Differential ecophysiological syndromes explain the partition of the thermal niche resource in coexisting Eucraniini dung beetles

VERDÚ, J.R.; OLIVA, DANIELA; GIMÉNEZ GÓMEZ, V.C.; CORTEZ, VIEYLE

ECOLOGICAL ENTOMOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2022

0307-6946

1. The authors investigated the role of thermoregulation mechanisms and thermallimits on thermal niche differentiation in two hierarchical similar Eucraniini dungbeetle assemblages inhabiting arid environments in north-western Argentina. Bothdung beetle assemblages showed temporal and thermal niche segregation betweenall sympatric species, minimising overlap during their daily activity and soil temperaturepreferences.2. Thermal tolerance of Eucraniini species was partially modulated by behaviouraladaptations and complementary thermoregulatory mechanisms related to eliminatingthe temperature excess, increasing the metabolic rate promoting an effectiveregulation of the excess heat that permitted a decrease in their body temperatureby evaporative cooling. Based on the physiological syndromes obtained, the authorsfound a greatest interspecific differentiation that allows us to differentiate eachspecies using ecophysiological traits. Interspecific body size differences in sympatricEucraniini contributed greatly to the metabolic capacity of individuals tothermoregulate.3. Eucranium species, the largest species showed the lowest capacity to respond tothermal stress decreasing heat excess temperature, presenting the lowest thermallimit values coinciding with a ?minithermy? strategy that explains the preferredlower soil temperatures around 30C. On the contrary, Anomiopsoides speciesshowed a clear adaptation to being active during periods of the day in which thesoil temperature reached over 50C, adopting a strategy of ?maxithermy? by foragingwhen temperatures are closer to their thermal limits.4. In conclusion, it can be determined that ecophysiological syndromes related to thermalstress regulation and thermal limits allowed a displacement in thermal nichedimension, minimising interspecific competition and so allowing species coexistencein Eucraniini dung beetles.