Striking similarity of predation pressures across Heliconius
species and populations
Our results of predator attacks on Heliconius models correspond
to the attack patterns observed in mark-release-recapture experiments,
where naïve predators significantly attack novel, exotic patterns
relative to native, common warning patterns
(Mallet and Barton,
1989; Langham, 2004). As may be expected, attacks of live prey showed
much greater differences for exotic and native morphs (36-37% versus
0%, respectively), than we observed with artificial models (5-11.5%
versus 4-6.5%, respectively; see Figure 3). This difference between
model and live prey experiments likely results from the inability of
models to replicate physical and behavioral cues recognized by potential
predators (i.e. crawling, wing flapping, flight). Although the attack
numbers on models likely do not reflect realized predation rates of live
butterflies, they do provide reliable means to compare relative
predation pressures due to differences in visual cues.
Importantly, there is a remarkable similarity in attacks ofHeliconius models in studies that span a variety of species and
geographic locations over the past decade
(Arias
et al., 2016; Chouteau et al., 2016; Finkbeiner et al., 2012; Finkbeiner
et al., 2014; Finkbeiner et al., 2018; Merrill et al., 2012; Seymoure et
al., 2018). Attack percentages in these studies range from 4-15%,
which overlaps our observed attack percentages that ranged from 4-12%
on H. doris morphs. This consistency in attacks of models
may reflect the similarity in avian predation pressures amongHeliconius species and populations. The Rufous Tailed Jacamar
(Galbula ruficauda ) has been reported as a common predator ofHeliconius in western South America
(Mallet & Barton, 1989) and
Central America
(Dell’aglio et al.,
2016; Langham, 2004). In line with these reports, we observed a Rufous
Tailed Jacamar successfully attack a Heliconius (likelyHeliconius sara ) at one of our inland experimental sites in
French Guiana. Collectively, this supports that Jacamars may be a common
predator driving similar attack rates in the various Heliconiusmodel experiments. Therefore, we can make direct comparisons among these
studies and general inferences about the relative effectiveness of
specific aposematic color patterns and corresponding selective
pressures.