Life history strategies of two springtails species (Hexapoda: Collembola) from saline soils

Springtails are a very common, widely spread component of soil fauna that play a significant role in numerous physical, chemical, and biological processes in the soil. Therefore, it is important to understand how their evolution and demographic parameters have changed throughout time. Since salinity is a relevant condition in the soils around the World and particularly in Mexico, the major goal of the current research is to understand the life cycle strategies of two springtail species from saline soils in Mexico. The studied species are Clavisotoma filifera and Brachystomella gabrielae, both widely distributed in Mexico, but their development or life history strategies are unknown. We found from laboratory cultures that C. filifera had a shorter life cycle and a faster reproduction rate than B. gabrielae. Nevertheless, both species show the same number of developmental stages, but there are interspecific differences in their duration. Although both species continuously reproduce throughout the year, the reproductive rate is lower in the months that are associated with the dry season at the source site. Additionally, we discovered variations in both the size and number of eggs in each species. It was found that the species under study had various life strategies for growth in the same environment. Clavisotoma filifera shows a more r-focused strategy (high fecundity, numerous offspring, shorter gestation and faster maturity), B. gabrielae shows an opposite strategy, closer to q strategy, with a lower fecundity, larger eggs, fewer reproductive events and slower maturity.