To answer this question, Dr. Gaume and her colleagues grew four different types of Sarracenia pitcher plants at their research station in Montpelier, France. They sampled the air above 39 of the pitchers, identifying dozens of volatile compounds, and sliced a number of pitchers open to sort through their contents. They also measured the pitchers’ width and depth, to see whether their shape contributed to the type of prey they caught.

Pitchers with aromas that were heavy on monoterpenes, fragrant substances known to attract pollinators, seemed to catch more moths and bees, the group found, while those emitting more fatty acids ended up with more flies and ants. Pitcher shape, too, was correlated with certain kinds of prey: Longer pitchers were heavier on bees and moths, while shorter pitchers caught more ants.

In other words, it seems unlikely that insects are just falling into a given pitcher by chance, Dr. Gaume said.

Future experiments might probe whether pitcher scents painted onto fake plants draw insects’ attention the same way, or whether altering pitcher color or shape affect the allure of the odors.

Some of the pitcher plants used in Dr. Gaume and colleagues’ research are native to North America — in fact, they can be found in the New Jersey Pine Barrens. Dr. Gaume wonders whether the same connections between scents emitted and prey caught would show up in plants grown outside of the experimental conditions of the study. She has hopes of a much larger study in North America someday to further explore these findings, with row after row of sprightly death traps, all releasing come-hither odors into the air.