SYSTEMATICS Description of the Larva of Loberus impressus (Coleoptera: Languriidae: Xenoscelinae) with Notes on its Natural History

CHRISTOPHER E. CARLTON, VICTOR R. TOWNSEND, JR.,1 PETER A. VAN ZANDT,1 1 AND SUSAN MOPPER

Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803

Ann. Entomol. Soc. Am. 93(3): 356Ð361 (2000) ABSTRACT The larva of Loberus impressus LeConte is described based on adult-associated and reared specimens collected from corollas and seed pods of Iris hexagona on the gulf coast of Louisiana. The larva of L. impressus is similar to larvae of Zavaljus brunneus (Gyllenhal) Hapalips prolixus Sharp, Pharaxonotha spp., and Bolerus angulosus (Arrow), the other described larvae within the Xeno- scelinae. Larval characters typical for the Loberini that are found in L. impressus include arrangement of integumental granules into rows, frayed and aciculate setae borne on spiny tubercles, and urogomphi spiny or tuberculate and recurved. The tarsungular setae of L. impressus and B. angulosus are single, in contrast to the dual setae present in other described larvae of Languriidae. Larva and adults of L. impressus were common in dried corollas and seed pods of I. hexagona that had begun to split open or had been invaded by Crematogaster ants. Fusarium and Cladosporium fungi were potential sources of food for L. impressus and other fungivorous beetles in the iris seed pods and on corollas.

KEY WORDS Loberus impressus, Iris hexagonica, larval morphology

Loberus LECONTE (1861) is the nominate genus of the Here we describe the mature larva of L. impressus tribe Loberini within the languriid subfamily Xenos- (LeConte) based on specimens from coastal Louisiana celinae (Sen Gupta 1968, Sen Gupta and Crowson collected in, and reared from, dried corollas and seed 1971, Leschen and Weˆgrzynowicz 1998). Other gen- pods of Iris hexagona (Iridaceae) during 1997 and era within Loberini include Acryptophagus Grouvelle, 1998. To further characterize and deÞne larval forms Bolerus Grouvelle, Fitoa Dajoz, Paphezia Zablotny & of the family, we compared the morphology of these Leschen, Stenodina Fairmaire, Telmatoscius Sharp, Ha- larvae to published descriptions of other larvae of palips Reitter, Truquiella Champion, and Pseudha- Loberini and Xenoscelini. We also describe the hab- palips Champion (Leschen and Weˆgrzynowicz 1998). itat and other life history details of the larva of L. In his provisional arrangement of the subfamilies of impressus. Languriidae, Crowson (1955) transferred Loberus and allied genera from Cryptophagidae: Telmatophilinae to Languriidae: Cladoxeninae, and noted “...Iamnot Materials and Methods aware that any larva of these has yet been described.” Within Loberini, larval descriptions are available for Specimens of larval and adult beetles were collected Hapalips prolixus Sharp (Sen Gupta 1968), Hapalips in the dried corollas and from mature, intact, or de- sp., and Bolerus angulosus (Arrow) (as Platycladoxena hiscing seed pods of Iris hexagona during August 1997 angulosa Arrow) (Rymer Roberts 1939). Within Xe- and July 1998 from Marsh Island Wildlife Refuge and noscelinae, other genera with described larvae are Game Preserve (Iberia Parish, LA). A series of Ϸ12 Zavaljus Reitter (Sen Gupta and Crowson 1967) and middle and late instars were preserved in either 95% Pharaxonotha Reitter (Bo¨ving and Craighead 1931, ethanol or TrumpÕs Þxative (Karnovsky 1965) (later Rymer Roberts 1939). Larvae within the nominate transferred to ethanol). Adults collected in 1998 were genus of Loberini have until now been undescribed, maintained in petri dishes with dried I. hexagona co- and presumed diagnostic larval characters of the tribe rolla tissue to serve as a substrate for feeding and egg are based on Hapalips (Sen Gupta and Crowson 1971). deposition, but no reproduction was observed. On 26 The absence of larval descriptions for Loberus and August 1998 we placed 7 late Þeld-collected instars in incomplete coverage of larvae within Xenoscelinae a petri dish along with pieces of corolla tissue. We has made intra- and intertribal comparisons of larval checked them periodically and observed 1 adult on 6 morphology among these languriid taxa problematic. October (42 d later). All other larvae were either dead or could not be located within the ßower tissue. Ver- 1 Department of Biology, University of Southwestern Louisiana, iÞcation of adult L. impressus was based on compari- Lafayette, LA 70504. sons with identiÞed specimens from elsewhere in the

