Abstract
BackgroundConcealing coloration in rodents is well established. However, only a few studies examined how soil color, pelage color, hair-melanin content, and genetics (i.e., the causal chain) synergize to configure it. This study investigates the causal chain of dorsal coloration in Israeli subterranean blind mole rats, Spalax ehrenbergi.MethodsWe examined pelage coloration of 128 adult animals from 11 populations belonging to four species of Spalax ehrenbergi superspecies (Spalax galili, Spalax golani, Spalax carmeli, and Spalax judaei) and the corresponding coloration of soil samples from the collection sites using a digital colorimeter. Additionally, we quantified hair-melanin contents of 67 animals using HPLC and sequenced the MC1R gene in 68 individuals from all four mole rat species.ResultsDue to high variability of soil colors, the correlation between soil and pelage color coordinates was weak and significant only between soil hue and pelage lightness. Multiple stepwise forward regression revealed that soil lightness was significantly associated with all pelage color variables. Pelage color lightness among the four species increased with the higher southward aridity in accordance to Gloger's rule (darker in humid habitats and lighter in arid habitats). Darker and lighter pelage colors are associated with darker basalt and terra rossa, and lighter rendzina soils, respectively. Despite soil lightness varying significantly, pelage lightness and eumelanin converged among populations living in similar soil types. Partial sequencing of the MC1R gene identified three allelic variants, two of which were predominant in northern species (S. galili and S. golani), and the third was exclusive to southern species (S. carmeli and S. judaei), which might have caused the differences found in pheomelanin/eumelanin ratio.Conclusion/SignificanceDarker dorsal pelage in darker basalt and terra rossa soils in the north and lighter pelage in rendzina and loess soils in the south reflect the combined results of crypsis and thermoregulatory function following Gloger's rule.
Highlights
Mammalian pelage coloration plays an important role in crypsis, intra-specific signaling, thermoregulation, and ultraviolet screening [1,2,3,4]
The maximum lightness score (‘L*’) of soils in our samples is found in S. judaei and S. galili in the Kerem Ben Zimra rendzina sample we tested (42.19–50.81), compared with S. carmeli (23.13–30.93) and S. golani (26.36–30.30)
KBZ displayed lighter pelage on lighter rendzina soil. How far do these results corroborate with the three functions of coat coloration: intraspecific communication, crypsis, and thermoregulation [8]? Intraspecific communication cannot be the case with Spalax ehrenbergi superspecies as the animal cannot use apparent coloration-based visual cues
Summary
Mammalian pelage coloration plays an important role in crypsis, intra-specific signaling, thermoregulation, and ultraviolet screening [1,2,3,4]. Several studies demonstrated a strong positive correlation between rodents’ coat color and background color of the environment in which they live, indicating that natural selection is operating [5,6,7,8,9] Such adaptive coat color variations are caused by the switch between ‘brown to black’ eumelanin and ‘yellow to red’ pheomelanin [10,11,12,13]. This dual melanogenesis is controlled by the interaction of two proteins: melanocortin-1-receptor (MC1R) and agouti-signaling protein (ASIP) [14,15,16]. This study investigates the causal chain of dorsal coloration in Israeli subterranean blind mole rats, Spalax ehrenbergi
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
