The immature instars and biology of the crane fly genus Brachypremna osten sacken (Diptera : tipulidae)

9 Pages·1991·4.1 MB·

by  J K Gelhaus

PROC. ENTOMOL. SOC. WASH.
93(3), 1991, pp. 613-621
THE IMMATURE INSTARS AND BIOLOGY OF THE CRANE FLY
GENUS BRACHYPREMNA OSTEN SACKEN
(DIPTERA: TIPULIDAE)
Jon K. Gelhaus and Chen W. Young
(JKG) Department of Entomology, The Academy of Natural Sciences, 19th and the
Parkway, Philadelphia, Pennsylvania 19103; (CWY)Section ofInvertebrateZoology, The
CarnegieMuseum ofNatural History, 4400 ForbesAve., Pittsburgh, Pennsylvania 5213.
1
Abstract. The egg, larva and pupa ofthe crane fly Brachypremna dispellens (Walker)
from Florida and of an incompletely reared species of Brachypremna from Peru are
described and illustrated, with briefcomments concerning the habitats and behavior of
the larva. Comparisons are made with the immature instars ofother Tipulinae, and the
phylogenetic position ofthis primarily neotropical genus is briefly discussed. This paper
represents the first detailed descriptions and illustrations ofthe semiaquatic larva and the
first complete treatment ofthe pupa for Brachypremna.
Key Words: Brachypremna, crane fly, larva, pupa
The immatures oftipuline crane flies are to Illinois and New Jersey (United States)
poorly known despite their great ecological (Alexander 1965), and two species occur-
(and sometimes economic) importance (Al- ring in Australia (Oosterbroek and Jonas
exander 1920, Pritchard 1983). While the 1989). The immatures ofonly B. dispellens
larvae and pupae of over 40% of the de- were previously known: the pupa was in-
scribed genera and subgenera ofTipulinae completely described and illustrated by Al-
are in some part known, this knowledge is exander(1920) and the larva wasdiagnosed
derived from only four percent ofthe spe- in a key (Alexander and Byers 1981).
cies. Ourignorance isproportionallygreater Recently, we were able to collect and rear
when examiningjustthe Neotropical fauna; numerous larvae of Brachypremna dispel-
ofthe 29 generaand subgenera ofTipulinae lens from Florida, and one ofus (JKG) col-
that occur there (Alexander and Alexander lected and incompletely reared anotherspe-
1970), we know the immatures for only 6 cies of Brachypremna from Peru. We
ofthesegroups(21%),andthisderivedfrom provide here the first complete descriptions
less than one percent of the species! This and illustrations ofthe immatures for these
paper, describingthe immatures oftwo spe- two species in the genus, as well as addi-
ciesofthetipulinegenusBrachypremna Os- tional information regardingthe biologyand
ten Sacken, is a small contribution toward behaviorofthe larvae. Terminology follows
rectifying this lack ofknowledge. that of Byers (1961) and Gelhaus (1986).
The genus Brachypremna has an essen-
Brachypremna Osten Sacken
tially Neotropical distribution; of the 38
species, 35 arestrictly Neotropical,with one Generic diagnosis. The immature stages
widespread American species, B. dispellens o^dispellens and the undetermined species
(Walker), extending from Brazil northward from Peruareverysimilar(detaileddescrip-
614 PROCEEDINGS OFTHE ENTOMOLOGICALSOCIETY OF WASHINGTON
tions followthisgeneric treatment, with the 977 lists Holorusia (in the generic key for
most distinctive features listed here): pupae of Tipulinae) as also having only a
Larva: Thoracic segments with short, slightly curved sheath, but the description
brown pile, contrasted with elongate and and illustration (Fig. 497) indicate a strong-
abundant, mostly reddish-brown hairs on ly recurved one; in addition, all specimens
posterior metathorax and abdomen (hairs of Holorusia we have examined have a
usually covered with debris) (Fig. 6); ab- strongly recurved sheath. In all other re-
dominalhairslaterallyforminglongitudinal spects, however, thesetwogeneraareunlike
fringe(Figs. 6, 10)andtransverseband ven- Brachypremna in the pupal stage, including
trally on segment VIII (Fig. 10); each ab- possessingextendedrespiratoryhorns(equal
dominal segment with about 6 annulations; to or far exceeding the length of the wing
minutedarkspiracleslaterallyonI-VII;spi- sheaths), and small inconspicuous abdom-
racular disc small, with six short spiracular inal spines.
