Table Of ContentPUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY
CENTRAL PARK WEST AT 79TH STREET, NEW YORK, NY 10024
Number 3680, 22 pp., 44 figures, 1 table March 4, 2010
Nests, Petal Usage, Floral Preferences, and
Immatures of Osmia (Ozbekosmia) avosetta
(Megachilidae: Megachilinae: Osmiini), Including
Biological Comparisons with Other Osmiine Bees
JEROME G. ROZEN, JR,1 HIKMET O¨ZBEK,2 JOHN S. ASCHER,3 CLAUDIO
SEDIVY,4 CHRISTOPHE PRAZ,5 ALIREZA MONFARED,6
AND ANDREAS MU¨LLER7
ABSTRACT
Hereinwedescribethenests(includingconstruction,closure,orientation,anddepthofcells)of
thebeeOsmia(Ozbekosmia)avosettaWarnckefoundnestingnearAntalya,Turkey,andSepidan,
Iran.Cellsareunusualinthattheyarelinedbytwolayersofcolorfulflowerpetalsthatsandwicha
thin middle layer of mud. Analyses of pollen taken from scopal hairs of specimens from the
Turkish site were identified as solely from Onobrychis viciifolia Scop. (Fabaceae) whereas those
fromtheIraniansitewerefromarelatedplant,HedysarumelymaiticumBoiss.andHausskn.These
facts coupled with analyses of scopal pollen from 11 other sites in Turkey, Jordan, and Syria
stronglysuggest that thisbee isoligolectic withrespect to the plant tribe Hedysareae.
1DivisionofInvertebrateZoology,AmericanMuseumofNaturalHistory,CentralParkWestat79thStreet,NewYork,
NY10024([email protected]).
2Atatu¨rk University, Faculty of Agriculture, Department of Plant Protection, 25240 Erzurum, Turkey (hozbek@
atauni.edu.tr).
3DivisionofInvertebrateZoology,AmericanMuseumofNaturalHistory,CentralParkWestat79thStreet,NewYork,
NY10024([email protected]).
4ETH Zurich, Applied Entomology, Schmelzbergstrasse 9/LFO, CH-8092 Zu¨rich, Switzerland (claudio.sedivy@
ipw.agrl.ethz.ch).
5CornellUniversity,DepartmentofEntomology,3119ComstockHall,IthacaNY14853([email protected]).
6YasoujUniversity,DepartmentofPlantProtection,FacultyofAgriculture,Yasouj,Iran(alirezamonfared1@yahoo.
com).
7ETH Zurich, Applied Entomology, Schmelzbergstrasse 9/LFO, CH-8092 Zu¨rich, Switzerland (andreas.mueller@
ipw.agrl.ethz.ch).
CopyrightEAmericanMuseumofNaturalHistory2010 ISSN0003-0082
2 AMERICAN MUSEUMNOVITATES NO. 3680
TheeggandlastlarvalinstarofOsmiaavosettaaredescribed.Thepresenceofaneggtakenfrom
acellandprovisionallyidentifiedasbelongingtoSapygapulcherrimaMorawitzsuggeststhatthis
cleptoparasite mayhave thisbeeas one ofits hosts.
Inaddition,wereportnewinformationonandreviewpublishedaccountsconcerningtheuseof
whole petals or large petal pieces in the construction of cell walls of osmiine bees. Only Osmia
(Ozbekosmia) avosetta and species of Osmia (Tergosmia) have three-layered cell walls with the
middle layer made of mud. Recorded also are the similarities and differences exhibited in pollen
andpetal preferences andnest characteristics of speciesin these tworelated subgenera.
INTRODUCTION mountain and fully exposed to the sun. The
groundwasmoderatelycoveredwithstandsof
We present for the first time information the food plant Onobrychis viciifolia Scop.
about the nesting biology, floral preferences, (Fabaceae) between which were more thinly
and immature stages of Osmia (Ozbekosmia) vegetatedareaswherewefoundnestentrances
avosetta Warncke, 1988. Although an uncom- (fig. 1). The slope of the surface varied here
monly encountered species, two nesting aggre- from 0u–20u. The surface soil was crusty with
gations of it were discovered almost simulta- pebbles and numerous fractures; beneath, the
neously, one in Turkey and the other in Iran, soil was dry and generally easily excavated,
andprovidedinformationforthecurrentstudy. thoughwithsomerocks.
