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Exploiters and Exploited
Term 1
Week 1 - Bee's
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A Honey bee is any member of the genus Apis
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Western Honey Bee - A
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mellifera originated in Africa and colonised
Europe twice, once giving rise to mellifera subspecies and the other giving rise to carnica and
ligustica
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Drone - 1000 per colony, Drones are ejected from the
colony during the autumn
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Colony life cycle - larvae, pupae, adult emerges
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Exploitation of bees - Honey hunting, provision of
nest building spaces, forest beekeeping, simple
hives, skeps, rational hives with moveable frames
- Hives - lots of experimentation to make a
durable, inexpensive hive with moveable frames,
A modular hive of tiered boxes (by 1649) 2
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Parallel top bars mimicking
natural comb spacing (by 1683) 4
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Moving
frame away from wall, so it can be removed 6
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Pollination - worth $2bn/year, Honey bees are generalist pollinators, Small – do not forage in
cold weather or rain, Find it difficult to physically pollinate some plants, e
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Alfalfa, Relatively
short tongued
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Bees spread - 300-500km/year
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With
killer Bee's causes problems - more aggressive, more attacks - 400 fatalities, produce little
honey, bee-keeping industry collapsed
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Varroa destructor - parasitic mite, ectoparasite, flattened, can fit between bee's abdominal
plates
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jacobsoni originally parasitized the Asiatic honey bee Apis
cerana
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mellifera where the two bees were in close contact - USSR,
philippines
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Control by monitoring, comb trapping, forcing an artficial swarm into a clean hive,
drone blood collecting
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Must be able to cope with – High temperature
32–37oC – Low relative humidity 40–50%
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Cerana - A
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Mellifera, A
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cerana can detect mites, uncap brood cells and kill them, A
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Week 2 - Sugar Cane
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Sugar - 4 types of sugar - jaggery, granulated, spun and rock
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Modern sugar industry - Global expansion of colonial powers creates
economic opportunity for tropical crops (tea, sugar, coffee)
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Recent realignment of sugar cane towards renewable energy
production
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Slash and burn gave only
temporary good yields, Perennial; needs feeding for ratoon crops, Thirsty – irrigation or
consistent rain supply for best growth
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Required
huge labour input in very hard conditions, Cost of labour too great; indentured labour didn’t
work, So slaves were used – the ‘triangular trade' - slaves to america -> sugar/tobacco/cotton
to europe -> textiles/rum and goods to africa -> slaves etc
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Attributes - stem storage of sucrose, rapid
perennial growth - C4 Photosynthesis
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Stem storage of
sucrose is unusual - most store starch instead, Sucrose storage requires specialized
accumulation apparatus - Internodes of stem, Vacuoles of parenchyma cells, Pathway – leaf
(sucrose) – phloem – apoplast – cytoplasm (as glucose/fructose) – vacuole (sucrosephosphate), Energy requiring
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Sugar cane – 1% of
sunlight used; 1/5th of this converted to dry matter
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25 tonnes/ha/year wheat in UK) C4 photosynthesis
optimizes dry matter production in high light/high temperature environment of tropics
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Becomes really prominent 5-7 million years ago when CO2 declined to current level
(350 ul/l)
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Bioethanol from sugar - see picture
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Endopterygpte
insects - complete metamorphosis
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Larval mouthparts - well developed silk gland - modified salivary gland through
labium, 3 segmented antennae, 6 ocelli
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Sericulture - production of cocoons for silk reeling, production of eggs, food plant production
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Egg production - Univoltine – 1 generation per year – Eggs hibernate autumn/winter, Bivoltine
– 2nd generation in autumn, Multivoltine – Tropical, poorer quality silk
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High
tensile strength, Elasticity, Drapes well, Size, weight, Warmth, Difficult to burn, Absorbs water,
Dye affinity, Does not rot
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White mulberry - morus alba, native of china
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Black mulberry - more cold-tolerant, known to greeks and
romans
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Prune using low cutting method
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Spread from Asia to Europe around 4th century
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America - Silk fever in 1820s, M
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Beauveria bassiana - Very wide host range, First infection of a pest species 1899, Strains for Corn borers, Homoptera, Thrips, Coleoptera
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1849 infected areas 1859: Recommended that eggs be destroyed in infected areas
1865: Pasteur recommends acceptance of this method 1865–7: Pasteur believed that Pébrine
caused by a physiological defect in the larvae, corpuscles just a symptom
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1866:
Pasteur isolates a non-corpuscular disease: – larvae become flabby, and weak ,1870:
Concluded that it was an accumulation of two bacteria species in the gut, spread by
contaminated excrement, Now thought that the bacteria are secondary invaders after virus
attack
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Terrestrial - Continents separate, Clear boundaries, Air – allows structural
complexity in vegetation, Photosynthesis by trees (etc), Complexity of vegetation increases
variety of physical environments in which animals live
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Biodiversity - the variety of living forms with which we share this planet
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Life originated in the
oceans – and the oceans therefore contain a greater variety of animal forms – 28 phyla,
including sponges, crustaceans, molluscs
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But
there is less variety at the species level in most ocean habitats – of the 1
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Most of these live on or close to the bottom in
shallow water
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Low ocean biodiversity - Copepods show relatively low species richness (a few thousand
species only), compared with that of, e
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insects on land (hundreds of thousands of species)
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(
Terms - pelagic organisms (not attached) - planktonic (free floating) or nektonic (swimming)
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Fish and invertebrates may use both pelagic and
benthic systems for dispersal
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Great ocean conveyor - Not wind-driven
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This moves north, enhancing Gulf Stream flows, Cools as it
reaches North Atlantic (around Iceland)
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Gradually rises in Pacific/Indian Oceans, recycles back to Atlantic
as surface water
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Takes oxygen down to depth in North Atlantic,
