lecture 27

Question 1

principles of diseases

Answer 1

natural selection favours colonies that have mechanisms for resistance and pest and pathogens that do not kill host

• mechanisms for persistence of disease: transmission between hosts and ability to survive unfavourable conditions
• during spring, colony is most susceptible because: worker population is smallest and stored pollen is low quality and old and worker bees are old and low protein in body
• stress is greatest

Question 2

american foulbrood

Answer 2

greasy sucked appearance of cell caps and holes chewed into caps
ropiness test: diseased material will stretch out 1.5 cm before it snaps (do test last because destroys other symptoms)
-check under microscope
- pupae hardens into persistent scales stick to cell walls because bees can get rid of infected tissue
-easily spread

Question 3

solutions for AFB

Answer 3

1) burn all frames and combs
2) antibiotics– icing sugar mixed with oxytetracycline but destroys beneficial bacteria in guts and selects for antibiotic resistant AFB bacteria
3) hygienic bees- uncapping of diseased cells and removal of infected tissues – resistance to AFB
4) propolis is antibacterial

Question 4

european foulbrood

Answer 4

infects young larvae and increases chemical begging for food

• worker bees detect and remove them
• easily overcome in spring

Question 5

Varroa mite

Answer 5

Varroa destructor is an external mite

• female detects pheromone from larvae and hides in cell to be sealed and then feeds on pupa and reproduces
• prefer drone pupae
• reduces weight of bees and shortens life span
• drones have reduced sperm count an flight ability and orientation ability
• transfer viruses

Question 6

history of Varroa mite

Answer 6

native host is apis cerana that infect drones but never caused damage.
apis mallifera colonies brought to easter russia where A. cerana were.
the colonies did very well so returned apis mellifera to western russia along with varroa mites that switched host
Therefore new parasite/ host relationship: lacked resistance

Question 7

solutions for varroa

Answer 7

• miticides: mites evolve resistance quickly and have incest mating therefore increases resistance quickly
• temporary solutions
• contaminates honey, and harm bees
• bee breeding is a long term solution - select mite resistance bees
• many bees have traits that have partial resistance: hygienic behaviour, physiological traits of bees that cause mite reproduction to fail/ be reduced, duration of pupal stage being more rapid, immune system of bee that can neutralize viruses

Question 8

DWV

Answer 8

deformed wing virus – virus transferred from adult bees and larvae by mites