Additionally, we review the use of petals as a The Iranian party discovered five nests of
building materialinosmiinebees and compare Osmia avosetta, which is a new species record
the biology of O. avosetta with that of species forIran,onMay31,2009,alongYasouj-Shiraz
belonging to Osmia (Tergosmia). These two new road, 6 km after Tange Tizab, at 10 km
subjectsaredealtwithintheDiscussionsection. northeast of Sepidan, Fars Province, Iran (N
The Turkish research party consisted of the 30u20960E51u509220,elev.2270m)(fig. 6).The
firstthreeauthors(Rozen,O¨zbek,andAscher), nesting site was a large, very steep scree slope
andtheIranianpartyofthenextthree(Sedivy, exposed to the north, with only scarce vegeta-
Praz, and Monfared). Mu¨ller was responsible tion.Thefoodsource,Hedysarumelymaiticum
forthestudyoffloralpreferences,thereviewof Boiss. and Hausskn. (Fabaceae) (fig. 7), grew
petal usage among osmiine bees, and the abundantly at the site and was visited by
section Comparative Biology of Ozbekosmia numerous females of Osmia avosetta, though
and Tergosmia, as Rozen was for descriptions no males were found. Although the ground at
ofimmaturestages. this site was mainly composed of stones and
gravel,allnestswerelocatedinsoilthatwasso
DESCRIPTION OF NESTING SITES loose and friable that we were able to dig out
the nests by hand. Where soil was more
In Antalya Province, Turkey, the Turkish compactonlessslopingsurfaces,nonestswere
partydiscoveredtwonestsofOsmiaavosettaat found. The five nests were scattered, and each
Seklik Mevkii (N 35u529520 E 30u229300), a containedonlyonecell.
smallvillage about6 kmeastofSaklıkent,the The first nest was found because we saw a
first nest on May 31, 2009, and the second on female enter a hole in the ground. This nest
June1,2009.Theelevationwasapproximately was still open, and the bee was inside the
1500 m on the east-facing slope of the brood cell. We found four more nests (each
mountain. The two nests were about 100 m containing a completely closed brood cell) by
apart,eachonasmall,partlytomostlybarren simply digging around other holes in the
mound of earth fully exposed to the sun. In ground, possibly an indication that the fe-
each case, the nesting surface sloped 20u–40u males do not fill the burrows with pebbles
from horizontal and the soil was moderately after finishing the brood cell.
fine,looselycompacted,andfriable.OnJune3, At the Turkish site, the entire nesting area
2009,wereturnedandfoundanaggregationof wasextensive,about30mlongand25mwide.
nesting females about 100 m from the closest Some nest entrances were circular holes, 5–
nestsitefoundearlier.Itwasataslightlyhigher 7mmindiameter,andotherswereirregularin
elevation, but still on the eastern slope of the shape,oftenassociatedwiththesurfacecracks
2010 ROZEN ETAL.: OSMIA(OZBEKOSMIA) AVOSETTA 3
(fig. 10). They were not uncommon (about side by side and contiguous, with one cell
1/m2), but irregularly distributed. Both males several millimeters higher than the other.
and females were seen at the nesting area However, in one nest the lower cell met the
visiting flowers of Onobrychis or landing side of the other at an angle.
briefly on the ground in barren areas. Cellstructure,alsoidenticalatthetwosites,
Several tumbling pairs observed from a is complicated, as must be the stereotypic
distance were probably mating, thus explain- procedure used by thefemalebee toconstruct
ing the appearance of both sexes in the area. it. In describing cells of most bees, the inner
dimensions (length and maximum width) of
NEST ARCHITECTURE the cavity are generally presented with some
idea of the shape of the lumen, but the cell of
Since it was our last day in the field at the this species isdelineated bythe externalshape
Turkish site, we hurriedly excavated approx- of the lining and characterized by the color
imately 10 nests, which we recognized by and materials that make up the lining. All
entering or departing bees. Only two or three materials used are collected and transported
consisted of two cells. All others contained a by the female from outside the nest. After the
single closed cell, an open cell being provi- femaledigsthemaintunnelandcavityforone
sioned, a cell being constructed, or no cell. At ortwocells,shebringsinlargepiecesofpetals
first we interpreted the paucity of cells to toline what will becometheouterenvelopeof
indicate that the foraging season was only the cell lining, probably first applying them to
starting.However,inhindsightwerealizethat, the lower surfaces of the cavity, and with
if completed nests normally contain only successive importations advancing the lining
single cells or two cells, we may well have upward on all sides, as evidenced by the
overlookednumerouscompletednestsbecause shingling of petals on the cell neck (fig. 12).