brings nutrient-rich water to surface around Antarctic, Don’t get sinking water in North Pacific
– too much ‘freshening’ from rainfall/ice melt, Freshening of water (by melting of
Arctic/Greenland ice) is making water of North Atlantic less salty
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Could greatly decrease/shut down Great Ocean Conveyor, This may
have been cause of the ‘Little Ice Age’
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Sargasson sea - A complex, nutrient poor ecosystem that teems with life
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The
probable vegetative reproduction-only of the Sargassum suggests that this organism,
however, has not needed to change much over a long period -area between Africa and north
America
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Phytoplankton (not the Sargassum weed or its ecosystem) are the most
important source of primary productivity in the Sargasso Sea
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Cyanobacteria – an important source of primary productivity in the Sargasso Sea
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rostrata)
eels (are believed to) spawn in the Sargasso sea, Japanese
eels (A
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Inhabitants of the sargassum eco-system - Blue-green bacteria – Prochlorococcus marinus,
Synechococcus), Anemones, Hydroids, Sea slugs, Sargassum crab, Sargassum angler fish
(Histrio histrio), Adapted to look like the pelagic Sargassum weed (S
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fluitans),
Also turtles (and eels)
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Root nodule - important in the Nitrogen cycle
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Need for sustainable
production of food - Fossil fuel currently source of H2 for Haber Process (industrial fixation of
nitrogen), This is where inorganic fertilizer comes from, Need to reduce dependence of
agriculture on this, Legumes provide nitrogen by a natural, sustainable process
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Biological N2 fixation - N2 is bound to the nitrogenase enzyme complex
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Reduced Fe protein binds ATP and reduces the
molybdenum-iron protein
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Two further cycles reduce HN=NH to
H2N-NH2, and finally to 2NH3
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The infected cells of the plant
produce leghaemoglobin, which scavenges oxygen and
controls the level of free oxygen, This is important
because oxygen irreversibly inactivates the nitrogenase
enzyme, Nevertheless, allows respiration which is
essential, particularly because of large ATP requirements
of N2 fixation
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Bacteria invade hairs and underlying cortical cells by infection threads; induce division in cells
of plant cortex, Bacteria differentiate into bacteroids; they are confined in symbiosomes
within plant cells, Symbiosome membrane has special channel and transporter proteins, Allow
movement of ammonium out of symbiosome, Allow movement of carbon skeletons (acids,
rather than sugars) to bacteroids to support their metabolism, In the nodule, plant cells
convert ammonium (product of nitrogen-fixation) to amides or ureides for transport to rest of
plant
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Nif genes involved in nitrogen fixation, Located on a
plasmid in Rhizobium, Plasmid of Rhizobium NGR234 now been sequenced
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Domestication - wild lentils and peas, chickpeas, faba beans,
cowpea, soybean, common bean (phaseolus), as part of maize-beans-squash cropping system
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Therefore legumes often add defence compounds to their seeds, e
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Lima beans (Phaseolus
lunatus) – bruising can liberate HCN from a glucoside precursor, Fava beans (Vicia faba) – can
cause anaemia in susceptible individuals
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Legume problem - Managing needs of both plant and bacterium, Evolution of trait in (nutrientpoor) tropical rainforest by arborescent legume ancestors - perennials, Annuality a necessity in
more seasonal climates, But need to re-establish symbiosis anew every year, Therefore annual
beans – e
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Phaseolus vulgaris (common bean) and Glycine max (soybean) - may not meet
their N-requirement through N-fixation
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Rhizobia - α-proteobacteria, Closely related to Agrobacterium, Some species and the plant
genera which host them: Rhizobium leguminosarum – Pisum (pea), Cicer (chickpea), Phaseolus
(bean) Mesorhizobium loti – Lotus (trefoil), Lupinus (lupin)
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Nodulation evolved at least 3 times during evolution of
legumes
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Transferring nitrogen fixation to cereals - 42 million tons of fertilizer applied annually to the
three major cereal crops – wheat, rice and maize
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Environmental damage by nitrogenous fertilizers,
Human disease due to nitrates, nitrites, amines; eutrophication; depletion of stratospheric
ozone due to NO and N2O
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Food production - Ancient civilisations - Old World - pastoral alongside arable agriculture
(domesticated cows, sheep), Population pressure: more efficient to directly consume plants
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New World - Incas, Mayans, Aztecs – no animals domesticated for meat
(apart from guinea pig)
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Green Revolution - Cereals 1960s and
1970s, Great increase in yields - Better partitioning to seed, Dwarfing – less lodging, Disease
resistance, Inorganic fertilisers
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Shoot module - short stemmed wheat gives more efficient cropping
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But this is inefficient and has to change
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Week 6 - Cephalopods
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Cephalopods are molluscs
Molluscs - Phylum Mollusca
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Mollusan radula:
The radula consists of rows of backward-facing teeth embedded in a membranous base, over
the cartilaginous odontophore
Muscles enable the odontophore to move in and out of the mouth, moving the radula, which
can also move against the odontophore
As the odontophore is projected out of the mouth the radula flattens and the teeth are
erected
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g
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g
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Foot is modified for burrowing
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 Cephalopods - 650 species, 7500 fossil species
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o Nautilodea - 2 species
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o Ammonoidea - All extinct, abundance of fossils
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 Subclass Coleoidea:
o Order Belemnoidea - Belemnites, all extinct
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o Differences - Locomotion (Funnel, forward & backwards), Reproduction, Rapid growth, Short
life-span, Daily vertical displacement
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o Oceanic/coastal down to 1000 m, Up to 100,000 eggs in egg masses up to 1 m diameter, hatch
after 9– 16 days, Eggs require 12–22oC to complete development, 12–18 month life cycle,
Maximum mantle length 30 cm
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o Peak squid fishing in the 1980's
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o Fished by using squid jigging - luring squid in using light
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 Fishing crashes - Overfishing
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illecebrosus – 1974: quotas, 1977: separate US & Canadian management
o T
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 Regime shifts:
o North Pacific, Winter 1976–7: Changes in current strength, water stratification, thermal fronts
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from 1
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5oC below
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 Squid fisheries management:
o Squids = marine weeds; Annual, grow very fast, opportunist, no age-class reserves, crash
suddenly
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Dynamic modelling required: Prediction? Environmental conditions?

