Spiders may have more diverse diets than previously thought. New research has revealed that the infamous insectivorous predators occasionally spice up their menu with a vegetarian meal.
Historically, spiders are known to feast on insects trapped in webs. However, there have also been reported instances of the arachnids enriching their diets with fish, frogs or even bats.
For their study, zoologists from the University of Basel, Brandeis University and Cardiff University gathered data from previous studies of spiders eating plant food. Based on their review, it is now believed that spiders of at least 10 families have been documented feeding on a wide variety of different plant types such as trees, shrubs, weeds, grasses, ferns and orchids. Furthermore, researchers also found that spiders have a diverse taste when it comes to the type of plant food and will feed on nectar, plant sap, honeydew, leaf tissue, pollen and seeds.
"The ability of spiders to derive nutrients from plants is broadening the food base of these animals; this might be a survival mechanism helping spiders to stay alive during periods when insects are scarce," explained Martin Nyffeler, lead author of the study from the University of Basel in Switzerland. "In addition, diversifying their diet with plant is advantageous from a nutritional point of view, since diet mixing is optimizing nutrient intake."
Researchers found that common jumping spiders belonging to the Salticidae family are the leading group of vegetarian spiders. Of the reported cases analyzed in the study, Salticidae accounted for up to 60 percent of all plant-eating incidents documented.
This, researchers say, did not come as a surprise, since the spiders are plant-dwelling, highly mobile foragers with an excellent capability to detect suitable plant food.
Their study also revealed that spiders feast on plants worldwide, with reported cases from all continents except Antarctica. Furthermore, it appears that this behavior is most common in warmer areas, which may in part be due to the fact that plants secrete greater amounts of nectar in tropical regions.
However, researchers note that the extent to which the different categories of plant food contribute to the spiders' diet is still unknown and will be explored in future studies.
Their findings were recently published in the Journal of Arachnology.