allbutoneneststudiedwereinitiallyidentified Theouterenvelopeisextendedintotheneckof
byadultsenteringorleaving.Hadwehadone the cell, well beyond (about 3 mm) what will
more day to identify and excavate nests becomethetopoftheclosedcell.Later,asthe
lacking evidence of adult activity, conclusions lastactofcellconstruction,thefemalewillfold
might have been different. Indeed, we now thesepetalsmesadtothelongaxisofthecellto
tentativelyconcludethattheynormallyconsist form theexterior cell closure of the completed
ofoneortwocellsbecausemostofthefemales cell (fig. 14). Apparently because petals of a
collected at the time of our fieldwork bear wide range of available flowers are used, the
lightly to moderately worn wings rather than colors on some cells include purple, blue, tan,
unworn wings. Nests at both sites were yellow, and red (fig. 11–13), but on other cells
shallow, with cells ranging in depth from 1.5 there is a more limited array of colors (figs. 8,
to at most 5.0 cm. In addition to the nest 9),probablyindicatinganarrowerselectionof
entrance, each had an open main burrow, 6– appropriateplantsinflower.
7mmindiameterthatinmostcasesdescended After the female completes the outer enve-
vertically,butinonecaseslantedsubstantially lope, she then brings in fine moist soil and
to one side, presumably because the female plasters it against the inner surface of this
had encountered a rock. There was no special lining,formingalayer 0.5–0.8mm thick. This
burrow lining nor did the burrow wall seem layer covers the entire inner surface of the
consolidated in any way, such as by tamping. outer envelope to where the closure will be
placed, so that the upper 3 mm of the petal
CELLORIENTATIONANDSTRUCTURE lining remains uncovered. The source and
nature of the moisture in the soil is unknown
Cells at both the Iranian and Turkish sites but may be water, a secretion, or possibly
were mostly vertical or nearly so, although a nectar. When the moist soil sets, it becomes
number tilted as much as 10u–20u from dull, pale, and hard (cause of the setting
vertical.Althoughonlysinglecellswerefound unknown, but perhaps simple drying). As the
inIran, wheretwocellswerefoundinasingle next step, the female imports petals to
nestinTurkey,theywerenormallypositioned completely line the cell cavity and thus forms
4 AMERICAN MUSEUMNOVITATES NO. 3680
the inner envelope, which extends upward moist soil or by adding some liquid to the dry
beyond the soil lining. At the entrance the soil to manufacture a smoothly concave outer
inner and outer envelopes adhere, forming a (upper)surfacetothesoilclosure(figs. 15–17).
central passageway through which the female Thisclosure,similarintextureandthicknessto
importsprovisionsanddepositshereggonthe the soil lining of the cell wall, bonds at its
top surface of the provisions (fig. 21). Thus, peripherytothesoillining.Howshemanufac-
the cell wall of the brood chamber before tures the smooth surface to the concavity
closure,exceptfortheupper3mm,consistsof remainsunknown.
three closely appressed layers: an outer enve- Asthefinalsteptoprotectheroffspring,the
lope of petals and an inner envelope of petals femalefoldsmesadthepetalsattheopenendof
that together sandwich a layer of soil. the outer envelope against the soil closure
At the Turkish site, we assumed that the (fig. 14).Onatleastthreeclosures,thefemales
petals were harvested from the numerous brought in and added several petals that were
adjacent flowering plants, including not part of the lining, presumably to augment
Onobrychis (fig. 1), as reflected in the multi- thethicknesstothetopoftheclosure.
