In the late 1990s and early 2000s, Juan Nuñez Farfan, Jesus Vargas and I traveled even more extensively, locating both isolated populations in distinct habitats and contiguous populations along an environmental cline from the wet tropical Gulf coast to the seasonally dry Pacific coast.
To estimate gene flow among populations, we used allozymes - proteins that vary slightly in structure presumably because of underlying differences in the DNA genes for these proteins. Thus far the data indicate that these populations are relatively isolated. In addition, Sheryl White and I analyzed the diversity of one section of the FLAG (flagelleform) silk gene, that codes for the spiral threads on the orb web.
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.Yellow:
desert and chaparral (site 1).
Green: mid-altitude temperate forest (sites 2, 3).
Blue: tropical forest (sites 4 – 8).
Green: mid-altitude temperate forest (sites 2, 3).
Blue: tropical forest (sites 4 – 8).
Red:
seasonally dry deciduous forest (sites 9-11).
Mustard: grasslands. (no Nephila).
Mustard: grasslands. (no Nephila).