Jumping spiders (Salticidae) enhance the seed production of a plant with extrafloral nectaries

Many plants secrete nectar from extrafloral nectaries (EFNs), specialized s tructures that usually attract ants which can act as plant defenders. We ex amined the nectar-mediated interactions between Chamaecrista nictitans (Cae salpineaceae) and jumping spiders (Araneae, Salticidae) for 2 years in old fields in New Jersey, USA. Previous research suggests that spiders are enti rely carnivorous, yet jumping spiders (Eris sp, and Metaphidippus sp.) on C . nictitans collected nectar in addition to feeding on herbivores, ants, be es, and other spiders. In a controlled-environment experiment, when given a choice between C. nictitans with or without active EFNs, foraging spiders spent 86% of their time on plants with nectar. C. nictitans with resident j umping spiders did set significantly more seed than plants with no spiders, indicating a beneficial effect from these predators. However, the presence of jumping spiders did not decrease numbers of Sennius cruentatus (Bruchid ae), a specialist seed predator of C. nictitans. Jumping spiders may provid e additional, unexpected defense to plants possessing EFNs. Plants with EFN s may therefore have beneficial interactions with other arthropod predators in addition to nectar-collecting ants.