colored outerenvelopes of thecells. However, In Turkey a single closed cell was acciden-
at the Iranian site the deep hue of the outer tally encountered when we were excavating
envelope (figs. 8, 9) did not appear at first to another nest. It contained an intermediate-
match any of the close-by flowering plants stagelarvaactivelyfeedingonprovisions.The
including the pale-flowered Hedysarum ely- colorful display of petals persisted on the
maiticum (fig. 7), the larval food source for outer envelope (fig. 5), but the soil lining to
Osmia avosetta at this site. Subsequently C.S. the cell had hardened considerably compared
concluded on reexamining the cells that all with this lining in fresher cells. Soon after
petals seemed to originate from the banner being collected the larva molted to the last
petalsofthisplantandthattheirdarker,more larval instar, described below. This accidental
purple hue resulted from withering after the discovery added to our suspicion the nests
petalsarecut.Henotedthatthepetalswereall containonlyoneortwocells,becausethiswas
shapedliketheupperpartofaheartandwere the only larva that we found in the 10 or so
arranged in the same manner: their tips nests we excavated at the Turkish site.
pointed downward and the cut side pointed Cells still open from both sites were
upward and they overlap like scales in both elongate(figs.4,11),becausethevisiblelining
the inner and the outer petal linings. includedboththecellitselfandthepetal-lined
Afteregglayingcomesthetaskofclosingthe neck. They measured 18.0–19.5 mm in length
cell, a process that the female carries out in (N 5 5). Closed cells were shorter since the
threesteps.Shefirstclosestheinnerenvelopby liningsoftheneckregionsarefoldedoverand
folding mesad the apical petals of the inner incorporatedintothecellclosure,asdescribed
envelope, thus closing the cell lumen and above. Closed cells measured 15.0–17.5 mm
formingatruncatedtopfortheinnerenvelope. (N 5 9) in length. All cells (open and closed)
This top measured about 4.5 mm in diameter were 7.0–9.0 mm in maximum outside diam-
(figs. 18, 19) in one case. She imports no eter (N 5 7). The widest part of closed cells
additionalpetalsfromtheoutside.Theclosure was between one-quarter and one-third of the
petals are somewhat moist and can be teased distance from the bottom of the cell. Cells
apart and unfolded with forceps to expose the were not symmetrical around their long axes;
celllumenbelow(fig. 20).Theeasebywhichwe all had one side that was convex while the
were able to unfold the inner closure without opposite side was slightly concave (figs. 2, 3).
tearing the petal tissue suggested the ease the Provisions were a sticky mixture of yellow-
femalebeehadinfoldingthesoftandcompliant orange pollen, homogeneously combined with
petaltissuewhenconstructingtheclosure. nectar. They occupied roughly the lower half
As the next step she brings in a small oftheinnerenvelopeofpetalsandconformed
quantity of dry soil to place into the slight totheshapeofthebottomofthecell.Ontheir
concavity formed on the top of the inner surface, the female deposited her elongate,
envelope closure, followed eitherby importing shiny egg (fig. 21), described below.
2010 ROZEN ETAL.: OSMIA(OZBEKOSMIA) AVOSETTA 5
FLORAL PREFERENCES being slightly shorter (2.5 mm long), much
thinner (maximum diameter 0.54 mm), faintly
At the nesting site near Saklıkent, Turkey,
curved, and broadly rounded at the anterior
females of Osmia avosetta were seen visiting
endbuttaperingposteriorlyandverynarrow-
only the flowers of Onobrychis viciifolia Scop.
ly rounded apically (fig. 31) with the widest
(Fabaceae) for larval provisions, although
part in the anterior one-quarter. We were
manyotherflowerswereavailableaspotential
unsuccessful in viewing its micropyle with an
pollen and nectar sources, e.g., Anchusa,
SEM. White in color like the host egg, it was
Salvia, Centaurea, Astragalus, and Melilotus.
suggestive of the egg of Sapyga luteomaculata
The microscopic analysis of pollen contained
Pic (Rozen and Kamel, 2009), which isfaintly
in the abdominal scopa of nine females
tan, shorter (length 1.96–2.1 mm), and slim-
collected at the nesting site on June 3, 2009,
mer (maximum diameter 0.44–0.46 mm). The
revealed that all females had indeed harvested
egg of S. louisi Krombein is similar though
pollen exclusively from Onobrychis viciifolia.
shorter(1.5mmlong)andnarrower(0.25mm
At the nesting site near Sepidan, Iran, the
atmiddiameter) (Mathews,1965: fig.16). The
females of Osmia avosetta were observed to
described egg of S. pumila Cresson (Torchio,
exclusively visit the flowers of Hedysarum
1972: figs. 2, 4) is even shorter (1.3 mm long)
elymaiticum,althoughmanyotherplantswere
and, proportional to its length considerably
flowering in the proximity of the nesting site,
slimmer (diameter at anterior end: 0.18 mm).
