The bug experts at Iowa State University’s Extension Service have been getting phone calls and email recently about butterflies. Entomologist Donald Lewis says apparently the weather earlier this year was “particularly conducive to the reproduction and survival” of butterflies.

“We have had reports of what some people would term an outbreak (of butterflies),” Lewis says.  “I think a plethora might be a kinder, gentler term, but just an overabundance of the medium-sized, bright-yellow butterflies.” 

The bugs are nicknamed the “alfalfa” butterfly.  “The alfalfa butterfly is also known as the clouded sulfur butterfly and depending on which website or which book you pick up, you may find either one or both of those names,” Lewis says.

There may be many as 100 different species of butterflies in Iowa, some of which are just passing through.  Lewis says in a “good year,” a butterfly specialist would likely find about 25 different species here. 

“So compared to tropical areas, we really do have a shortage of butterflies which might be why we appreciate the ones we get,” Lewis says.

Alfalfa butterflies have brown bodies and yellow wings.  There are distinctive black dots in the two upper wings, right in the center of each.  The larvae that turn into these butterflies feed on alfalfa, sweet clover and soybeans.