AUSTIN (KXAN) — What’s the deal with all the butterflies? KXAN viewers have been reaching out, wondering about the increase in butterflies in Central Texas this fall.

The unusual butterflies you’ve been seeing are known as the American Snout Butterfly. The unusually hot and dry weather this past summer is to blame for the increase of butterflies.

Meteorologist Kristen Currie spoke with Dan Hardy, president of the Austin Butterfly Forum, about the butterflies. You can watch the interview above or read the transcript below to learn more.

KRISTEN CURRIE, KXAN NEWS: Dan, let me ask you, what are these butterflies we’re seeing around?

DAN HARDY, AUSTIN BUTTERFLY FORUM: We’re seeing a lot of butterflies called snout butterflies, the American Snout. And it’s kind of an exciting time of the year for us, because we have these giant explosions of these butterflies that come out of South Texas and Mexico, stream through Austin and kind of hit north, northeast.

It’s kind of a phenomenon. We have them about once or twice every couple of years.

CURRIE: Wow. Are they okay to have around?

HARDY: Well, they feed on hackberries. They’re not harmful at all. This year’s movement is a good one. Although in past years, there’s been, you know, humongous movements, sometimes hundreds of thousands or millions come through where they’ve been counted.

It’s kind of a phenomenon, and people note about this for decades, and it’s related to weather events in South Texas and northern Mexico.

It appears to be there’s a drought in South Texas or Mexico, which we have no problem getting, and then … all the predators of the snout butterflies are killed off.

Then there’s a huge rain, and the drought is eliminated, and then there’s a huge flush of growth on hackberry trees, and the snouts lay their eggs on these new hackberry leaves, and they just reproduce profusely.

In fact, you’ll go down to the valley, and you’ll see trees, completely denuded of leaves, hackberry trees, and then they’ll pupate and then the adults will emerge and they’ll discover that all the leaves are eaten in that area.

There’s no leaves; there’s no food. So they will migrate … just flood out of that area, going all different directions but particularly no work. Then they’ll hit areas like San Antonio, Corpus, Austin.