including several Fabaceae species of the
The slender, distinctive torpedolike shape of
genera Astragalus, Lotus, and Trifolium.
all previously described eggs strongly suggests
Microscopic pollen analysis corroborated the
that the parasitic egg found in the cell of
narrow host-plant preference of Osmia avo-
O. avosetta is a Sapyga or some related
setta at the Iranian site: pollen masses
Sapygidae. Because two individuals of
removed from the abdominal scopa of 15
Sapyga pulcherrima Morawitz, 1894, were
femalescollectedatthenestingsiteonMay31,
collected (but not entering nests) at the nest
2009, were entirely composed of Hedysarum
site during our study, it likely is that species.
pollen as were the pollen provisions of five
brood cells dug out the same day.
The exclusive utilization of pollen of IMMATURE STAGES
OnobrychisandHedysarum,whichformawell-
supported clade within the tribe Hedysareae ImmaturesofOsmiaavosettaandtheeggof
(Wojciechowski et al., 2004; McMahon and Sapyga pulcherrima described were collected
Sanderson, 2006; Ahangarian et al., 2007), at Seklik Mevkii, 6 km east of Saklıkent,
indicates that Osmia avosetta is most probably Antalya Province, Turkey, June 3, 2009 (J.G.
aspecialistonthisplanttribe.Thisconclusionis Rozen).
supported by microscopic analysis of scopal
pollencontentsof13additionalfemalescollect- DESCRIPTIONOF EGG
edat11differentlocalitiesinTurkey,Syria,and
Jordan,whichwereallexclusivelycomposedof Figures 21, 30
tricolpate Fabaceae pollen typical for
Onobrychis and several Hedysarum species as DIAGNOSIS: The egg of Osmia avosetta
well as for two other genera of the Hedysareae appears unremarkable, although we were
(ChoiandOhashi,1996). unable to examine it with an SEM and
therefore cannot describe its micropyle.
PARASITISM DESCRIPTION: Length 2.93 mm (N 5 2);
approximate maximum width 0.93 mm (N 5
Figure 31 3). Egg index 0.81 (see Remarks). Upper
surface slightly curved in lateral view
No cleptoparasites were seen entering any (fig. 30); ventral surface nearly straight; ante-
of the nests at either site, but we retrieved rior end (identified by developing embryo)
from a cell a single egg unlike that of Osmia slightlymorenarrowlyroundedthanposterior
avosetta at the Turkish site. It differed by end in lateral view (fig. 30); sides subparallel
6 AMERICAN MUSEUMNOVITATES NO. 3680
when viewed from above; micropyle not Lithurgini because the former have conspicu-
visible with stereomicroscope. Egg color ousbodysetaeandthelatterdonot.However,
white; chorion under stereoscope clear, shiny, we still do not know how to recognize the
glassy, thin throughout. tribes of the more advanced megachilids on
MATERIAL STUDIED: Three eggs. the basis of their mature larvae, much less to
REMARKS: The egg index of 0.81 was distinguish larval Osmia from other Osmiini.
calculated by dividing the average lengths of Because the osmiine Hoplitis monstrabilis has
two eggs by the distance between the outer approximately five setae on the pleural swell-
rimsofthetegulaeofafemalefromwhichone ing of abdominal segment 8 (Rozen, et al.
of the eggs was collected (Iwata and 2009), in contrast to approximately 80 in O.
Sakagami, 1966). This value falls well within avosetta has and perhaps also the same
themediumcategoryofIwataandSakagami’s number in O. (O.) ribifloris Cockerell, we at
(1966: table 2) classification of bee egg size firstthoughtthatsetalabundancemightprove
relativetofemalebodysize.Thisisthesecond valuable.However,thelarvaofO.(Pyrosmia)
species of osmiine bee with an egg index submicans Morawitz from Egypt has only 12
reported in this category; Hoplitis (Hoplitis) setae on this swelling, suggesting that setal
monstrabilis Tkalcu˚ has an egg index of 0.77 abundance may prove unreliable for generic
(Rozen et al., 2009). recognition after more species are surveyed.