Week 7 - Grapevine
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Grapevine - vitis vinifera - originated in the Caucasus mountains of eastern Europe
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Exploitation - by 5000BC, sine trading by 1000 BC, great variety of vines by roman times,
modern production for wine, table grapes, raisins etc
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Plant facts - liana or woody vine, adapted for rapid growth
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Perenniallity complicates cultivation, flowers initiated year
before emergence
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Small flowers in
inflorescences, self fertile
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Grapevine climbing - Shoot meristem from young
plant produces leaves and lateral meristems
alternately
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Tendrils grow, grab
and coil, hoisting plant upwards
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How tendrils work - Gives new ideas for spring
design – biomimetics
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g
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Then it
stiffens
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How grapevine flowers - When plant is mature (after 2-5 years), inflorescences form in place
of some tendrils
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Weather (temperature)
has big impact
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Mean temp <10degrees - summers too short, cold winters kill plants
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Grape Phylloxera - A devastating pest of vines
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Destroys vineyards within 3 to 10 years of infection
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Originated in North America, where native vines have tolerance
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Solution was to graft scion cultivars on to phylloxera-resistant rootstocks bred from North
American vine species – V
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riparia, V
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(rootstocks also give other
valuable traits like soil and cold tolerance)
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Vectored
by humans/human activity so strict hygiene and movement restrictions needed

