Wednesday update — Increasing cicada sightings

The warm, rainy weather seems over the last 24 hours seems to have brought out the cicadas in slightly greater numbers. While the swarm has yet to arrive and will probably be headed off for a while by cooler weather in the coming days, numerous readers have sent us pictures since Tuesday evening:

Original article from Tuesday

Cicada sightings are starting to slowly increase, but the swarm still awaits. In recent days, we have received several reports of the insects slowly creeping out of their holes, but it is still a trickle rather than an explosion. The anticipated outburst may hold off for another week or so.

Based on Twitter reports, we know the bugs were sighted in College Park last week, Great Falls over the weekend, and in Vienna on Monday, but most cicada nymphs remain underground. They are waiting for the proper temperature, humidity or rainfall, or a combination of all three to trigger a mass exodus.

A well-documented trigger for cicada emergence is a soil temperature surpassing 64 degrees. Daniel Gruner, a professor in the entomology department at the University of Maryland, shared data with us showing soil temperature sampled by his students are around that threshold presently.

He noted, however, that “soils are slightly cooler in closed canopy forests” so that even Tuesday’s very warm weather may not be enough “to set the masses free.”

Gruner’s colleague in the entomology department, Paula Shrewsbury, wrote in an email that “we will likely see an uptick in emergence with the warm days and rains this week.” However, she wrote that she agrees with the idea that “there will be more massive emergence next week.”

The current toasty weather would seem to draw the cicadas out but much cooler conditions will arrive by Wednesday night, which may keep them at bay. By the second half of the next week, another period of warm weather may provide the necessary trigger for the bugs to break out in abundance.

In the meantime, numerous cicada nymph holes (tunnels) have appeared in lawns and wooded areas. Some tunnels have mud turrets above the ground, which occur when the soil is moist.

However, many of the cicada nymphs are remaining in their tunnels, close to the surface, waiting to emerge. Foxes and other animals, including dogs, are digging them up for a juicy treat.

During this month, American Humane reminds us that “cicadas should be celebrated, not vilified.” They issued a news release on Monday that describes their benefits, including aerating and fertilizing the soil, and pruning mature trees.

“In addition to their ecological role, cicadas are genuinely fascinating creatures, despite their alien-like appearance,” their release states. “This spring, young learners will have a firsthand educational experience to observe one of nature’s most bizarre animals.”