lobes, dorsal pair oflobes scarcely evident Unlike the pupal head illustrated in Al-
(Fig. 9); lateral and ventral pairs of lobes exander(1920: Fig. 474), specimensofboth
short and extensively darkened, each with species ofBrachypremna showed the apices
large translucent spot; spiracles nearly oftheantennalandmaxillarypalpal sheaths
quadrate in outline; anal papillae absent, closelyapproximate(Fig. 13), andthesheath
butapairofoval, raised membranousareas of the labium narrowly divided medially.
closebehind hairs on segment VII (Fig. 10). The posterior spiracles ofthe pupa are not
Pupa: Sheaths of maxillary palps short recessed as seen in some other Tipulinae
and only slightly curved overall, not re- (e.g. Dolichopeza) but, as noted by Byers
curved (Fig. 12); thoracic respiratory horn (1961), a spiracular yoke is nonetheless
relativelyshort; mesonotumwith threepairs present in Brachypremna.
oflargetubercles(Fig. 1 1);abdominal spines Relationships.—The generic relation-
generally slender, those ofgenital segment ships of the Tipulinae are poorly known,
particularly well-developed dorsally (Figs. andthefewattemptsatgroupingshavebeen
14, 15), segment also with only two pairs of made withoutjustification or lack discrim-
ventral spines. ination between ancestral and derived fea-
Discussion.—ThelarvaofBrachypremna tures (e.g. Alexander 1965). Although
is unlikely to be confused with that ofany Brachypremna, Megistocera and Dolicho-
other tipuline genus. Although as noted by peza have sometimes been grouped in the
Rogers (1949), the larva ofBrachypremna subtribe Dolichopezaria (e.g. Alexander
does bear a superficial resemblance to that 1920), this is based on only a general sim-
of Tipula (Schummelia) (Gelhaus 1986, ilarity of the adults, and is not supported
Figs. 93, 98, 99), it is easily distinguished by an examination ofthe immature stages
from all tipulines, including Tipula (Rogers 1949). The adults of Megistocera
(Schummelia), by the presence of a longi- and Brachypremna do share some similar
tudinal abdominal hair-fringe on each side, features of wing venation, and the pupae
the lack ofanal papillae and the contrast in have slightly curved maxillary palpal
length between the thoracic and abdominal sheaths,butthelattercharacterstate,atleast,
hairs. The pupaofBrachypremnadiffersless maybetransitionalbetweenashort,straight
from other tipulines, but the apex of the sheath (found in the Limoniinae and Cy-
maxillary palpal sheath is only slightly lindrotominae) and the strongly recurved
curved, not strongly recurved, which serves sheath found in most ofthe Tipulinae. This
toseparateitfrompupaeofmostNewWorld characterinterpretation also correlates with
tipuline genera, except Leptotarsus (Lon- the probable phylogenetic position ofthese
gurio) and Megistocera. Alexander 1920: twogenera, alongwith others, as beinggen-
VOLUME 93. NUMBER 3 615
erally "primitive" within the TipuHnae as raisedventrolateral swellingslargeandcon-
a whole (Alexander 1965, Gelhaus, unpub- spicuous.
