World's Biggest Testicles

Tuberous bushcricket, a katydid, has world's biggest testicles(relative to body weight).

For the testicle study, Vahed and colleagues dissected specimens from 21 bushcricket species collected around Europe. The organs account for 14% of the body mass of males of this bushcricket species. The previous record holder's testicles—belonging to the fruit fly Drosophila bifurca—tipped the scales at about 11% of its body mass. If we have testicles that size, it would weigh at a staggering 10 kg for a healthy 72 kg man.

The orange bulk is the testicles of the fruit fly Drosophila Bifurca. Image: scienceblogs.com

"I was amazed by the size of the testes—they seemed to take up the entire abdomen," said study leader Karim Vahed, a behavioral ecologist at the University of Derby in the U.K.

Ecologist Karim Vahed holds a male tuberous bushcricket and its removed testicles. Richard Richards, University of Derby

But you need not to be sad, gentlemen. The huge sperm-producing organs doesn't pack much of a punch-- huge muscle doesn't guarantee massive power.
The study showed that for the 21 bushcricket species, ejaculation volume decreases with the increment of testicle size.

The team was surprised to discover that tuberous bushcrickets have smaller ejaculations than bushcricket species with smaller testicles. This seems to contradict with previous findings in other species—-especially mammals. Usually the male with the biggest testicles has more sperm in each ejaculation, thus giving him higher chances of fertilizing females, Vahed explained.

Turkeys' tecticles. Image: examiner.com

But this disadvantage of lesser ejaculation comes with a bonus--large testicles give males a more plentiful sperm reservoir for multiple matings. Female tuberous bushcrickets mate an average of 11 times in their two-month life spans.

In short, larger testes enables higher mating rate, but it also comes with lower sperm count. So having large testicles doesn't seem like a good idea after all, if you plan to have children. But if you would like to increase the joy of love-making, then a testicle-size-increment operation would be a good idea.

Having a 10 kg bulk hanging under your crotch doesn't sound good to me though =P

Image: wonderfactory.org 

Malcolm
info:
http://news.nationalgeographic.com/news/2010/11/101110-biggest-testicles-size-bushcrickets-biology-vahed-science-animals/