AimWe investigated changes in dung beetle β‐diversity components along a subtropical elevational gradient, to test whether turnover or nestedness‐related processes drive the dissimilarity of assemblages at spatial and temporal scales.LocationAn elevational gradient (200–1,600 m a.s.l.) of the Atlantic Forest in southern Brazil.MethodsWe investigated the extent to which β‐diversity varied along the elevational gradient (six elevations) at both spatial (among sites at different elevations) and temporal (different months at the same site) scales. We compared both the turnover and nestedness‐related dissimilarity of species and genera using multiple‐site or multiple‐month measures and tested whether these measurements were different from random expectations.ResultsA mid‐elevation peak in species richness along the elevational gradient was observed, and the lowest richness occurred at the highest elevations. We found two different groups of species, lowland and highland species, with a mixing of groups at intermediate elevations. The turnover component of β‐diversity was significantly higher for both spatial (i.e. elevational) and temporal changes in species composition. However, when the data for genera by site were considered, the elevational turnover value decreased in relative importance. Nestedness‐related processes are more important for temporal dissimilarity patterns at higher elevation sites.Main conclusionsSpatial and temporal turnover of dung beetle species is the most important component of β‐diversity along the elevational gradient. High‐elevation assemblages are not subsets of assemblages that inhabit lower elevations, but this relationship ceases when β‐diversity is measured at the generic level. Environmental changes across elevations may be the cause of the differential establishment of distinctive species, but these species typically belong to the same higher taxonomic rank. Conservation strategies should consider elevational gradients in case‐specific scenarios as they may contain distinct species assemblages in lowlands vs. highlands.

Subspecies is a debated taxonomic rank that, in some cases, could indicate that a speciation process is taking place. Studying the degree of co-occurrence among subspecies along environmental gradients may help to determine its taxonomic status. In this study, we explore the distribution of two subspecies of Canthon rutilans along spatio-temporal and temperature gradients in the Atlantic Forest of southern Brazil in order to reinforce their current subspecies status or to support their consideration as two different species. A yearly survey conducted along an elevational transect (from 250 m to 1630 m) shows that there is no spatio-temporal overlap between the two taxa. We collected 899 individuals of Canthon rutilans cyanescens and 29 individuals of Canthon rutilans rutilans. C. rutilans cyanescens can be found at 250 m (all year except in June), 430 m (August to April), and 840 m (September to April) in elevation, and when the air temperature oscillates from 15.3 °C to 24.0 °C. C. rutilans rutilans can be found at 1360 m (October to February), 1630 m (January) in elevation, and when the air temperature oscillates from 14.4 °C to 18.6 °C. Furthermore, local temperature data taken during the survey indicates that both subspecies also have a limited overlap in their thermal response curves. All these results suggest that these two taxa could be considered as two different species with dissimilar physiological and ecological requirements probably as a consequence of temperature-mediated divergent adaptation. Further molecular data can confirm or reject this supposition in the near future.

Dung consumption and removal is a fundamental ecological process carried out by dung beetles that drive soil nutrient cycling and associated ecosystem services. In this study, the removal rate of small droppings by dung beetles was estimated in natural subtropical rainforests of southern Brazil located along an elevational gradient, in order to understand the factors influencing variation in dung removal. To do that, the comparative explanatory capacity of three main types of variables was quantified: assemblage characteristics, local climatic and habitat conditions, and seasonal variation. The complete disappearance of dung within 48 h after deposition occurs in 73% of occasions. The highest explanatory capacity correspond to the combined effects of the three types of variables; however, average air temperature during the sampling period, total volume of dung beetles collected in the traps in which dung removal was measured, and the seasonal transition from summer to winter were the most important and representative predictors of dung removal. Thus, the dung nutrient incorporation into the soil will most likely be greater during spring‐summer conditions, when the air temperature at the time of dung deposition is high and the biomass of the dung beetle assemblage is bigger.

Basic characteristics of species assemblages are frequently related to temperature variables recorded at a coarse‐grained scale. In this study, 15 min instant‐measurements of environmental and soil temperatures were recorded during 1 year in six Atlantic Forest sites of southern Brazil, ranging from 250 to 1,630 m a.s.l. These measurements were used to examine the comparative explanatory capacity of several temperature variables in predicting species richness and total or specific variations of dung beetle abundance. The results suggest that temperature measurements obtained during the survey period have the highest explanatory capacity. Furthermore, average temperature values seem to have a relatively higher explanatory capacity than absolute minimum or maximum values reflecting extreme conditions. In general, there is no rule in selecting a temperature variable when the objective involves explaining the variation in species abundances. Both soil and air variables can have similar explanatory capacities. The present results should be considered when designing future ecological studies in Neotropical conditions.

Two dung beetle subspecies of Canthon rutilans Castelnau (Coleoptera: Scarabaeidae, Scarabaeinae), C. rutilans rutilans and C. rutilans cyanescens, inhabit different environmental temperature conditions in southern Brazil. We developed a laboratory breeding experiment with 60 pairs of individuals of the two subspecies at five temperature conditions (from 15 to 35 °C) to compare the influence of temperature on the behaviour of adults and the development of larvae. The behavioural patterns of the adults in both subspecies differ according to temperature. The size of food balls was smaller and lighter in C. rutilans cyanescens. Although temperature did not influence the feeding behaviour (measured as the number of food balls made), reproductive behaviour (measured as the number of brood balls made by pair) was significantly lower at 15 °C for both subspecies. Besides that, brood balls from C. rutilans rutilans were bigger and heavier at lower temperatures. The number of offspring and the time of emergence depend on temperature too. However, the weight of the offspring and the longevity of adults depend on the subspecies and temperature treatment. These results demonstrate that the subspecies have different thermal adaptations: C. rutilans rutilans has reproductive behaviour adapted to living under colder and broader conditions than C. rutilans cyanescens.