Details of mandibular and atrial morphology
DESCRIPTIONOF LAST LARVAL INSTAR seem to vary among the Megachilinae and
mayprovehelpfulinrecognizingtribesand/or
Figures 32–40 genera despite the high degree of larval
homogeneity.
The single larva recovered was an interme- The peculiar absence of a sclerotized cardo
diate instarthat moltedto thelast instarsoon inthepresenceofawell-sclerotizedstipitalrod
afterward. Last instars of larvae of probably is a feature unknown in several other mature
all Megachilinae (except for the Lithurgini) larval Osmia that we have examined.
can be recognized because of extensive body DESCRIPTION: Head(figs. 33,34,37):Setae
setae, which are absent on earlier instars longandabundant;thoseoffronsshorterand
(Baker et al., 1985; Rozen and Kamel, 2009). those oflabrum veryshort;thoseofmaxillary
The larva was preserved after it had started and labial apices straight, forward projecting.
defecating and spinning silk. Although a Following areas moderately to faintly pig-
considerable amount of uneaten provisions mented: labrum including labral sclerite (ex-
remained in the cell, most fecal material had clusive of middle part), darkest part of which
beenvoidedbythetimeofpreservation.Head is along subapical row of sensilla; area apicad
capsule pigmentation was evident although ofdarkestpartalsosclerotizedandpigmented,
whetheritwasatitsmaximumdevelopmentis but extreme apical labral margin unpigment-
unknown.Afterbeingclearedbyboilinginan ed, nonsclerotized; mandibles especially at
aqueous solution of sodium hydroxide, pig- apicesandpointsofarticulation;internalhead
mentation was greatly reduced. ridges at articulation with mandibles; dorsal
DIAGNOSIS: As was pointed out earlier, surface of premental sclerite between attach-
larvae of the Megachilidae are ‘‘very homo- ment of articulating arms of stipites; antennal
geneous’’ (Michener, 1953: 1040). Since then papilla and all palpi only faintly pigmented.
mature larvae of other megachilid taxa have Finespiculationrestrictedtodorsalsurfaceof
been described (see McGinley, 1989, and maxilla and lateral lobes of hypopharynx.
references therein; Baker et al., 1985; Rozen Area immediately above hypostomal ridge
and O¨zbek, 2004; Rozen and Kamel, 2007, and just behind posterior mandibular articu-
2009; and Rozen et al., 2009). From these lation not produced as downward-directed
works, we see that the Osmiini, Anthidiini, tubercle as present in many Coelioxys
Dioxyini, and Megachilini as mature larvae (Rozen and Kamel, 2007: fig. 47). Coronal
can be easily distinguished from those of the ridge nearly absent; postoccipital ridge well
more basal Pararhophitini, Fideliini, and developed; hypostomal ridge well developed,
2010 ROZEN ETAL.: OSMIA(OZBEKOSMIA) AVOSETTA 7
giving rise to pronounced dorsal ramus that consistingoftwowidelyseparatedlaterallobes
extends posteriorly from middle of ridge that are spiculate.
