The biology of Hoplitis (Robertsonella) simplex (Cresson), with a synopsis of the subgenus Robertsonella Titus

2009·11.7 MB·English

by  John L Neff

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The Biology' of Ho'ji'litis 'Robertsomila' si'Kvlr^: 'Cressoni, with a
SjTLopsis of the Subgenus Ro'Os:-f^sc?:6llu Titus
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152 Journalof Hyaiexoptefla Research: Festschrift Hoxorixg Roy Sxellixg
are recorded at the county level. Abbrevi- found Herfades simplex Cresson to be a
ations are as in Neff (2004). Statistics were senior synonym of R. gleasoni. He also
calculated with JMP® and are presented relegated Robertsonella crataegina Cockerell,
as the mean ± 1 s. d. a species described from Texas (Cockerell
Institutions or collections where para- 1909), to subspecific status under R. sim-
types are deposited, as well as the sites for plex. Hurd and Michener (1955) later
other material examined, are as follows: placed Robertsonella as a subgenus of
American Museum of Natural History, Hoplitis stating that its primary distin-
New York, New York (AMNH); Snow guishing character, the near horizontal
Entomology Museum, University of Kan- metanotum, did not outweigh its many
sas, Lawrence, Kansas (KSEM); Museum of similarities with Hoplitis. Later, the place-
Entomology, Florida State University, Tal- ment of Robertsonella in Hoplitis was
lahassee, Florida (FSCA): Texas A & M strengthened by the discovery that Robert-
University Insect Collection, College Sta- sonella shared the key synapomorphy of
tion, Texas (TAMU); U. S. National Muse- Hoplitis, the flap-like gradular projections
um of Natural History, Smithsonian Insti- of the male S6 (Griswold and Michener
tution, Washington, D. C. (USNM); Utah 1998; Michener 2007).
State Universit\^ Bee Biology and System- Species concepts in Robertsonella were
atics Laboratory, Logan, Utah (BLCU); greatly altered by Mitchell (1962). He
North Carolina State University Insect described a new species, Hoplitis (Robertso-
Collection, Raleigh, North Carolina nella) micheneri MitcheU, from Kansas and
(NCSU); Purdue University Insect Collec- Georgia, resurrected gleasoni as a distinct
tion, WestLafayette, Indiana (PURC); M. S. species (with crataegina as a synonym), and
Arduser Collection, St. Louis, Missouri described a new male that he associated
(MSAC); Central Texas Melittological In- with H. simplex. Although he separated the
stitute, Austin, Texas (CTMI); Bracken- females oigleasoni andsimplexinhis key on
ridge Field Lab Collection, The University the basis of their tergal punctation (close
of Texas at Austin, Austin, Texas (BFLC). and coarse in H. gleasoni, finer and sparser
in H. simplex), he stated in the text that the
TAXONOMIC HISTORY
females of the tv\^o species could not be
Robertsonella has had a troubled taxo- reliably separated. He went on to note that
nomic history. The name was originally he might have erred when he associated
proposed by Titus (1904) for Robertsonella his new male with H. simplex, a species
gleasoni Titus, a new genus and species of previously known only as a female. A re-
megachilid bee from Grand Island, Illinois. examination of the types of H. simplex and
For many years there was confusion as to H. gleasoni, plus an analysis of the distri-
identity ofthesebees since,whilethemales bution of males, discussed below, involv-
are fairly distinctive among osmiine mega- ing more material than was available to
chilids, the females are not. Females of Mitchell, indicates the sexes were indeed
Alcidamea, another group previously given misassociated. A new species is described
generic status but now also considered to below for the male he incorrectly assigned
be a subgenus of Hoplitis, were commonly to H. simplex.
A
misidentified as Robertsonella, leading to a fourth species, Robertsonella himachalli
misleadingly expansive distribution (Grae- Gupta was described from northwestern
nicher 1909; Hurd et al. 1980; Michener India in 1991, apparently under the erro-
1941, 1947; Pearson 1933) and some spuri- neous impression that females of Robertso-
ous host-parasite associations (Swenk 1914; nella have an apico-median clypeal projec-
Hurd 1979) for Robertsonella. In the first tion. If validly placed, this would be a
revision of Robertsonella, Michener (1938) remarkable range extension. Although I
Volume 18, Number2, 2009 153
have seenno specimens ofthis species, itis
clear from the description and the charac-
ters used in the generic key (Gupta 1991,
1999) that this large (12 mm), metallic-blue
species, the males of which have an
apically emarginate T6 does not belong in
Robertsonella and almost certainly is not a
Hoplitis.
SYSTEMATICS
Hoplitis (Robertsonella) micheneri
• = nemophilae
Mitchell = micheneri
• = simplex
Hoplitis (Robertsonella) micheneri Mitchell, 1962.
