For
my blog this week the focus will be on a coevolutionary relationship that could
date back to the Eocene epoch, 40 million years ago! It is also a major model system for the study
of coevolving species interactions.
The
yucca moth and yucca plant share an obligate mutualistic relationship, meaning
that both organisms depend entirely on each other for survival. Yucca moths provide
an important pollination service to the plant. In return, as well as providing
a meal in seeds for the moth larvae, the plant allows with moth to lay its eggs
in a deep place within the flower so that they are protected from predators
(Pellmyr & Leebens-Mack, 1999).
Before a female moth lays her eggs she collects
pollen from a flower; to do this she must scrape pollen from the anthers of the
flower with specialised mouth parts and packs it into a ball, securing it under
her head. After that she flies to another flower and climbs to the deepest part
of the flower, opens a hole in the ovary and lays her eggs inside the ovary of
the flower. She then climbs to the flowers’ stigma, retrieves the ball of
pollen that she collected earlier and packs it into the tiny depressions that
are within the style. Interestingly, before she moves on to a different flower,
she marks it with a pheromone to notify any other moths that she has already
laid her eggs here. This is done because if too many eggs are laid in the
flower, the plant itself will abort the flower.
Both
organisms show coadapted traits; mediated pollinator specificity due to structural
adaptations in the flower; and specific behaviours for collection and
deposition of pollen in the moth.
References:
Pellmyr, O.,
Leebens-Mack, J. 1999. Forty million years of mutualism: Evidence for Eocene
origin of the yucca-yucca moth association. Proc.
Natl. Acad. Sci. USA, 96(16), 9178-1983.
Image sourced
5/5/14:
That is amazing! It is so incredible to think that these two organisms are so dependent on each other! Does the yucca plant produce an over-abundance of seeds to counter those lost to predation by the moth larvae? It is fascinating that this seemingly costly behaviour would have evolved in the plant, and I was wondering if this has to do with the likelihood of successful pollination by the moth. Is there any evidence of pollination success rates in this system? Very cool!
ReplyDeletethey are both stuck in this system
ReplyDeleteif the plan is not good to the moth the next season it will have no pollinator
if the moth eats too much there will be no plants for its kids to eat
loss of one will kill both