Lecture 10 Flashcards
what type of predators over come ground beetles? & what are some exs? (5)
bigger predators including:
o Mongoose o Camelion o Crow o Frogs o Ants – see carabidae beetles as their competitors
Usually ____ visible segments, but ___ abdominal segments in total (usually some are hidden)
6
7-10
when are the abdominal segments of the ground beetles hidden?
when mating
pygidium
abdominal segments
pygidial glands
defensive glands
come in a pair on either side of the anus
located in the hindgut
where are the pygidial glands located?
hindgut
secretory lobes
where secretion occurs
collecting canal
duct
efferent duct
goes from an organ to the outside
why is the efferent duct thick-walled?
Thick-walled b/c it contains muscles that force the liquid out
opening muscle
controls when the muscle is open
valve
muscle that controls where the liquid is directed
how do you describe thin-walled pygidial glands
membranous, no muscles
accessory gland
adds surfactant to the mixture
what effects does a thin-walled reservoir have?
secretion oozes out for the surface of the beetle causing itself to be distasteful
where does the liquid secrete?
simple pore in the abdominal surface
what effects does a thick-walled reservoir have?
forcibly contract enabling spraying for several cm
contain a nozzle which can direct the spray
the chemical composition of the liquid is: ____ irritant & ___ sufractant
> 90%
<10%
surfactant
cause liquids to spread on surfaces, hits target & spreads (influences surface tension)
what is the most common irritant?
formic acid
what % of formic acid is the defensive secretion? & who uses this?
95%
Harpalus
describe the irritant in Pterostichus
90% methacrylic acid
describe the irritant in Chlaenius
96% 3-methylphenol
describe the irritant in Brachinus
100% quinones
describe the defensive mechanism of Anthia, the Oopister beetle
formic acid in a directed spray (muscular reservoir)
Synthesized spray
aposematic yellow & black colouration (other organisms mimic it)
describe the defensive mechanism of Brachinus, the Bombardier beetle
aposematic
quinones - directed
has a exploison chamber complex - unique
what enzymes are produced in Brachinus, the Bombardier beetle
Catalase: convert hydroquinone –> Benzoquinone (more reactive)
Peroxidase: produces the propulsion
H2O2 –> H2O + O2
what are the final products released by Brachinus, the Bombardier beetle when making an attack?
o Benzoquinone
o Oxygen
o Steam at 100C
what is the function of the inlet valve?
prevents back splash when there is an exploison
what are the steps in the exploison of Brachinus, the Bombardier beetle?
- Inlet valve opens, charging rxn chamber (from the reservoir)
- Valve closes & enzymes are released
- Heat-producing rxn brings liquids to boil
- Pressure increase opens pressure relief valve
- Reduced pressure causes steam explosion
- Spray is released through aimed nozzle (directed)
- Temp & pressure drop, relief valve closes
duct
sclerotized cuticle on one side & the other side is flexible
describe the diff in headspace volatiles during the reproductive stages?
male - high levels
females - low levels
what is the primary ingredient in C.cordicollis?
3 methylphenol (irritant)
describe the concentration of 3,5- dimethylphenol during the reproductive season in C. cordicollis
males - 2%
females - 0.5%
females have about 1/4 of what the males have
why do females have so much less irritant in C. cordicollis during the reproductive season?
E expense to produce
not investing in that when wanting to mate
C. cordicolis - there is a ____ _____ in defensive secretions during the reproductive season
sexual dimorphism
