New Tools for Conservation Biological Control: Testing Ant-Attracting Artificial Nectaries to Employ Ants as Plant Defenders.

Enrico Schifani,Daniele Giannetti,Stefano Leonardi,Fiorenza Augusta Spotti,Cristina Castracani,Roberto Reggiani,Donato Antonio Grasso,Alessandra Mori

doi:10.3390/insects11020129

Enrico Schifani, Daniele Giannetti + Show 6 more

Open Access

https://doi.org/10.3390/insects11020129

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Abstract

Knowledge of the role of ants in many agroecosystems is relatively scarce, and in temperate regions the possibility to exploit ants as biocontrol agents for crop protection is still largely unexplored. Drawing inspiration from mutualistic ant–plant relationships mediated by extrafloral nectaries (EFNs), we tested the use of artificial nectaries (ANs) in order to increase ant activity on pear trees and to evaluate the effects on the arthropods, plant health and fruit production. While EFNs secrete a complex solution mainly composed of sugars and amino acids, ANs were filled with water and sucrose only. The results suggest that ANs can be used as manipulative instruments to increase ant activity over long periods of time. High ant activity was significantly linked to lower incidence of the pathogen fungus Venturia pyrina (pear scab) on pear leaves, and of the presence of Cydia pomonella (codling moth) caterpillars on pear fruit production. These results further encourage exploring underrated possibilities in the development of new tools for conservation biological control (CBC).

Highlights

Plants have evolved very complex relationships with ants, and have been fundamental to the rise of many modern lineages of these insects [1,2,3,4]
As concerns the total number of trees where ants were allowed to climb (n = 10), Formica cunicularia, Camponotus piceus and Plagiolepis pygmaea were respectively recorded in 100%, 90% and 70% of the trees
A relatively simple protocol was employed, very encouraging results on fruit production and plant health were achieved, many of which solicit the need for additional investigation

Summary

Introduction

Plants have evolved very complex relationships with ants, and have been fundamental to the rise of many modern lineages of these insects [1,2,3,4]. Some of these relationships are strictly antagonistic, revolving around herbivory in a few New World species and more commonly around seed predation [5]. Ants may protect sap-feeding insects in exchange for honeydew [8,9,10,11].

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