Composition of a chemical signalling trait varies with phylogeny and precipitation across an Australian lizard radiation

Abstract

Signalling systems serve important functions in animals that influence survival and reproduction: finding and choosing mates; orientation; warning, detecting and assessing competitors; recognizing kin and familiars; deceiving rivals, prey and predators; and alerting others of-and being alerted to-danger (Bradbury & Vehrencamp, 2011). These functions influence the fitness of both signallers and receivers; an individual that cannot attract a mate or that does not heed a warning call in the presence of a predator will have fewer offspring. To function effectively, a signal must be transmitted through and perceived against its background environment (Endler, 1992). For example, blue colouration is an ineffective signal for fish inhabiting murky water where blue wavelength light is scarce

Initiation of speciation across multiple dimensions in a rock‐restricted, tropical lizard

“…Notably, among-lineage genetic divergence across the H. planiceps complex spans the "grey zone" of speciation (Roux et al, 2016), highlighting the suitability of this system for studying incipient speciation. In accord with expectations, both the diversity and geographical localization of lineages in H. planiceps far exceed that of its more ecologically generalist relative Heteronotia binoei, which itself has high levels of localized lineage diversity across other areas of the monsoonal tropics where H. planiceps is absent (Moritz et al, 2016;Zozaya et al, 2022a). Furthermore, the chemical composition of epidermal pore secretions differed more among lineages than did morphology in both species, and with clearer chemical signal divergence within H. planiceps.…”

“…We used data from Zozaya et al (2022b) to assess how among‐lineage divergence in a chemical signalling trait (male epidermal pore secretions) compares to morphological divergence among lineages in each of the two species groups. Chemical data were available for the six relevant lineages of H. binoei , but only eight lineages of H. planiceps : plan‐A, plan‐I, plan‐J, plan‐L, plan‐M, plan‐N1, plan‐N2 and plan‐N3.…”

“…Details on the design of our exon capture system are identical to those presented in Zozaya et al ( 2022a ). Briefly, following Bi et al ( 2012 ) we designed a custom exon capture system using de novo assembled adult liver transcriptomes obtained from individuals of three lineages of H. binoei (NWK, VRD, SM6N) and one of H. planiceps (plan‐A), as outlined in Zozaya et al ( 2022a ). Following the strategy in Bragg et al ( 2016 ), we targeted 4406 protein‐coding exons longer than 200 bp and represented just once in the Anolis genome (Alföldi et al, 2011 ).…”

“…Chemical signals vary in association with precipitation in Heteronotia (Zozaya et al, 2022a), and with temperature and other climatic factors in other lizards (Baeckens et al, 2018;Campos et al, 2020). As (Butlin, 1987;Higgie et al, 2000;Hoskin et al, 2005;Howard, 1993;Noor, 1999).…”

“…Across this region, two species of Heteronotia geckos co‐occur (Figure 1a ): Heteronotia binoei (Gray, 1845 ), a terrestrial habitat generalist that is found across much of Australia; and Heteronotia planiceps Storr, 1989 , a rock‐associated species that is endemic to the Kimberley–Victoria River regions. Previous sampling and multilocus sequencing of H. binoei has identified multiple species‐level phylogeographical lineages across tropical Australia, including in the Kimberley and Victoria River regions (Fujita et al, 2010 ; Moritz et al, 2016 ; Zozaya et al, 2022a ). Preliminary multilocus sequencing has also revealed strong genetic differences among some H. planiceps , but geographical sampling was limited (Oliver et al, 2017 ; Pepper et al, 2011 ).…”