Neither ant dominance nor abundance explain ant-plant network structure in Mexican temperate forests

Abstract

Background Ant-plant mutualistic networks tend to have a nested structure that contributes to their stability, but the ecological factors that give rise to this structure are not fully understood. Here, we evaluate whether ant abundance and dominance hierarchy determine the structure of the ant-plant networks in two types of vegetation: oak and grassland, in two temperate environments of Mexico: Flor del Bosque State Park (FBSP) and La Malinche National Park (MNP). We predicted that dominant and abundant ant species make up the core, and submissives, the periphery of the network. We also expected a higher specialization level in the ant trophic level than in plant trophic level due to competition among the ant species for the plant-derived resources. Methods The ant-plant interaction network was obtained from the frequency of ant-plant interactions. We calculated a dominance hierarchy index for the ants using sampling with baits and evaluated their abundance using pitfall traps. Results In MNP, the Formica spp. species complex formed the core of the network (in both the oak forest and the grassland), while in FBSP, the core species were Prenolepis imparis (oak forest) and Camponotus rubrithorax (grassland). Although these core species were dominant in their respective sites, they were not necessarily the most dominant ant species. Three of the four networks (oak forest and grassland in FBSP, and oak forest in MNP) were nested and had a higher number of plant species than ant species. Although greater specialization was observed in the ant trophic level in the two sites and vegetations, possibly due to competition with the more dominant ant species, this was not statistically significant. In three of these networks (grassland and oak forest of MNP and oak forest of FBSP), we found no correlation between the dominance hierarchy and abundance of the ant species and their position within the network. However, a positive correlation was found between the nestedness contribution value and ant dominance hierarchy in the grassland of the site FBSP, which could be due to the richer ant-plant network and higher dominance index of this community. Conclusions Our evidence suggests that ant abundance and dominance hierarchy have little influence on network structure in temperate ecosystems, probably due to the species-poor ant-plant network and a dominance hierarchy formed only by the presence of dominant and submissive species with no intermediate dominant species between them (absence of gradient in hierarchy) in these ecosystems.

Impact of land-use changes on ant communities and the retention of ecosystem services in Rashad District, Southern Kordofan, Sudan

“…These findings are consistent with those found in the scientific literature; several studies with various taxa show that conversion of natural habitats and intensification of agrosystems leads to species reduction and changes in composition, as well as changes in the structure and functioning of the ecosystem. [36][37][38] examples in the literature of how conversion of native areas for food production affected the local fauna, perhaps the best studied is that of coffee production in Latin America, according to which a reduction in the diversity of ants was noted in a review by Eldridge et al 39 However, the magnitude of this reduction was dependent on the type of land management (monoculture of coffee or coffee in the shade of native trees), in addition to considering ecological services. 14,40 Similar patterns of reduction in ant diversity or richness in planting systems were also found in the Amazon 41 , Argentina 42,43 , Australia 44 , Africa 45 , and China 46 .…”

Synthesis and perspectives on the study of ant‐plant interaction networks: A global overview

“…(Lara et al, 2020) and the other at 2300–2900 m a.s.l. (Juárez‐Juárez et al, 2020). It is well known that ant‐plant interactions may vary in relation to temperature, precipitation, and temporal fluctuations in the availability of plant‐provided resources (Lange et al, 2017; Rico‐Gray et al, 2012).…”

“…At high elevations, it has been observed that the ant‐plant interaction networks that involve floral and EFN and forage substrate are reduced in the number of interacting species (small network size), possibly due to climatic conditions and plant resources. However, despite being networks with small size, these sites at high elevations have a nested structure (Juárez‐Juárez et al, 2020; Lara et al, 2020). In specialised networks, such as ant‐plant interactions involving myrmecophytes, a study performed by Plowman et al (2017) showed that the networks become more connected and less specialised at higher elevations, which directly affect the benefits obtained from this association.…”

“…In this study, we identify that most studies of ant-plant networks have been conducted at low elevations, mediated by different plant resources. Eight articles (15%) have studied these interactions at elevations >1500 m a.s.l., in deserts and xerophytic shrublands, tropical and subtropical moist broadleaf forests, and tropical and subtropical coniferous forests (Corro et al, 2019;Fagundes et al, 2017;Guimarães et al, 2006Guimarães et al, , 2007Juárez-Juárez et al, 2020;Lara et al, 2020;Luna et al, 2018;Plowman et al, 2017). Of those eight articles, only two were at elevations >2000 m a.s.l.…”

Changes in the core species of the ant-plant network of oak forest converted to grassland: replacement of its ant functional groups

“…Prenolepis imparis is a dominant ant found foraging on practically all plants in the oak forest of FBSP. This ant is characterized by its adaptation to cold environments, aggressive behavior, and ability to forage at low temperatures ( Wheeler, 1930 ; Lynch, Balinsky & Vail, 1980 ; Fellers, 1989 ; Andersen, 1997 ; Juárez-Juárez et al, 2020 ). Prenolepis imparis depends heavily on honeydew at the study site, with a marked seasonality to its foraging; it is almost exclusively found collecting honeydew on plants in the rainy season (Cuautle per.…”