Week 8 - Atlantic Salmon
Atlantic salmon - salmo salar
 Largest Uk salmonidae
 Distribution - north Atlantic
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 Life cycle:
o October - salmon swim upstream, adults assembled in pools close to spawning areas in rivers
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Eggs and sperm
released together
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Nest called a Redd
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o Spring - Alevins are first larval stage, still have yolk sac, feed for weeks on gravel, yolk ac
disappears ad they move t surface of gravel as Fry
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o Smolt - morphological, physiological and behavioural changes
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Moves down rived and into the sea as maturing into smolt
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o Anadromous - moving from freshwater to salt water as they mature
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o After spawning a kelt, drop downstream and may return to breed in 6-18months
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 Drift netting - Irish fishery closed in 2007, limitations on amounts and licensing in UK to stop
over fishing
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Salmon farming:
 Collect brood fish, strip milt and eggs
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 Smolts - indoors, 10m diameter tanks, 20,000 per tank
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 Grow out sites - stocked in spring
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 Feeding - processed commercial feed, white fish, shrimp waste, soymeal, need to feed little
and often
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o Benefits - over 6200 jobs in Scottish aquaculture and another 4700 dependent, worth £400m
to economy
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Sea bed below cages can take 18months to recover
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Originally 20% of food lost, now only 5%
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 Stock escape - 1% escaped from Scottish farms in 2000, about 440,000
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Competition between wild and farmed salmon, farmed more
aggressive but worse at mating and surviving in wild, farmed salmon spawn later, can destroy
redds of wild fish
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Successively hybridise with brown
trout and salmon, hybrids contain transgene, this can be introgressed into gene pool of trout
or salmon by back crossing, hybrids grew quicker than their parents, in semi-natural
experiments the hybrids outcompeted native species
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Sea louse - free living planktonic nauplius stage, released onto water by female
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Lay 100-1000 eggs, can survive winter
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Add
antibiotics to salmon diets
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Fallowing - wait 2-3months before restocking, vaccines, cleaner fish
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Lepus Mountain/common hare
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Doe makes nest in a short blind tunnel (a stop), closes tunnel mouth
when absent, Ovulation induced by coitius, Bucks wait for does at mouth of nesting burrow
and mate when they emerge after dropping litter – a doe can be both pregnant and lactating,
Does generally monogamous
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Rate of increase 12x annual increase, with mortality is around 8x increase
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6 million pet rabbits and 40 million wild rabbits in UK,
Domesticated in last 1500 years from single origin in southern France, founding population of
less than 1200 – Probably from a decree by Pope Gregory the Great that new born rabbits
were not meat and could be eaten during Lent, 200 breeds today, most arose in last 200 years,
Domestic rabbits have lost 37–44% of their genetic diversity, more than in other domesticated
mammals
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Inland by 13th century: Guildford 1241
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History - The rabbit becomes a game animal - 1765: Anyone caught stealing rabbits at night
could be transported for 7 years – 1828: Night Poaching Act – 1831: Game Act – rabbits could
be sold – 1880 Ground Game Act: tenants given right to kill rabbits on their land, landowners
set up warrens to breed them for sport
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1917: rabbit order in the Defence of the
Realm Act, rescinded 1921, 1920: Forestry Act, 1938: Destructive Animals Act, 1939:
Prevention of Damage by Rabbits Act – Landowners could be made to control rabbits, 1939:
Rabbits Order under Defence of the Realm Act – Officials could enter and take rabbits from
any land anytime anyhow, Late 1930s: 50 million wild rabbits, Early 1950s: 100 million, 1954:
Pests Act: Rabbit Clearance Areas established
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Decline of warrening - Became less attractive during 18th and 19th centuries, In Yorkshire
Wolds 25% of warrens destroyed between 1760 and 1800, Surviving warrens often poorly
managed
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Rabbits in Australia - Five introduced 1788 with first penal colony, 1825: domestic rabbits
breeding in Sydney, Wild rabbits (24 pairs) introduced 1859 – For hunting – Put into a warren
at Barwon Park – 1865: 6000 harvested in 8 months – 1864: some sent to New Zealand – By
1880s spreading at 70 miles a year, 1875: first rabbit destruction act passed, 1880: NSW
government introduce a scalp bonus = rabbiting becomes profitable, 1880: cats, lizards etc
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1887: Government of NSW offered £25,000
for eradication of the rabbit, Pasteur proposed using chicken cholera bacillus Pasteurella
multocida, Kills rabbits but not contagious, Proposal rejected
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A large virus
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Myxomatosis - Myxoma virus: double stranded DNA virus, 171 genes, natural host Silvilagus
brasiliensis - 1919: suggested to be imported into Australia
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1936–8: further
releases, same results 1937: controlled field experiment, Wardang Island, Spencer Gulf
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1942: field trials, Mt Victor, S Australia, In all cases, myxoma virus
killed infected rabbits, but did not spread, and died out during winter 1950: trials at 4 sites,
Infectivity decreased with every generation, no sign over winter
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Week 10 - Oak and woodland
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Uses of oak - Food, tannin(g), wood, timber, culture, Problems with tannins – horses; red
squirrels, along with squirrel poxvirus
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g
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Types of Oak - Famly - Fagaceae - chestnut, oak, beech
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Quercus petraea: sessile acorn, prominent petiole
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quercuscalicis a recent introduction, Masting
and ecological interactions in eastern American oak forests (including the introduced
Lymantria dispar (gypsy moth)
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Knopper gall - andricus quercuscalicis
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Oak travels - European climate change since the last glaciation, What the trees did: refugia and
migration, Order of arrival in Britain, wildwood by 6000BP
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Oak lineages – invasion through
Cornwall and East Anglia
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Acute oak decline - A new disease of both English oak species which appears to be caused by a
pathogenic bacterium, Causes bleeding of the trunk death can ensue in 4 – 5 years
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NOT bacteria or virus
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vivax, p
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malaiae and p
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Mosquito - only female mosquitoes,
Anopheles sps are only vectors
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Mosquito stages - picture
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Then hepatic schizont - merozoites
released from hepatic schizonts into blood
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In the blood - merozoites attracted to red
blood cell, receptors bind, merozoite
becomes part of red blood cell
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Red blood cell then bursts and the cycle starts over
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Takes around 2-3 days to complete cycle
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Malaria effects:
cyclical fever as P
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No symptoms when in
liver as hypnozoites, fever when merozoites leave liver, ever when blood cells rupture
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falciparum - merozoites released all at once from liver, stupor, fits,
coma, and often death
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Also inflammation and endothelial dysfunction important
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These are then