nearly to postoccipital ridge (fig. 33) where it Body (figs. 32, 41): Body setae short, rising
abruptly stops; anterior tentorial pit approx- from swollen bases, abundant dorsally and
imately equally distant from anterior mandib- laterally; pleural area of abdominal segment 8
ular articulation and basal ring of antenna; with approximately 80 setae (fig. 41); integu-
epistomal ridge present only laterad of ante- ment in areas without setae with patches of
rior tentorial pits; tentorium robust including veryfinespicules.Bodyform robust;interseg-
dorsal arms. Parietal bands faintly evident. mental lines weakly incised on predefecating
Diameter of basal ring of antenna somewhat larva; intrasegmental lines not evident but
less than twice distance from ring to center of possiblyvisibleonpostdefecatingform;paired
anteriortentorialpit;antennalpapilla(fig. 39) body tubercles absent; middorsal body tuber-
small, slender, gradually, evenly tapering cles very evident on midbody segments,
apically, about three times as long as basal decreasing in size posteriorly (fig. 32); pleural
diameter, bearing two to three sensilla swellings moderately developed; abdominal
(fig. 39). Lower margin of clypeus strongly segment 10 attached to approximate middle
angled upward at midline (fig. 34), so that at of segment 9; anus positioned toward top of
midpoint margin nearly at level of anterior segment 10. Spiracles well sclerotized, unpig-
tentorial pits. Labral sclerite transverse, pig- mented,subequalindiameter;atriumglobular
mented(exceptatmidline),withlowermargin with width considerably greater than depth,
extending beyond apical band of sensilla; projecting above body wall, with rim; peri-
labrumlackingdarklypigmentedmedianspot treme narrow, so that diameter of atrial
extending from labral sclerite to apical labral opening as much as four times peritreme
margin as in fully pigmented Coelioxys larvae width; atrial inner surface with rows of
(Rozen and Kamel: 2007: figs. 44, 45); apical wrinkles (figs. 42–44) concentric with primary
labral margin moderately broad, distinctly tracheal opening; atrial wall also with fine,
concave (figs. 34, 37). sharply pointed, concentrically directed spic-
Mandible (figs. 35, 36) moderately robust; ules; primary tracheal opening with collar;
subatrium variable in length, with from four
apex bidentate with ventral tooth longer than
to10chambers;externally,subatriumtapering
dorsaltooth;bothteethacutelypointed;dorsal
in side view. Male with small crescentic
apical edge of dorsal tooth finely, regularly
(almost circular) median integumental scar
crenulated; ventral apical edge of upper tooth
on venter of posterior edge of abdominal
and both edges of ventral tooth unmodified;
segment 9; female sex characters unknown.
apical concavity pronounced, sharply defined
basally; cuspal area not developed; outer MATERIAL EXAMINED: One fifth instar.
surface without setae or tubercles. Cardo as a
sclerite absent; stipes a slender sclerotized rod DISCUSSION
posteriorly ending abruptly at point where it
BIOLOGYOF OSMIAAVOSETTA
wouldhavearticulatedwithcardo;articulating
arm of stipes evident; maxillary palpus mod- In light of the hazards that confront a nest
erately small, about same size as antennal shallowly situated in loose soil on a slopping
papilla and labial palpus. Labium clearly surface,wecanspeculateastohowacellwith
divided into prementum and postmentum; this construction might be beneficial. With
apex normally wide (figs. 34, 37); premental little or no rain during the summer months,
sclerite weakly sclerotized, most evident dor- rainfall leading to soil erosion is not a
sally;postmentumnonsclerotized.Salivarylips significant threat until after the immature
projecting, transverse, width about equal to reaches hibernation in its cocoon. However,
distance between bases of labial palpi; inner if the cell should be flooded by an unexpected
surface of at least upper lip, visible only after early storm, the double petal lining would
specimen subjected to critical-point drying seemingly deflect much water, and the air
process, with numerous parallel, raised ridges trapped by two layers of petals would help
extending outward (fig. 40). Hypopharynx float a cell that was eroded from the ground.
8 AMERICAN MUSEUMNOVITATES NO. 3680
Probably a more significant hazard is (Isosmia) rubrella Michener to build entire
desiccation especially in very shallow nests; brood cells(Yanega, 1994), and some osmiine
the double layer of petals, which are a source beespecies,whichusuallyutilizechewedgreen
of moisture in themselves, should help retain leaves as nest-building material, occasionally
moisture during larval development. Because also use chewed petals, e.g., Hoplitis
megachilid larvae in general seem little both- (Dasyosmia) biscutellae (Cockerell) (Rust,
ered by water loss, we wonder whether 1980), Osmia (Allosmia) rufohirta Latreille
maintaining the water content of the provi- (Grandi, 1961), or O. (Helicosmia) caerules-
sions might be the selective force for the cens (Linnaeus) (Westrich, 1990). However,
evolution of this elaborately structured cell theuseofwholepetalsorlargepiecesofpetals
wall. The rigidity added by the soil lining, of forbroodcellconstructionisrestrictedamong
course, protects the cell contents from being the Osmiini to O. (Ozbekosmia) avosetta, two
crushedorinvadedbypredatorsandparasites. species of Wainia (Caposmia), most Hoplitis
Although the patchwork of colors on the species of the subgenus Anthocopa as well as
outersurfaceofacell(figs.2–5,11)oreventhe all Osmia species of the subgenus Tergosmia
strong colors (figs. 8, 9) is a striking phenom- whose nesting biology has been recorded so
enontothehumaneye,colorofthecellsurface far (Mu¨ller et al., unpubl.). In the two Wainia
isobviouslynotimportanttothefemalebeeor species, which both nest in empty snail shells,
her nest. We think the survival value of the partitions between the brood cells are
constructing this elaborate cell lining of petals constructed from large petal pieces glued
andsoilisthetexture,watercontent,andwater together, whereas the nest plug is built from
repellent– and humidity-retaining nature of petals followed by a thick layer of cemented
petals. High water content provides moisture, sand(GessandGess,2008).Thebroodcellsof
thesofttissueofpetalsmakesthemeasyforthe Hoplitis(Anthocopa),whicharegenerallybuilt
femalestoharvest,thecompliantnatureofthe in excavated or preexisting burrows in the
tissue is easily folded, and the lack of plant groundor,morerarely,infissuresandholesin
hairsallowspetalstoadheretooneanother. rocks and bark, under stones or in empty
We here have interpreted the closure of the snail shells, are entirely constructed from
brood cell of Osmia avosetta as an integral foreign material (Mu¨ller et al., unpubl.).
