Fire ants: What do rural and urban areas show us about occurrence, diversity, and ancestral state reconstruction?

Manuela De O Ramalho,Leonardo Menino,Victor H Nagatani,Maria S C Morini,Otávio G M Silva,Odair C Bueno,Juliana M C Alves,Ricardo Harakava,Rodrigo F Souza,Débora Y Kayano

doi:10.1590/1678-4685-gmb-2021-0120

Abstract

In South America, Solenopsis saevissima and S. invicta are the most common fire ants. Nests are founded in areas under anthropic interference like urban or rural areas, but S. invicta is found preferentially in those with the greatest anthropic interference. However, we do not know the rates at which they exist in anthropized areas next to high density of native vegetation. Areas with 60 to 90% of native Atlantic Forest were selected to verify the occurrence of both species in rural and urban areas. We investigated the molecular diversity and applied the reconstruction of the ancestral state analysis for each species. A total of 186 nests were analyzed and we found that the two species had the same proportion in the urban area. However, S. saevissima had a higher rate of prevalence in the rural area, in addition to having a greater number of haplotypes and ancestry associated with this type of habitat for the region. S. invicta had the same number of haplotypes in both rural and urban regions, and less haplotypic diversity. We conclude that S. saevissima is a species typically associated with rural areas and S. invicta, although present, is not dominant in urban areas.

Highlights

Solenopsis (Myrmicinae: Solenopsidini) has 196 species, in addition to 22 subspecies (Bolton 2021), with a widespread distribution
Solenopsis saevissima can be distinguished from S. invicta, and both from the others fire ant’s species, by these diagnostics characters, as described by Pitts et al (2018)
Regarding the haplotype diversity recovered in the present study, S. saevissima has the greatest haplotype diversity compared to S. invicta (Table 1)

Summary

Introduction

Solenopsis (Myrmicinae: Solenopsidini) has 196 species, in addition to 22 subspecies (Bolton 2021), with a widespread distribution. Fire ants are found in South America (Pitts et al, 2018), where they exhibit omnivorous, opportunistic and aggressive behavior (Pitts, McHugh and Ross, 2005). They display variation in social structure (Tschinkel, 2006) and in larvae morphology (Pitts et al, 2018). Fire ants cause damage to biodiversity (Dejean et al, 2015), crops (Chan and Guenard, 2020) and health problems for people who are allergic to the venom (Haddad Junior and Larsson, 2015). In Brazil, there is little knowledge about the impact caused by fire ants on agriculture, there are records of large infestations associated with health problems, mainly due to allergies (Fernandes et al, 2016)

Methods

Results

Discussion

Conclusion