photo by Frank S. Model

The giant swallowtail, a southern butterfly historically only seen occasionally in New England, has been present in high numbers in Massachusetts in recent years, with scores of reports in 2011 and 2012. This individual was photographed Aug. 15 in Westport.

photo by Frank S. Model

The Atlantis fritillary, a northerly distributed species, has declined by more than 80 percent in Massachusetts in the past 19 years but has no formal protection.

photo by Frank S. Model

The Acadian hairstreak, another northern species, also has declined by more than 80 percent in Massachusetts in the past 19 years and also has no formal protection.

photo by Frank S. Model

The frosted elfin, a southern species, has increased by 1,000 percent in 19 years in Massachusetts, and receives formal protection and active management by the state.

photo by Frank S. Model

Observations of the zabulon skipper, another southern butterfly historically rare in Massachusetts, have increased by 18 fold in the past 19 years. This individual was photographed Aug. 15 in Westport.