component of the lining of the cell. Still to be Petals are used by most of these species as
exploredistheconstructionofthecellclosures the exclusive cell building material. However,
of other osmiine taxa that use whole petals or the two closely related H. (Anthocopa) graeca
largepetalpiecestoformcellwalls.InHoplitis (Tkalcu˚)andH.(Anthocopa)villosa(Schenck)
(Anthocopa) dalmatica (Morawitz), whose apply mud in varying quantities to cement
cells consist of an outer layer of roughly the petals together (Ducke, 1900; Friese,
chewedleavesandaninnerlayeroflargepetal 1923; Petit, 1970; Westrich, 1990; A. Mu¨ller,
pieces, the females immediately close the cell personal obs.). In contrast to O. avosetta,
after egg deposition by folding mesad the however, the cells of these two species are not
apical petals (Mu¨ller, Krebs, and Amiet, three-layered; instead petals and mud are
1997), corresponding to the first step of cell more thoroughly mixed. A three-layered cell
closure in Osmia avosetta. With newly collect- structure consisting of a mud layer sand-
ed leaf material that is applied onto the petal wiched between two layers of petals, which is
layer, H. dalmatica then finally closes the verycharacteristicofO.avosetta,isalsofound
brood cell. in O. lunata Benoist (A. Mu¨ller, personal
obs.), O. rhodoensis (Zanden) (C. Praz and C.
Sedivy, personal obs.) and O. tergestensis
PETALSAS NEST BUILDING MATERIALIN
Ducke (Ferton, 1897; Mu¨ller et al., 1997),
OSMIINE BEES
which all belong to the subgenus Tergosmia.
Among the osmiine bees, the use of petals This unique cell structure shared by both
for brood cell construction is not confined to Ozbekosmia and Tergosmia indicates that
Osmia avosetta. Roughly chewed petals of these two subgenera most probably form a
Dalea (Fabaceae) are used by Ashmeadiella monophyletic group within the genus Osmia.
2010 ROZEN ETAL.: OSMIA(OZBEKOSMIA) AVOSETTA 9
Fig. 1. Nesting site of Osmia avosetta in Seklik Mevkii, Turkey, to the left of observers in fore- and
midground;notepinkish-redflowersofpollenplant,Onobrychisviciifolia.Figures2,3.Closedbroodcellsof
O.avosetta,sideviews,showingshapeandvariationincolorationofouterenvelopes.Figure4.Opencellof
same,side view. Figure5. Closed cellof same containing intermediate stagelarva. (PhotosJ.G. Rozen.)
This hypothesis is supported by the close 2007). Indeed, Warncke (1988) placed O.
morphological similarity of O. avosetta to avosetta in the subgenus Tergosmia before
Tergosmia, e.g., in the form of the female Zanden (1994) moved it to the new subgenus
clypeus and of the male sterna (Michener, Ozbekosmia due to several deviating charac-
10 AMERICAN MUSEUMNOVITATES NO. 3680
Figs.6–9. NestingofOsmiaavosettaat10kmnortheastofSepidan,Yasoujregion,Iran.6.Thesite.7.
Pollen plant,Hedysarum elymaiticum.8, 9. Twobroodcells.(Photos C.Sedivy).
