Megachile (Eurymella) patellimana

Gess, Sarah Kathleen & Roosenschoon, Peter Alexander, 2017, Notes on the nesting of three species of Megachilinae in the Dubai Desert Conservation Reserve, UAE, Journal of Hymenoptera Research 54, pp. 43-56 : 47-49

Megachile (Eurymella) patellimana

Taxonomy.

In Gess and Gess (2003) and in Gess and Roosenschoon (2016) Megachile patellimana is given as belonging to the subgenus Eutricharaea , following Michener (2007) who did not consider the subgenus Eurymella Pasteels (1965) to be distinct from the subgenus Eutricharaea . Michener’s opinion was generally accepted (e.g. Eardley et al. 2010, Eardley 2013). However, in their analysis Trunz et al. (2016) revisit the status of Eurymella and recognize it as a valid subgenus distinct from Eutricharaea Their opinion has been accepted and in the present contribution Eurymella is recognized as being distinct from Eutricharaea given that both groups appear distantly related in the phylogeny of Trunz et al.

The female of Megachile patellimana , like most species of Eurymella , has robust mandibles with particularly large and acute teeth, as also seen in the subgenus Creightonella . In Eutricharaea , in contrast, the female mandibles are mostly less robust and the teeth smaller.

Distribution.

Widely distributed in western Palaearctic, particularly in the Mediterranean, Asia Minor, Egypt and UAE, also south-western Africa, Sudan, Niger and Mozambique ( Gess and Roosenschoon 2016).

Flower visiting.

In the DDCR Megachile patellimana has been recorded from flowers of Apocynaceae: Asclepiadoideae, Leptadenia pyrotechnica ; Asteraceae: Centaurea pseudosinaica Czerep.; Boraginaceae: Heliotropium kotschyi ; Brassicaceae: Farsetia linearis Decne ex Boiss.; Fabaceae: Mimosoideae: Prosopis cineraria ; Fabaceae: Papilionoideae: Crotalaria aegyptiaca Benth.; Zygophyllaceae: Tribulus maropterus Boiss.( Gess and Roosenschoon 2016).

In Namibia this species has been recorded from flowers of Crotalaria podocarpa DC ( Papilionoideae) ( Gess and Gess 2003).

Nesting.

The only published mention of the nesting of Megachile patellimana appears to be the statement in Alfken (1934, page 148) that "Als echte Blattschneiderbiene ist auch Megachile patellimana M. Spin. beobachet worden" [ Megachile patellimana has also been observed as a true leaf-cutting species]. The nesting situation does not seem to have been recorded.

The only other observations on nesting by a species of the subgenus Eurymella seem to be those for Megachile bucephala (Fabricius) (as Megachile semifulva Friese, recently placed in synonymy with Megachile bucephala (Eardley, 2013); this synonymy requires confirmation given that Pasteels (1965: 127) mentions that there are sculptural differences between Megachile semifulva and Megachile bucephala (C. Praz, pers. comm.)). These observations "Nests in ground 6-7 inched vertical; lined with blade of certain grass, selected them before biting; measures it by running up and down. The pieces varied in length from 3-4 inches. St. W. Warley, 29.X.1916" quoted by Pasteels (1965: page 127) are from manuscript copies in the Natal and Durban museums.

It therefore seems worth recording the fragmentary observations on the nesting of Megachile patellimana in the DDCR where it was observed to be nesting at Tawi Manana in burrows excavated in compacted sand beneath Heliotropium kotschyi plants and at the Camel Farm in burrows excavated in the compacted sand banks of an irrigation furrow. It was not clear whether the burrows had been originated by Megachile patellimana or were pre-existing.

At Tawi Manana a female was captured carrying a piece of cut green leaf (approx. length 10 mm and approx. width 5 mm) and at the Camel Farm a female was captured carrying into a burrow a piece of tough green plastic approximately 10 mm in length cut from a strip 2 mm wide and almost 1 mm in thickness (Fig. 16 ). Attempts to excavate the nests did not yield nest plans. In the nest of the female carrying plastic six more identical pieces of plastic (average length10 mm) were discovered grouped together in an apparent attempt to construct a cell. The cutting of the tough plastic would have been possible by using the large, robustly and acutely toothed mandibles.

The use of plastic by Megahile patellimana , though surprising, is supported by the observations of MacIvor and Moore (2013) who reported that Megachile rotundata Fabricius, which normally uses cut pieces of plant leaf, was found constructing brood cells out of cut pieces of polyethylene-based plastic bags. In addition to recording the use of plastic bags by Megachile rotundata MacIvor and Moore reported, even more surprisingly, that Megachile campanulae (Robertson), which uses plant and tree resins, was found to have made brood cells constructed out of a polyurethane-based exterior building sealant. In their discussion they suggested that "Although perhaps incidentally collected, the novel use of plastics in the nests of bees could reflect eco logically adaptive traits necessary for survival in an increasingly human-dominated environment".

It is clear that the flexible pieces cut from polyethylene bags by Megachile rotundata were successfully used to construct cells whereas it is seems unlikely that Megahile patellimana would have successfully constructed cells from the stiff, narrow strips of plastic that she was assembling within her nesting burrow.

Provision. As both the nesting females were captured carrying nesting materials their scopae were empty and as nesting was in an early stage no provision was obtained from the nests.

Figures

Figure 16. Megachile patellimana: female (actual length approx. 16 mm) with a leaf piece (green and fresh when collected) and female (actual length approx. 16 mm) with cut lengths of plastic, one from female and the rest from her nesting burrow.