How to use different font sizes in ggplot facet wrap labels?

I want to create two different sizes of text in the labels of my facet wrap.

For example:

• Species X (size 14)
• Total catch (n=133) (size 12)

test <- read.csv(paste0(path, "Costello Artvgl2 for Stack.csv"), sep = ";", dec = ",", header = T)

str(test)


test$Wert <- factor(test$Wert, levels = c("one","two","three","four","five","six")) 


test$Sampling.site <- factor(test$Sampling.site, levels = c("Species X Area T","Species Y Area T","Species X Area A","Species Y Area B","Species X Area B","Species Y Area C"))


levels(test$Sampling.site) <-  c("Species X\nTotal catch (n=133)", "Species Y\nTotal catch (n=185)", "Species X\nSampling area A (n=57)", "Species Y\nSampling area B (n=122)",
                             "Species X\nSampling area B (n=76)",  "Species Y\nSampling area C (n=63)")

theme_new <- function(base_size = 12, base_family = base_family){
theme_bw(base_size = base_size) %+replace%
theme(
  axis.text.x =       element_text(size = 8 ),
  axis.text.y =       element_text(size = 8 ),
  axis.title.x =        element_text(size = 12, vjust = 0.01),
  axis.title.y =        element_text(size = 12, vjust = 0.9, angle = 90),

  plot.title =        element_text(size = 10, face = "bold"),

  legend.key=         element_rect(colour= NA, fill =NA, size = 0.5),
  legend.key.size =   unit(1, "lines"),
  legend.text =       element_text(size = 8),
  legend.title =      element_blank(),

  strip.background =  element_rect(fill = NA, colour = NA), 
  strip.text =        element_text(size = 8, face = "bold",hjust = 0.5, vjust = 0.9),

  panel.background =  element_rect(fill = "white"), 
  panel.border =      element_rect(fill = NA, colour="black"), 
  panel.grid.major =  element_blank(),
  panel.grid.minor =  element_blank(),
  panel.margin =      unit(1, "lines")

)
}

ggplot(test, aes(Fi, Pi),group=Wert)+
geom_point(aes(colour = factor(Wert),shape = factor(Wert)),size=3)      +                         
  scale_shape_manual(values=c(20,18,19,15,16,17))+                    
  scale_x_continuous(limits=c(0, 1),breaks=c(0,0.2,0.4,0.6,0.8,1.0))+     
  scale_colour_brewer(type = "qual", palette = "Paired")+
  scale_y_continuous(limits=c(0, 100),breaks=c(0,20,40,60,80,100))+        
  labs(x = "Frequency of occurrence", y = "Prey-specific abundance [%]")+ 
  facet_wrap(~Sampling.site,scales = "free",ncol = 2) +
  theme_new()

Is there a possibility to realize that?