BIOL 3P64 Lecture Notes - Lecture 10: Entomophily, Anemophily, Hoverfly
5 May 2018
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• Pollination
o Pollinating insects are estimated to be worth at least 8 billion dollars annually
o Dozens of species of Diptera, Syrphidae and Hymenoptera inadvertently transfer pollen
from one flower to another as they gather nectar to feed themselves and their yound
o Insect pollination is important especially when outcrossing using wind pollination woud
be too inefficient
o Success of angiosperms (flowering plants) depend on mutualism with insects
o Diversity of insects depend on mutualism with angiosperms
o Pollination- transfer of pollen from the male anther to the female stigma
o
o Sexual reproduction produces variable offspring upon whch natural selection can act
• Monoecious vs. Dioecious
o If both male and female flowers live on one plant it is called monoecious
o Plants with make and female flowers borne on separate plabts are termed dioecious
• Self Pollination
o Mant flowering plants have perfect flowers
▪ Both male and female oarts on the same individual flower
▪ They may self pollinate
▪ Transfer pollen from the anther to stigma within the same flower
• Cross Pollination
o More desirable for a plant to have imperfect flowers
o A unisex flower (has stamens and no carpels or has carpels and no stamens)
o Make and female parrs on separate individual flowers
o Sexual reproduction is most advantageus if an organusms mates with an individual
other than itself
o This pricess is called outcrossing or cross pollination
• Outcrossing vs. Selfing
o Many flowering plants have evolved special wats to promote outcrossing or cross
pollination and prevent selfcrissing or self pollination
o Stamens and carpels mature at different times (even if monoecious)
o Foral structural arrangement is configured to reduce the chance that pollinators will
transfdter pollen from anthers to the stigma or the same flower
o Be self incompatible
▪ Can recognize its own pollen and reject it
▪ The rejection of pollen by the stigma of the sma eplant
▪ However, imperfect flowers are the BEST method that plants use to promote
outcrossing
• For insect pollination, plants must
o 1) supply some reward, frequently food for the insect pollinator
find more resources at oneclass.com
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o 2) advertise the presence of the reward to attract isect visitors
o 3) have a way of putting pollen on the pollinator so it is transfterred to the next
plant/flower
o
• Passive Pollination
o Passive pollination by those insects that are generalist nectar feeders
o Not adapted to collect pollen
o Maybe plant adaptations to help facilliate pollen attachments
▪ Sticky pollen
o This is ACCIDENTAL pollination
o Passive Pollen Transfer
▪
▪ Some plants have not co-evoled with a specific pollinator but are visited by a
wide variety of insects
▪
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
In tubular flowers with porcidal antehrs, pollen is released through pores on the end of the anther (found in blueberries and relatives) ; when the anthers are shaken or agitated by an insect, they release pollen. Flower odour flower shapenectar/pollen broad landing platform" yes tubular yes sweet strong. The pollinium releases its pollen on the next flower of the sma especies that the bee visits: orchids as extreme examples, some orchids mimic females, pseudocopulation occurs, flower looks" like a female, males try to mate but fail. Pollen is deposited on them: some orchids mimic hosts, pseudoparasitism occurs, parasitic insects land thinking it"s a host. Pollen attached: some orchids mimc insects, pseudoantagonism occurs. Insect attacks flower thnink it is a threat. Insects that lay their egges in or on other insects: braconid wasp. Apanteles sp: the adult wasp inserts its eggs beneath the eggs beneath the skin of the hornworm larva.
