The summer weather may be bugging more Hilo residents than usual this year as ants take to the sky in swarms.

After several humid weeks with relatively little wind, many Hilo drivers and pedestrians have encountered swarms of tiny flying insects around grassy areas. But while the insects are annoying, their behavior isn’t anything out of the ordinary.

The bugs are most likely dark rover ants, said Darcy Oishi, acting manager of the state Department of Agriculture’s Plant Pest Control Branch. The insects — also called black rover ants — tend to establish colonies in soil, leaf litter and mulch, and take to the skies during the summer months to seek out places to establish new colonies.

Although the ants are invasive — “Hawaii has no native ant species,” reminded Oishi — they are largely benign compared with more pernicious species like little fire ants. The insects don’t bite or sting and are not known to carry any diseases harmful to humans or pets.

“They’re a nuisance species more than anything,” Oishi said. “There’s plenty of other ant species that outperform them. I can think of maybe five other ant species that are more of a concern than these. People are probably mostly just encountering them when they’re out running or driving.”

However, the insects — like most ants — are drawn to sugar and can infiltrate homes to forage among unsecured food waste or other garbage.

Oishi said an abundance of swarming ants is typical of the season, but added that the fluctuation of the El Nino/La Nina cycle can lead to a stronger season for them.

“Are there more out there than in previous years? Probably,” Oishi said, adding that the insects’ activities are fairly localized to less breezy areas.

El Nino conditions — characterized by a warmer Pacific Ocean surface — have persisted through the first half of this year, but meteorologists predict the cycle will likely transition to La Nina later this year.

Oishi said that while the ant prefers humid weather, the drier conditions of El Nino have been in the insects’ favor and that the frequent rain from La Nina should bring the swarms back to earth.