Nest refuse of Acromyrmex balzani (Hymenoptera: Formicidae) increases the plant vigor in Turnera subulata (Turneraceae).

L Sousa-Souto,R S Santos

doi:10.1590/1519-6984.244732

Abstract

Some studies report the positive effect of organic residues from ant nests on soil properties and on the structure of the adjacent plant community in field experiments, but there is a gap about the effect on individual species. The purpose of the present study was to compare the soil nutrient content and the development of Turnera subulata Smith, an ornamental species, in the presence of the nest refuse (basically composed of fragments of grass leaves and the symbiotic fungus) produced by the leaf-cutting ant Acromyrmex balzani (Emery, 1890) or in control soil through a greenhouse pot experiment. The experiment was carried out with two treatments: control soil and soil with 25% of nest refuse. The plants were kept in 1L pots for 90 days. We evaluated the parameters: plant height, stem diameter, root length, number of leaves, dry weight of the root, dry and fresh aboveground biomass. Additionally, the relative chlorophyll content and leaf nutrients were used as nutritional parameters. As a result, plants that grew in the soil with nest refuse showed significant higher values of all parameters evaluated when compared to the control treatment (p < 0.001). We conclude that this biofertilizer contributed to the production of more vigorous plants, being able to act on the local dynamics of nutrients in the ecosystems where A. balzani occurs. As it is relatively abundant and easy to collect, the refuse of A. balzani has the potential to be used as an alternative substrate in the production of shortlife cycle plants.

Highlights

Since there were no variations in the proportions of chlorophyll a and b, we considered for analysis only the total chlorophyll content
There was an increase of 3.6 times in the dry aboveground biomass (Figure 2e), and an 8.5-fold increase in the fresh aboveground biomass (Figure 2f) when compared to the control treatment (CONT) treatment
We confirmed the hypothesis tested that plants treated with NR present greater vigour and biomass than non-treated plants and we demonstrated that the beneficial effects of nest refuse go beyond the increase in soil fertility

Summary

Introduction

Nutritional deficiencies in soils are among the main limiting factors for the functioning of tropical ecosystems, negatively affecting the species diversity and the structure of plant communities (Walker and Syers, 1976; Dalling et al, 2016; Delavaux et al, 2017). The causes of nutritional deficiencies in the soil are diverse, it is known that in newly disturbed environments this limitation is partly attributed to the reduction of soil organic matter content and the low rate of nutrient mineralization (Neill et al, 1995, 1996; Sousa-Souto et al, 2013; Delavaux et al, 2017). The negative effects of low availability of nutrients in the soil in these environments are often mitigated by the activities of “ecosystem engineers” (Lavelle, 1997)

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