Capacity for heat absorption by the wings of the butterfly Tirumala limniace (Cramer)

Huaijian Liao; Ting Du; Yuqi Zhang; Lei Shi; Xiyu Huai; Chengli Zhou; Jiang Deng

doi:10.7717/peerj.6648

Capacity for heat absorption by the wings of the butterfly Tirumala limniace (Cramer)

PeerJ. 2019 Mar 25:7:e6648. doi: 10.7717/peerj.6648. eCollection 2019.

Authors

Huaijian Liao^{1

2}, Ting Du¹, Yuqi Zhang³, Lei Shi¹, Xiyu Huai¹, Chengli Zhou¹, Jiang Deng¹

Affiliations

¹ Research Institute of Resources Insects, Chinese Academy of Forestry, Kunming, Yunnan, People's Republic of China.
² Institute of Leisure Agriculture, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, People's Republic of China.
³ College of Life Science, Southwest Forestry University, Kunming, Yunnan, People's Republic of China.

Abstract

Butterflies can directly absorb heat from the sun via their wings to facilitate autonomous flight. However, how is the heat absorbed by the butterfly from sunlight stored and transmitted in the wing? The answer to this scientific question remains unclear. The butterfly Tirumala limniace (Cramer) is a typical heat absorption insect, and its wing surface color is only composed of light and dark colors. Thus, in this study, we measured a number of wing traits relevant for heat absorption including the thoracic temperature at different light intensities and wing opening angles, the thoracic temperature of butterflies with only one right fore wing or one right hind wing; In addition, the spectral reflectance of the wing surfaces, the thoracic temperature of butterflies with the scales removed or present in light or dark areas, and the real-time changes in heat absorption by the wing surfaces with temperature were also measured. We found that high intensity light (600-60,000 lx) allowed the butterflies to absorb more heat and 60-90° was the optimal angle for heat absorption. The heat absorption capacity was stronger in the fore wings than the hind wings. Dark areas on the wing surfaces were heat absorption areas. The dark areas in the lower region of the fore wing surface and the inside region of the hind wing surface were heat storage areas. Heat was transferred from the heat storage areas to the wing base through the veins near the heat storage areas of the fore and hind wings.

Keywords: Heat absorption; Heat absorption area; Heat storage; Heat transfer; Tirumala limniace; Wing.

Grants and funding

This study was sponsored by the National Natural Science Foundation of China (NSFC 31702072), the Fundamental Research Funds for the Central Non-profit Research Institution of CAF (CAFYBB2017QA012), and the Special Fund for Forest Scientific Research in the Public Welfare of China (201504305). There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.