Photograph by Bill Curtsinger, National Geographic

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A male olive ridley turtle (Lepidochelys olivacea) is dragged by a longline set for sharks. The line snagged and drowned the turtle.

Photograph by Bill Curtsinger, National Geographic

Science Roundup: Swarm Intelligence, Longline Fisheries, and Insect Mating

Some interesting science finds you might have missed this week.

In the mad rush to cover the grand experiment called science, all kinds of exciting studies fall through the cracks. We've summarized three of the more interesting ones below for your reading pleasure.

Forge ahead to learn about insect quickies, the consequences of a longline fishery, and swarm intelligence.

Storm Prep

Storm preparation for people usually means boarding up windows and stocking up on batteries and bottled water. But for the cucurbit beetle (Diabrotica speciosa), it means getting down to the business of mating.

Researchers report in a study published online this week in the journal PLOS One that when this beetle senses a drop in atmospheric pressure—a precursor to a storm—16 of the 26 males they studied jumped on female beetles and immediately began to mate.

The eager suitors dispensed with the usual courtship behaviors that they all displayed during conditions with steady atmospheric pressure ("good" weather conditions).

Storms are usually associated with higher mortality for insects, the authors wrote, as strong winds and pounding rain are too much for their smaller bodies to handle. "This modified behavior could be a response to a perceived reduction in life expectancy."

An Unintended Catch

The promise and perils of fishing are well known. The economic benefits—it is a multibillion-dollar industry—keep fishing fleets afloat. But overfishing and the unintended catch of endangered or nontarget species continue to be problems.

Researchers report in a study published this month in the Journal of Experimental Marine Biology and Ecology that Costa Rica's longline fishery ends up catching large numbers of olive ridley sea turtles and silky sharks in addition to target species like mahi-mahi.

From 1999 to 2010, observers on six medium-size fishing vessels—out of a fleet of 350—counted 31 mahi-mahi caught per thousand hooks set. The next most common catch was the olive ridley turtles, with about nine caught per thousand hooks set, and silky sharks, with eight caught per thousand hooks set.

When extrapolated to the entire fishing fleet, the researchers estimate that fishers caught almost 700,000 turtles during the 11-year study period. The scientists also note that olive ridley populations declined on nearby nesting beaches such as Nancite (map) in the 1980s and Ostional (map) in the 2000s, and haven't since recovered.

Swarm Intelligence

In light of the U.S government shutdown, sparked by a serious difference in opinion among elected representatives, this study is perhaps instructive. Researchers in Germany and England report that groups make better decisions when their members have differing preferences and opinions.

As long as the overarching goal of the group remains the same—such as the ultimate destination for migrators or where to forage for food—a diversity of opinion on how to reach those goals results in smarter decisions.

Published in the November issue of the journal American Naturalist, the study looked at how group members in a computer simulation fared under different conditions. Groups with limited information in uncertain environments made much better decisions about what to do when they included a diversity of opinion than if they all wanted to reach their goal in the same way.

"These results provide a strong argument in the interest of all stakeholders for not excluding other (e.g., minority) factions from collective decisions," wrote the study authors.