A non-destructive method for identifying the sex of ant larvae

Brood recognition and discrimination in ants

“…In the past, comparisons of sex-specific brood traits, and in particular brood odor profiles, were hindered by the lack of appropriate methods with which researchers themselves could differentiate between the sexes. Fortunately, a recent study describing differences in male and female genital disc morphology in larvae has taken a first step towards overcoming this hurdle (Penick et al 2014). In the future, systematic studies of sexspecific brood traits across different kin structures will help us understand the causes and constraints of brood discrimination according to sex.…”

Larval sex identification of in vivo and long‐term ethanol‐preserved social wasps

“…Social insect larvae are assumed to have reduced morphological features; yet, larval sexual dimorphism on externally visible body structures has been reported previously (Yamane, 1976; Duchateau and van Leeuwen, 1990; Santomauro and Engels, 2002; Cotoneschi et al, 2007; Penick et al, 2014). Our findings that genital discs in the abdomen of wasp larvae are sex specific (in at least five vespid species) and visible (in at least 26 vespid species) open up new avenues for more detailed research on immature forms (e.g., sex‐specific taxonomic studies).…”

“…There is validation evidence from a few species of ants [ Harpegnathos saltatory (Jerdon), Aphaenogaster cockerelli (André), and Camponotus floridanus (Buckley)] and wasps [ Polistes dominula (Christ)], suggesting that within each species, genital discs have two distinct morphological patterns associated with sex (Cotoneschi et al, 2007; Penich & Moore, 2014). In both bees and wasps, these structures are visible in short‐term ethanol‐preserved larvae after staining with dye (Yamane, 1976; Duchateau & van Leeuwen, 1990; Cotoneschi et al, 2007), whereas in ants, they are visible only in live larvae (Penick et al, 2014).…”

Maternal control over caste allocation in the ant Cardiocondyla obscurior

“…General morphologies of ant larvae have been extensively described, e.g. [37–40], and non-invasive identification of larval sex has been demonstrated previously [41]. Traits that distinguish late-stage worker from sexual larvae (males, queens) have been discovered in six ant species from three subfamilies; these are largely continuous measures, including body size ( Aphaenogaster senilis [42]; Harpegnathos saltator [43]; Myrmica rubra [44]), cuticle “shininess” ( Linepithema humile , [45]), hair density ( Monomorium pharaonis [46]), and hair morphology (Acromyrmex echinatior [47]).…”