Addendum: Here are species that I didn’t have on pins.
These are 164 of the 206 species that have been recorded in El Paso County. Many of the rest are rare strays, but we may see them more commonly as the climate warms. Adelpha bredowi, for example, used to be a rare stray, but it shows up almost every year now in the region. I will continue to add to this set as new photos come in from the Pikes Peak Region, with your permission, of course.
Here are the results from two sweep samples of insects taken ten years apart at exactly the same location on the Section 16 Trail west of Colorado Springs. In both cases, 100 sweeps were made. In this area, which is relatively undisturbed in terms of regular application of pesticides, herbicides, and insecticides, total numbers of insects seem very similar after ten years. T-Tests, both one-tailed and two-tailed, show p values that do not suggest significance. I chose a date one week later in 2019, as the season appears a bit behind average in terms of butterfly emergence dates.
As it currently sounds…
As a follow up to my earlier report on the butterflies and diurnal moths of the Pikes Peak Region, I took the advice of Steve Taylor and prepared a graphic of all 255 dates on which I counted butterflies, and on which the time, temperature, and other conditions were favorable to flight. This shows the “noise” encountered in this sort of work, as well as the extraordinary summers of 2012-2014. If there is a trend, it might show up as a decline after 2015, when levels are about as they were early in the study. Note that most of the points from 2015 on fall below the mean score of 72.5/h. However, the overall slope is very slightly up (+0.032x). I can’t wait to continue observations this summer.
If I restrict the data to just the 145 dates that are from Bear Creek Canyon, there is a very slightly different trend, this time downward (–0.12x), from about 91 to 74 over the 35 years. Maybe this is the apocalypse! More later!