N. C. Agr. Expt. Sta. Tech. Bui. 152: 65 (m, f)
—
Distribution. USA: Florida (Jackson, Su- Fig. 1. Map of the distribution ofHoplitis (Robertso-
wannee); Georgia (Cobb, Fulton, Hamilton): nella) spp. based onmales.
Kansas (Douglas, Miami, Riley); Missouri
Stange stated they were "around small
(Shannon, Stoddard); North Carolina (Rich-
holes in old trees'', suggesting this species
mond).
utilizes smallpreexistingholes forits nests.
While sometimes locally abundant, (in- Females are about the same size as
dicated by multiple collections from Su- Hoplitis simplex (HW = 2.19 ± 0.11 mm,
wanneeCo.,Florida),thisbee appearstobe 1.84-2.44, n=33; BL = 7.31 ± 0.52 mm,
rare with a possibly disjunct distribution. 6.16-8.48, n = 25) and are easily separated
Populations are known from Kansas and
from other Robertsonella by having Tl
Missouri and the southeastern U.S. (Flor-
shining with the punctures very fine and
ida, Georgia and North Carolina) (Fig. 1). sparse. Males have the same pattern of
Originally known only from Kansas and
facial pubescence as H. nemophilae but are
Georgia (Mitchell 1962), newer records about the same size as H. simplex (HW =
from Missouri, North Carolina and Florida 1.94 ± 0.05 mm, 1.79-2.20, n = 10 in H.
suggest additional fieldwork may elimi- micheneri vs. 1.92 ± 0.10 mm, 1.68-2.12, n
nate the current disjunction in its distribu- = 66 in H. simplex). Males are distinctive in
tion. Available floral records for females
having S3 deeply emarginate (Fig. 5)
indicate it is specialist on Amorphafruticosa [emargination of S3 very shallow and
(L.) (Fabaceae), a widespread shrub of the obscure in H. nemophilae and H. simplex
eastern U. S. It has repeatedly been
collected on A. fruticosa in Kansas and (Fig. 4)].
Missouri and pollen analysis ofthe females Hoplitis (Robertsonella) simplex (Cresson)
from Florida collected at a nest site
indicated scopal loads of nearly pure A. Heriades simplex Cresson, 1864. Ent. Soc. Phila.
fruticosa pollen. Other floral records in- Proc. 2, p. 384, f.
Robertsonella gleasoni Titus, 1904. N. Y. Ent. Soc.
clude Rubus (Rosaceae) and Melilotus offi- Jour. 12, p. 23, f, m.
cinalis (L.) Pall. (Fabaceae). Hoplitis miche- Robertsonella crataegina Cockerell, 1909. Ann.
neri, like other Robertsonella, is a vernal bee Mag. Nat. Hist. (8) 4. 28.
with flight records from 16 April (in Robertsonella simplex simplex: Michener, 1938.
Florida) to 13 June (in Missouri). Labels Ent. News 49, p. 131.
from a series of females from Suwannee Robertsonella simplex crataegina: Michener, 1938.
River State Park, Florida collected by L. Ent. News 49, p. 130.
154 Journalof Hymenoptera Research: Festschrift Honoring Roy Swelling
Hoplitis (Robertsouella) gleasoni: Mitchell, 1962. simplex are, on average, slightly larger and
N. C. Agr. Expt. Sta. Tech. Bui. 152: 65 (m,fin more coarsely punctate than those of H.
part) nemophilae, their size ranges overlap great-
— ly, and, as the coarseness of the punctation
Distribution. USA: Arkansas (Washing-
varies with size, that character does as
ton); Connecticut (Hartford); Illinois (Jack-
well.
son Kansas (LaBette); Missouri (Dent,
); New Hoplitis simplex appears to be an oligo-
Jejferson, Shannon); Jersey (Camden); lege of the Boraginaceae: Hydrophylloi-
North Carolina (Wake); Oklahoma (Atoka,
deae. The vastmajority offloral records for
Kiowa); South Carolina (Anderson); Texas
females are for various Nemophila and
(Bastrop, Bee, Bexar, Blanco, Burleson, Goliad, Phacelia species. The only plants from
Gonzalez, Grimes, Guadalupe, Karnes, Lamar,
which I have observed H. simplex females
Lee, Limestone, Travis, Washington, William-
collecting pollen are Nemophila phacelioides
son); Virginia (Fairfax). Nutt., N. sayersensis Simpson et ah, Phacelia
Males of Hoplitis gleasoni and H. simplex congesta Hook, andP. strictiflora (Engelm. &
(sensu Mitchell 1962) are easily separated Gray) Gray in Texas (all Boraginaceae:
by the characters in the key of Mitchell
Hydrophylloideae). Unfortunately, there
(1962). Males of Hoplitis gleasoni (sensu are very few floral records for specimens
Mitchell 1962) occur from Connecticut fromthe northern part ofits range. Hoplitis
and New Jersey to central Texas while simplex is a vernal bee, active from mid
males of H. simplex (sensu Mitchell 1962) March and April (in Texas) to late May (in
are known from Indiana and North Car- Connecticut). A number of simplex-like
olina to central Tamaulipas (Fig. 1). As females have been collected in Maryland
notedby Mitchell (1962), the female type of in early June, but as no males were
H. simplex, and females from thetype series associated with these specimens, it is not
ofH. gleasoni arenot distinguishable soitis clear ifthey are H. simplex or H. nemophilae.
