Potential Distribution of Wild Host Plants of the Boll Weevil (Anthonomus grandis) in the United States and Mexico

Simple Summary The boll weevil (Anthonomus grandis Boheman) (BW) is one of the most well-known and historically important insect pests in the Americas. Presently it is a key pest of cotton in Mexico and Central and South America. In the United States, a successful area-wide pest management program has eradicated the pest from nearly the entire country, except for the Lower Rio Grande Valley region of extreme southern Texas. Eradication in the US has been successful, in part, because the insect can only develop on a narrow range of host plant species besides cotton, none of which occur outside of Texas and Arizona. However, wild host plants are an important consideration for management of this pest in regions where they are present and for preventing reinfestations in areas where eradication has been successful. Here, we present the first detailed analyses of the potential distributions of all known significant wild host plants of the boll weevil in the United States and Mexico. These analyses will enable management to better evaluate the role of wild host plants in their management areas, improve existing boll weevil eradication strategies, and provide insights into the evolutionary history of this important pest insect. The boll weevil (Anthonomus grandis Boheman) reproduces on a reported 13 species of wild host plants in North America, two in the United States and 12 in Mexico. The distributions of these plants are of economic importance to pest management and provide insight into the evolutionary history and origin of the BW. However, detailed information regarding the distributions of many of these species is lacking. In this article, we present distribution models for all of the reported significant BW host plants from Mexico and the United States using spatial distribution modelling software. Host plant distributions were divided into two groups: "eastern" and "western." In Mexico, Hampea nutricia along the Gulf Coast was the most important of the eastern group, and the wild cottons, Gossypium aridum and Gossypium thurberi were most important in the western group. Other species of Hampea, Gossypium, and Cienfuegosia rosei have relatively restricted distributions and are of apparent minimal economic importance. Cienfuegosia drummondii is the only truly wild host in the southern United States, east of New Mexico. Factors determining potential distributions were variable and indicated that species were present in five vegetation types. Ecological and economic considerations of host plant distributions are discussed, as well as threats to host plant conservation.