But the process of scientific knowledge-gathering can be messy, and scientists with Luquillo’s Long Term Ecological Research (LTER) Program—which furnished much of the data underpinning Lister and Garcia’s conclusions—now believe many of those conclusions are false.

These researchers aren’t disputing the fact that climate change is occuring in Puerto Rico, or that insect declines are a serious issue. They just don’t see evidence for a simple link between the two in this particular ecosystem. Instead, they see a rain forest experiencing profound boom-and-bust cycles in response to disturbances such as hurricanes. In an effort to set the record straight, the researchers wrote a formal rebuttal letter in the spring and have given presentations at conferences, most recently at the Ecological Society of America meeting this month.

Despite the pushback, Lister and Garcia are standing by their conclusions: Even with imperfect data, they say, what they found is cause for concern.

Read: Is the insect apocalypse really upon us?

The seed of their original study came from weather-station data in Luquillo, where Lister had done fieldwork in the 1970s. He became concerned about the rain forest’s insects after noticing that temperatures at two sites had risen by about 2 degrees Celsius (3.6 degrees Fahrenheit) in the intervening decades. Some laboratory evidence suggests that tropical insects might be highly sensitive to temperature increases. And so he returned to the same spot where he had studied insects in 1976 and 1977 to see if the forest had changed. On several trips from 2011 to 2013, Lister and Garcia placed sticky traps on the ground and in the canopy, and used sweep nets to collect insects and estimate their total abundance.

Their findings were alarming: Compared with the 1970s, the surveys from 2011 to 2013 turned up 98 percent less insect biomass in ground traps, 83 percent less in sweep nets, and 65 percent less in canopy traps. The scientists also found close to 60 percent less anoles, a diverse family of lizards that eat insects.

To put this worrying data in a broader context, Lister and Garcia looked at the abundance of other animal populations—canopy arthropods, walking-stick insects, frogs, and birds—elsewhere in the forest. In each case, the LTER’s long-term data sets, compiled over several decades, seemed to confirm the researchers’ fears: Everything was declining. After showing that rising temperatures correlated with declining abundances and, according to Lister, eliminating other factors such as pesticides, the researchers concluded that climate change was the most likely culprit.

When Lister and Garcia published their findings in October, Tim Schowalter, an entomologist at Louisiana State University who has spent decades surveying insects at the Luquillo LTER, thought they looked solid. Other research groups in Europe were documenting long-term insect declines; this seemed like evidence that such declines could be global. Mike Willig, a co–principal investigator for the Luquillo LTER, says his first reaction was: How did we miss this?