Men love sex and men love food — this we know. But which one they love more, well that’s up for debate. Or is it? A recent study from the University of Rochester may have answered this age-old question, in worms at least. The researchers found that time and again male worms would ignore food in order to mate, while the “modified female” worms weren’t as inclined to pass up a meal. This discovery could help to explain everything from behavior differences between sexes to gender specific neurological disorders.

In a study, now published in the online journal Current Biology, a team of researchers used a species of microscopic roundworms called C. elegans to analyze behavior differences between the sexes. The male C. elegans and “modified females,” which are hermaphrodites that are able to both self-fertilize and mate with males, were placed in front of food and the company of a potential mate. Researchers then observed how time and again, the modified female worms stayed near the food bowl, but the males left the food bowl and proceeded to mate, according to the press release.

The reason that male and hermaphrodite worms responded differently to their food was found to be due to a difference in the biology of their brains. A single pair of neurons called AWA control the sense of smell in the C.elegans. The sensory mechanisms of the AWA neurons, called chemoreceptors, control the expression of a receptor called ODR-10, which proceeds to control how strongly the worms can smell their food. This sensory mechanism was discovered to be gender specific.

“To the best of my knowledge, our finding that food chemoreceptors are regulated by sexual identity is novel," Dr. Douglas Portman, lead researcher of the study told Medical Daily in an email. Ultimately, this meant that males were simply less sensitive to the scent of food than their hermaphrodite counterparts. However, in starved male worms, the need for food overtook the need to reproduce.

To further test this finding, the researchers altered the biology of male C.elegans and overexpressed their ODR-10 receptors. They also altered the biology of hermaphrodites and caused a suppression of the same receptors. This resulted in a near opposite course of behavior for the worms. While changing the behavior of microscopic worms may not immediately sound exciting, according to Portman, “These findings show that by tuning the properties of a single cell, we can change behavior.”

While Portman didn’t want to assume too much on how these findings could be related to human behavior, he did tell Medical Daily that “the "genetic sex" of the mammalian brain — in addition to its exposure to gonadal hormones like testosterone — is important for its function,” and his work aims to help better understand why this is so.

The behavior has not been mirrored in humans, but the results do suggest that for all animals, sex-specific regulation of gene expression may play a bigger role than originally believed in both the way our brains work and, subsequently, how we behave.  

Understanding the gender-specific neurological differences could do a lot more than explain how much an individual thinks about sex. It could help to understand why some conditions, such as autism, have disproportionate diagnosis among the sexes.

“Understanding how the chromosomal sexual state of the nervous system influences its development and function is likely to provide important insights into the biological basis for sex differences in disease susceptibility,” Portman said.

Source: Portman DS, Ryan DA, Miller RM. Sex, Age, and Hunger Regulate Behavioral Prioritization through Dynamic Modulation of Chemoreceptor Expression. Current Biology. 2014.