Using ultraviolet fluorescent powder (UVFP) as a surrogate pathogen across 134 origin bats in 8 pre-WNS and 5 post-WNS hibernacula, the authors found statistically supported increases in per-contact transmission post-WNS (Ξ² = 1.26, 95% CrI: 1.00β1.53), the strongest recipient-exposure increase in M. lucifugus (1.53 β 4.77 colors received, 3.12-fold), and ~73% more environmental contamination per origin M. lucifugus (Ξ² = 0.55, CrI: 0.22β0.88). Space use expanded (Ξ² = 0.66, CrI: 0.29β1.04), and infection severity increased cross-species transfer to E. fuscus (Ξ² = 0.74) but not within-species transfer (Ξ² = -0.21).
Strengths: a rare before-after natural experiment with identical protocols across periods, rigorous Bayesian modeling (convergence diagnostics, LOO comparisons), and honest null results β environmental contact frequency showed only weak support (Ξ² = 0.37, CrI: -0.11 to 0.84) and P. destructans prevalence/intensity did not differ between periods.
Blindspots and caveats: the before-after design is non-randomized and confounded by time; four of eight original sites were dropped post-WNS due to extirpation, biasing inference toward persisting communities; M. septentrionalis (46 pre-WNS origins) vanished entirely, so the most disease-sensitive node is unmeasured post-WNS; P. subflavus post-WNS estimates rest on very small samples (N=6 origins); and UVFP reflects only one transmission chain, not onward spread.
Interpretation caution: the authors' claim that behavioral benefits of sociality "far outweigh" infection costs is an inference; the data show elevated transmission but do not directly measure fitness tradeoffs. The mechanism for increased transmission (expanded space use, possibly selective survival of more social individuals β supported by the years-banded slope Ξ² = 0.33, CrI: 0.09β0.57) remains correlational.
Confidence: moderate β effect estimates are credible-interval supported but derive from one region, few sites, and a surrogate (not live pathogen) system; independent replication in other hibernacula would be the decisive test.
Know what changed, what holds up, and what remains uncertain. Every Friday. No ads.