transmitted by the mosquito
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Anopheles mosquitos - many species which all have their own requirements, temperature,
development speed ect
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Control - quinine - bark of cinchona tree, native to south America, evergreen tree
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1850 possibility of a famine, seeds harvested
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Quinine discovered to be poisonous
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Malaria eradication - target mosquitoes, kill adult females in resting place, prevent larvae
breeding - drainage, covering water bodies
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Benefits host specific, vector specific, vector behaviour, duration of sporogony, new insecticides
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Insecticide resistance to DDT
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No vaccine as multistage life cycle, stage specific expression of proteins
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Only RTS, S vaccine has made it to phase 3 trial
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Bed nets - can easily be ineffective unless treated with insecticide, reduced infection and
death significantly
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Artemisinin - from artemisia annua plant
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Artemisinin less toxic than quinine, can be
given rectally, currently supposed to be most useful anti-malarial treatment
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Week 2 - Barnacles and biofouling
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Barnacles - subphylum crustacea
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Class Cirripedia: Barnacles – 900 sps
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Classified in Mollusca
until 1830s
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6 instars, 3 pairs segmented
appendages – Antennules /
antennae / mandible
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Settlement:
attachment – exploration – fixation
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Metamorphosis stage - Cirri elongate, Body undergoes flexion, Primordial plates appear
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Adult barnacle - can live 2 - 6 years, plankton feeding by cirri
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Eggs brooded in
mantle cavity from autumn to spring, 13,000 per female
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Stage 2: microbial biofilm – Takes 1–24 hrs, Bacteria, Diatoms (need light), Secrete a sticky
extracellular polymer matri
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Protozoans Vorticella
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Economic effect - Annual cost to US Navy US$ 1 billion, Total cost of barnacle fouling £ 2 x
10^8 per year, Barnacles dominant, responsible for 80–90% of all ship fouling, Increase fuel
consumption up to 40%, Increase in corrosion – Cyprid larvae will crack paint
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1850s-1950 - Iron and steel hulls - cannot have copper sheathing
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1950 onwards - soluble matrix - sprayed onto large ships, lasts 12-15months, poor effect when
stationary
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Self polishing paints - long lasting, no need for repeated scrubbing, saved
large amounts of money
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Causes
mutations of shells
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Acrylic co-polymer with tributyl tin (TBT) - Incredibly toxic - hard to detect at low
concentrations, long half life, lipid soluble so bioaccumalates, toxic to many degrading
organisms
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Other treatments - biocide-free paints - silicones - expensive, last 3years, can still get fouling
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Week 3 - Plant toxins
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Ricin - Glycoprotein from the seeds of the castor oil plant
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The B-subunit gives ricin access to the cell by binding to glycoproteins on the cell
surface (i
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it is a lectin) and triggering receptor-mediated endocytosis
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Cicuta maculata
would give a violent, convulsive death due to cicutoxin
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However, Digitalis lanata is cultivated specifically as a source of the chemically similar but
more effective digoxin
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3 main groups alkaloids, phenolics, terpenoids
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Produced to attract animals
that pollinate and disperse seeds
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Used as a defence
mechanism
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Toxicity depends
on dose
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Nitrogen based - Non-protein amino acids, alkaloids, peptides, proteins, glucosinolates
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Large compounds, produced by 15% of plants,
bacteria and fungi
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g
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The solanaceae - an important crop family which can be toxic due to alkaloids
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Potato is fourth largest world
production
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3 main solanaceous
alkaloids - tropane alkaloids, steroidal alkaloids, pyridine alkaloids
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g
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High doses - hallucinations and
extreme fatigue
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Uses - pupil dilation (‘bella donna’) in
ophthalmology (atropine); motion sickness (scopolamine)
Why do plants make toxins - co-evolutionary theory
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'Produced a series of chemical compounds
not directly related to their basic metabolic pathways but not inimical to normal growth and
development'
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Danes
plexippus (Monarch butterfly) has co-evolved with milkweed (Asclepias spp
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g
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Pyrrolizidine alkaloids - for scent pheromones
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Senecio jacobae is Highly toxic to herbivores but food for cinnabar
and tiger moth
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Hydrolysis is strictly controlled by compartmentation of glycosidase enzyme and its
substrate within plant cell
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Control of cyanogenesis in clover - Two genes (Ac and Li)
control production of HCN: one (Ac) controls production of substrate (linamarin), the other
(Li) production of the enzyme (linamarase) which hydrolyses the substrate
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Correlation with temperature
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Locusts are
grasshoppers which become gregarious
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Gregarious - Adults and nymphs
congregate, adults move during day in
swarms, hoppers move together in bands,
different colouration and morphology,
increased disease and resistance, lower
fecundity
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Desert locust - swarming species, swarms
1500-4500km between breeding, no
permanent breeding areas
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Rest at night,
roosting in vegetation, move 1-10m/min
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Gregarisation - an adaptation to unpredictable environments Opportunistic gregarious swarms
overwhelm plant defences and also predators
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Weather conditions - Sufficient rain to allow formation of
vegetation patches, Locust breeding, Survival of egg pods
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International cooperation,
1945: Anti-locust research centre set up, 1941: International red locust control service,
Tanzania, 1948: Migratory locust control centre, Mali
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Early control - against hopper bands - dig trenches, beat, burn, baiting ect
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Major advances after WW2 - Insecticides, spray techniques, better scouting and prediction
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Positive – Give employment to lots of people, Low
levels of insecticide targeted at organisms, Can see effects quickly
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Aerial spraying - ULV spinning disc sprayers
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1986-1989 Plague - control - halted by
drying up of breeding grounds, larger number killed in Atlantic, control operations cost £200m,
problems included lack of preparation, inadequate early control, decreased use of dieldrin,
lack of security in areas effected
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Spread in
19th century in China, mainly around trade routes, this caused i to travel world wide, hit UK,
North and South America, Southern Africa, and most of Asia
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Yersinia pestis - Gram negative - coccobacillus,
Enterobacteriacaea - including E
...