not obvious why the new male described The nest biology of H. simplex is de-
by Mitchell was assigned to H. simplex. As scribed below.
the female type of Hoplitis simplex (Cres-
son) is from Connecticut but the nearest Hoplitis (Robertsonella) nemophilae Neff,
male of H. simplex (sensu Mitchell 1962) new species
occurs some 1300 km awaywhile a male of
H. gleasoni (sensu Mitchell 1962 is known Hoplitis (Robertsonella)simplex: Mitchell, 1962. N.
C. Agr. Expt. Sta. Tech. Bui. 152: 66. (m, f in
from Connecticut (Fig. 1) , it seems clear part)
thatthe sexes were misassociated in Mitch-
—
ell (1962). Thus, the original judgment of Diagnosis. Males of Hoplitis nemophilae
Michener (1938), that H. gleasoni is ajunior are distinguished from males of H. simplex
synonym of H. simplex, is correct and H. by the longer, more erect clypeal pubes-
simplex sensu Mitchell needs a new name cence, shorter mandibular fringe. They
that is provided below. differ from H. micheneri by the weakly
Males of Hoplitis simplex are easily emarginate margin of S3 (strongly emar-
distinguished from other Robertsonella, ginate in H. micheneri). Females of H.
and all other North American osmiines, nemophilae differ from those ofH. micheneri
by the long mandibular fringe and the by their denser punctation of Tl and lack
short, dense, appressed pubescence ob- the antero-median scutellar groove of that
scuring the clypeal surface. Females of H. species. As noted above, females of H.
simplex can be distinguished from H. nemophilae tend to be smaller and more
micheneri by the characters listed above finelypunctate than those ofH. simplex,but
and in the key. Although females of H. I know of no characters that consistently
VoLL^iE IS, X-.3ZR2, 2009 155
distinguish females ofH. nemophilae and H. pimctures, punctures larger than on scu-
simplex. tum. Legs normal. Abdomen: Terga shining,
—
Description. Male: Measurements; BL = punctures fine, 1-3 P\V apart, becoming
5.84 ± 0.32 mm, 5.04-6.65, n = 21; H\V = sUghtly finer, denser to^vards distal mar-
1.70 = 0.08 mm, 1.54-1.84, n = 57. Head: gins. Terga 3-7 ^vith narrow, impunctate
Face approx. 1.2 x as broad as long, eyes distal margins, impunctate areas broadest
convergent below (UIOD 1.4 x LIODj. on T6 and T7 ^vhich are slightly upturned,
Ch'peus sHghtlv convex, apical margin tlange-hke. T6 with minute lateral tooth, T7
nearly straight, disc shining ^vith fine, rounded apically and ^vith disc ^veaklv
subcontiguous punctures. Supracl}"peal ar- depressed. S2 subconvex, most of apical
ea, parocular area, frons, vertex and gena margin straight, ^vith dense, shallo^v punc-
finely, denselv punctate. Labrum ^vith tation. Apical margin S3 ver^- ^veaklv
apical margin ^veakly concave;basal width emarginate mediallv, other^vise nearlv
approx. 1.6 x length; apical ^vidth sub- straight, punctures as in S2 laterallv but
equal to length; basal 1 3 to 1 2 smooth becoming ven* fine and dense medially.
and shiny ^vith ver}- fine, ver\- sparse Margin S4 straight, punctures as in S2.
punctures, punctures of distal half stron- Margin S5 straight but more rounded
ger, denser. Lateral ocelli closer to vertex laterally, punctures as in S4. Margin S6
than to eye (OC-O OC-V = 1.5) with more convex but almost straight medially,
distance bet^veen lateral oceUi subequal to surface smooth, nearly impunctate. 54-6
distance from lateral ocelli to eve. Scape with narrow, translucent gradular tlaps.
