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The role of flourescence and ultraviolet rays reflection on prey attraction by spiders

Grant number: 19/06244-5
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): June 01, 2019
Effective date (End): May 31, 2021
Field of knowledge:Biological Sciences - Ecology
Principal Investigator:João Vasconcellos Neto
Grantee:Yuri Fanchini Messas
Home Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil


Understand the functional significance of animal color patterns is one of the central themes in evolutionary ecologists' research. The order Araneae is widely used in studies on animal coloration given that it is a megadiverse and ubiquitous group, with several coloration patterns. The prey attraction hypothesis predicts that some spider species attract their prey by reflecting ultraviolet (UV) wavelength rays and mimic the reflectance spectrum of sympatric flowers. However, recent studies demonstrated that some spiders that attract their prey also fluoresce. Our aim is to investigate separately the role of UV reflection and fluorescence on orb-weaver spiders. We will conduct the study in an Atlantic Forest fragment located in the Serra do Japi (Jundiaí, SP). We will use chemical elements, as well as photography techniques, spectrophotometry and fluorimetry to create models with the same spectral characteristics of Gasteracantha cancriformis, chosen for its ability to both fluoresce and reflect UV. We will conduct field experiments in different periods of the day, containing sticky traps distributed in five treatments: without spider (control for spider presence); with non-reflective spiders (control for spectral characteristics); with UV reflective spiders; flourescent spiders; and spiders with both spectral properties (UV + fluorescence). After analyzing the insects captured by the traps, we will perform mixed model analyzes for each response variable (prey abundance and distance between the prey's interception point and the trap center) to test our hypothesis.