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