Natural Selection: experimental evidence
Do Tephritid flies mimic jumping spiders?
Zonosemata
Coevolution
• Two or more species.• Change in one species serves as a selector for
change in the other species.• Interplay of changing gene frequencies.• Parallel evolutionary paths.
Models of coevolution
Phylogenies of coevolving species1. Perfect congruence between mutualistic species
tryptophan
2. Partial congruence between hosts and parasites
A famous Müllerian mimicrycomplex.
Each species withsubspecies defined bycolor pattern and geography.
What happens at subspecificboundaries?
Micrurus eryxanthus: Western coral snakeAposematic colorationProblem: how established?
A mimetic system
Batesian and MüllerianMimicry
Aposematic coloration
Parallel geographic variation
Micrurus 6 species. Highly venomousFixed front fangsNeotropicalElapidae
Pliocercus 1 or 2 species.Mildly venomousFixed rear fangsColubridae
Does aposematic coloration work?Plasticine models
Forest floor: on white paper and on forest floor
Experiment carried outin natural habitat
Resemblance does nothave to be perfect to confer protection
Significantdifferences
• Is avoidance of aposematic coloration innate?
• Naïve motmots (Neotropical birds)
• Caged birds presented with:
– 1. coral snake models
– 2. models of natural prey species.