On October 23, 2019, a group of researchers experimented with several species of spiders and bacteria, and they reported to the Journal of Experimental Biology regarding their new explanation to the spider web’s resistance to rotting. 

When you enter an abandoned house, or even a haunted house at an amusement park, you first notice the spider webs that seem to have been there forever. A spider can’t always be producing the webs over and over, so how do the webs last so long? 

Previously, it was believed that spider webs have “some kind of antimicrobacterial property,” states Jeffery Yarger, a biochemist at Arizona State University. This means that they are capable of physically killing bacteria. 

In the new research, however, the researchers placed the strands of three different spiders on petri dishes and grew four kinds of bacteria. If the spider webs had antimicrobacterial property, there should not be any growth between the silk and bacteria. Dakota Piorkowski explains, “The microbes don’t seem to affect spider silk.” They noticed no dead bacteria where the bacteria came in contact with the silk.

Then, the researchers wet the webs with different nutrient solutions and discovered that bacteria successfully grew on all three webs when extra nitrogen was present. This showed that when nitrogen was available, the bacteria were capable of growing and decomposing the silk threads. 

From this, the researchers hypothesize that that an extra coating on the spider webs prevent the bacteria from accessing the nitrogen within the webs. The hypothesis explains how spider webs don’t rot even though spiders store dead insects on them and cover them leaves which, an optimal environment for bacteria to growth.

by SangHyun Kim