A new genus and species of Allantinae (Hymenoptera: Tenthredinidae) from southeastern United States

5 Pages·1997·2.2 MB·

by  D R Smith

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PROC. ENTOMOL. SOC. WASH.
99(3), 1997, pp. 472-476
A NEW GENUS AND SPECIES OF ALLANTINAE (HYMENOPTERA:
TENTHREDINIDAE) FROM SOUTHEASTERN UNITED STATES
David R. Smith and Terence L. Schiefer
(DRS) Systematic Entomology Laboratory, PSI, Agricultural Research Service, U.S.
Department of Agriculture, c/o National Museum of Natural History, MRC 168, Wash-
ington, DC 20560, U.S.A.; (TLS) Mississippi Entomological Museum, Box 9775, Mis-
MS
sissippi State, 39762, U.S.A.
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Abstract. Allantunicus autumnalis, a new genus and a new species ofTenthredinidae,
subfamily Allantinae, is described from the sand dune area ofcoastal Alabama. The genus
and species are diagnosed and compared to other North American Allantinae. Evidence
strongly suggests that the larva feeds on inflorescences ofPolygonella gracilis (Polygon-
aceae).
Key Words: sawfly, Tenthredinidae, Allantinae, Polygonella gracilis, Polygonaceae
The specimens on which the following no genus and species comparable to it from
new genus and new species are based were the rest of the world.
collected in autumn from Polygonella grac-
ilis (Nutt.) Meisn. (Polygonaceae) in the Allantunicus Smith, new genus
sand dune area of coastal Alabama. Obser-
Type species. Allantunicus autumnalis
vations from separate larval collections in Smith, new species.
this same area strongly suggest that the lar- Antenna (Fig. 4) filiform; 1st and 2nd
va feeds on the inflorescences of Polygo-
segments each longer than broad; 3rd seg-
nella gracilis, a plant ofthe sandhills ofthe ment about 1.7 X longer than 4th segment.
Coastal Plain of the southeastern United Head narrowing behind eyes in dorsal view,
States. A single specimen was initially dis- distance behind eyes equal to half visible
covered in the collection of the Mississippi eye length; postocellar area as broad as
Entomological Museum. In October 1996, long; mandibles symmetrical, each biden-
thejunior author visited the same collecting tate; malar space nearly linear; clypeus
area and obtained additional specimens, in- shallowly emarginate, laterally acute with-
cluding males. The new genus and species out rounded lobes; short genal carina indi-
is morphologically distinct from all other cated only below eye near mandible. Pro-
North American Allantinae, and its pre- pleura broadly rounded and meeting on
sumed habits are unique among the Allan- meson; mesopleuron and mesonotum
tinae. Some of the remaining sawflies to be smooth, without punctures. Tarsal claw
discovered in the Nearctic Region no doubt (Fig. 3) with small inner tooth at center of
live in restricted habitats and are active dur- claw, shorter than outer tooth; basal lobe
ing an unusual time ofthe season. The pos- absent. Abdomen without pairs of white
sibility of this being an adventive species spots on dorsum. Forewing with anal cross-
M
was explored; however, there are no Neo- vein oblique, with 4 cubital cells, and Rs
M
tropical allantines similarto this species and + meeting Sc + R at same point. Hind-
VOLUME NUMBER
99, 3 473
wing without cells Rs and M; length ofpet- claw, a compressed antennal flagellum, sub-
iole of anal ce—ll about half width of cell. symmetric mandibles, and a very deeply,
Etymology. The name is based in part semicircularly incised clypeus with long,
on the subfamily name, Allantinae, and the acute lateral lobes. Heptapotamius differs
Latin imicus, indicating the unusual and by the head strongly enlarged behind the
unique characte—ristics of the genus. eyes in dorsal view, and the clypeus incised
Discussion. The genus is separated for about a quarter of its medial length and
from other allantine genera by the follow- with blunt lateral teeth.
ing combination of characters: short genal
AUantunicus autumnalis Smith,
carina present only near mandible below
new species
eye; shallow clypeal emargination with
acute lateral lobes; smooth, shining thorax — (Figs. 1-7)
without punctures on mesepistemum; short Female. Length, 8.5-9.0 mm. Antenna
inner tooth ofthe tarsal claw; lack ofclosed and head black; mandible dark orange with
M
cells Rs and in the hindwing; and third apex blackish, clypeus whitish; basal 3
antennal segment longer than fourth seg- maxillary palpal segments and labial sub-
ment. AUantunicus will key to Somanica mentum orange, rest of palpi and labium
Smith in couplet 12 of my key to genera blackish. Thorax orange with anterior mar-
(Smith 1979). Somanica differs iiom.AUan- gin of propleuron, entire prostemum and
tunicus by the subequal third and fourth an- mesosternum, and spot on lower portion of
tennal segments, lack of a genal carina, metepimeron, black. Abdomen orange;
rounded lateral lobes of the clypeus, and sheath black. Legs orange with apical 3
long inner tooth of the tarsal claw, nearly midtarsal segments and entire hindtarsus
as long as the outer tooth. In addition char- blackish. Wings moderately, uniformly in-
acteristics of the sheath and lancet (Figs. 1, fuscated; veins and stigma black.
