Malvaceae. Fryxell had both 

 male and female specimens 

 and easily recognized that 

 HaDipca belonged in the Mal- 

 vaceae. Even more, it was a 

 member ot the cotton tribe. 



Taxonomy is often 

 thought of as a descrip- 

 tive science with a lot of name 

 shuffling that yields no 

 testable hypotheses. But 

 Fryxell's seemingly minor 

 taxonomic change turned out 

 to be the most important clue 

 in the search for the boll wee- 

 vil's origins. For if Haiiipca is 

 closely related to cotton, 

 irdght some species of Hani- 

 pea also have boll weevils? 



The question was an- 

 swered in 1966, when Fryx- 

 ell and his colleague, the late 

 Maurice J. Liikefahr, discov- 

 ered boU weevils on a com- 

 mon, but at the time unde- 

 scribed species of Hampea growing far from com- 

 mercial cotton farms in the Gulf Coast region of 

 Veracruz, Mexico. On the basis of the large, appar- 

 ently well-established populations of boll weevils 

 they discovered, Fryxell and Lukefiihr concluded 

 that Hainpca, not cotton, is probably the boll wee- 

 vil's ancestral host. Fryxell namecl the species Hai)i- 

 pea nutricia, for its role in providing nutrition and 

 shelter to the boll weevil and another cotton pest, 

 the cotton leafworm. 



Evidence gathered in subsequent years has bol- 

 stered their conclusion. In 1979 Horace R. Burke 

 and James R. Gate, both entomologists at Texas A&M 

 University in GoUege Station, discovered a previously 

 unknown weevil species (Anthonoinus hunteri), living 

 exclusively on another species of Hainpca in the Yu- 

 catan Peninsula. The discovery was important be- 

 cause the boll weevil had always been something of 

 an orphan within Aiithoiionnts, its megadiverse genus. 

 More than 300 species of Antlionoiiuis are recorded 

 in Gentral and North America alone, yet no close 

 relative of the boll weevil had ever been found. 



Farmer dusts a cotton field against boll weevils in Scott, Mississippi, in 1919. Dusting with 

 calcium arsenate was the principle means of weevil control until after the Second World 

 War Arsenic residue from the pesticide persists in soils throughout the South to this day. 



In the past six years Burke and I have filled in more 

 of the boU weevil's family tree. We have described 

 three more species of Anthoiiomus, closely related to 

 the boll weevil, which also live on various species of 

 Hainpca in southern Mexico and Gentral America. 

 The fact that the boll weevil's closest relatives are re- 

 stricted to Hampea, whereas the boU weevil alone 

 Hves on cotton, suggests that Hainpca and its associ- 

 ated weevils have had more time than cotton and the 

 boll weevil to co-evolve. Hainpca is thus a more like- 

 ly original host than cotton. 



If the boll weevil first evolved on Hampea, when 

 did it shift to cotton? The question remains an open 

 one, but it is intriguing to note that Mexico's Gulf 

 Goast region along the border between the states of 

 Tabasco and Veracruz is most likely where cotton was 

 first domesticated in the Americas. That region cor- 

 responds precisely with the distribution of H. initri- 

 cia. The plant is a vigorous colonizer of disturbed soils, 

 and so it is common near agricultural fields. The boll 

 weevils that feed on it almost certainly had intimate 

 and sustained contact with cotton plants cultivated 



1950s Boll weevil and other insect pests grow 



increasingly resistant to certain insecticides. 



SILI'Nl 

 Sl'RlNC 



Cai-son 



1962 Rachel Carson publishes Silent Spring, 



sparking public concern over insecticide use. 



1969 USDA investigators isolate boll weevil sex pheromone 

 and use it to design the first effective weevil trap. 



1971 First pilot eradication program begins 

 in Alabama, Louisiana, and Mississippi. 



34 



NMUKAI lllsroRY February 2006 



1978 NationwK 

 traps dete 

 malathic 



