Cardinal predation of the invasive Jorō spider Trichophila clavata (Araneae: Nephilidae) in Georgia

Abstract

The invasive Jorō spider (Trichophila clavata L. Koch: Araneae: Nephilidae), which was found to be established in Georgia in 2014, has become abundant and spread to many other states. Almost nothing is known about what predates the Jorō spider in its invasive range. A previous paper reported a Northern Cardinal (Cardinalis cardinalis L. [Passeriformes: Cardinalidae]) perching on the web of a Jorō spider and lunging towards it, in what was interpreted to be a predation attempt. This note reports attacks by two Northern Cardinals (referred to hereafter as Cardinal) on Jorō spiders in Atlanta, Georgia. The first attack was observed when a male Cardinal continuously pecked at the top of a caged Jorō, just above the large female spider. Shortly after this attack a large living female Jorō spider was tethered by a thread around the pedicel and hung above and near to the caged Jorō that was attacked. After nearly an hour had passed, a female Cardinal flew in and grabbed the Jorō in its beak and tried to fly away with the spider. The Cardinal quickly returned and attacked the spider two more times but was unable to fly away with it because the tether held the spider in place. The spider was killed but not dismembered. Cardinals may be responsible for the destroyed and empty Jorō webs that are commonly seen. Although Cardinals are thought by many people as seed feeders, research has shown that they are among the most insectivorous of common birds.