slender, unmodified (scape length 2.8 S7, S8 and genital capsule as in figure 25 of
times apical ^vidth); pedicel completely H. simplex sensu Mitchell (Mitchell, 1962);
exposed; length flageUum (excluding ped- gonocoxites ^vith hairs of ventral surface
icel) 5x scape length; flagellar segments erect, primarily in median portion. Vesti-
(except first which tapers and is about as ture: Hair aU pale, sparse, erect except:
long as its apical %\idth) slender, simple, ch"peu5 ^vith dense, erect to semi-erect,
mm
about 1.5 X as long as ^\-ide. Gena about as 0.32-0.35 long hairs with numerous
wide as eye medially (in lateral view), short branches, hairs obscuring surface on
tapering belo^v. H^-postomal area shining, apical 4 5 of ch"peus; hair of supracl\~peal
sparsely punctate. Mandible bidentate. area ver\- short (0.04-0.08 mm), sub-ap-
Extended tongue length (glossa - premen- pressed, sparse; hairs ofparocular area and
tum 2.0-2.2 mm, roughlv 1.3 x head lateral areas of frons similar to those of
length). Ratio lengths labial palps: 3:6:1:1. ch"peus but sparser, not obscuring surface;
Four maxillar}' palps, ver}* short, fourth mandibular fringe weak, hairs 0.22-
mm
greatly reduced. Tliorax: Scutum 2.9 x as 0.35 long, sparse Tl-4 ^\ith narrow^
;
long as scuteUum, TRV = scutal length. apical fascia of appressed, short hairs;
Discs of scutum and scutellum shiny, \\ith fascia broadlv interrupted on Tl, more
strong deep punctures approx 1-2 P\V narro^vly on T2, complete on T3-4, al-
apart, scuteUum densely punctate on pos- though often worn medially; chscs of Tl-7
terior margin. Tegula shining, sparsely ^Nith ver\' sparse, ven* short, erect hairs;
punctate. Metanotum dull, roughened, S3-5 ^vith apical fringe of posteriorly
obscurely punctate. Propodeal triangle oriented fine hairs (ver\- ^veak mediallv
shining, impunctate,^vithnarrow, shallo^v- on S2); S3 ^vith apicomedial triangular
ly, irregularly quadrately pitted apical patch of appressed hair in area of medial
area. Propodeal surfaces outside triangle emargination, triangular patch of ver\'
roughened posteriorlv, ^vith shallo^v dense short, ver\' fine hairs basal to this. Color:
punctation more evident on anterior sur- Black except cla^vs, distal tarsomeres, and
faces. Mesepisterum ^vith strong dense apex of mandible reddish browTi; tibial
156 Journalof Hymenoptera Research: Festschrift Honoring Roy Snelling
—
Spurs translucent yellow; wings lightly Material examined. Holotype o^ USA, Texas,
infuscated, nerves brown. HidalgoCo., Bentsen-RioGrandeStatePark,29-
Female: BL = 6.61 ± 0.54 mm n = 43, iii-1991, J. L. Neff K09033 , deposited KSEM.
5.60-7.36; HW = 1.77 ± 0.10 mm,, n = lb, Allotype 9: same data except K09128, collecting
1.48-1.96. Head: Face approx. 1.07 X as mud, deposited KSEM. Paratypes: MEXICO:
broad as long, eyes convergent below Tamaulipas: 6 3", Guemez, Hcda. Santa Engra-
(UIOD 1.3 X LIOD). Clypeus similarPtWo c1ia^,,lsl-aimiie-1d9a9t1,aJe.xLc.epNetffo,noSnalPirxonsiogprias;g2laSnfdusloasmae;
male but punctures shallow, 0.5 to 1 data except on Persea americana; Llera: 2 S,
apart. Punctation of supraclypeal area, Ciudad Victoria, 16 mi. S, 18-iii-1987, J. L. Neff,
parocular area, frons, vertex and gena on Prosopis glandulosa (all CTMI);. USA: Mis-
similar to male but slightly less dense. souri: Jefferson Co.: 1 cJ, 1 9, La Barque Creek
Labrum similar to male butbasal width 1.2 Core Area, T43NR3ES32 to (SE4), Sandstone
X length; apical width slightly less (0.9 X) Glades, 6-7-V-2006, M. A. Arduser, ex yellow
than length; basal 1/5 shiny, impunctate, pan trap; Shannon Co.: 3 (^, 1 9, Ozark N.
