Bad news has turned to worse for an already suffering monarch butterfly population.

Near the butterflies’ over-wintering sites, storms in Angangueo, Mexico, have decimated an already low monarch population suffering the effects of last year’s poor weather.

That will mean significantly fewer monarchs flying through areas like Lawrence, said Chip Taylor, director of Kansas University’s Monarch Watch program and a professor of ecology and evolutionary biology.

Taylor has led monarch-tagging efforts in the city and beyond during the monarchs’ peak fall migration — typically around mid-September in Lawrence.

“The bottom line is, we’ve lost at least 50 percent of the population — at least,” Taylor said. “My concern is we’ve lost much more than that.”

As rain and mudslides have made transportation in the monarchs’ winter habitat difficult, accurate counts are hard to come by.

Taylor said it will take several consecutive seasons with favorable conditions for the butterflies to begin replenishing their numbers.

“It’s going to take two good years in a row to bring this population back,” he said. “That means a good spring, a good summer, a good winter and a good fall.”