It is found on all continents with woodlands and is one of the most widespread ambrosia beetles internationally,[1] primarily in areas with humid tropical climates like Florida.

[1] This species is also found in regions of South and Central America, such as the Antilles, Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, and Argentina.

Xyleborus adults are sexually dimorphic, which means that the size, shape, and structure of bodily characteristics differ between males and females.

[1] Although the female to male sex ratio has been reported as 14 to 1 in a study by Roeper et al. (2017), it widely varies and has not yet definitively been identified.

[1] The beetles inoculate large trees in a series of stages, first inhabiting dead phloem and then moving onto the xylem, which is where most eggs are laid.

[1] Although Xyleborus affinis is not particular about choosing the species of its host tree, it is selective based on how deteriorated and damp the fallen log is.

[1] These beetles favor large and moist pieces of wood that are early on in the decay process, which is believed to be due to the symbiotic fungus' moisture requirement for survival.

[1] Because males remain confined to their original host tree and their only purpose is to fertilize nearby females, many of these eggs are their sisters.

[1] In contrast to most ambrosia beetles in which each generation seeks a new host, Xyleborus affinis' ability to maintain consecutive populations in the same log is atypical.

[11][12][13][14][15] In research conducted by Ospina-Garcés, Sandra M., et al. (2021), an analysis was carried out to assess the differences in size and shape of the elytra and pronotum between sexes.

[5] This dimorphism is thought to be influenced by the species' haplodiploid sex determination system and prevalence of inbreeding, as well as the fact that only females spread out and colonize.

[5] Although the inoculation of Xyleborus affinis on fallen logs can accelerate the decay process, these beetles typically seek out weak and injured timber that are already deteriorating.

[17] These spores proceed to contaminate the xylem bu cutting off the vascular system, leading to wilting and mortality in as quick as weeks to months after inoculation.

[17] Xyleborus affinis can also compromise the structural integrity of freshly cut natural wood more than any other ambrosia species because of its family arrangement and labor division.

[1] In most ambrosia beetle species, the mother is solely responsible for burrowing galleries, but in Xyleborus affinis, the daughter females help expand the tunnel system as well.