Males may search for sex instead of food because their brains are programmed that way

There are some pretty basic building blocks to the survival of a species: that whole eating thing, and sex. Animals logically focus on both activities. But males prioritize the search for a mate over the hunt for grub, something that may be attributed to how their brains are programmed, according to new research published Thursday in the journal Current Biology.

According to Washingtonpost, for this study, researchers experimented on a microscopic roundworm (C. elegans) that has been used in labs for decades to understand the nervous system, with lessons applicable across the animal kingdom. They come in two genders: male and "females" (which are technically hermaphrodites since, in some cases, they can self-fertilize).

Scientists had previously discovered that the males and "females" end up making different decisions about feeding vs. finding a mate. The hermaphrodites prioritize finding food. But the males will "spontaneously leave a food source" to look for a mate in a lab setting, even "suicidally," ending up dead on a petri dish, said Douglas Portman, a University of Rochester associate professor and lead author of the new study.

Portman and others wanted to figure out just why the males did that. Could it be their genetic makeup, by virtue of being males, has programmed them to behave this way? Researchers zeroed in on the roundworm's sense of smell, and specifically, one particular gene that is related to receptors sensitive to the smell of food. The "females" produced more of these receptors, whereas the males just had less.

Researchers genetically modified a batch of males to produce more of the smelling-receptors, and compared them to normal males. "Females" were placed in the middle of a petri dish, and males were next to a food source on the edge of a petri dish, with another ring of food serving as a barrier between the two sexes. As expected, the normal males left their food source, went around the barrier and mated. But the genetically-modified males were much less successful at mating -- possibly because they were too busy eating.

Before you go thinking, "Ugh. Typical. Men," remember, it's not the male roundworms' fault! They aren't making a conscious decision to go mate instead of eat. Part of the reason the males leave food to mate is that they don't smell it as well.

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