Coloring and abundance of Dendroctonus mexicanus Hopkins, 1905 from four regions of Mexico

Abstract

The increase in the abundance of bark beetles in the pine and pine-oak forests in Mexico causes the death of large forest stands. It is estimated that such behavior responds to an increase in temperatures due to the effect of climate change; however, the role of other climatic variables such as humidity and how they may influence other characteristics, such as variation in intensity of exoskeleton coloration between regions, is unknown. In the present study, the variation in the intensity of the coloration and abundance of D. mexicanus populations from four regions (Hidalgo, Oaxaca, Jalisco and Nuevo León), and its relationship with humidity, temperature and aridity were analyzed. Some individuals of D. mexicanus exhibited a darker coloration, which may be associated with a higher percentage of humidity, and others with lighter shades (reddish brown) from regions with lower humidity (AMF: 82 % = darker; 66 % = clearer). The region of the state of Hidalgo presented the largest number of D. mexicanus individuals compared to the regions of the states of Nuevo León, Jalisco and Oaxaca. The maximum average aridity indexes and minimum average aridity indexes generated evidence of ideal climatic conditions for the presence of more abundant D. mexicanus populations. Extreme temperatures and relative humidity in the environment function as limiting factors in the exponential increase in the abundance of debarker populations.