Xylocopa ( Neoxylocopa ) augusti Lepeletier de Saint Fargeau, 1841

Almada, Valentín, Ramello, Pablo José, González, Víctor Hugo & Lucia, Mariano, 2022, Descriptions of new gynandromorphs of Xylocopa augusti Lepeletier (Hymenoptera: Apidae: Xylocopini) from Argentina, Papéis Avulsos de Zoologia 62, pp. 1-7 : 2-4

Xylocopa ( Neoxylocopa) augusti Lepeletier de Saint Fargeau, 1841

Gynandromorph 1 ( Figs. 1 b-f)

Description: Body length 22.1 mm, head length 5.1 mm, head width 7.1 mm, mesosoma width 9.5 mm, metasoma width 10.7 mm. The specimen displays female and male traits distributed irregularly along the body (mixed). Head: ( Fig. 1b ) with a mixture of female and male characteristics. The left half of the supraorbital area, vertex, frons, paraocular area, supraclypeal area and clypeus with yellow integument and pubescence as in the male. The right half with integument and pubescence dark brown to black, female-like, except malelike yellow integumental maculations as follows: frons, lower side of clypeus and left upper and lateral paraocular area. Genal areas female-like with integument and pubescence dark brown to black, except medially and basally with a yellow spot and yellow setae. Labrum with integument and setae as in the male, except for a small apical portion on its right side with integument and features as in the female. Mandibles female-like, except right mandible with a small yellow spot basally, similar to that of the male. Upper interorbital distance 3.9 mm; lower interorbital distance 4.2 mm; interalveolar distance 1.1 mm. Antennae with 11 flagellomeres as in the male, integument with a combination of coloration of both sexes, dorsally predominantly yellowish and ventrally dark brown (length of scape, pedicel, and F1: left 2.72 mm, 0.28 mm, and 0.97 mm, respectively; right side, 2.35 mm, 0.25 mm and 0.85 mm, respectively). Mesosoma: ( Fig. 1 c-d) female-like; right foreleg female-like, left foreleg with mixed features of both sexes, structurally female-like; profemur with three yellow stripes on ventral surface; protibia with yellow stripes in internal, ventral, and dorsal surfaces. Left procoxa and trochanter with yellow setae mixed with black. Middle and hind legs female-like. Wing dark brown with violet highlights. Metasoma: predominantly female-like ( Fig. 1 c-d), with six exposed terga and sterna. Terga with integument and pubescence as female. Sterna with mixed features of both sexes,T1-2 female-like,T3-6 with some spots tawny to black with yellow setae mixed with black setae. Genitalia bilaterally asymmetric, right half composed of hemi-male genitalia showing part of the gonobase, a penis valve and gonostylus; left half female-like with part of a sting ( Fig. 1 e-f).

Nesting and biological data: The nest from which the gynandromorph emerged ( Fig. 1a ) had five brood cells (cell 1 is the innermost cell, farthest from the nest entrance); the foundress female was killed by the conopid fly Physochepala wulpi Camras ( Diptera : Conopidae ). When the nest was found, cells 1-3 contained pupae in an advanced stage of development, cell 4 had an intact pollen mass (no larva developed), and cell 5 had a post-feeding larva that pupated on 17-XII-2018. Normal females emerged from cell 1 and 2 on 28-XII-2018 and 30-XII-2018 respectively, the gynandromorph emerged from cell 3 on 31-XII-2018, and a male emerged from cell 5 on 01-I-2019.

Material examined: One gynandromorph of Xylocopa ( Neoxylocopa) augusti ; Argentina, La Plata , Buenos Aires, collected on 31-XII-2018, Col. M. Lucia; deposited in the collection of División Entomología del Museo de La Plata, Argentina ( MLP) .

Gynandromorph 2 ( Fig. 2 )

We observed and photographed this second gynandromorph ( Fig. 2 ) on 09-XI-2018 from a trap nest located within the same group of trap nests of the same bee hotel where we found the first gynandromorph. We did not collect it because disappeared on the second day of its detection in the field. However, we observed that this gynandromorph had the general aspect of a female except for its head (mesosoma and metasoma female-like). Based on a photograph ( Fig. 2 ), we could characterize its head. Head: left eye, left half of the supraorbital area, vertex, frons, paraocular area, supraclypeal area, clypeus, and labrum with integument and pubescence as in the male, right side of the head female-like.

Frequency of gynandromorph types in Xylocopa

Both gynandromorphs described here are in the mixed category, the most common type recorded in Xylocopa . Among the 25 gynandromorphs reported for Xylocopa ( Villamizar, 2020; supplementary matreial; table 1), the overall proportion of mixed to bilateral types is 7 to 1. No specimen shows the transverse or anterior-posterior types, according to Michez et al. (2009). Mixed phenotypes are recorded in at least a tagma of 22 specimens recorded to date. The remaining three specimens exhibit a bilateral pattern in at least a tagma. Although the mixed pattern occurs in at least a tagma (head 45.5%, mesosoma 68.2% and metasoma 47.6%), it was significantly more common on the mesosoma (Χ² = 6.36, df = 1, p <0.01; Fig. 3 ) than in other tagmata. The head and metasoma showed a similar tendency to display a mixed pattern (head Χ² = 0.22, df = 1, p = 0.63; metasoma Χ² = 1.67, df = 1, p = 0.19). The bilateral condition exhibited different proportions among tagmata, as well as in the occurrence of female and male features on each side of the body.

Figures

Figure 1.Gynandromorph of Xylocopa (Neoxylocopa) augusti Lepeletierde Saint Fargeau:(A) Sagittal sectionof a trapnest showing differentdevelopmental stages and pupa of Gynandromorph 1, which is indicated by the arrow in the third cell. (B) Head in frontal view. (C) Habitus in lateral view. (D) Habitus in ventral view (E) Genitalia in ventral view;(F) Genitalia inlateral view.Scale bars:(A) 2 cm; (B) 2 mm;(C-D) 1 cm;(E-F) 1 mm.

Figure 2. Gynandromorph 2 in frontal view inside the trap nest.This individual was not captured.

Figure 3. Frequency of gynandromorph types among tagmata in Xylocopa.