Colors of night: climate–morphology relationships of geometrid moths along spatial gradients in southwestern China
Color lightness of insects is an important ecological trait affecting their performance through multiple functions such as thermoregulation, UV protection and disease resistance. The geographical pattern of color lightness in diurnal insects are relatively well understood and largely driven by thermal melanism through the enhancement of insect activity. In nocturnal insects, however, the ecological function of color lightness in response to climatic factors is poorly understood, particularly at small spatial scales. In this study, we investigated color lightness of nocturnal moth assemblages along environmental gradients. Using geometrid moths collected with comparable methodologies (light trapping), we examined assemblage-level changes in color lightness across elevational gradients and vertical strata (canopy vs understory) across three climatically different locations in Yunnan, China. The results showed that moths are darker in color at higher elevations. Such patterns are most apparent in canopy assemblages. In addition, the strength of the elevational pattern on color lightness varied across location, being most pronounced in the canopy of the subalpine site. These patterns are likely driven by UV protection and/or thermoregulation. Our study highlights the importance of abiotic factors such as temperature and solar radiation in structuring morphological patterns of nocturnal ectothermic assemblages along elevational gradients of climatically harsh environments.
KeywordsMorphology Solar radiation Temperature Nocturnal Insect
We thank Gray Williams, Jacintha Ellers and Richard Saunders, and three anonymous referees for valuable comments on the manuscript. Discussions with Evan Pickett and Toby Tsang also improved the statistical analyses. This research was supported by the Queensland/Chinese Academy of Sciences Biotechnology Fund (GJHZ1130). SX and TCB were supported by the Research Grants Council (GRF 17152316) of Hong Kong, ZS by the Applied Fundamental Research Foundation of Yunnan Province (2013FB079) and AN by the National Natural Science Foundation of China General Program (31770472), and the CAS 135 Programs (2017XTBG-T01 and 2017XTBG-F01).
Author contribution statement
SX and RLK originally conceived the idea. RLK, LAA, AN, TCB and SX developed the methodology. LAA, RLK, MC, ZS and AN collected the field data and specimens. SX and JCH conducted the morphological analysis. SX performed the statistical analysis. SX and AN wrote the manuscript; other authors provided editorial advice.
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