Beediverse - Asian Monodontomerus osmiae Kamijo found in USA

Asian Monodontomerus osmiae Kamijo found in USA

Folks- my apologies for the bulk mailing of blind copies (Bcc) and possible cross-listings in the interests of efficiency and speed. We apprently now have an Asian parasite of Osmia in our midst. Eric Grissell only brought this finding to my attention this morning, after corresponding with Frank Parker about it yesterday. I hope to have pictures to add to his descriptions below to allow distinction of this species from the native congenerics that plague Osmia here. We also hope to discover if it is staying with its Japanese host or has moved over to O lignaria, at least in nesting materials from Eric's home. If you have any Monodontomerus emerging from your O lignaria holdings, you might want to freeze a hundred or two of the little devils to await guidance on their identification. If we are lucky, perhaps they have not yet travelled far.

jim cane

RE: Discovery of Monodontomerus osmiae Kamijo (Hymenoptera: Torymidae) in
the New World

From: Eric E. Grissell, Systematic Entomology Laboratory, USDA, ARS, PSI, c/o
National Museum of Natural History, Washington, D. C. 20560-0168, USA
(email: egrissel@sel.barc.usda.gov)

Monodontomerus osmiae Kamijo is a gregarious parasitoid of megachilid bees
(Hymenoptera: Megachilidae). It was first discovered and named in Japan
where it was reared from Osmia taurus Smith and O. excavata Alfken (Kamijo
1963). Subsequently it was reared from O. cornifrons Radoszkowski, the
Japanese hornfaced bee, in Japan (Kamijo 1965). This latter bee was released
into the United States sometime in the 1970's, and is available
commercially (MAAREC 2001). Other than Japan, Monodontomerus osmiae has been
reported only from the "Russian Far East" (ex Osmia taurus) by Zerova and
Romasenko (1986) who keyed and figured the species in a paper on the
parasitoids of megachilid bees in the former USSR.

Recently I discovered Monodontomerus osmiae attacking Osmia spp. nesting in
paper tubes that I set out in my Silver Spring, Montgomery County, Maryland
garden. These represent the first known specimens of the parasitoid in the
New World.

I recently revised the genus Monodontomerus for the New World (Grissell
2000). This genus has a number of species that parasitize solitary bees. In
spring of 2001 I placed about 100 bee-nesting tubes (paper straws), used to
attract solitary bees, in a sheltered overhang near my house. No attempt was
made to exclude parasitoids from these nesting tubes. In June and July of
2002 I collected a total of 214 adult parasitoids as they were flying around
and landing on the nest tubes. Of these wasps, 38 were M. osmiae (37
females) and 176 were the locally common M. obscurus Westwood. These
collections were two random samples one month apart. Both species of wasp
were collected both times, and they represented only a small fraction of the
total number of adult parasitoids flying around the nest site.

Virtually nothing is known about the biology of Monodontomerus osmiae.
Iwata and Tachikawa (1966) reported a preponderance of females for rearings
of this species from Osmia taurus. From 61 cocoons 87 males and 726 females
emerged. The number of parasitoids per host (counted for 4 cocoons only)
varied from 14 to 26. This highly skewed female sex ratio and gregarious
larval behavior is typical for known species of Monodontomerus (Grissell
2000) and makes them especially effective parasitoids.

[Eric writes the following regarding distinguishing this species from our native ones on Osmia]
"as a quick id tool, the wasp is smaller than Monodontomerus obscurus (and
aeneus), is metallic blue (not green), the female has the ovipositor about
as long as the abdomen (longer in other monos) and the male has the face
severely concave between the eyes (I've attached a jpg of the male) so that
it appears to be collapsed but it is structural and not due to drying out
(the males are uncommon, but reliably bizarre). the face of the female is
also slightly modified, but it's not easy to describe."

Literature Cited
Grissell, E. E. 2000. A Revision of New World Monodontomerus Westwood
(Hymenoptera: Chalcidoidea: Torymidae). Contributions of the American
Entomological Institute 32 (1): 1-90.

Iwata, K., and T. Tachikawa. 1966. Biological observations on 53 species of
the superfamilies, Chalcidoidea and Proctotrupoidea, from Japan
(Hymenoptera: Apocrita) [sic]. Trans. Shikoku Entomol. Soc. 9: 1-29.

Kamijo, K. 1963. A revision of the species of the Monodontomerinae
occurring in Japan (Hymenoptera: Chalcidoidea) [Taxonomic studies on the
Torymidae of Japan, II]. Insecta Matsumurana 26: 89-98.

Kamijo, K. 1965. A new host-record of Monodontomerus osimae Kamijo. Insecta
Matsumurana 28: 78.

MAAREC 2001. Basic biology and management of the Japanese hornfaced bee.
Mid-Atlantic
Apicultural Research & Extension Consortium. Publication 5.5. 3 pgs.

Zerova, M. D., and Romasenko L. P. 1986. [Chalcidoids (Hymenoptera,
Chalcidoidea), parasitoids of leafcutting bees (Hymenoptera, Megachilidae),
in the fauna of the USSR]. [In Russian]. Zoologicheskii Zhurnal 65:
1631-1643.