lished data), and Brachypremna itself may Fourth (final) instar larva: Length 15.0-
represent an eariy, and isolated, lineage of 18.5 mm, width 2.3-2.8 mm. Head: Mas-
the Tipulinae. The phylogenetic position of sive, well-sclerotized, oval-shaped and
Brachypremna will remain questionable slightly depressed (Figs. 1, 2). Each antenna
until many more of the Southern Hemi- about3X aslongaswide. Foursensorypores
spheregenerabecomeknownasimmatures. laterally at boundary offrontoclypeus, with
severalothersclusteredoppositebaseofeach
Brachypremna dispellens (Walker) antenna; no setae on frontoclypeus. Ante-
riormargin ofheaddorsallydividedbypair
Alexander (1920): 984-985, pupal descrip- ofsclerotized bands, enclosing lateral areas
tion. Figs. 474^77 (head, respiratory of epipharynx, basal half of enclosed area
horn, leg sheaths, male caudal sheaths); with pair ofsensory pores, apical halfwith
Alexander and Byers 1981: 10, larval di- fineyellowhairandscatteredsensoryblades.
agnosis. Mandible with two distinct teeth apically,
Description.—£'^^.- Length: 0.7 mm; an additional tooth ("molar ridge," Byers
width: 0.4 mm. Black, surface of chorion 1961) and hair tuft ("brustia," Byers 1961)
smooth, with no terminal filament. nearbase(Fig. 4). Maxillaasin Fig. 2, paired
Firstinstarlarva:(Fig. 5). Length: 2.0mm; setae on cardo extremely sort and incon-
width: 0.2 mm. Head: pale, but similar to spicuous. Hypopharynx (Fig. 3) with five
fourth instar. Antenna a single segment, rounded teeth; hypostomal bridge (Fig. 2)
granulose. Mandible with proportionally with seven, relatively acute teeth. Thorax:
larger basal tooth, mandible appearing Pro-, meso- and anterior one-fourth of
equally bifurcate. Hypopharynx with three metathoracic segments completely covered
teeth, lateral teeth divergent, median tooth with microscopically short, fine, brown pu-
highestandbroad. Maxillarycardowithtwo bescence,contrastedwithlong, patchymac-
sockets (setae not evident). Thorax: Mostly roscopic hairs foundelsewhere on metatho-
with fine, appressed, short hairs in closely- rax and abdomen (Fig. 6). Macrosetae
set distinct transverse rows. Abdomen: extremely short, pale and difficult to see.
Sparsecoveringofscattered, erectshort, pale Abdomen: Macrosetae dark and uniformly
hairs; macrosetae longer, slender and pale. short (difficult to see among the hairs),
Spiracularregion:Witheightapparentlobes, placement as in Figs. 7 and 8. Macroscopic
a singlepaireachofdorsalandventral lobes, hairs elongate and abundant, dorsally ar-
and divided lateral lobes; ventral lobes ranged in six or seven irregular transverse
broadest and pigmented. Each lateral lobe rows ofpatches, the longest hairs dark, ob-
with a narrowupperpartand broaderlower scuring the macrosetae, all others reddish
part. Apical margin ofeachdorsal lobewith brown (Fig. 7); hairs similarly arranged but
two groups oflong hairs, each group ema- less abundant ventrally (Fig. 8). Short hairs
nating from single base. Dorsolateral lobes scatteredthroughout. Lateralhairsin nearly
each with apical margin oflong hairs, each continuous longitudinal fringe or row, best
ventrolateral lobe with one long seta, and seen viewed dorsally or ventrally (Figs. 6,
one short sensory peg, remainder ofmargin 10); longest hairs completely encircle pos-
withhair. Apical margin ofeach ventral lobe terioredge ofsegment VIIL Spiracles small,
with four majorgroups ofhairs, each group dark, oval located above lateral setae on
emanating from single base, three smaller each segment I-VII (in addition tolargeter-
groupsanda single, short, forkedhair. Spir- minal pair on spiracular disc). Spiracular
acles each with about 10 pores. Two oval, disc: Small and strongly invaginated me-
616 PROCEEDINGS OFTHE ENTOMOLOGICALSOCIETY OF WASHINGTON
dially. Sixshortlobesencirclingdisc, lateral reaching to venter of abdominal segment
andventrallobeseachaboutaslongaswidth IV, sheaths ofprothoracic legs the shortest
at base, dorsal lobes scarcely evident, with (Fig. 12). Abdomen: Slender spines laterally
length half basal width (Fig. 9). Posterior andalongposteriormarginsofallsegments,
surface of each dorsal lobe smooth and spines elongate and thin, about one-third
lightly sclerotized, sclerites extending be- length ofabdominal segment III (Fig. 11).