distal 4/5 punctate. Lateral ocellus closer Riverway, Round Spring Area, T30NR4W sect
to vertex than to eye (OCED/OCVD = 1.4) 19, lO-v-1990, M. Arduser, on flowers of
with distance between lateral ocelli sub- Phacelia; 1 ^, Chitter Creek Preserve by Cook
Hollow, T28NR1WS21, 4-V-1998, M. Arduser,
equal to distance from lateral ocellus to
on flowers of Phacelia (all MSAC); North
eye. Scape slender, unmodified (scape
Carolina: (Raines Co.): 5 ^, Bryson City, 23-iv-
length 3.5 X apical width); pedicel com- 1923, J. C. Crawford, on Fragaria virginiana; 1 c^,
pletely exposed; length flagellum (exclud- same data except l-v-1923 on Potentilla cana-
ing pedicle) 2.5 X length scape; first five dense (all AMNH); Texas: Austin Co.: 1 ^,
flagellar segments slightly shorter than Stephen F. Austin S. P., 9-iv-1966, J. C. Shafter
broad, gradually increasing in length and (TAMU); Bastrop Co.: 2 (^, Sayersville, 15-iv-
width distally, segments 6-9 as long as 1987,J. L. NeffonNemophilasayersensis (CTMI);;
wide, segment 10 1.8 X as long as broad. 1 9, same data but 2-iv-1995 on Nemophila
Gena as in male. Hypostomal area shiny, sayersensis (CTMI); 1 9, Stengl Lost Pines
impunctate. Mandible tridentate, middle Biological Station, 3-iv-2008,J. L. Neff, onRubus
tooth slightly nearer lower tooth than trivialis (CTMI); Bee Co.: 3 c^, 4 9, Pettus, 3-iv-
1988, L. Neff, on Phacelia congesta (CTMI);
upper. Mouthparts as in male. Thorax: J.
As in male. Abdomen: Terga shiny, puncta- BParrakz,os7C-o1.7:-13987c^,. CollHeegreatSytat&ion,WoLoilclkeyC,reeexk
tion and surface sculpture as in male. intercept/Malaise (J.TAMU); 3 9, 17-30-iv-1987,
Tl-6 with distal margins very narrowly Woolley & Heraty, ex intercept/Malaise
impunctate. T6 nearly straight in lateral (TAMU); Burleson Co.: 3 d", 4 9, Burleson,
profile, with apical margin very narrowly 3 mi. N, J. L. Neff (CTMI), 8-iv-1986, on
produced, shelf-like. Vestiture: Hair entire- Nemophila sayersensis; Dimmit Co.: 6 c^, 1 9/
ly pale, similar to male on head and Carrizo Springs, 6 mi. E, 31-iii-1994, J. L. Neff
thorax except sparse, semierect on clypeus and A. Hook (CTMI); Goliad Co.: 2 ^, Charco,
and parocular areas, not obscuring sur- 1 mi. W, 18-iv-1987, J. L. Neff (CTMI), on
face; hypostomal area fringed laterally Nemophila phacelioides; 1 9, same data but on
by long, erect, apically recurved hairs. Phacelia congesta (CTMI); Grimes Co.: 4 ;^, 2 9,
Tl-4 with narrow apical fascia of ap- Navasota, 2 mi. N, 6-iv-1988, J. L. Neff, on
Nemophila phacelioides (CTMI); Hidalgo Co.: 1 3",
pressed, short hairs; fascia broadly inter-
rupted on Tl, very weak medially on T2 same data as holotype (USNM); 23 9, same data
and entire on T3 & 4 (although often worn assamalelodtaytpaee(xCcTeMpIt);171-i9i,is-1a9m89eodantaLe(pUiSdiNuMm);vi4rg(a^-,
away); T6 with dense semi-appressed tum (CTMI); 7 samedataexcept17-iii-1989 on
c^,
simple hairs giving disc whitish appear- Teucrium cubanense (CTMI); 15 ^; 1 9, same data
ance. Scopalhairs simple,erect. Color: As in except 16-iii-2007 (CTMI), on Salix nigra; 1 (^,
male. same data except 16-iii-2007 on Ehretia anacua
Volume 18, Number1, 2009 157
(CTMI); 7 (^, 6 9same data except 19-iii-1992, A. Hoplitis simplex in the south-central United
W. Hookand C. R. Nelson (BFLC), nohost;2 S, States, H. nemophilae has a more southerly
samedataexcept15-iii-1982,C.Porter (FSCA);3 distribution than H. simplex, ranging from
S, same data except 16-iii-1982 (FSCA); 1 c^, 1 9, southern Indiana to central Tamaulipas
ssaammee ddaattaaeexxcceepptt2137--i1i1i1--11998842((FFSSCCAA));;36S,(^,sa1m9e, (Fig. 1). The name nemophilae refers to
Nemophila (Boraginaceae: Hydrophylloi-
data except 22-m-1985 (FSCA); Karnes Co.: 1 S,
NPeamrompahiMlaaripah,ac1elmiio.ideSs, 1(8C-TivM-I1)9;87,LeJ.eL.CoN.e:ff2, o^n, cdeoame)m,ontlheyafslsoowceirastedthwisitshpienciceesntrisalmToesxtalsy.
