Invisible but Identifiable: p-Chips as a Reliable Marking Method for Amazonian Bats

Juan Jesus Pellón, Naija Cuzmar, Jorge Luis Mendoza, Cristian Tirapelle, Nick Fluker, Gideon Erkenswick, Mrinalini Watsa

Marking techniques are essential for studying bat ecology and informing conservation efforts, yet many existing methods present challenges related to size, tag detectability, and long-term retention. p-Chips, ultra-miniaturized transponders detectable via red laser light, offer a promising alternative to traditional banding or passive integrated transponder (PIT) tags. While their use has been successfully demonstrated in captive bats, their effectiveness in free-ranging populations remains largely untested. We individually tagged 31 species of bats with p-Chips during a 3-year study in the Peruvian Amazon. We documented 88 recaptures, with all p-Chips remaining functional over both short-term (within the same sampling season, ≤ 40 days) and long-term (across sampling seasons, more than 170 to more than 850 days) periods. Notably, no adverse effects such as scarring or tissue damage were observed. Red light-emitting diode (LED) illumination facilitated rapid visual detection of tags, reducing handling time. These findings support the use of p-Chips as a viable, detectable, minimally invasive, and cost-effective alternative to PIT tags, particularly for small-bodied species. We recommend further research to optimize p-Chip technology for broader application in wildlife tracking and conservation.