Richard Wall - Dung

Question 1

uses of dung

Answer 1

fuel for cooking in india - forms dried out ‘cakes’
Masai house roofed with dung, grass and mud.
Burkina Faso - buildings made from clay soil, straw and dung

Question 2

how much dung is produced in the UK per day?

Answer 2

300,000,000kg per day

10m cattle each produce 25-30kg per day.

Question 3

what communities live in dung?

Answer 3

Coprophage communities, with v complex food webs.
high water content, 70-90%
relatively high energy content

Question 4

3 types of dung beetles and behaviour

Answer 4

1. Endocoprid beetles
   dig tunnels and lay eggs within brood chambers, in or just beneath the dung pat.
2. Paracoprid beetles
   tunnel down and build brood chambers well below dung. roll balld of dung down into chambers and lay eggs inside ball. M+F work together to excavate chambers. some beetles rob existing tunnels, or build side tunnels to sneakily mate with other females.
3. Telocoprid beetles. roll fresh dung away to suitable dry sandy site, dig and drop ball underground. brood ball can be 50x weight of beetle., sexual display.

Question 5

example of a specialist dung breeder fly

Answer 5

Yellow dung fly, Scatophaga stercoraria
very early in succession of dung.
adaptations for v wet environments eg respiratory horns/siphons

Question 6

describe colonisation and succession of cow pat

Answer 6

flies first
beetles a few hours later
crust forms after a few weeks making colonisation difficult, broken up by insects.
earthworms last, bring bits underground.
the pat only gets colonised by half the species present in the pasture, as species are highly aggregated due to oviposition.

Question 7

where are dung Insect communities more complex?

Answer 7

in temperate habitats the dung remains available longer.
May contain more than 1000 insect inhabitants from over 400 sp.
faeces from different hosts have a unique decomposer fauna. specialists due to chemical and physical properties of the dung

Question 8

what is colonisation affected by?

Answer 8

Age of the pat
Time of year
Water content 
Surrounding habitat 
Weather 
Soil type 
Continuity of dung availability
Position within a field
Stochasticity
Dung composition – grass, grain other forage
FOLLOWING INITIAL COLONisAtiON - competition, predation and parasitism.

Question 9

Why are insect dung-colonizers important?

Answer 9

1. decomposition must occur, otherwise causes pasture fouling.
2. dung insects provide food for other animals.
3. N and C cycles: to maintain pasture fertility. measurable growth response by surrounding herbage, plus decrease in soil density and increase in porosity.
4. reduced GH gas emissions.

Question 10

monetary value of dung insects

Answer 10

£300million per year
£37 per cow
quantification of GH emissions based on quite flimsy data/

Question 11

life cycle of cattle GI parasites

Answer 11

eg Haemonchus

eggs laid in dung, develop L1 to L2in dung then escape to pasture. L3 in pasture, infect grazing cattle.

Question 12

describe an investigation which lead to conclusion that insect dung commuities, mainly small endocoprid Aphodius sp, can reduce availability of livestock gastrointestinal parasites on pastures

Answer 12

collected 400kg dung from organic farm, didnt contain deworming treatment.
- made 260 ‘pats’ in fields, 4 groups
mesh to exclude insect colonisation, natural, added beetles, enhanced rainfall.
- counted FEC and larval culture , identified L3.
- found 109 eggs per gram.
66% Cooperia oncophora, 29% Ostertagia ostertagi; 5% Cooperia spp.
- also sampled grass around pats by cutting it and putting in a muslin bag and tube with liquid at one end. causes larvae to migrate towards water, so can remove and count.
- no. larvae increases over 6 weeks then stays high.
concluded aeration of pats by beetles prevents unfavourable anaerobic conditions which promote L3 development. rainfall slightly enhanced this.

Question 13

how is marsupial dung decomposed in australia?

Answer 13

• native dung beetles adapted to remove it
• imp as w/o it, build up of cattle dung on pasture and loss of grazing space.
• would have increase of dung breeding bush fly, musca vetustissima.

Question 14

what came major problem after cattle introduced in Australia? how was this combated and was it successful?

Answer 14

dung breeding bush fly , musca vetustissima.
a very thorough quarantine, selective breeding programme to release more dung beetles. after 8 years released 20 species. However, did not spread, required repeated introduction to new areas. worked well on local scale.

Question 15

describe exclusion experiment son dung beetles.

Answer 15

left dung covered for different amounts of days. worked out % weight loss of dung.
most dung loss in first two days - showing earlier colonisers most imp.

Question 16

what is a ruminal bolus?

Answer 16

capsule sent down throat of cows and into digestive system. releases chemicals in pulses over time. eg Ivermectin (macrocyclic lactone)

Question 17

describe an experiment looking at long term effect of ivermectin

Answer 17

Sommer et al 1992.
calves fitted with ruminal bolus delivering ivermectin at 40µg/kg
made pats of control and test dung.
at 38 days, saw crumbly appearence, due to colonising beetles breaking the surface.
94 days - ivermectin treated dung surface not broken.
control at 93 days almost completely decomposed.
suggests chemicals have long lasting effect, mainly on flies and beetles.
90% of dose is excreted, unchanged.

Question 18

is a pour on or injection of ivermectin more damaging?

Answer 18

pour on reaches much higher concentration faster than injection. also remains detectable in dung for 2 weeks . intramuscular injection remains longer so ends up being more damaging

Question 19

what was found from comparing dung treated with ivermectin, doramectin and control.

Answer 19

found control had highest number of fly larvae at each time period.
Ivermectin had more than doramectin.
most fly larvae 29 days after treatment.

also compared ch concs in faeces. after treatment, IVM conc declines.
post deposition, conc increases and remaining IVM is locked away in dung and stays there at toxic levels.

Question 20

5 sub lethal effects of macrocyclic lactones persisting in dung.

Answer 20

Reduction in fecundity
  Increased larval development time
  Morphological abnormalities
  Disruption of water balance
  interference with moulting

Question 21

fly repellant with very short effect

Answer 21

deltamethrin. short pulse ofactivity 2-3 days after treatment.

Question 22

why is it often difficult to see the effects of insecticides in dung?

Answer 22

dung beetles roll it underground, toxic effects occur underground

Question 23

experiment to measure effect of pyrethroid insecticide in botswana.

Answer 23

botswana - dosed dung and measured the number of dead dung beetles.

Question 24

what is an alternative to conventional insecticides

Answer 24

dried planktonic diatoms
dessicates environment, causing damage to bed bug cuticle
as effective as ivermectin at reducing dung fauna.

Question 25

what do longer term ecological effects of anthelmintic residues depend on?

Answer 25

Compound used,
Metabolism/storage/excretion route and rate
Dose rate,
Formulation and delivery method (pour on, injection, bolus)
Number and age-classes of treated animals
Frequency and seasonal time of use
Husbandry practices (stocking density, housing)
Weather
Nature of the dung insect community