Fedor, 7-iv-1919, Birkmann (KSEM); 2 c^, 1 9, Despite the name, the species is probably
Lexington, 1 mi. N, 8-iv-2005, J. L. Neff, on not oligolectic on Nemophila, or even more
Nemophilasayersensis (CTMI);WashingtonCo.: 1 generally oligolectic on the Hydrophylloi-
c^,Washington,3 ml.W,8-lv-1987,J. L. Neff, on deae. None of the collections from the
Nemophila phacelioides (CTMI); 1 male, Pickens southernmostportionofits range (southern
N
Rd., 2.75 mi. of rt. 105, 12-iii-2000, Panero, Texas andMexico) havebeenfromNemoph-
Crozier and Helfgott, on Nemophila phacelioides ila or other Hydrophylloideae. In fact, no
(CTMI); Zapata Co.: 1 9, San Ygnacio, 30-iii- NemophilaorPhaceliaspecieswereflowering
1(9C9T1M,I)J.;L.1N9e,ffSaanndYAg.naHcoioo,k,1o3nkPmhylNa,st(rAirgurlooysoa in the vicinity of my collections of H.
Dolores), 2-iv-1994, A. W. Hook (BFLC). Other nemophilae in south Texas and Tamaulipas.
specimens: MEXICO: Tamaulipas: (Padilla), 12 The few pollen records from this area
(^, 14 9, Rio Corona, 18 mi. N. of Ciudad suggest that Prosopis (Fabaceae) and Rubus
Victoria, 1977, R. Schmidt (BLCU); USA: Ar- (Rosaceae) arepollenhostsintheabsenceof
kansas: (St. Francis Co.), 2 c^. Forest City, 11-iv- Hydrophylloideae. Females were also ob-
1946, C. D. Michener (KSEM); Indiana: Posey served at male catkins of Salix nigra Marsh,
Co.: 2 ^,HoveyLake,EntRecons. Station 12, 13- in south Texas, although none bore scopal
v-1958 (PURC); Texas: Colorado Co., 1 ^, pollen loads. Like otherRobertsonella, Hopli-
Columbus, 2-iv-1947, H. Townes (KSEM); Gon- tisnemophilaeisavernalspecies,activefrom
zalez Co.: 2 c^, Luling, 30-iii-1951, R. H. Beamer, mid March through mid April (in Texas)
on Salix (KSEM); 1 S. same data (NCSU); 1 S, 2
9, Palmetto State Park, 5-iv-1954, R. E. Beer & butas late as earlyJune inthenorthernpart
party (KSEM); Hidalgo Co.: 1 (^, Bentsen-Rio ofits range (Indiana).
Grande S. P., 14-iii-1983 (BLCU), C. Porter; 1 (^, Nests are unknown but numerous fe-
same data except 15-iii-1983 (BLCU); 2 c^, 1 9, males of Hoplitis nemophilae were observed
same data except 17-iii-1983 (BLCU). gathering mud at communal mud-gather-
—
Discussion. This species is described to ing sites on the banks of resacas (oxbow
include the males associated with Hoplitis lakes), wildlife watering areas and the Rio
simplexby Mitchell (1962). Thejustification Grande at Bentsen-Rio Grande State Park,
forthisis giveninthe discussionofHoplitis Hidalgo Co., Texas indicating that it, like
simplex. Although broadly sympatric with H. simplex, uses mud for nest construction.
KEY
MALES
1. Clypealpubescenceofveryshort(0.08-0.10 mm),branched,dense,appressedhairs,hairs
particularly dense on apical half; mandibular fringe of hairs on lower margin of
mandibleslong(max.length0.53-0.65 mm)anddense(Fig. 2);S3withaveryshallow,
medianemargination, area ofemarginationwithtriangularpatch ofsemi-appressed
setae (Fig. 4);mandiblesbroadbasally,basalwidth0.4 X eyelength
H.simplex(Cresson)
158 Journalof Hymenoptera Research: Festschrift Honoring Roy Snelling
HH^^HH^ '.v.^ia^ '../ '^^^Hl
gnunpF'
"^^jgl^^
';
"^'^^^Wm/hyh^^^^-^
'^ssSm
yjk.
. ,
*
Fig. 2. Head ofHoplitis simplexmale, lateral view.
Fig. 3. Head ofHoplitis nemophilae male, lateral view.
Fig. 4. S3 ofHoplitis nemophilaemale.
