|dc.description.abstract||Individual differences in male sexual behav~our and the factors
influencing calling behaviour were studied in the field crickets Gryllus
2 integer and Q. veletis. In a large (13m) outdoor arena individually numbered
adult male ~~ integer started calling at three to five days of age but thereafter
the age of individual G. integer males did not affect nightly calling duration.
Calling also did not correlate with individual weight. In this study individual
male calling was continuously distributed from 0 hrs. per night to 3.5 hrs.
per night, on average. A temporal effect on the number of G. integer males
calling was observed. The number of males calling through the night was uniform,
but a sharp increase in the number calling was observed in the early morning.
No difference in calling times was observed between the night and dawn callers.
AlsC)' males calling at dawn usually didnotc'all during the preceeding night.
Calling and reproductive success in 1979 demonstrated a negative
logarithmic relationship while in the 1980(initial) population a negative
linear relationship was observed. No relationship was seen in the 1980
high density population. The ratio of non-callers to callers also affected
the mating of individuals in the 1979 and1980(initial) densities:-non~callers
(males calling .5 hrs. per night, on average, or less) obtained more females
when the population contained a high number of callers, this being a
negative logarithmic relationship to, No such relationship was observed in the
1980 high density population.
Individual displacement varied nightly and was not correlated to
amount of calling or reproductive success of individual G. integer males.
G. integer males were displa~ed more when in a higher density in the outdoor arena
Male G. integer and G. veletis behaviours were also observed in
an indoor arena at different densities and, in G. veletis, with respect to
female presence. When females were present in the arena, in G. veletis, male
calling was reduced. Males of both species called less, on average, when in
~ higher density, than when they were in a lower density. Male displacement of
both species increased on average when in a higher density as compared to
displacement in a lower density.
Aggression was measured by aggressive call-ing and fighting and was
studied in regards to density.G. integer demonstrated less aggression in
all but one comparison at higher density. No difference was observed in
the ratio of aggressive calling to f.ighting comparison in G. integer.
G. veletis demonstrated mixed results. No difference in aggression between
densities was observed in comparisons. Less.aggression did occur
in higher densities when comparisons invol.ved fighting behaviour.
Male behaviour represents a competitive strategy against ot~er males,
strategy being defined as a genetic (in part) alternative to other strategies.
In this sense, the factors of time, density, male-male aggression, and female
presence are conditions demonstrated to affect male behaviour in G. integer
and G. veletis. Individual male differences and other considerations suggest
that alternative male behaviours are represented by at least two conditional
strategies. This possibility, and the transient 'or stable nature of genetic
polymorphisms in field cricket behaviour are considered.||en_US