Avian predators avoid attacking artificial aposematic millipedes in Brazilian Atlantic Forest

Abstract

Abstract:Avian predators may represent an important selective pressure favouring the evolution of aposematic colouration in millipedes that present chemical defences. However, the role of their warning colouration in predator avoidance remains poorly explored under field conditions, especially in Neotropical forests. Thus, to evaluate the hypothesis of the predator avoidance, we conducted a factorial experiment utilizing artificial replicas of millipedes constructed from plasticine and placed in the natural habitat of Odontopeltis aleijadinho (Polydesmida, Chelodesmidae), an Atlantic Forest endemic aposematic millipede. We assessed patterns of attack to aposematic and non-aposematic replicas applied with repugnant fluid extracted from living millipedes and two control treatments, distributed as a total of 300 replicas exposed for 48 h on the forest floor. The average percentage of replicas attacked was nearly 10-fold higher on those non-aposematic control replicas (13.3% ± 3.3%) than on aposematic replicas (1.3% ± 0.9%). In 24 replicas attacked by avian predators, no effect of millipede repugnant fluid was found, but the effect of colouration pattern was statistically significant. Our data support the hypothesis that a warning colouration pattern involving yellow spots symmetrically distributed along the millipede body can mediate avian predator avoidance.

Too hard to swallow: A secret secondary defence of an aposematic insect

“…In addition to lizard (reptilian) predation, avian and mammalian predation constitute the other two major selective forces on tropical insects with aposematic or cryptic colouration (Mappes et al, 2014;Roslin et al, 2017). Avian predation is likely to be essential for the evolution of aposematism and defence strategies in Pachyrhynchus weevils because, in general, birds possess a wide range of colour spectra (Bennett and Théry, 2007), and they are primary predators of aposematic insects (Iniesta et al, 2017). In the Green and Orchid Islands, there are approximately 62 bird species that eat insects as part of their diets (Chen et al, 2008;Li et al, 2010;Severinghaus et al, 2012) (Table S3).…”

Effects of reflective warning markers on wildlife

“…White-bellied pheasants were the only species that showed no avoidance response in the RWM groups during daytime. Red colored RWMs can increase visual stimulation in a manner similar to the alert color of insects (Stevens, 2007; Iniesta, Ratton & Guerra, 2017). A bird-repelling device has invented and functions effectively by using a red material that reflects light in an intermittent pattern (Doty III, Turkewitz & Byers, 2003).…”

“…The materials used in RWMs are not self-luminous and directs people with conspicuous colors in the daytime and by reflection at night. Conspicuous colors, such as red, are commonly considered to be aposematic, or natural warning signals, and are used by insects and birds to signal their undesirability to potential predators (Stevens, 2007; Myczko et al, 2015; Iniesta, Ratton & Guerra, 2017). Although the intensity of reflected light at nighttime is low intensity but noticeable, it is still regarded as a special source of light pollution (defined as secondary light pollution).…”

Peer Review #4 of "Effects of reflective warning markers on wildlife (v0.2)"

“…White-bellied pheasants were the only species that showed no avoidance response in the RWM groups during daytime. Red colored RWMs can increase visual stimulation in a manner similar to the alert color of insects (Stevens, 2007;Iniesta, 2017). A bird-repelling device has invented and functions effectively by using a red material that reflects light in an intermittent pattern (Doty et al, 2003).…”

“…The materials used in RWMs are not self-luminous and directs people with conspicuous colors in the daytime and by reflection at night. Conspicuous colors, such as red, are commonly considered to be aposematic, or natural warning signals, and are used by insects and birds to signal their undesirability to potential predators (Stevens, 2007, Myczko et al, 2015, Iniesta et al, 2017. Although the intensity of reflected light at nighttime is low intensity but noticeable, it is still regarded as a special source of light pollution (defined as secondary light pollution).…”