Insect Pollinators

Plant Reproduction

• Asexual reproduction

  • Genetic copies of the parent

• Sexual Reproduction

• Genetic information from both parents produces a unique individual

Pollination

• Transfer from male flower structure to female flower structure

• Can be done through wind, water, or animals like birds, bats, and insects

Pollination and Fertilization

• Pollen grain is deposited on the stigma

• Pollen tube grows down style to the ovary

• A sperm nucleus from pollen grain unites with an egg inside the ovary

• Each fertilized egg in the flower’s ovary is a seed

• Ovary may enlarge and become fruit

Flower Constancy

• Tendency for a pollinator to visit flowers of the same species on a foraging trip

• Plants have an increased chance of receiving pollen from a member of their own species

Dioecious Plants

• Each flower has only male or only female parts

• Male flowers on some plants and female flowers on other plants so have male and female plants

• Ex: marijuana plant, holly plant, etc.

Monoecious Plants

• Each flower has only male or only female parts

• Each plant has both male and female flowers on it

• Ex: black walnut, corn, etc.

Hermaphroditic Plants

• Each flower has both male and female components

• This is, by far the most common situation

• Occurs in 95% of flowering plants

Wind-Pollinated Plants

• Pollen is small and dry

• Flowers

  • Not colorful

  • Often without petals

  • Lack odor

  • Lack nectar

  • Frequently are pendulous

• Ex: ragweed, oak flowers

• Crops

  • Corn

  • Wheat

  • Oats

  • Rice

  • Barley

  • Hops

  • Walnuts

  • Pecans

Animal-Pollinated Plants

• Pollen is sticky and rough

• Flowers usually colorful with developed petals

• Have odors

• Different odors and colors depending on the pollinator

• Benefits

  • Animals get nectar

  • Pollen gets protein and fat

Deceit Pollination

• Flower offers no pollination reward, but lures pollinators in by deceiving them

• Ex: orchid species lure in male bees and wasps

Hummingbird-Pollinated Flowers

• Good eyesight

  • Flowers are bright orange or red

• Poor sense of smell

  • Flowers have little or no odor

• Tube-shaped flowers with deeply hidden nectar to make sure head gets dusted with pollen

• In the tropics, other birds are pollinators too

Bat-Pollinators Flowers

• Nocturnal Animals

  • Flowers: large and white so visible

  • Open only at night

• Good sense of smell

  • Flowers have fruity, fermenting, or musky odor

• Pollinate 300 species of fruit, some cacti, agave