Readers bugged by wine-spoiling stinkbugs

Eau de stinkbug

Stinkbugs accidentally harvested with grapes and fermented during the wine­making process release a pungent stress compound. It takes only three stinkbugs per grape cluster to ruin red wine’s taste, Elizabeth S. Eaton reported in “Red wine has stinkbug threshold” (SN: 3/18/17, p. 5).

“Does contamination of wine by the bugs’ stress compound pose any health risk to consumers?” asked Hal Heaton. “And does someone really count the number of stinkbugs on each of the huge number of grape bunches picked?”

The hormone emitted by stressed stinkbugs, (E)-2-decenal, is also found in cilantro, says Elizabeth Tomasino, a food scientist at Oregon State University in Corvallis who did the research. “It is actually found at much higher concentrations in cilantro than in wine and is not a health risk,” Tomasino says.

As for counting stinkbugs, there are people who count bugs on the vines, but not by bunch as the researchers did. “What typically occurs is that someone will put a sheet under a plant and beat the leaves to see how many fall out,” Tomasino says. Another approach involves walking through the vineyard and counting as many bugs as possible in three-minute increments, she says.

Troubled waters

Science journalist Dan Egan’s book, The Death and Life of the Great Lakes, chronicles the impacts of global trade, u­rbanization and climate change on the lakes and communities that depend on them. Invasive species, including zebra and quagga mussels, have been particularly damaging, Cassie Martin wrote in her review “Invaders, climate change threaten Great Lakes” (SN: 3/18/17, p. 30).

“I thought that the zebra mussels cleaned up Lake Erie?” asked online reader Robert Stenton. “The Great Lakes are too important economically to let them perish, so as we learn from our mistakes, we will correct the problems.”

The billions of invasive zebra mussels that blanket lake beds, boat hulls and water intake pipes didn’t clean the once “dead” Lake Erie of pollutants. The lake was revived thanks to the Clean Water Act. “In fact, the mussels do more harm than good,” Martin says. True, a single adult zebra mussel can filter a liter of water every day, but it also removes the nutrients vital for healthy ecosystems.

Although Lake Erie recovered, it has faced setbacks in recent years. Fertilizer runoff from farms causes huge blooms of toxic blue-green algae. One such bloom left nearly half a million people in Toledo, Ohio, without drinking water for three days in the summer of 2014. Researchers think that booming populations of invasive mussels may contribute to the algae explosions. Mussels don’t eat the toxic algae, feeding instead on other p­lankton that usually help keep the algae in check.

Smell-or-vision

Unlike some of their New World monkey relatives, howler monkeys can see in full color thanks to three types of proteins in their eyes that detect various wavelengths of light. This three-color vision may have evolved thanks to the monkeys’ preference for eating bright red young leaves, Laurel Hamers reported in “Leaf hue shaped howler monkeys’ color vision,” (SN: 3/18/17, p. 16).

Online reader Jan Steinman wondered if howler monkeys’ sense of smell might be compromised by their three-color vision. “Smell and sight seem to compete for scarce neural resources” in other animals, Steinman wrote.

“The jury is out on whether or not some primate species sacrificed sensitive sniffers for enhanced color vision,” Hamers says. A study published in PLOS Biology in 2004 suggested that primates with three-color vision had more nonworking smell-related genes than primates with two-color vision.

But a study a few years later came to a different conclusion: Primates’ smell-related genes may have degraded independently of the development of three-color vision, another group of researchers reported in 2010 in Molecular Biology and Evolution.