are individuals harboring both male and female tissues. The causes of these anomalies remain poorly understood though several hypotheses have been proposed to explain them (Michez et al. 2009; Sommaggio et al. 2021). There are more and more descriptions of gynandromorph bees recently, and more behavioral observations of these bees in nature (Krichilsky et al. 2020). These new observations and descriptions can be valuable to understand how these phenomena occur (Michez et al. 2009; Sommaggio et al. 2021). Most of the current descriptions concern relatively large bees in which there is a relatively striking sexual dimorphism (Michez et al. 2009; Lucia et al. 2013; Lucia et al. 2012). A few descriptions of gynandromorph bees of the genus Halictus Latreille exist in the literature (Brau et al. 2024, Michez et al. 2009) however no descriptions of such a case in the species Halictus scabiosae (Rossi, 1790) was found.
The bee was observed on Asteraceae flowers on 4 July 2023 in a suburban area near a forest in Besançon (25), France (47.2698, 6.0514). It was not collecting pollen but rather feeding on nectar. Male tissues are present on the left part of the body, and female tissues on the right part of the body except on metasomal segments 2-4 which are only female. The genitalia are similar to those of a female with small narrow and unmodified gonostylus and a sting (Table 1, Figure 1). The shape of the metasoma is closer to that of a female, less elongated than what we can observe in male specimens.
From these observations, this individual can be considered a mosaic gynandromorph (Michez et al. 2009), though it is close to a bilateral gynandromorph. The behaviour of the individual before capture is not sex-specific, so it is not possible to say whether the individual behaved as a male or a female. The lack of previous description of such a gynandromorph individual for this widespread and common bee species in Western Europe is quite surprising.
Brau T, Rosa P, Carion F, Flaminio S, Ghisbain G (2024). A new case of gynandromorphism in the Halictus simplex species group (Hymenoptera: Halictidae). Specimen. 37. https://doi.org/10.56222/28166531.2024.37
Krichilsky E, Vega-Hidalgo Á, Hunter K, Kingwell C, Ritner C, Wcislo W, Smith A (2020). The first gynandromorph of the Neotropical bee Megalopta amoena (Spinola, 1853) (Halictidae) with notes on its circadian rhythm. Journal of Hymenoptera Research 75: 97-108. https://doi.org/10.3897/jhr.75.47828
Lucia M, Alvarez L & Abrahamovich A (2012). Gynandromorphism in Xylocopinae bees (Hymenoptera: Apidae): description of four new cases. Zootaxa. 3401(1): 37-42. https://doi.org/10.11646/zootaxa.3401.1.2
Lucia M & Gonzalez V (2013). A new gynandromorph of Xylocopa frontalis with a review of gynandromorphism in Xylocopa (Hymenoptera: Apidae: Xylocopini). Annals of the Entomological Society of America. 106(6): 853–856. https://doi.org/10.1603/AN13085
Michez D, Rasmont P, Terzo M, & Vereecken N J (2009). A synthesis of gynandromorphy among wild bees (Hymenoptera: Apoidea), with an annotated description of several new cases. Annales de La Société Entomologique de France (N.S.), 45(3), 365–375. https://doi.org/10.1080/00379271.2009.10697621
Rossi P (1790). Fauna etrusca sistens insecta quae in provinciis florentina et pisana collegit. Tomus secondus. Liburni. 348 pp. https://biodiversitylibrary.org/page/15597242
Sommaggio D, Fusco G, Uliana M, Minelli A. (2021). Possible epigenetic origin of a recurrent gynandromorph pattern in Megachile wild bees. Insects, 12(5): 437. https://doi.org/10.3390/insects12050437
Character | Male (♂) | Female (♀) | Gynander |
Head | head narrow and elongate (0.8-0.85 times larger than long) | head large (1.05-1.1 times larger than long) | (♂) on left part, (♀) on right part (as large as long) |
Clypeus | partially yellow | completely dark | (♂) on left part, (♀) on right part |
Antennae | scape partially yellow, 13 segments, segments larges and last segment curved | scape completely dark, 12 segments, all segments straight and narrow | (♂) on left part, (♀) on right part |
Legs | tibia, tarsus and apical part of femur yellow | all segments dark, scopae present on hind tibia | (♂) on left part, (♀) on right part |
T1 | narrow, spot of pubescence on the sides at the basis of the segment | large, without spot of pubescence on the sides | (♂) on left part, (♀) on right part |
T2-T4 | narrow, a basal band only on T2 and T3 | large, basal band on all segments | (♀) on both sides |
T5-T6 | without a furrow and with an apical hair band | with a furrow and without an apical hair band | (♂) on left part, (♀) on right part |
Genitalia | with penis valves and large gonostylus | with a sting and small narrow gonostylus | (♀) |
Fig. 1. Gynandromorph of Halictus scabiosae, specimen AB230168. Photo stacking made using a Canon 7D mark ii with a 90mm Tamron macro lens. A: Gynandromorph on Asteraceae flower; B: Face; C: Metasoma dorsal view; D: Habitus right side (female); E: Habitus left side (male); F: Genitalia (latero-dorsal view of left side); G: Genitalia (dorsal view); H: Genitalia (latero-dorsal view of left side).