BIOMI 3310 Lecture Notes - Lecture 21: Flea, Proventriculus, Rodent
28 Apr 2018
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Lecture 21 – Siphonaptera (Fleas)
Siphonaptera: fleas
• Continuous plague to people
• Two major kinds of infestations:
o Take a blood-meal from their host (most common)
o Embed themselves in their host for extended periods
• Three Groups:
o Sedentary fleas, which live in the nest of their hosts
o Mobile fleas, which require a nest but can also live on the host
o Stick-tight fleas that attach themselves to the host
• Holometabolous (undergo complete metamorphosis: larva → pupa → adult)
• Laterally compressed
• Found only on birds and mammals
• Morphology
o Head is ~ the same height as the 3 thoracic segments.
• Each side of the head has an eye and an antenna (lays in the antennal groove).
o Each thoracic segment has a pair of legs.
• The last pair of legs is adapted for jumping.
o Abdomen = 10 segments
• Contains reproductive structures
o Genal and Pronotal Combs: thickened, teeth-like hairs on the cheek and 1st thoracic
segment
• Used in flea identification
• Unique to a few groups of insects that have an intimate association with the fur
of the host
o Mouthparts: blades and cutting structures
• When a hole is cut in the skin, the flea begins to pump blood into the pharynx.
• Blood passes through the buccal cavity and esophagus to enter the
proventriculus, which has long chitinous teeth that break up the red blood cells
before they enter the stomach.
▪ The ventriculus plays an important role in the transmission of plague by
infected fleas.
• The majority of flea species are associated with mammal hosts.
o ~74% of species are recorded from rodents
o Various rodent fleas are significant in human medicine because they transmit diseases
from animals to humans.
• Life Cycle
o Female lays an egg (~0.5 mm long, ovoid, glistening white - similar to a chicken egg)
o Eggs fall off the host, onto the carpet/soil/nest.
o Fleas of birds and some rodents live in nest materials and will climb onto the host to
feed. Fleas of humans, dogs, and cats prefer to stay on their host.
o After the egg has been in the environment for several days to a week, a larva will
hatch.
• Larva = small, legless, caterpillar-like creature
• Feeds on organic debris and the dried blood that has been passed in the feces of
the adults
