Duda, where'd my spines go?

Jan 07, 2010
UC biologist Michal Polak uses a laser to ablate genital spines. This image shows an ablated and an intact spine. Credit: Michal Polak, University of Cincinnati

UC researcher finds that when it comes to hooking up with the opposite sex, genital complexities do matter.

Charles Darwin spent eight years studying barnacles and their genitalia. In much less time than that, University of Cincinnati evolutionary biologist Michal Polak (and co-author Arash Rashed now at the University of California, Berkeley) have confirmed one of Darwin's theories: that genitalia complexities in some male species have developed because they assist the male in "holding her securely."

As just published online in the , "Microscale Laser Surgery Reveals Adaptive Function of Male Intromittent Genitalia" Polak's research showed that without a doubt among the fruit fly species Drosophila bipectinata Duda, the males' penile peculiarities assisted them in copulation.

Polak, an associate professor in the Department of Biological Sciences in McMicken College of Arts and Sciences at UC, used a laser ablation technique to cut off tiny "intromittent" spines on the genitalia of virgin male D. bipectinata Duda fruit flies.

"We refer to these genital spines as intromittent because they insert [them] into female external during copulation, and not because they insert into the reproductive tract," Polak and Rashed explain in their paper.

Polak's study concluded that the male genital spines serve two functions. When the spines were removed, the experienced drastic reductions in ability to copulate and ability to compete against rival males for mates. However, if the males were able to copulate, they found that insemination and fertilization rates were not significantly different.

They're not done yet, says Polak.

"We are using the laser for a variety of projects, including to surgically excise other genital traits and the tiny but elaborate male sex 'combs' used in courtship, and to study their adaptive function in sexual selection."

Explore further: Fewer students study botany, more plant collections closing

More information: "Microscale laser surgery reveals adaptive function of male intromittent genitalia," rspb.royalsocietypublishing.org/content/early/2010/01/05/rspb.2009.1720.abstract

Related Stories

Hidden genitalia in female water striders makes males 'sing'

Jun 11, 2009

In a study published in PLoS ONE June 10, Chang Seok Han and Piotr Jablonski at Seoul National University, Korea, report that by evolving a morphological shield to protect their genitalia from males' forceful copulatory attemp ...

Female choice benefits mothers more than offspring

Oct 22, 2009

The great diversity of male sexual traits, ranging from peacock's elaborate train to formidable genitalia of male seed beetles, is the result of female choice. But why do females choose among males? In a new study published ...

Sex is thirst-quenching for female beetles

Aug 28, 2007

Female beetles mate to quench their thirst according to new research by a University of Exeter biologist. The males of some insect species, including certain types of beetles, moths and crickets, produce unusually large ejaculates, ...

Male flies: Not the world's most sensitive lovers

Jun 12, 2009

In order to increase their chances of reproductive success, male flies of the species Drosophila montana try to copulate for much longer than the females would like. Researchers writing in the open access journal BMC Evolution ...

Recommended for you

Birds time breeding to hit 'peak caterpillar'

19 hours ago

When oaks burst into life in spring populations of oak-leaf-eating caterpillars boom: this offers a food bonanza for caterpillar-munching birds looking to raise a family.

11 new species come to light in Madagascar

May 25, 2015

Madagascar is home to extraordinary biodiversity, but in the past few decades, the island's forests and associated biodiversity have been under greater attack than ever. Rapid deforestation is affecting the ...

Birds 'weigh' peanuts and choose heavier ones

May 23, 2015

Many animals feed on seeds, acorns or nuts. The common feature of these are that they have shells and there is no direct way to know what's inside. How do the animals know how much and what quality of food ...

User comments : 0

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.