VL 8 Flashcards
What are biotic and abiotic pollination agents?
Biotic: insects, birds, mammal
Abiotic: wind, water
What are examples of crops that have wind pollination (Anemophily)?
Many staple crops
Grasses (Poaeae): Maize, Rice, Wheat, Barley, Millet
Juglandaceae: Walnut, Pecan
What are the 10 most important animal pollinators of the most important 101 food crops?
- Bees
- Honeybees
- Flies
- Beetles
- Hummingbirds
- Wasps
- Thrips
- Moths
- Bats
- Ants
Bees
Most important grpuo of pollinators
~20k species worldwide
Social bees: Honeybees, bumblebees, stingless bees
solitary bees: no queen, no hive
Life stages
Larvae: mostly pollen feeding
Adults: mostly nectar feeding
Hoverflies
Important pollinators
About 6000 species worldwide
Some species have predatory larvae: pest control
Others have herbivorous, detritivorous larvae
Important to IPM systems
Other Diptera
Other flies can also pollinate crops and wildflowers
Bombylidae (bee flies)
Ceratopogonidae (e.g. cocoa midges, ca. 1-3 mm)
Varied lifestyles and requirements
What are threats to insect pollinators?
Climate change & weather events
Competition
Invasive & Exotic species
Habitat loss / land use change
Nutrition
Nectar and Pollen toxins
Parasite & disease
Pesticides
Parasites in bees
Bees naturally suffer from broad range of parasites, parasitoids and pathogens, the latter including protozoans, fungi, bacteria and virus
The mite Varroa destructor originally associated with the Asian honeybee Apis cerana is now a parasite of the honeybee
Varroa has since jumped hosts to the European honeybee Apis mellifera, which has little resistance to this pest
The mite acts as a vector for pathogens such as deformed wing virus (DWV) and the combined effect of the mite and the diseases it transmits is a major contributor to honeybee colony losses in North America and Europe
Fortunately, the mite appears unable to survive on bees outside the genus Apis, but in fact very little is known about the pathogens of other wild bee species
What is the importance of pesticides in regard of pollinators?
Neonicotinoids banned in Europe - these are neurotoxins that target the insect central nervous system leading to lethal and sublethal effects
they have been found at biologically relevant concentrations in the pollen and nectar of wildflowers near crops because despite their water solubility they are highly persistent in soil and soil water
Herbicides that are highly effective at minimizing weed problems in most cropping systems, enable farmers to grow near-pure monocultures, but their use inevitably reduces the availability of flowers for pollinators and can contribute substantially to rendering farmland and inhospitable environment for bees
Colony Collapse Disorder (CCD)
Sudden loss of a colony’s worker bee population with very few dead bees found near colony
Queen and brood (young) remained and the colonies had relatively abundant honey and pollen reserves. Hives cannot sustain themselves without worker bees and would eventually die
CCD has affected mainly honeybees as well as bumblebees. Yet it is difficult to assess the actual number of bees lost because of CCD, especially among wild bees
S. 38
P. 38
in general look at lecture slides
