ARS | Publication request: Cuticular Lipids of Female Solitary Bees, Osmia lignaria Say and Megachile rotundata (F.) (Hymenoptera: Megachilidae)

Submitted to: Comparative Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 28, 2009
Publication Date: June 1, 2009
Repository URL: http://ddr.nal.usda.gov/bitstream/10113/29904/1/IND44209856.pdf
Citation: Buckner, J.S., Pitts Singer, T., Guedot, C.N., Hagen, M.M., Fatland, C.L., Kemp, W.P. 2009. Cuticular Lipids of Female Solitary Bees, Osmia lignaria Say and Megachile rotundata (F.) (Hymenoptera: Megachilidae). Comparative Biochemistry and Physiology B. 153(2):200-205.

Interpretive Summary: The cavity-nesting adult solitary bees, alfalfa leafcutting bees (Megachile rotundata) and blue orchard bees (Osmia lignaria) are proficient pollinators of forage crops and orchard crops, respectively. ARS scientists at Logan, UT and Fargo, ND are using gas chromatography (GC) and GC-mass spectrometry to learn more about the natural chemicals in nests of these pollinating non-honey bees and in finding the source of nest-marking chemicals that each female bee secrete in order to locate her own nest. Possible sources of chemical cues can include the female bee’s own cuticular (surface) lipids, and in this study, the cuticular lipids of female adult M. rotundata and O. lignaria were identified and quantified. The cuticular lipids of these female bees consisted of mainly hydrocarbons with lesser quantities of long-chain wax esters. For M. rotundata, 48% of the cuticular lipids were C23-C33 saturated hydrocarbons (alkanes) with nearly the same quantities of the same chain length unsaturated hydrocarbons (mono-alkenes). For O. lignaria, nearly 64% of the cuticular lipids were C25-C31 mono-alkenes. For the mono-alkenes of O. lignaria, 14 mono-alkene constituents were identified and two alkenes, 9-C27 and 7-C29, comprised 67% of the total alkene distribution. For M. rotundata females, the mixtures of mono-alkenes were more complex with 26 constituents identified and quantified.

Technical Abstract: The cuticular lipids of the cavity-nesting adult female solitary bees, Osmia lignaria Say and Megachile rotundata (F.) (Hymenoptera: Megachilidae), were analyzed by gas chromatography (GC) and combined GC-mass spectrometry. The cuticular lipids of these female bees mainly consisted of hydrocarbons. For O. lignaria, nearly 64% of the cuticular lipids were C25-C31 mono-alkenes. For M. rotundata, 48% of the cuticular lipids were C23-C33 alkanes with nearly the same quantities of the same chain length mono-alkenes (45%). For the mono-alkenes of O. lignaria, 14 mono-alkene constituents were identified, with two of these, 9-heptacosene and 7-nonacosene, comprising 67% of the total alkene distribution. For M. rotundata females, the mixtures of mono-alkenes were more complex with 26 constituents identified and quantified. For the M. rotundata mono-alkenes, 57% of the total composition consisted of the three alkenes, 7-pentacosene, 9-pentacosene and 7-heptacosene. For both bee species, small quantities of C40-C48 wax esters were also characterized with the major components possessing a C18 mono-unsaturated fatty acid (9-octadecenoate) moiety esterified to even-carbon number (C22-30) fatty alcohols. The possible role of these cuticular lipids as nest recognition chemicals is discussed in light of nesting behavior of managed crop pollinators.