0013-8746/00/0356Ð0361$02.00/0 ᭧ 2000 Entomological Society of America May 2000 CARLTON ET AL.: LARVA OF L. impressus 357 eastern United States deposited in the Louisiana State Arthropod Museum. The description was based on ßuid-preserved, cleared, and slide-mounted late instars and scanning electron micrographs (SEMs). A single specimen was soaked overnight in cold 10% potassium hydroxide and dissected. The head was detached, ventral mouthparts were removed, and a single mandible was removed. The body was cut lengthwise along one lateral margin, and the integument was laid open and mounted in glycerin with the head capsule and mouthparts. Fol- lowing preparation of the description, the slide mounted specimen was washed in 95% ethanol and permanently mounted in euparol. The alcohol-pre- served and slide-mounted specimens and associated adult beetles are deposited in the Louisiana State Ar- thropod Museum. Specimens used for the SEMs were Þxed in TrumpÕs Þxative, rinsed in a 0.2 M sodium cacodylate buffer (pH ϭ 7.4), and dehydrated in a graded alcohol series. Specimens were chemically dried using hexamethyl- disilazane (Nation 1983) and mounted on aluminum stubs with double-stick tape. Specimens were sputter- coated with 20-nm gold for 2 min and examined with a JEOL 6300-F Þeld emission scanning electron mi- croscope at an accelerating voltage of 15 kV. Larval Description. Mature larva (largest of 6 spec- imens) (Figs.1Ð2)) 3.25 mm long, 0.80 mm wide across metathorax. Body shape weakly fusiform, widest at metathorax, weakly tapering anteriorly, more strongly tapering posteriorly, color pale gray, surface granula- tions and debris brown, imparting a slight brownish Figs. 1–2. Mature larva of L. impressus. (1) Anterior- speckling. Dorsal aspect with two pairs of lateral rows oblique view. (2) Anterior view of head capsule and mouth- and a single pair of submedian rows of single or parts. branching setiferous tubercles, each bearing 1Ð4 stout aciculate setae. The longer of these setae simple, the shorter setae bifurcate or bearing numerous short times length of A3. Labrum free, broadly rounded, branches, or both. Dorsum of each segment bearing a bearing 6 marginal setae and 2 near middle of dorsal sparse to dense arrangement of star- or polygon- face. Ventral surface of labrum with a submarginal shaped integumental granules (Fig. 5), more dense on median pair of sensory pegs, 3 pairs of stout recurved thorax. Fine asperites and microsetae located near setae lateral to pegs, and a single pair near lateral basal intersegmental boundaries. Integument of living spec- angle. Anterior margin of epipharynx with 2 transverse imens prone to accumulation of Þne debris. Ventral submarginal rows of 4 larger and 10 smaller sensory aspect bearing 2 pairs of lateral rows of weak setate pits. Remainder of epipharynx consisting of a lobes and low tubercles, each bearing 2Ð4 simple ac- Y-shaped mass of Þne asperites. Mandibles (Fig. 9) iculate setae. symmetrical, each with 2 teeth, one terminal, the other Head prognathus (Figs. 2Ð3), 0.40 mm long, 0.50 mm subterminal; prostheca hyaline, triangular; mola large, wide. Frons (Fig. 3) covered with granules arranged mesal face with 9 rows of densely set tubercles, ventral in irregular polygons, vestiture a mixture of long, sim- face with regularly spaced smaller denticles; lateral ple, and short branched setae, each seta borne on a margin with 2 setae; large basal, ventral grinding tooth raised base. Epicranial stem absent, frontal arms present. Ventral mouthparts retracted. Maxilla (Figs. vaguely U-shaped near occiput, then becoming indis- 4 and 10) with falciform mala bearing 3 recurved tinct. Endocarinae absent. Frontoclypeal suture ab- apical teeth, an apical triÞd sensilla, and a pair of basal sent. Five stemmata on each side arranged in dorso- setae. Stipes simple, with undifferentiated palpiger ventral rows of 3 and 2 immediately posterior to and a pair of lateral setae. Maxillary palpi (Fig. 10) antennal base. Antennae (Figs. 2Ð3) approximately 3-segmented, I and II subequal, bearing 2 setae each, one-sixth width of head, with relative antennomere 1 ventral, the other lateral, III slightly longer and lengths of 2(A1), 4(A2), 1(A3). Antennal base wrin- narrower, also bearing ventral and lateral setae, apex kled, membranous. A1 simple, asetose, A2 with 4 short with a cluster of Ϸ9 short sensillae. Cardo distinct, subterminal setae and a sensory appendix 3 times divided into larger lateral and smaller medial triangu- length of A3 arising ventral to base of A3, A3 bearing lar sclerites. Maxillary articulating area prominent, 4 short subterminal setae and a single terminal seta 2 simple, and unsclerotized. Stipes with low rounded 358 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 93, no. 3

Figs. 3–8. Mature larva of L. impressus. (3) Dorsal view of head. (4) Anterior view of maxillary lacinia and palpi. (5) Integumental granules on pronotum. (6) Mesothoracic spiracle. (7) Urogomphi. (8) Fungal hyphae and spores on surface of fecal strand.

