Family: poisson  ( log )
Formula:          
Activity ~ TreatmentAge + FieldSeason + Lepidoptera + (1 | Site)
Data: df

     AIC      BIC   logLik deviance df.resid 
   545.2    557.2   -267.6    535.2       78 

Random effects:

Conditional model:
 Groups Name        Variance Std.Dev.
 Site   (Intercept) 1.228    1.108   
Number of obs: 83, groups:  Site, 26

Conditional model:
             Estimate Std. Error z value Pr(>|z|)    
(Intercept)   -0.3736     0.3598  -1.038 0.299084    
TreatmentAge  -0.6804     0.2703  -2.517 0.011848 *  
FieldSeason    0.4935     0.1400   3.524 0.000424 ***
Lepidoptera   -0.4595     0.1687  -2.725 0.006440 ** 
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Signif. codes:  
0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1