In NJ pines, trouble on six legs.

[mike_c]

4. the current range has long been limited by winter temperatures....

SPB routinely manages four or five generations annually in the warmest parts of its range, i.e. the southeastern coastal plain, but only a single generation at the northern limits, so not only do winter temperature extremes that kill developing brood limit its range, but also the slower development times it experiences in the northern portions of the current range. SPB is a good indicator organism in this case because its habitat limitations are well studied and understood. Occasional brood success north of the Mason-Dixon line is not unusual, but sustained brood success likely represents a northern range extension. I was shocked when I read the linked article-- I expected it to be about an invasive exotic beetle, not the SPB.