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

Abstract

Many plants secrete nectar from extrafloral nectaries (EFNs), specialized structures that usually attract ants which can act as plant defenders. We examined the nectar-mediated interactions between Chamaecrista nictitans (Caesalpineaceae) and jumping spiders (Araneae, Salticidae) for 2 years in old fields in New Jersey, USA. Previous research suggests that spiders are entirely carnivorous, yet jumping spiders (Eris sp. and Metaphidippus sp.) on C. nictitans collected nectar in addition to feeding on herbivores, ants, bees, 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 jumping 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 (Bruchidae), a specialist seed predator of C. nictitans. Jumping spiders may provide additional, unexpected defense to plants possessing EFNs. Plants with EFNs may therefore have beneficial interactions with other arthropod predators in addition to nectar-collecting ants.

Recruitment of predators and parasitoids by herbivore-injured plants

“…In the same way, reduction of herbivory has recently been demonstrated in mutualisms between extrafloral nectaries and spiders (Ruhren and Handel, 1999), as well as predatory wasps (V. Rico-Gray, personal communication).…”

“…Extrafloral nectar can also be extensively used by other predators (Bakker and Klein, 1992;Ruhren and Handel, 1999), as well as parasitoids (Bugg et al, 1989). In some instances, these carnivores, rather than ants, might represent the primary force protecting the plant (Ruhren and Handel, 1999;V. Rico Gray, personal communication).…”

“…In other plant species, the benefit of ant attendance is not always as clear (O'Dowd and Catchpole, 1983;Koptur and Lawton, 1988). In these species, the provision of extrafloral nectar may serve to enhance the effectiveness of other plant-predator (Ruhren and Handel, 1999) or plant-parasitoid interactions (Lingren and Lukefahr, 1977;Bugg et al, 1989;Koptur, 1994), or serve other (non-defensive) functions.…”

First observation of alternative food usage (extrafloral nectar) by the assassin bug Atopozelus opsimus (Hemiptera, Reduviidae)

“…A large group of animals are attracted to EFNs (Koptur 1992), such as spiders (Ruhren & Handel 1999;Nahas et al 2012) and ants (Oliveira & Brandão 1991;Nascimento & Del-Claro 2010) which provide protection to the plant against herbivores. In return, the animals get the nectar which is an important part of nutrition and can enhance growth and reproduction (Byk & Del-Claro 2011).…”

Odour‐mediated response to plants byevarcha culicivora, a blood‐feeding jumping spider from East Africa

“…Plants bearing sticky glandular hairs may even function as insect traps, facilitating prey capture by the spiders that associate with these plants (Vasconcellos-Neto et al 2007). Moreover, plants may benefit from the presence of spiders through increased seed production (Ruhren & Handel 1999;Whitney 2004).…”