Academy entomologist Charles Griswold inspects spider web
Charles Griswold reveals webs by dusting them with corn starch. Qiqi, northern Gaoligongshan. Photo: Dong Lin.

Acadmy Research : New Discoveries

To find the world's smallest spiders, it helps to have corn starch. Academy arachnologist Charles Griswold went to China not knowing what spiders live in the forests of Gaoligongshan nor the kinds of webs they build. He sought micro orb-weavers, the spiders he studies to discern relationships among groups of species and how each group evolved. In dark corners of the mountain forests, Griswold dusted the air with corn starch, which reveals the presence of any web. Orb-weavers construct elaborate two- and three-dimensional webs with hubs and sticky spirals. The size, shape, and position of webs provide clues to spider behavior, but Griswold needs to find and identify the web maker, too.

So far, Griswold has discovered six new species of mysmenid spiders and this summer he made the first recorded find in China of an even tinier symphytognathid spider. Monsoon rains hampered his spider collecting, but Griswold was lucky to be the first person ever to observe the symphytognathid's unique habit of suspending separate eggs from the edge of its web. That novel behavior poses a puzzle for how this species may be related to other orb-weavers. In partnership with scientists at Hunan Normal University, the Academy will seek answers to this and other questions about the spiders of Gaoligongshan.

 

starburst shaped web of mysmenid spider
male symphytognathid spider
Starburst shaped web of a mysmenid spider that has been dusted with corn starch. This is a 3 dimensional orb web with radii that extend in all directions. QiQi, northern Gaoligongshan. Photo: Dong Lin.

Portrait of a male symphytognathid spider. Photo: Charles Griswold.

 

Griswold in banboo forest
Charles Griswold in bamboo forest at 3000m in DanZhu Valley, nothern Gaoligongshan, China. He holds a "beating sheet." The beating sheet is held beneath vegetation and insects and spiders are knocked from vegetation onto the sheet. Photo: Darrell Ubick

 

eggs suspended in sympytognathid web
Eggs suspended at the margin of a symphytognathid web, which has been dusted with corn starch. QiQi, northern Gaoligongshan. Photo: Dong Lin.

planar, horizontal web of symphytognatid spider
Planar, horizontal orb web of a symphytognathid spider that has been dusted with corn starch. Eggs are suspended at upper margin of web. QiQi, northern Gaoligongshan. Photo: Dong Lin.