Fig 1.
Morphometric correlation matrix.
Computed Kendall rank correlation coefficients A) queens (n = 42) for thorax width (QTW), thorax length (QTL), head length (QHL), head width (QHW), and spine distance (QSpD). All the performed morphometric correlations were highly significant (τ, p < 0.001). B) Wingless male morphometric correlations (n = 42) for thorax width (MTW), thorax length (MTL), head length (MHL), head width (MHW), mandible length left (MDL) and right (MDR), sperm viability (Viab), as well as the median sperm length (Median_L), standard deviation (SD_L) and coefficient of variance of sperm length (CV_L). The correlation coefficient ranges from a strong negative correlation (r = 1.0, blue) to a strong positive correlation (r = 1.0, red). Only significant correlations (p < 0.05) are shown.
Fig 2.
Correlation of queen body size with fertility (n = 39).
A statistically significant positive correlation was found between queen’s thorax length (QTL) and the total A) pupae (light blue), egg (black), B) larvae, and C) worker pupae production. A positive correlation was found between QTL and D) the production of winged male pupae (green), with no significant effect on wingless male pupae (‘ergatoid’, dark blue) production. No difference in queen production (S2 Fig in S1 File) translates into E) a lower caste ratio (queens/queens+workers), and F) a lower sex ratio (queens/queens+males) for larger queens.
Fig 3.
Offspring production was monitored 12 weeks after egg laying started, but queens varied in the onset of sexual production. The earlier a queen started producing queen pupae, the more A) wingless male pupae but not winged male pupae were produced. B) The timing of sexual production was correlated with B) queen pupae production and C) the caste ratio (queens/queens+workers).
Fig 4.
Influence of male sperm viability on offspring production (n = 39).
A) Higher sperm viability correlated significantly with a stronger female-biased sex ratio (queens/queens+males). B) A tendency was found between the sperm viability and the negative production of wingless males.