Yucca–Moth Mutualism
These insects are the obligate pollinators of Yucca plants.
Yucca moths
What is the term for species that benefit from a mutualism without providing the expected service, as seen in some yucca moths?
Cheaters
Approximately what fraction of the estimated 18,500 orchid species are thought to be pollinated by deceit?
One third
Define 'autogamy'
A form of self-pollination where a flower is fertilized by pollen from the same flower.
Yucca moth larvae feed on what part of the yucca plant—yet still leave enough intact for the plant to benefit overall?
The seeds
A burst of yucca moth diversification around 3.2 Mya coincided with environmental changes in North America. What major habitat shift occurred then?
Evolution of arid/desert habitats
In sexually deceptive orchids, which type of sensory signal is of primary importance for attracting pollinators?
Floral odor signals
What is Gst?
A measure of population differentiation that ranges from zero to one.
What type of interaction is the yucca–moth relationship classified as?
Obligate mutualism
Cheater yucca moths evolved from pollinating ancestors. About how long ago did these cheater lineages arise?
About 1.26 million years ago
How do mean Gst values compare between rewarding and deceptive orchid populations?
Rewarding orchids have significantly higher mean Gst values, meaning there's less gene flow among their populations compared to deceptive orchids.
A gene that has a large effect on one trait and also affects the expression of other traits is an example of _____.
Pleiotropy
The yucca-yucca moth mutualism originated around this geologic epoch?
The Eocene
This key behavior evolved rapidly—within ~0–6 million years after moths first colonized yuccas.
Pollination behavior
How does pollinator behavior typically differ between patches of rewarding and deceptive orchids?
Pollinators in rewarding patches visit neighboring plants, while pollinators visiting deceptive orchids often leave the patch immediately.
What is sexual deceit?
A pollination strategy where flowers mimic mating signals of female insects and are pollinated by deceived males while they attempt to copulate with the flower.
What is the approximate age (in millions of years) by which yucca moths had colonized yuccas, according to the molecular clock?
About 41.5 million years ago
What genetic region within the mitochondrial DNA was used to build the molecular clock?
COI-COII genes
What is 'pollination by deceit' in the context of orchids?
The plant attracts pollinators using signals typically associated with a reward (like nectar) but provides no actual reward.
The unique process in which an orchid flower rotates 180 degrees just before opening is called ____.
Resupination