tween spiracles; each lobe with a border of Two spines laterally on II-VII, with a small
short dark hair around apex and meeting tubercle located between (Fig. 12). Dorsal
between lobes. Posteriorsurface ofeach lat- spines along posterior margin ofsegments,
eral lobe brown, surrounding a subcircular four spines on I (two long, two short), 5-6
translucent area; each lobe black on apical on II-VII (fourlong. Fig. 1 1); ventral spines
half, withbrush ofbrown stouthairsatapex. alsoalongposteriormargin,twolargespines
Posterior surface ofeach ventral lobe shelf- onIII-IV, fourlarge spineson V-VII, apair
like with sclerite at base below spiracles, of minute spines anterior to these on III-
apical halfoflobe black with large, subcir- VII (Fig. 12). Terminal segment with two
cular, translucent spot subapically, two long pairs of elongate spines, one pair directed
macrosetae arising within each spot. Each dorsally, one pair posteriorly, posterior
ventral lobe with a border of dark hair spines each with small tubercle near base;
around edge. Spiracles flatandnearlyquad- two pairs of short spines anterior to both
rate. Apatchoflonghairanteriorlybetween large spines and to genital sheaths (Figs. 14,
dorsal and lateral lobes with shorter hair 15). Genital sheaths ventral to large spines;
continuing to near ventral lobes, short hair malesheathsasinglepair,short,andslightly
in two isolated bands extending anteriorly curved, with constrictionsat midlength and
to dorsal lobes, and also below anus. Anal subapically (Fig. 14); two pairs of closely
papillae absent from around the anus. A appressed female sheaths (Fig. 15). Minute
pair ofoval, darkened, raised areas ventro- spiraclessublateral oneach segment III-VII,
laterally on segment VII (Fig. 10). posterior pairon terminal segment exposed
Pupa: Length 16.2-18.6 mm, width 2.8- and larger.
3.0 mm. Overall dark reddish brown, Specimens examined. U.S.A.: D.C.:
darkest sublaterally along abdomen. Head: Washington, May 1913, R. C. Shannon,
Antennal sheath expanded along first four head of pupa (UMAA). Rorida: Alachua
segments with distinct tubercle at base. Co., nospecifiedlocality,J. S. Rogers, larval
Sheaths of maxillary palps short, slightly head capsule (UMAA); Highlands Co.,
curved overall (not recurved as in other Ti- Archbold Biological Station (near Lake
pulinae), apices lying close to those of an- Placid), outflow stream ofAnne Lake, IV-
tennal sheaths (Figs. 12, 13). Sheaths ofla- 15-1989, J. Gelhaus, C. Young, 6 larvae, 2
bial palpi separated and indented medially, pupae, 5 larval and pupal skins (reared).
apices slightly divergent. Thorax: Respira- Highlands Hammock State Park, small
mm
tory horn 1.0-1.4 in length, with slight stream, IV-16-1989 (female collected), J.
bend at midlength and minute annulations Gelhaus, C. Young(eggs and first instarlar-
alongentire length (Fig. 1 1), apex darkened vae); Putnam Co., Welaka, R. E. Bellamy,
with transverse series ofsmall pores. Dor- Jr., larval headcapsule (UMAA). We have
sum ofthorax with three pairs oflarge tu- deposited specimens in the collections of
bercles in transversely oblongarrangement, the Academy of Natural Sciences, Phila-
a pair oflow tubercles located further pos- delphia, PA; Carnegie Museum ofNatural
teriorly, anotherpairlaterallyatbaseofeach History, Pittsburgh, PA and Snow Ento-
wing sheath (Figs. 11, 13). Leg sheaths mological Museum, Lawrence, KS.