Fig. 5. S3 ofHoplitis micheneri, male.
la. Clypeal pubescence longer (0.32-0.36 mm), erectto suberect; mandibular fringe short
(max. length 0.22-0.35 mm) and thin (Fig. 3); S3 variable; base of mandible
narrower, basal w^idth narrowrer, 0.3 X eye length 2
2. Apical margin of S3 nearly straight, emargination very weak, area of emargination
with triangular patch of semi-appressed white hair (Fig. 4) . . . . H. nemophilae Neff
2a. Apical margin of S3 deeply emarginate, emargination approximately % as broad as
sternum and lined with a dense fringe of long white hair (Fig. 5)
H. micheneri Mitchell
FEMALES
1. Punctation ofTl very fine and sparse,punctures 4+ PW aparton disc; scutellum with
narrow, impunctate antero-median depression H. micheneri Mitchell
2. Punctation ofTl fine and deep, punctures 2-3 PW apart on disc, scutellum uniformly
punctate H. nemophilae Neff or H. simplex (Cresson)*
Femalesofnemophilaeand simplexcannot be reliably separated withoutassociated males.
Volume 18, Number2, 2009 159
BIOLOGY OF HOPLITIS SIMPLEX sions or added later while the bee was
—
working in the nest.
Nests and nest construction. Hoplitis sim-
plex is a cavity renting species. There is no Nest architecture varies with the rela-
evidence it ever excavates its ownburrows tdiioanmsehtiepr.ofWhbeeenbboedeybdoidaymedtiearmeatnedr naensdt
inpithystems like some otherHoplitis (Rau
nest diameter are similar, nests are simple
1928; Michener 1955). Natural nests have
linear arrays of cells separated by soil
been observed in small diameter beetle
closed with an outer mud plug. Occasion-
galleries in tree branches and stems.
ally, when the cross-sectional diameter of
Hoplitis simplex females also readily accept
trap nests bored in pine blocks. Trap nest the bee is significantly smaller than the
diameters utilized by H. simplex ranged diametmermof the cavity she is using (such as
from 2.8 to 4.8 mm. Larger diameter nests liinne4.t8he celldwiaalmlestewritthrampundesttos)c,resahtee cmeallys
were presentbutnotutilizedbyH. simplex.
whose diameter more closely matches her
The diameter most frequently occupied by
H. simplex was 3.2 mm during my obser- own. In 60% of the measured nests, the
posteriorend ofthenestwas indicatedbya
vations but the nest arrays were not
relatively thin (1.4 ±1.3 mm, n = 7) soil
appropriate for determining nest size pref- mm
partition. In borings less than 50 long,
erences. Reuse of nests, either of old H.
this was almost always flush with the end
simplex nests, or those of various mud-
of the boring, but in longer holes this final
using eumenine wasps, was common.
partition oftenwasplaced some distance in
Nests plugs, partitions, and sometimes
front of the end of the boring. Vestibular
wall linings, are constructed only of fine cells (length = 15.0 ± 9.0 mm,5.1-42.0,n =
soil, without any added pebbles or vegeta- 18) were present in 58.3% of the nests.
ble material. Females have repeatedlybeen mm
Eighty percent ofthe nests in 100 long
observed collecting mud at communal borings had vestibular cells compared to
mud gathering areas at the edge of only 50% of the nests in borings less than
streams,seeps orponds (Fig. 7). Numerous 50 mm long. In addition to the vestibular
females repeatedly visited communal sites cells, short intercalary cells were observed
on the edge of streams or seeps to gather in 5% (2 of 38) of the nests. The number of
fine-grained mud. Such areas take on a cells pernestaveraged 7.9 ± 2.1 (n = 10,5-
honeycombed appearance from the many 11) in 100 mm long borings and 2.5 ±1.0
small tunnels and pits excavated by the (n = 26, 1-4) for borings less than 50 mm.
mud collecting bees. This mud is held Celllength averaged 9.0 ± 2.3 mm (n = 73,
beneath the mandibles as a pellet on the 5.2-19.7). No position-specific significant
smooth, hairless surfaces of the hyposto- differences were found between lengths of
mal area, a corbicula-like area fringed cells within the nests. The cell partitions
laterally by long curved hairs. In the are concave on their anterior surface, flat
absence of appropriate mud sources, H. posteriorly, rather thin medially (0.5 ±
simplex may create its own mud by adding 0.1 mm, n = 8, 0.4-0.6) and wider on the
fluids, probably regurgitated nectar, to dry cell walls (1.4 ± 0.7 mm, n = 7, 0.5-2.3).
soil. A single female was observed doing The cell plug was rather short (4.0 ±
so near Sayersville, Bastrop Co., Texas. 1.5 mm, n =27, 1.2-7.5) and flush with
Many ofthe soil-gathering trips (discussed the entrance in 39.4% of the nests. In the
below) timed at BFL seemed tobe toobrief remaining nests it was slightly recessed
to allow for flight to distant mud sites. (2.5 ±1.4 mm, n = 9, 1.0^.2) from the
Moreover, tests of the partitions proved entrance.