2, 5) oiAUantunicus are unique among Ne- Antenna as in Fig. 4, length 1.6X head
arctic Allantinae, namely the emarginate width. Eyes slightly converging below;
apex of the sheath in lateral view, slight lower interocular distance subequal to eye
widening of the sheath toward the apex in length. Hindbasitarsus shorter than remain-
dorsal view, and presence ofctenidia on the ing hindtarsal segments combined, ratio
annuli of the lancet. 1.8:3.0. Head and body entirely shining and
AUantunicus belongs to the tribe Empri- impunctate. Sheath (Figs. 1, 2) in lateral
ini, as defined by Smith (1979): mandibles view with posterior margin slightly con-
symmetrical, bidentate; clypeus shallowly cave, in dorsal view slightly expanded to-
emarginate, propleura meeting broadly on ward apex with indication of small scopa;
the meson; mesopleuron without punctures; with long hairs curved mesally. Lancet as
M M
and veins and Rs+ meeting Sc+R at in Fig. 5, with stout ctenidia on annuli; ser-
the same point in the forewing. rulae low, only apical 7 with fine posterior
This does not appear to be an adventive subbasal—teeth.
taxon. A survey of material in the National Male. Length, 8.0-9.0 mm. Coloration
Museum of Natural History, Smithsonian similar to fe—male. Genitalia as in Figs. 6, 7.
Institution, and use of Malaise's (1963) key Holotype. Female from Alabama, la-
to world genera indicated no similarities to beled "Ala., Baldwin Co., Gulf Shores,
exotic taxa. AUantunicus runs to couplet 30°16'47" N, 87°42'49" W, 16 Oct. 1996,
106 in Malaise's key which identifies Mal- TL. Schiefer," "on flowers of Polygonella
lachieUa Malaise (from Burma and the gracilis in dredge spoil dunes," Deposited
Himalayas) and Heptapotamius Malaise in the National Museum ofNatural History,
(from Turkestan). MaUachieUa differs by Smithsonian Institution, Washington D.C.
the presence of a basal lobe on the tarsal on indefinite loan from the Mississippi En-
474 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
'^.s V \f,j.^y/^-^.
J
Figs. 1-7. Allantimicusautumnalis. 1, Sheath, lateral view. 2, Sheath,dorsal view. 3,Tarsalclaw.4,Antenna.
5, Lancet. 7, Male genitalia, genital capsule, left side, ventral view. 7, Male genitalia, penis valve, lateral view.
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VOLUME 99, NUMBER 3 475
tomological Museum, Mississippi State It appeared to be tapping the flowers with
University. — its antennae, but no oviposition was ob-
Pai-atypes. ALABAMA: Same data as served. The next morning another individ-
holotype (4 $); same data but 17 Oct. 1996 ual was observed flying from one flower
(3 9); same data but 14 Oct. 1991 (1 9); cluster to another on the same plant and
same data but 17 Oct. 1996, in flight near then tuming around several times like the
Polygonella gracilis in dredge spoil dunes one observed the previous afternoon. Two
(5 6); same data but 17 Oct. 1996, individuals were on flower clusters in
30°16'52" N, 87°42'03" W, on flowers of which most of the flowers had not yet
Polygonella gracilis in dredge spoil dunes opened. The five specimens collected in
(2 9, 1 S). Deposited in the Mississippi flight that morning flew among the Poly-
Entomological Museum, Mississippi State gonella in a fairly slow and erratic zigzag
University; National Museum of Natural pattern. However, their evasive flight was
History, Smithsonian Institution, Washing- very fast and direct. After about 10:30 am,
ton, D.C.; and Canadian National Collec- there appeared to be a marked decrease in
tion, Ottawa. — sawfly activity, and no additional specimens
Etymology. The name is derived from were observed at the type locality. This cor-
the autumn flight of the species. responded to an increase in temperature and
Host. Polygonella gracilis (Nutt.) increased pollinator activity. However,
Meisn., wireweed (Polygonaceae) (see dis- three additional specimens were collected
cussion). — about noon in similar habitat 0.6 miles from
Color variation. Several specimens dif- the original site. Only males were caught in
fer in color from the typical form as de- flight; all females and one male were taken
scribed. The mesosternum and mesepister- on the flower clusters.
num oftwo females are mostly blackexcept Polygonella gracilis grows in the pure
for the orange upper third of the mesepi- white sand characteristic of the dune habi-
stemum and most of the metepisternum, tats in the vicinity ofGulfShores. The fore-
cervical sclerites, metapleuron, and base of dune and backdune habitats close to the
midcoxa. One male has a black mesoster- coast would seem to be suitable habitats for
num and mesepistemum except for a small the sawfly since P. gracilis is present. But
orange spot on the upper comer of the me- despite several Malaise traps set for two
sepistemum, the metepleuron, and most of days in these habitats and much visual
the lateral lob—es of the mesonotum. searching, no sawflies were found there.
