Impact of ambient humidity on traction forces in ladybird beetles (Coccinella septempunctata)

Lars Heepe*, Jonas O. Wolff, Stanislav N. Gorb

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

Many insects possess hairy adhesive foot pads, supplemented with a tarsal secretion, which allow them to securely and reversibly attach to various kinds of natural substrates, also under complex environmental conditions. Conditions such as ambient temperature and humidity have been shown to influence the attachment ability of the dry adhesive foot pads in spiders and geckos. For insects, however, the influence of the environment on attachment ability is lacking. In the present study, we therefore studied the attachment ability of the seven-spotted ladybird beetle (Coccinella septempunctata) at different humidities by traction force experiments. Our results indicate an optimal range of relative humidity with maximal traction forces. At both low (15%) and high (99%) relative humidity a decrease of attachment ability was found. At 60% humidity, the highest attachment forces were revealed. This relationship was found both in female and male beetles, despite of a deviating structure of adhesive setae and a significant difference in forces between sexes. These findings demonstrate that humidity similarly affects the function of both dry and wet adhesive pads, although both types of adhesive systems (wet and dry) are supposed to be based on different physical interactions (capillarity versus van der Waals forces).

Original languageEnglish
Title of host publicationBio-inspired structured adhesives
Subtitle of host publicationbiological prototypes, fabrication, tribological properties, contact mechanics, and novel concepts
EditorsLars Heepe, Longjian Xue, Stanislav N. Gorb
Place of PublicationCham, Switzerland
PublisherSpringer, Springer Nature
Chapter2
Pages21-32
Number of pages12
ISBN (Electronic)9783319591148
ISBN (Print)9783319591131
DOIs
Publication statusPublished - 2017

Publication series

NameBiologically-Inspired Systems
PublisherSpringer
Volume9
ISSN (Print)2211-0593
ISSN (Electronic)2211-0607

Bibliographical note

Previously published by Heepe, Wolff, and Gorb (2016) "Influence of ambient humidity on the attachment ability of ladybird beetles (Coccinella septempunctata)" in Beilstein Journal of Nanotechnology, Vol. 7, pp. 1322-1329. http://dx.doi.org/10.3762/bjnano.7.123.

Cite this

Heepe, L., Wolff, J. O., & Gorb, S. N. (2017). Impact of ambient humidity on traction forces in ladybird beetles (Coccinella septempunctata). In L. Heepe, L. Xue, & S. N. Gorb (Eds.), Bio-inspired structured adhesives: biological prototypes, fabrication, tribological properties, contact mechanics, and novel concepts (pp. 21-32). (Biologically-Inspired Systems; Vol. 9). Cham, Switzerland: Springer, Springer Nature. https://doi.org/10.1007/978-3-319-59114-8_2