When we think of spiders, we most often picture webs of cobwebs that they use to capture their prey. Now, new research published in Ecology and Evolution reveals another surprising way a spider uses its thread—one species in Madagascar has been observed sewing leaves together to create a trap in which it traps a frog.
The unusual sight was an accidental discovery made by a team of researchers conducting ecological studies in Madagascar. One morning, after completing a bird count in Ambodiala, they spotted a spider (Sparassidae, Damastes sp.) feeding on a frog. Invertebrates preying on vertebrates is not unheard of, but the researchers believe their report is one of only two to describe such predation in Madagascar.
The same type of spider has also been spotted on three other occasions, mostly in vanilla plantations across the region. Most interestingly, all the spiders have been spotted either near or inside a hiding place of leaves “stitched” with thread. The shelters are partially open on one side, making them look like cool hiding places for the frogs, warmed by the Madagascar sun, who have no idea that a spider is lurking inside.
The first spider found eating a frog retreats back into its leafy hiding place as researchers approach to take a photo. The remaining spiders are either near or still in similar leaf shelters. They do not seem to show a preference for certain tree species, as the leaves of various trees have been used in the crafts of creating such hiding places. What connects them, however, is that they are all “stitched” to each other with the silk thread of the spiders.
“When temperatures rise, frogs seek shade and hide away from the ground, which spiders provide in the form of shelter,” the authors wrote in their paper. “Frogs may select the seemingly protected traps in an attempt to hide from other predators, such as birds that scan the vegetation for prey … We hypothesize that amphibians may not only be opportunistic, indiscriminate or accidental prey, but rather purposefully exploited food source of spiders Damastes sp.”
The researchers acknowledge the study’s limitations, as only one observation was made of a spider feeding on a frog. They also note that large prey such as a frog are more easily spotted by the human eye and should not be taken as evidence that this is a common behavior. However, the behavior of spiders that “sewing” leaves to create shelter is impressive.
Photo: Seemingly peaceful cool shelters turn out to be a trap for some animals. Photo: Thio R Fulgence et al (2020), Ecology and Evolution
Source: IFLScience – Madagascan Spider Observed Sewing Leaves Together To Create Tempting Trap For Frogs