Discussion. On 16-17 October 1996, The sandy areas where the sawflies were
the junior author collected most of the type collected are along the north side of the In-
series from Polygonella gracilis in a sand tracoastal Waterway where P. gracilis is
dune area at Gulf Shores, Alabama. All more abundant. This habitat is apparently
were net-collected on flowers or in flight man-made having been created through the
near the plants. The 1 1 specimens collected dumping of spoil from the dredging of the
on flowers were always oriented in align- waterway. The area has subsequently been
ment with the axis of the flower cluster. colonized by vegetation more characteristic
They were found on both horizontal and of the foredune and backdune habitats that
vertical flower clusters with their head fac- lie several miles closer to the coast. Ac-
ing either toward or away from the main cording to Paul Warren, Army Corps ofEn-
stem of the plant. All except two of these gineers, Mobile District, Irvington Office
individuals were sitting motionless on the (personal communication), the first channel
flowers. One female observed in late after- for this section of the waterway was dug in
noon occasionally turned around on the 1934 and then enlarged in 1944. This prob-
flower cluster to face the opposite direction. ably accounts for much of the dredge spoil
476 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
that created the sawfly habitat. However, nalis feed on the inflorescences of Polygo-
since that time the waterway has continued nella gracilis.
to be dredged periodically, most recently in Polygonella gracilis is an annual ofsand-
the mid-1980's. The habitat at the type lo- hills and occurs in the Coastal Plain from
cality has recently been greatly altered by South Carolina to Rorida west to Louisiana
the removal of much of the sand. Most of (Rickett 1967). The sawfly may have a
the remaining habitat suitable forthe sawfly much wider distribution but has escaped
lies in a narrow band at the south end of discovery because of its restricted habitat
the spoil area. and late seasonal occurrence which is very
This is probably the species discovered unusual for sawflies.
in the larval stage by W. McDearman, Mu- Acknowledgments
seum of Natural Sciences, Jackson, Missis-
sippi. According to McDearman (1990 in W. McDearman provided information on
litt.) when he was at GulfShores, Alabama, larval observations. Figure 5 was drawn by
in early November botanizing along the Linda Lawrence, staffartist. Systematic En-
dunes, "I collected what appears to be saw- tomology Laboratory, USDA. Cathy An-
fly larvae which were exclusively feeding derson, Museum Technician, Systematic
on PolygoneHa gracilis (Nutt.) Meisn. (wire- Entomology Laboratory, USDA, assisted
weed). The flowering period for these with the final draft of the manuscript. The
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plan—ts is a bit unusual late summer and contribution by TL. Schiefer was approved
fall from September through November. for publication as Journal Article No.
As with Rhadinoc—eraea [see Smith and J-9121 of the Mississippi Agricultural Ex-
McDearman 1990] flowers were the pri- periment Station, Mississippi State Univer-
mary food. These plants are indeed very sity, with support from State Project MIS-
slender and wiry with very little stem cor- 6538. I thank the following for reviewing
tex (stem diameters rarely over 5 mm). I the manuscript: Henri Goulet, Agriculture
Canada, Ottawa; Nathan N. Schiff, USDA,
did not observe any indications that larvae
emerged from eggs laid within the stem. I Stoneville, Mississippi; and N.E. Woodley
and A.S. Menke, Systematic Entomology
watched one larva disperse over a period of
— Laboratory, USDA, Washington, DC.
about an hour but didn't see it burrowing
in the soil to pupate. No adults were seen." Literature Cited
In a subsequent letter, McDearman (1991 in
Malaise, R. 1963. HymenopteraTenthredinoidea,sub-
litt.) stated that he returned to the coast in family Selandriinae, key to the genera of the
September 1990 hoping to find some larvae world. Entomologisk Tidskrift 84: 159-215.
and adults on Polygonella gracilis, but was Rickett, H. W. 1967. Wild Flowers of the United
too early as few plants were in flower. States. Volume Two. Part One. The Southeastern
Adults were collected near the area States. McGraw-Hill Book Company. New York.
McDearman made these observations, from 322 pp.
Smith, D. R. 1979. Nearctic sawflies IV. Allantinae:
Polygonella gracilis flowers, and were col- adults and larvae (Hymenoptera: Tenthredinidae).
lected late in the year (mid-October) during United States Department ofAgriculture, Techni-
the flowering time of the host (larvae were cal Bulletin Number 1595, 172 pp. -I- 24 plates.
Smith, D. R. andW. McDearman. 1990. AnewRhad-
observed in November by McDearman).
inoceraea (Hymenoptera: Tenthredinidae) feeding
These pieces of circumstantial evidence on Zigadeniis (Liliaceae) from southeastern Unit-
strongly suggest that larvae of A. autum- ed States. Entomological News 101: 13-19.