Army Ants
Army ants are characterized by their aggressive social behavior: their hives send out enormous numbers of ants to forage a given area and attack prey as a group. They have a nasty bite, attack creatures much larger than themselves, and in Mexico are considered a good way to control scorpions.
Mexican Unicorn Mantis
This insect is similar to the common praying mantis, but has the added characteristic of a "horn" in the center of its head. In the United States, it is called the Texas praying mantis, probably because it is found no farther north than that.
Killer Bees
Africanized honey bees, or "killer bees," are a highly aggressive bee type introduced to South America in the 1950s. The bees spread north, stopping in Mexico and the southern fringe of the American Southwest. Their aggressive behavior makes them a persistent menace, and in 2008 a bee attack sent more than 70 Mexican police officers to the hospital.
Mosquitoes and Disease
Mexico has been making inroads into controlling malaria, but it remains a problem. Mexico also has a small problem with dengue fever. Both of these are mosquito-borne diseases, making mosquitoes in Mexico potentially dangerous.
Butterfly Migration
The Monarch butterfly's path of migration starts every spring in Mexico. The head to Mexico in the fall, spend the winter in the mountains of central Mexico, and return to the United States starting in March.
Food
Mexico has offered some insects on its dinner menu for a long time, including grasshoppers, ant larvae and maguey worms.