Trophic egg production is widespread in ants. Simplified phylogenetic tree of ant families redrawn after Romiguier et al. (2022). The number of species with documented trophic egg production by queens, workers or both castes, as well as absence of trophic eggs, is indicated for each family. Details on the species and related references can be found in Supplementary Table 1.

Morphology and development of eggs laid by P. rugosus queens. Reproductive egg general morphology (A), with embryonic development at approximately 25 hours (B) and 65 hours (C). In trophic eggs (D), there is no embryonic development at 25 hours (E) nor at 65 hours (F). Panels B, C, E, F represent fluorescence images with DAPI-counterstained nuclei.

Wald-Wolfowitz runs tests on the queen’s egg sequence. Significant p-values (corrected for multiple testing) indicate that queens do not lay reproductive and trophic eggs in a random sequence.

Egg laying sequences from eleven P. rugosus queens. Every row shows the sequence of reproductive R and trophic T eggs laid by a given queen (queen ID in the orange cell). Each egg laying session lasted 10 hours. Each yellow square separates two egg laying sessions and represents an interval of minimum 16 hours to several days.

Concentration of protein (A), triglycerides (B), glycogen (C) and glucose (D) in reproductive and trophic eggs. Each dot represents the average of the two replicates per colony.

First two principal components (PC1 and PC2) explaining size distribution variation for (A) miRNA and (B) tRNA across egg samples, with reproductive eggs in grey and trophic eggs in black. There is a separation of the samples by egg types for miRNAs, but not for tRNA. Ellipses enclose each of the egg type groups.

(A) Percentage of larvae which developed into queens in recipient colonies without (grey) or with (black) trophic eggs. (B) Scatterplot of the relationship between the percentage of larvae which developed into queens and the percentage of survival from larvae to pupae.