An analysis of iNaturalist data on several taxonomic groups of insects in Mexico is presented. I found evidence of a decreasing trend in diversity of species per year, for four families of butterflies, the bumblebees and the dragon and damselflies. I performed the anlayses on several of the Potential Vegetation types of J. Rzedowsky, and explore the role of deforestation and pesticide use on the trends I found. I discuss the challenges of using unsystematic data to estimate trends and provide several hypotheses to explain them.