Megachile (Sayapis) mendozana Cockerell, 1907

Torretta, Juan Pablo & Durante, Silvana Patricia, 2011, Nesting ecology of Megachile (Sayapis) mendozana Cockerell and its synonymy with Megachile (Sayapis) santiaguensis Durante (Hymenoptera: Megachilidae), Zootaxa 3008, pp. 63-68 : 64-65

Megachile (Sayapis) mendozana Cockerell, 1907

( Figs. 1–4 )

Megachile cornuta Smith, 1879: 78 (non Latreille 1805); Cockerell, 1905: 341

Megachile rhinoceros Friese, 1906: 97 (non Mocsáry 1892); 1908: 68; Jörgensen, 1909: 215; Vachal, 1909: 15; Moure, 1943: 178.

Megachile mendozana Cockerell, 1907: 50 . Replacement name for M. cornuta Smith ; Jörgensen, 1912: 128; Schrottky, 1909: 267; Cockerell, 1914; 428.

Megachile (Sayapis) mendozana Mitchell, 1943: 664 ; Moure, 1943: 178.

Eumegachile (Sayapis) mendozana Mitchell, 1980: 46 .

Eumegachile (Sayapis) santiaguensis Durante, 1996 (in Durante & Díaz, 1996): 334–336. [New synonymy]

Megachile (Sayapis) santiaguensis (Durante) , Raw 2002: 34.

Material studied. New records: ARGENTINA. Buenos Aires. Rivadavia, 1 male, Ea. Trébol Curá, J.P. Torretta & G. Cilla, XII-2006; Carlos Casares, 2 females, Ea. San Claudio, J.P. Torretta & G. Cilla, II-2007; 3 males and 1 female from nests, J.P. Torretta, XII-2010. Córdoba. Roca, 1 male, J.P. Torretta, G. Cilla & N. Montaldo, I-2007. La Pampa. Toay, Ea. Anquilóo, 1 male, J.P. Torretta, XI-2008; 5 females and 1 male, H.J. Marrero I-2009; 2 females, H.J. Marrero II-2009; 1 male, H.J. Marrero XII-2010.

Distribution. In Argentina, this species is found in Buenos Aires, Catamarca, Chaco, Córdoba, La Pampa, La Rioja, Mendoza, Misiones, San Juan, Santa Fe, and Santiago del Estero ( Fig. 1 ). It is also present in Paraguay ( Raw 2007) and São Paulo, Brazil ( Moure et al. 2007).

Comments. All individuals that emerged from the trap-nests (1 female and 3 males) share morphological similarities that support the synonymy. Both sexes have black integument; wings hyaline; costal area, radial cell and distal margin of fore wing dark brown; tegula brown. Pilosity white or pale yellowish. Integument of the head generally coriaceous, small, deep and abundantly punctate, larger on basal area of clypeus. Scutum, scutellum, and axilla with large and abundant punctures. Metasoma with larger, slightly deep and abundant punctures; fifth tergum with irregular and close punctures. Moreover, the distributions of both entities exhibit a broad overlap in Argentina. This overlapping distribution also supports the synonymy proposed in this paper.

Biological observations. Nesting ecology. A total of seven nests of M. mendozana were collected in traps. Five nests were gathered in January 2010, while the remaining two in March 2010. The length of the trap-nests used by females of M. mendozana were 233.4 ± 21.7 mm (range: 205–258) with apertures of 6.85 ± 0.69 mm (range: 6–8) in diameter. The nests contained from 2-12 cells (4.86 ± 3.29 cells; n= 34). Of the total cells, 20 larvae died during early stages of development and 10 post-defecting larvae were attacked by Melittobia hawaiiensis Perkins ( Hymenoptera : Eulophidae ) ( Table 1).

placement to removal of the traps. Nester associates in block are other Megachile species that occupied the same block.

Block Nest Nesting Cells Adults emergence (date; position of Dead offspring Nesters associates in

period (n) cell in nest) block female male larvae Melitmum- tobia mified attack

Total 34 1 3 20 10 The females of M. mendozana construct cells that are separated from each other by partitions and are not surrounded by a leaf/petal/mud envelope ( Figs. 2–3 ). These partitions are formed by small pieces of leaves not sealed to the trap-nest, followed by chewed plant material and earth and small pebbles (2–3 mm of thickness). All the nests were closured with masticated plant material and mud. Pollen masses were moist and sticky, homogenously mixed with nectar, occupying half or 2/5 of the cell volume ( Figs. 2–3 ). The color of the nests provision varied according to the host plant ( Figs. 2–3 ). The eggs were placed on the pollen masses ( Fig. 2 ). Adults of M. mendozana hatched between 17 and 27 December 2010 ( Table 1).

Pollen analysis. In all cells analyzed, we found 8 pollen types ( Fig. 4 ). Only grains type- Carduus , were present in all cells (62.1±29.4%), and in three cells pure pollen (100%) loads were found. Other pollen types found in various cells were type-Brassicaceae (21.3±16.1%, in 8 cells) and type-Lactuceae (7.5 ± 14.1%, in 5 cells). Pollen type- Centaurea was only found in two cells but in high percentages (39.2 and 57.2 %) each. The average percentage of Asteraceae pollen was 78.5 ± 28.6%.

Floral hosts. Adults of M. mendozana were collected in flowers of the following plant species: Baccharis pingraea , Carduus acanthoides , Centaurea solstitialis , Cirsium vulgare , Helianthus annuus , and Senecio pampeanus (Asteraceae) .

Figures

FIGURES 1 – 4. Megachile (Sayapis) mendozana. 1. Distribution records for females (●), males (Ο), and both sexes (). 2 - 3. Trap-nests removed and opened to expose cells. 2. Photographs of live eggs on provisions (cells 3 and 4 of nest # 38). The color of masses pollen is due to pollen of Carduus acanthoides and Cirsium vulgare. 3. Photographs of early instars 4. Percentage of pollen types found in the provisions and in fecal pellets. Scale lines. Figs. 2 – 3, 10 mm.