VOLUME 93, NUMBER 3 617
'"*5^ '*">. ft^Ti^ >s^^
mm
.1mm 1
Figs. 1-5. Brachypremna dispellens larva. 1, head, dorsal. 2, head, ventral. 3, hypopharynx, ventral. 4,
mandible, ventral. 5, first instar larva, lateral. Scale: 1 mm, Figs. 1, 2; 0.1 mm. Figs. 3-5.
Brachypremna sp. Description.—As in dispellens except as
follows:
Although reared to pupal stage, the male Fourth (final) instar larva (from exu-
genitalia ofthe pharate adultwere not com- vium): Bodylength 16.0mm;width 2.7 mm.
pletely developed in the single specimen to Macroscopic hairs on dorsum ofabdomen
allow identification. In addition, eight spe- reddish brown, longest hairs not darkened.
cies ofthis genus have been recorded from Long hairs anterior to spiracular disc ex-
Peru, with several species occurring at the tending ventrally as semicircular fringe be-
same locality where this single larva was tween dorsal lobes and anterior to anus, all
taken. hairs in fringe equally long.
618 PROCEEDINGS OFTHE ENTOMOLOGICALSOCIETY OF WASHINGTON
':'''
"^'^^%.Yr-'^7f/!^-^'y^-^ ^ ' '"*"^^^'^-"^*r^*v-*-'*^>*-^...- ^S
''<.
^'^^4.,,,.,,.,,.,^^
-^
;.AH..*,-in-*'^'^*'^-*''-'^'*''-'
"">s.^'
1mtn
.1mm
Figs. 6-10. Brachypremnadispellenslarva. 6, habitus, lateral, insetshowinglateral macrosetae. 7-8, typical
abdominalsegment,dorsalandventral, insetofmacroseta. 9,spiraculararea. 10,terminalabdominalsegments,
ventral aspect. Scale: 1 mm. Figs. 6-8; 0.1 mm, Figs. 9, 10.
Pupa: length 15.8 mm; width 2.8 mm. acters listed in the description of the Pe-
Respiratory horn notsostronglybent, length ruvian species.
1.2 mm. Dorsal spines on I-II subequal in
Biology
length. Malegenital sheathsshortandthick,
without subterminal constriction. Habitat: Virtually our entire knowledge
Specimens examined. Peru: Madre de ofthe larval habitat o^Brachypremna isde-
Dios: Parque Manu, Pakitza, elev. 250 m, rived from the widely distributed species,
seepage area, IX-17-1989, J. Gelhaus, lar- dispellens. Although the first known larva
val skin, pupa (Academy of Natural Sci- was taken from a log near a stream (Alex-
ences, Philadelphia). ander 1920), Rogers(1949: 13)reported that
Discussion.—The immatures of the two larvae were taken from "wet to saturated
known species of Brachypremna may be black organic soil of seepage areas, damp
easily separated by the distinguishing char- shaded stream banks, or low, wet grass-
VOLUME NUMBER
93, 3 619
mps
^C>h^ nn
i^.
i-si'
#t
(l''Cf^
-rg* 1(191 t-!
I;-
W^^ff^
1mm
-i>=^ 15
mm
1
Figs. 11-15. Brachypremna dispellem pupa. 1 1-13, habitus, dorsal, ventral, lateral; mps-maxillary papal
sheath. 14-15, terminal abdominal segments, lateral; 14, male; 15, female. Scale: upper, Figs 11-13" lower
Figs. 14-15.
