Centris (Paracentris) pallida Fox

Barret, Meghan, 2021, The first case of gynandromorphy in Centris pallida (Hymenoptera: Apidae: Centridini), Journal of Melittology 2021 (104), pp. 1-8 : 2-4

Centris (Paracentris) pallida Fox

Gynandromorph

( Figs. 1–10 )

DESCRIPTION: Body length 8.3 mm; head height 3.9 mm (w/labrum: 5.0 mm), head width 5.4 mm; mesosoma width 6.2 mm; metasoma width 5.9 mm.

Head. General appearance male-like; 11 flagellomeres on each antenna and clypeus yellow ( Fig. 1 ). Pubescence mostly white on labrum, vertex, and parocular area, sides of head pale grey, pubescence on frons darker brown or tan around ocelli; no distinct morphological differences between sides ( Figs. 1–4 ).

Mesosoma. Mix of male and female features. Bilateral split in pubescence coloration on the mesoscutum and mesoscutellum, right side generally pale in coloration like large male morph, except for a tan spot near tegula, left side pubescence tan, more similar to a small morph male or female in coloration ( Figs. 2–4 ). Fore and middle legs generally female in appearance. Hind right leg female, hind left leg a mix of male and female features ( Figs. 6–9 ). Medial side of leg appears female – darker colored, bushy scopal hairs on tibia and basitarsus ( Fig 7 ). Lateral side of leg appears male – pubescence light grey and less dense in appearance on tibia and basitarsus ( Fig. 8 ). Hind right leg with smaller than normal (for females) basitibial plate, centered towards the medial side of the tibia ( Figs. 2, 4 ).

Metasoma. Not strongly sexually dimorphic in the first four terga/sterna, greyish-brown dorsally, with overall shape, and ventral setae density patern female-like. The specimen has seven exposed terga as in males (terga 1–5 easily visible in figure 5, terga 6 and 7 most visible in figure 10); terga 5 and 6 more closely match a male morphology, missing the heavily raised pygidial plate, and darker pygidial and prepygidial fimbria, of a female ( Figs. 10–12 ). The genitalia appear to be female; on T6, there is a sting that may only be partially developed (recessed; Fig. 10 ) along with sting sheath (clearly visible surrounding the female sting in figure 12), however these could also be weakly developed male gonostyli (see figure 11 for comparison to a large male morph). To preserve the integrity of the specimen, dissection of the genitalia was not possible.

MATERIAL EXAMINED: The specimen is at the University of Arizona Insect Collection, Number UAIC 1052985.

Figures

Figures 1–5. Gynandromorph of Centris pallida Fox. 1. Head in frontal view. 2. Left side of body in lateral view. 3. Right side of body in lateral view. 4. Mesosoma and head in dorsal view (image reflected horizontally – pin is in right side). 5. Metasoma in dorsal view. Scale = 2 mm except 1 mm in figure 1.

Figure 6–9. Hind legs of gynandromorph of Centris pallida Fox. 6. Left hind leg in lateral view. 7. Left hind leg in medial view. 8. Right hind leg in medial view. 9. Right hind leg in lateral view. Left hind leg shows partial female, partial male characteristics; right hind leg shows all female characteristics. Scale = 1 mm for all figures.

Figures 10–12. Apex of metasoma of Centris pallida Fox. 10. Gynandromorph. 11. Large morph male. 12. Female. Scale = 0.5 mm.