Host-Parasite biogeographic interactions: modelling the distribution of Phyllotis xanthopygus rodents complex and their flea assemblage using the favorability function

Host-parasite systems play a key role in biogeography, with parasites
influencing the distributions of their host and vice versa. The
biodiversity of flea species on the subfamily Sigmodontinae is especially
valuable for studying parasite-host-environment interactions. This study
evaluates the biogeographic relationship between rodents of the Phyllotis
xanthopygus complex and their flea assemblage applying the favorability
function in the modelling distribution, to identify the different
environmental factors that favor the distribution of both, and to detect
areas of greater shared favorability. This is the first study on fleas
using a methodology based on fuzzy logic that helps to disentangle the
main factors that determine favorable environmental conditions for
parasites and hosts. Using favorability functions as the fuzzy logic
modelling technique and fuzzy intersection, union, and inclusion as the
fuzzy operators, we were able to specify the territories with maximum
simultaneous fleas-Phyllotis xanthopygus complex favorability in the study
area. The model results showed that climate was the main factor
influencing the distributions of fleas and hosts. The variables most
relevant to the rodents were the minimum temperatures in the coldest month
and the annual temperature range. The most important predictors for fleas
were the mean diurnal range temperatures and the precipitation in the
coldest quarter. The maximum simultaneous rodent-flea favorability
occurred in the Cuyan High Andean and Puna provinces (South American
transition zone). This study explores the influence of environmental
factors on the distribution of rodent-flea associations highlighting their
ecological and public health implications.