envy.
May 13, 2015
This comment has been removed by a moderator.
not rated yet May 13, 2015
Is this what biologists do when they're bored?
not rated yet May 13, 2015
I new grants for real science had become terribly hard to get. So, now it's come to this - measuring bugs' "manhood."
not rated yet May 13, 2015
Now I know why my penis is 2/3 the length of my body! (I knew there had to be a reason).!
not rated yet May 14, 2015
No shit...?
not rated yet May 14, 2015
We also found that gluing the female reproductive organs shut reduced the likelihood of reproduction.
not rated yet May 17, 2015
So they gave needledick the bug fukker a vasectomy?!
not rated yet May 17, 2015
Cutting off a researchers head is found to reduce the chances of stupid news articles!
not rated yet May 17, 2015
" come equipped with a penis that is very nearly comical in its length"...poor bug, nothing to laugh at.
not rated yet May 18, 2015
Last week we put liquid paper on a bee... and it died.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.