Land planarians (Platyhelminthes) also prey on web-building spiders

By

Cardoso, João C. F.
Carbayo, Fernando
Gonzaga, Marcelo O. (Marcelo de Oliveira)

Type

Article

Date of Publication

2023-9-27

Original Publication

Neotropical Biology and Conservation

Volume

18

Series / Issue

Issue: 3

Pages

157--162

Subjects

Araneae , Atlantic forest , Geoplaninae , predation

Contributed by

Pensoft Publishers

Language

English

Published by

Brazil Universidade do Vale do Rio dos Sinos

Identifiers

DOI: https://doi.org/10.3897/neotropical.18.e103322

 

Abstract

Although spiders and land planarians constitute diverse groups of terrestrial predators, interactions between them are still unknown. Here, we describe a predatory event of a land planarian (Choeradoplana cf. gladismariae) on a web-building spider (Helvibis longicauda) in the Brazilian Atlantic Forest. The prey was constricted and covered with sticky mucus while remaining on its web trying to protect its egg sac. The event was observed in the middle-end afternoon at ca. 1.80 m height. Our observation broadens the scope of possible natural enemies of web-building spiders and the prey items of land planarians. It also indicates that these organisms can capture and overpower dangerous predatory arthropods, suggesting that even complex three-dimensional sticky webs can be ineffective against the attack of land planarians. Finally, we also show that land planarians can exhibit a flexible foraging strategy, exploiting the environment during the day and at higher heights from the ground. Our observation opens new possibilities involving focal observations and experiments using spiders and land planarians as models in predator-prey research.