620 PROCEEDINGS OFTHE ENTOMOLOGICAL SOCIETY OF WASHINGTON
lands. They occurbeneath the liverworts or of the long hairs seen abundantly in later
damp moss mats ofswamp hummocks and instars.
beneath and among the matted stolons and The larvae of both species have the cu-
roots of the luxuriant carpet grass sods of rious habit ofpropelling the fecal material
low, wet, meadow-like situations." into the air, even while remaining in the
We collected larvae of B. dispellens by soil, and the lid of any rearing chamber
sieving the soil of a heavily shaded bank quickly becomes fouled with many fecal
along a small sandy stream; the soil was pellets. This behavior has been seen in oth-
damp, dark humus, with little sand and er, mostly semi-aquatic, tipuline larvae,
many fine plant roots. Surroundingareas of particularly species of Tipula {Yamatoti-
more sandy soil contained no larvae. Soil pula), and can serve as an easy way to de-
had a slight cover ofleaflitter, and the lar- termine positions of the larvae in the soil
vae were found within 3-4 cm of the soil in the rearing dishes. In natural situations,
surface. though, this peculiar behavior may serve
The single larva of the species found in the opposite purpose.
Peru was collected from the surface ofsat-
urated mud under a thin layer ofleaflitter Acknowledgments
in a densely shaded seepage area. We would like to thank Mark Deyrup,
Developmentaltime: Larvae ofdispellens
directorofthe Archbold Biological Station,
collected in mid-April began pupating by
lateApril; thepupal periodrangedfrom 10- Lake Placid, Florida, forallowing us to col-
14 days. Eggs were obtained from a single lectatthe Station whileattendingthe North
American Dipterists' Society meetings, and
female of dispellens and took 30 days to
Mark L. O'Brien, University of Michigan,
hatch.
AnnArbor(UMAA) fortheloan ofBrachy-
Food: Because of the sluggish nature of
the larvae and the difficulty of observing premnadispellens larvae from the J. S. Rog-
them in soil, no direct observations were ers' Collection. We would also like to thank
made on larval feeding in either species of George Byers, University ofKansas and an
Brachypremna. Fecal pellets of dispellens anonymousreviewerfortheircommentson
were examined, though, and were found to the manuscript. Fieldwork in Peru by the
consist of recognizable plant fragments, firstauthorwassupportedbyanawardfrom
probably derived from leaflitter. the Biological Diversity in Latin America
Larval behavior: As noticed by Rogers (BIOLAT) Project, Smithsonian Institu-
(1949), larvae of Brachypremna are ex- tion, Marsha Sitnik, (acting) program ad-
tremely sluggish. For example, in the lab- ministrator, and this paper is contribution
oratory, one healthy larva ofdispellens re- no. 14, BIOLAT Project, Smithsonian In-
mained still and curled on the soil surface stitution. Fieldwork in Florida by the sec-
ond author was supported by the Graham
forover40 minutes, although most tipuline
Netting Research Fund, Carnegie Museum
larvaewould have burrowed away from the
ofNatural History.
light within a few minutes. This unrespon-
siveness, combined with the "dirty" ap-
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of soil among the long body hairs), make Alexander,C. P. 1920. Thecrane-fliesofNewYork.
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soil, except by sieving the soil with water. sityAgriculturalExperimentStation,Memoirs38:
691-1133.
Even first-instar larvae of dispellens were
noticed to have debris adhering to them al- A..et1a9l6.,5.edsF.,amAilCyatTailpougliodfateh,epDpi.pt1e6r-9a0o.f/A/m/eStroincea,
though they possess only a sparse covering northofMexico.UnitedStatesDepartmentofAg-
VOLUME NUMBER
93, 3 621
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Agriculture Canada, Monograph 27, 674 pp. memberofthe neuston fauna. Occasional Papers
Byers, G. W. 1961. Thecrane flygenusDolichopeza Museum Zoology, University Michigan 521: 1-
inNorthAmerica.UniversityKansasScienceBul- 14.
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