Within Mexico, Juan Nuñez Farfan and I have located both isolated peripheral populations in distinct habitats and contiguous populations along an environmental cline from the wet tropical Gulf coast to the seasonally dry Pacific coast.  Some of these populations I have studied since 1989.  Thus we can compare subpopulations that vary in habitat type, proximity, and perhaps also in degree of genetic connectedness. 

To estimate gene flow among populations, we used protein allozymes.  Thus far the data indicate that these populations are relatively isolated, and a gene tree does not show any correlation of genetic and geographic distances.   Sheryl White and I sequenced  a section of the FLAG (flagelleform) silk gene, but these data were not useful for population genetics. 

Map of the distribution of N. clavipes in Mexico (none are recorded from Baja California), modified from a faunal map from INEGI.  Each number refers to a known population,  listed below.  Clicking on high-lighted names will produce photographs of the habitats. Blue:  tropical forest (sites 4 – 8).  Red:  seasonally dry deciduous forest (sites 9-11). Green:  mid-altitude temperate forest (sites 2, 3).  Mustard:  grasslands.  Yellow:  desert and chaparral (site 1).

Study sites:  East Coast 1.  Tehuacan, Puebla 2:  Fortín de las Flores, Veracruz 3.  Xalapa, Veracruz 4. Quiahuiztlan, Veracruz 5, 6:  Los Tuxtlas and Nanciyaga, Ver

Study sites, Tehuantepec and West Coast 7:  Sayala, Oaxaca 8:  Mateos Romero, Oaxaca 9:  Pinotepa, Oaxaca 10:  Chamela, Jalisco 11:  Arroyo Frio, Michoacan

This research supported by a grant from the National Science Foundation