positive for sucrose, although this could Females averaged 2.70 ± 2.33 min per
have been contamination from the provi- trip (0.03-24.35, n = 388) for soil collecting
160 Journalof Hymenoptera Research: Festschrift Honoring Roy Snelling
trips and spent an average of 2.07 ± five nectaries. The nectaries are located
2.68 min (0.03-25.00, n = 380) in the nest between the anther bases and are hidden
constructing cell partitions or nest plugs. by scales. Females of H. simplex are able to
Time spent gathering mud at communal simultaneously forage for pollen and nec-
sites averaged 21.8 ± 6.1 sec (12.7-37.5, n tar by perching on individual anthers
= 30). It took an average of 10.7 ± 5.0 soil (Fig. 8). A female scrapes pollen directly
gathering trips (5-24, n = 12) to construct a from the anthers into her abdominal scopa
mm
partition in a 3.2 diameter nest, 12.5 ± using her hind legs while tapping the
2.9 (8-16, n = 6) for 4.0 mm nests and 10 anthers with her abdomen. At the same
mm
trips (n = 2) for4.8 nests. Usuallyonly time, she inserts her mouthparts into the
two trips were required to close a cell and nectary below. Unlike females of Andrena
the remaining trips were for adding addi- sagittagalea Ribble, anotherbee common on
tional soil to the partition or cell walls. Nemophila in central Texas, H. simplex
mm
Time to construct a partition in a 3.2 females do not vibrate or buzz the anthers
diameter nest averaged 52.27 ± 26.08 min of N. phacelioides while harvesting pollen.
(24.00-106.97, n = 12), 80.35 ± 27.38 min Hoplitis simplex is not an early foraging
(57-117, n - 6) in 4.0 mm nests and 52.00 bee, at least at BFL. Foraging by females
± 11.31 min (44.00-60.00 min, n = 2) for usually begins after 1000 AM, a time that
mm
4.8 nests. Times and number of trips corresponds with the usual initiation of
mm
for constructing partitions in the 4.8 nectar production in N. phacelioides flowers
nests are not strictly comparable to those at BFL. Pollen availability from N. phace-
mm
for the 3.2 and 4.0 nests because the lioides continues through the day as anther
former had previously been occupied by dehiscence and floral anthesis occurs asyn-
eumenine wasps and had pre-existing chronously; foraging continues until near
partial partitions, while the latter nests dusk.
—
were previously unoccupied. Nest closure Provisioning. Females ofHoplitis simplex
(sometimes the closure for the last cell plus are able to construct and provision up to
the cell plug when a vestibular cell was three cells per day, although typically they
present) required an average 22.67 ± 5.61 complete only one or two. On average it
trips (14-34, n = 9) for 3.2 mm nests, 22 took10.8 ±1.8 (7-15,n = 27) pollentrips to
trips (n = 1) for 4.0 mm nests and 34 trips provision a cell. The distribution of pollen
(n = 1) for 4.8 mm nests. Time to complete trips per cell was unimodal (mode of 10)
the closure averaged 83.07 ± 25.59 min with 85.2% of the provisioning series
(43.9-148.77, n = 9) for 3.2 mm nests, entailing 9-12 pollen trips. The mean
123.67 min (n = 1) for 4.0 mm nests and duration of a pollen collecting trip was
127.1 min (n = 1) for 4.8 mm nests. The 8.38 ± 4.59 min (1.50-33.02, n = 320). For
mm
basal partition of a 3.2 nest was individual cell provisioning series, the
accurately timed only once and required mean duration of a pollen collecting trip
2 trips and 14 min. ranged from 3.21 to 17.50 min with mean
—
Intrafloral behavior. Visits to flowers of trip duration decreasing through the day
Nemophila phacelioides, the primary host of (Mean Trip Duration = 28.222-1.506 X
Hoplitis simplex at BFL, are typically brief. Start Time, r^ =0.468, F = 0.0003). Time to
Females foraging at midday on flowers of provision a cell (including time in the nest)
N. phacelioides at BFL averaged 5.5 ± averaged 114.11 ± 40.02 min (61.00-192.60,
4.1 sec (n = 50, 0.9-19.6) for nectar and n = 27). Although the correlation is
pollen collecting visits and 4.8 ± 2.9 sec (n weaker, provisioning time per cell also
= 15, 0.9 = 9.4) for nectar only visits. The decreased through the day (Provisioning
pale blue flowers of N. phacelioides have Duration per Cell = 280.05-12.402 X Start
rotate corollas with five erect stamens and Time, r^ = .262, F = .0063