Transmission in flea - Bacteria taken up in a
blood meal in the flea, Multiplies rapidly in mid
gut and proventriculus, Blocks gut, When
feeding subsequently the blockage forced out
into the host – Lots of bacteria reinjected
...

Bacterial biofilms - bacteria forms a biofilm to colonise hydrophobic proventricular spines
...
Not all fleas are good transmitters
...

Plague types :
Primary bacteraemic plague – When a flea bites into a vein, or dose so large that lymph system
overwhelmed, goes into blood stream – 100% mortality, 24 hrs (septicaemic plague) – ‘Fever
in the morning, death in the afternoon’
...

Secondary pneumonic plague – Bacteria move out of bubo into lungs, causing pneumonia,
occurs in 25% of bubonic plague cases
Primary pneumonic plague – Cross-infection direct to lungs by the air
Primary pneumonic plague does not crossinfect easily – Patients live less than 2 days, and are
infective for less than 24 hrs at most (towards end of life), many die before becoming infective
– Bacteria need large droplets to carry them, which don’t contain many bacteria – Such large
droplets do not get into lungs easily
Pneumonic plague - History - Manchuria 1910–11 – City dwellers travel to Manchuria to hunt
Tarbagan for fur, Catch slow ones, infected with plague, bring back to communal lodgings,
Overcrowding led to spread to pneumonic plague, Spread by railways, overcrowded carriages
etc
...

Plague as a weapon - Japanese Army - used 'flea bombs'
...

Treatment - Untreated bubonic plague 50–90% fatal, With very rapid treatment, 5–15%
fatality, Streptomycin best, Need to control rats and fleas at same time – control rats alone
and more fleas move to humans
...
The Black Death - 1346 until mid 18th century 3
...

Twigg - Rat biologist - Rate of spread – Plague slow – Black Death very quick; ge-specific
mortality rate different, Should expect it to occur in the same seasons in areas with the same
climate
...
Rat flea breeds between 13 and 34oC and needs good humidity – Average UK
summer temperature 15
...
5oC - 1300–1850
...

Cohn - Historian - In Indian 19th century outbreak of plague: – When Yersin found the causal
bacteria in 1894 he immediately proclaimed he had found the cause of the Black Death, Much
higher level of intervention by British than with other diseases, More intensely studied than
any other tropical disease, Assumption that the microbiology of modern plague and black
death the same – Did not believe fleas were vectors – could not transmit fast enough – Rats
not involve
...
In order to ‘fit’ modern
plague to the Black Death, it had to be ‘modified’: e
...
Black Death much more virulent than
modern plague, 30% population death rate compared to less than 1%
...
Black Death very virulent, spreading quickly, infecting whole households, the
opposite of modern plague, Therefore again must have been pneumonic plague – but this
does not spread well from person to person
...


Week 6 - Invasives and bracken



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Invasive - alien species, not native to area
...

Many invaders introduced deliberately - 235 spp of woody plant invaders; 82% introduced as
ornamentals for landscaping, In Australia 46% of noxious weeds were introduced deliberately,
often for ornament, In New Zealand nearly 50% of the vascular plants are non-native
...

Kudzo - Pueraria lobata - Introduced after being exhibited at the Japanese Pavilion in the US
Centennial Exposition in 1876
...
Soil conservation –
from 1935 – 1942 millions of kudzu crowns planted all over southern US
...
Economic costs of kudzu control in US $50 million
annually, Plants that are good for erosion control have attributes which make them threats as
invasives
...
japonica var japonica in Britain, Perennating rhizome, British population
clonal, derived from single female individual
...

Giant Hogweed - Heracleum mantehazzianum - Brought to Kew from the Caucasus in 1893,
Key features - Monocarpic perennial – up to 4 years to flower, then dies
...

Common cord-grass - spartina anglica - Arose through hybridisation of American S
...
maritima in Southampton water; this had happened by 1870, and
gave S
...
This is diploid and sterile
...
anglica
...
Key

features - Rhizomatous perennial, Rapid vegetative spread, High density of tillers excluding
other species, C4 photosynthesis in a C3 climate, Salt tolerance, Two genomes and polyploid,
Phenotypic plasticity
...

