2.7. Impact of female stridulation on male mating readiness
Every female was tested on 13 consecutive days after imaginal
moult. For each day, the mating attempts directed toward a specific
female were counted. For each observation period the total
number of stridulating females in the experimental cage was
determined and it was noted, whether the particular female itself
was stridulating. Data were analysed in a generalized estimating
equations (GEE) model. Due to overdispersion the data were fitted
to a negative binomial distribution with a log-link function and a
robust estimation of covariance was chosen. ‘Behaviour’ (female is
stridulating: yes = 1/no = 0) was defined as a factor in the model,
age (day after the female’s imaginal moult) and singers (number of
stridulating females in the cage) as covariates.