Rain and warmth gave a positive beetle catch interaction only in early Scotland among four UK samples in 1993-2015

We tested whether rain changes the link between warmth and ground beetle pitfall catches. We used 2,776 positive-catch ten-trap collections in England and Scotland in 1993-2003 and 2004-2015. Models controlled location by calendar month, year, collection length and date. The rain times temperature term was +0.152 in early Scotland, with a four-test adjusted interval of +0.031 to +0.274. The other three intervals included zero. Curved weather main effects and a zero-catch check gave the same interval sign pattern. Site omission changed the early Scottish estimate from +0.028 to +0.232. The test gives no clear repeated interaction across countries and periods. Catches combine population density, movement and capture. Country monthly weather, quality-based selection, few sites and few year clusters limit inference. No causal climate, extreme-weather or air pollution effect is estimated. The package gives code, exact source hashes, aggregate evidence, checks and a figure. External raw and record-level data remain outside the bundle.

ground beetles · temperature · rainfall · interaction · pitfall traps · observation bias · regional comparison