 Invasive plant - Although it is hard to generalize, the ‘Tens rule’ encapsulates what is known
about most invaders: 1 in 10 of those imported appears in the wild (become ‘introduced’); 1 in
10 of those so introduced becomes established; 1 in 10 of those established becomes a pest
(Williamson & Fitter, 1996
...
Exceptions: British crop plants; Hawaiian
birds; biological-control insects; island mammals – all have higher rates of ‘success’
...
Life history trait – short time to first
flowering
...

Bracken:
 An indigenous species that has become invasive
...
Relative decline in land floras since Angiosperms originated about 130
million years ago
...
One of the five most common plants in the world –
everywhere except Antarctica, Invasive at 1
...

 Features that make bracken invasive - Big, competitive, photosynthesis doesn’t saturate at low
light levels, Cold hardy (deep rooting)
...
Rapid vegetative spread; morphological plasticity, Good coloniser via spores which colonize new areas, after fire or removal of tree cover, Unpalatable
...
Also invades clearings in woods described as one of three ‘native thugs’ (along with Hedera helix and Rubus fruticosus agg
...
Change in UK land management in past 200 years has given it
opportunities - sheep for cattle, Less resource for manpower to control, Reduced use of
bracken – bedding, thatch, feed
...
g
...
Rapid vegetative spread, does well in high light
...

 Dangerous - To animals - Thiaminase causes induced thiamine deficiency in cattle, sheep,
horses, Acute haemorrhagic disease in cattle and sheep, Bright blindness in sheep, Carcinomas
of upper alimentary tract
...
Ptaquiloside in water and/or milk, Spores can reach high
concentrations and have been shown to contain a carcinogen
...
Eventually, with build-up of bracken
litter, may diminish due to frost/drought damage to young fronds growing in litter
...

 Controlling bracken - Physical means – expensive; marginal land makes cost hard to justify,
Herbicides – asulam – but needs repeated applications in combination with physical control
...
Africa, Conservula cinisigma and Panotima
sp
...
Should have few natural enemies in UK
...


Invasions:


Biological invasions: Arrival & Establishment - Most arrivals associated with human activity,
Most invasions fail (Tens Rule), All communities are invasible, Factors which influence success:
r (intrinsic rate of natural increase); abundance in native habitat, and match of new habitat to
old; vacant niche
...
Consequences - Where major, include depression of native populations
or extinctions, Evolution may occur following invasion - species try to adapt to survive invasion
or invader survives to try and invade better
...
Organism which spends a significant part
of its life-cycle on (ectoparasites) or in (endoparasites) another organism (the host), is
dependent on that host, and which benefits from the association at the host’s expense
...
Host may be definitive (where sexual reproduction typically
occurs), or intermediate (where parasite development continues) and which can also act as
vector
...

Protozoan parasites - Amoeboid: Entamoeba histolytica – causes amoebic dysentry, Flagellate:
Trichomonas, Giardia, Trypanosoma, Sporozoan: no locomotory structures, e
...
Plasmodium
(malaria parasite)
...
g
...
Digenea
(flukes): e
...
Fasciola hepatica (liver fluke)
...
g
...
But also include the most significant metazoan
parasites of humans; and plant parasitic nematodes are serious problems in crops
...
Filarial
nematodes (Order Spirurida) – e
...
Brugia malayi and Loa loa – indirect lifecyles, serious
disfiguring diseases of humans in tropical regions
...
See picture above right
...

Complex life-cycles including arthropod intermediate hosts (e
...
insect or crustacean) and
vertebrate definitive host
...

Indirect, behavior modification of intermediate host
...
Insecta: lice,
fleas; Dipterans - parasitic flies like warble and bot flies; Hymenopterans - parasitoids
...
The adult is
parasitic on a range of crab species
...

 Hymenoptera (nees, ants, wasps)
...
Holometabolous; adult is free-living
...
Can place eggs within a concealed host
...

 Birds - brood parasites
...
E
...
Common cuckoo, relies on host species to rear
progeny
...
Evolutionary arms race - Host and parasite evolve in an aggressive
manner towards each other
...

nSelection on host towards better resistance to parasite
...
Dependent on host for water, nutrients and organic solutes
...
Holoparasitic (20%) or hemi-parasitic (80%)
(absence/presence of chlorophyll
...
Host range often broad (e
...
witchweed,
Striga asiatica; dodder) but often show strong selectivity (i
...
preference – e
...
dodder selects
most nutritious shoots)
...
Can be very
damaging to crops (e
...
Striga and Orobanche), as well as to trees (e
...
Arceuthobium on
timber trees in western North America)
...
Members of five families aithin the order
santales
...
Therefore
...
Establishment
is a key stage
...
Once (parasitic) link to host
achieved, less vulnerable
...
Hemi-parasites - Most
do photosynthesize; some carbohydrates may be obtained from host, As a result of parasitic
life-style, most are buffered against the edaphic and nutritional factors that limit most plants
...
‘normal’ plants
...
May account for mystical/folklore association
...

