Breeding systems and genetic diversity in tropical carpenter ant colonies: different strategies for similar outcomes in Brazilian Cerrado savanna

Abstract

Eusocial insects tend to present low genetic diversity (GD) within colonies, which can increase with the co-occurrence of multiple queens (polygyny) or with multiple mating by a single queen (polyandry). Therefore, it is important to elucidate how these strategies influence GD, which in turn mediate population ecology and how organisms respond to their environment. We studied two carpenter ant species from the Brazilian savanna, Camponotus renggeri and C. rufipes. Using microsatellites, we evaluated the number of breeders, the genetic relatedness and the contribution of polygyny and polyandry to GD within colonies. Both species exhibited facultative polygyny. In C. renggeri, low related queens formed colonies jointly and present low mating frequency. In this species, colony GD increased with the number of queens. Contrastingly, closely related queens of C. rufipes formed polygynous colonies, exhibiting high mating frequency. In C. rufipes, both queens and males contributed to colony GD. Despite the differences, the two species have similar GD at the colony scale. Under low mating frequency, our data support that polygyny has evolutionary importance for increasing GD in ant colonies, a mechanism mainly conferred to polyandry. Although the impact of GD in variable ecological and adaptive contexts remains uncertain, this study highlights how distinct reproductive strategies may generate similar patterns of GD in ants.

Natural history of Camponotus renggeri and Camponotus rufipes (Hymenoptera: Formicidae) in an Atlantic Forest reserve, Brazil

“…The closely related carpenter ants Camponotus renggeri (Emery 1894) and C. rufipes (Fabricius 1775) have been extensively studied in terms of physiology (Takahashi-Del-Bianco et al 1998;Galizia et al 1999), natural history (Ronque et al 2016;Ronque et al 2018) and genetics (Azevedo-Silva et al 2015;Ronque et al 2016;De Aguiar et al 2017;Azevedo-Silva et al 2020).…”

“…Despite similarities in distribution and interactions with plants, these species differ with respect to nest architecture, foraging areas, and breeding systems. C. renggeri occupies nests built in dead tree trunks or underground, whereas C. rufipes may also construct nests out of dry straw (Ronque et al 2016;Ronque et al 2018;Azevedo-Silva et al 2020). Both species occur across South America in different ecosystems (Janicki et al 2016), but most research on these species is restricted to the Brazilian savanna, known as Cerrado.…”

Microsatellites for the Neotropical Ant, Odontomachus chelifer (Hymenoptera: Formicidae)

“…Several characteristics make them ideal studies on population genetic, genome mapping, and marker-assisted breeding ( Sun et al 2011 ). Previous works have used microsatellites to identify ant species ( Goodisman and Hahn 2005 , Ronque et al 2016 ), describe their breeding systems ( Azevedo-Silva et al 2020 ), and analyze dispersion strategies ( Pérez-Espona et al 2012 , Soare et al 2014 ), colony spatial distribution ( Debout et al 2007 ), and population genetics patterns ( Pamilo et al 2016 ). Given that genetic diversity is key for the persistence and adaptation of populations to environmental changes ( Seppä 2008 ), the development of molecular tools to portray such diversity is crucial for elucidating species biology and conservation.…”

Microsatellites for the Neotropical ant,Camponotus leydigi(Hymenoptera: Formicidae)

“…For ants in particular, microsatellites are useful tools to investigate colony genetic structure (Bolton et al 2006;Qian et al 2012), breeding systems (e.g. number of queens and queen mating frequency in colonies; Goodisman & Hahn 2005;Azevedo-Silva et al 2020), kinship between individuals, population and colony delimitation (e.g. identification of polydomy; Elias et al 2005;Ellis et al 2017).…”