Leaves are favoured food for many folivorous mammals – deer, gorillas, possums
...
Must provide transport and placement on appropriate host plant
...
Characteristics – large, sweet,
conspicuous fruits, with high carbohydrates and/or lipids and proteins
...
Sole living member of
ancient marsupial order Microbiotheria
...
Fruits are green at
maturity (colour associated with mammalian dispersal)
...
Nesting sites: witches’ broom and mistletoe
clumps - Evergreen, Good as nest lining (Viscum antibacterial; also immunostimulant)
...


Week 8 - Red kite
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o

o

o
o

o

o

Birds - weight reducing adaptations - Hollow thin bones, light and strong – No bladder/urethra,
No teeth, Concentrated uric acid excretion, Usually one ovary and oviduct, Never carry more
than one mature egg at a time, Reproductive organs atrophy outside breeding season
...
5oC in thrushes, Metabolic rate
8–10 times comparable sized vertebrates, Feathers for insulation, Rapid digestion of energyrich food, Large heart, High blood sugar concentration, Up to 2 x human, Air sacs as well as
lungs, air capacity up to 20% of body volume
...
Order: Falconiformes - Diurnal birds of prey, Order:
Strigiformes – Owls, nocturnal
...

Red kite - milvus milvus - Phylum - chordata, sub-phylum - vertebrata, class - aves
...

Flying - Seek out and ride air currents – Slope/obstruction currents, Updrafts of steady wind
over a building or hill, Thermals - Uneven heating of air near the surface
...

Food - Generalist opportunist scavenger - Some live prey, but is not powerful or aggressive,
Mainly carrion – Weak bill, usually goes for larger carrion after foxes etc have broken it up,
Rabbits most important, lambs, Some insects etc taken on the wing
...

Habitat - Open mixed countryside - trees and woodland for nesting, open arable land for
hunting
...
At 3–4 wks no longer fed directly, food left at side of
nest
...
By 10–12 wks are fully independent
...
Was then reintroduced in
1989 - suitable sites selected with sustainable food supply in summer and winter, high
breeding success, no hunting
...


Week 9 - Wolves



The wolf - canis lupus
...

Canidae - Bering land bridge between America and Eurasia opened up 30 mya, True dogs
remained in America until 6 mya, Some moved to Eurasia and gave rise to modern lineages 5–
7 mya
...
Evolution from
movement and then separation



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
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

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Genus - canis - wolves and dogs, canis lupus - wolf
...
aureus - jackal, d
...
Many members of the genus can interbreed successfully
...

Evolution - Wolf reinvaded N America 700,000 years ago, Earliest wolf possibly represented by
Red Wolf, Evolved into Canis lupus, Several extinct species, including very large Dire Wolf, C
...

Wolf - generalist carnivore - Flexible and opportunistic, scavenger, Relatively short gut, Teeth
& skull: – Makes numerous shallow bites – Bites without precision, can dislocate lower jaw
...

Prey - Mainly large ungulates, deer, elk, moose if available, with loss of these prey turns to
livestock
...
Stalking - prey, alpha in lead, encounter, rush to get larger animal moving, chase to single
animal out, Although the whole adult pack may participate in the chase, killing is usually done
by a couple of wolves, smaller animals also taken
Wolf packs - Alpha male and female – Usually the only pair that breed in the pack, Offspring
from a number of years, Uncles and aunts – Often with babysitting duties, Adopted wolves –
Sometimes from other packs, Pack size 2–42
...
Complicated dominance hierarchies maintained within pack, prevents serious
fighting
...
Submissive, tail between legs, head lowered, ears
back
...
Each pack has a territory, the size of which depends on food availability
...
Wolves usually die either from starvation or fights with other wolves
...

Wolves and dogs - Generally accepted that dogs evolved from wolves alone
...
US wolf removal - Started with first import of
livestock, 1609, By 1700 extinct in New England, 1750: better traps and strychnine, 1870:
disappearance of buffalo, more wolf attacks on livestock
...

Great lakes - By 1965 wolves removed from 97% of their former range in USA • 700 left in NE
Minnesota • 1978: recovery plan – Prevent hunting – Protect habitat
...

Wisconsin - extinct in 1960s, in 1970s wolves recolonized from Minnesota
...

Yellowstone - Eradication campaign, 1905: bill passed to mandate infection of wolves with
mange, Strychnine, Most wolves disappeared 1920s, Last 2 killed in Yellowstone 1924, Last
one killed 1943
...
Wolves have become used to humans, Wolf









tourism at Yellowstone adds USD 35 million per year to economy
...

Red wolves - Last population in swamp, interbed with coyotes, much disease All 400 removed
1970s to Washington Extinct 1980
...
100 in wild
...
A review underway of the
reintroduction programme
...

Alaskan wolves - 1980 onwards, 'wolf wars'
...
Sterilisation - remove all males from pack, sterilise alpha
and return to pack - stops breeding, also expensive
...
Killed off Red deer
which were at carrying capacity - overgrazing, difficult to control

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