ßeshy process near base. Labium (Fig. 10) bearing 1 Prothorax slightly narrower and longer than meso- pair of setae at base, another near middle, and 2 pairs thorax, meso- and metathorax subequal in length and on palpifer. Ligula membranous, bearing a single pair width, granules (Fig. 5) of terga irregularly arranged. of setae between the palpi and a pair of sensory pegs Two pairs of gray spots present on prothorax, a larger between the setae. Hypopharynx with an ill-deÞned pair just behind middle and a smaller slightly more transverse submarginal row of Ϸ15 sensory pits and 2 lateral pair at about middle. One pair of spots each on lateral Þnely asperite lobes. meso- and metathorax the same size and in the same May 2000 CARLTON ET AL.: LARVA OF L. impressus 359

Figs. 9–11 Mature larva of L. impressus. (9) Left mandible, ventral view. (10) Maxillary-labial complex. (11) Legs: (a) prothoracic leg, (b) mesothoracic leg, (c) metathoracic leg. position as the larger prothoracic spots. Thoracic rows, each segment with a pair of small gray spots. Ab- sterna unsclerotized and simple, with a single median dominal sterna simple and unsclerotized, each with a pair of long, simple setae and a few shorter, simple transverse row of 6 simple setae. Segment 9 with granules setae. Legs (Fig. 11 aÐc) with coxae distinctly sepa- sparse and irregularly distributed, bearing a sharp pair of rated, bearing Ϸ5 simple setae. Trochanter, femur, and sclerotized urogomphi (Fig. 7), the basal half of each tibia with 3 long, simple setae along ventral margins, bearing strong spines and a pair of long simple setae; and a few shorter setae in other positions. Tarsungulus distal half simple, recurved and sharply acuminate. Py- with a single ventral seta. gopod low and bilobed, difÞcult to see. Abdominal terga 1Ð8 with integumental granules ar- Spiracles (Fig. 6) annular-biforous, borne on low ranged in well-deÞned transverse anterior and posterior papillae, spiracular papillae of mesothorax and A1 360 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 93, no. 3 slightly larger than on A2Ð8. Main opening circular, Sen Gupta and Crowson (1971) proposed diagnos- accessory openings V-shaped, diverging dorsally or tic characters for adult and larval genus-group taxa in anterodorsally away from main opening. Languriidae and Cryptophagidae in a series of char- Comparison with Larvae of Other Languriidae. The acter matrices (Sen Gupta and Crowson 1971, pp. larva of L. impressus generally conforms to the char- 30Ð34). In the matrix dealing with larvae (Sen Gupta acterization of larvae of Languriidae given by Sen and Crowson 1971, Text Fig. 13, p. 32), all 16 characters Gupta and Crowson (1971) and Lawrence (1991) but given for Loberini are found in L. impressus, with the differs in the following details: a single tarsungular seta exception of the number of tarsungular claws (char- present instead of 2 (Fig. 11); and spiracles borne on acter 6) (1 instead of 2), as described above. low papillae (Fig. 6) which are longer on the meso- Notes on Life History. Iris hexagona is a long-lived thorax and 1st abdominal segment, instead of sessile. perennial endemic to southern Louisiana, where it On ßuid-preserved and slide-mounted specimens, the occurs in hydric soils associated with lakes, bayous, spiracular papillae appeared slightly longer than those and coastal areas (Viosca 1935, Bennett 1989). The on stud-mounted specimens used for SEMs. This may species is unique in that it is tolerant of short-term have been caused by slight shrinkage of those struc- salinity peaks of up to 15 ppt, and grows in profusion tures during the dehydration process. The presence of in marshlands along the central coast of Louisiana. a single tarsungular seta, and spiracular papillae are Dried Iris corollas are retained for several months similar to those described for the presumed larva of after pollination and are present during seed pod mat- Xenoscelinus australiensis Sen Gupta & Crowson uration, providing substrate for fungal growth and (Cryptophilinae: Xenoscelinini) (Sen Gupta and habitat for Loberus and other fungivorous species. Iris Crowson 1971), but, according to Lawrence (1991), hexagona has large seed pods (Ϸ8 cm long, diameter the larvae upon which that description was based were 5 cm, 12 g wet mass) that have thick, Þbrous husks misidentiÞed. which apparently prevented the entry of both adults Many characters are consistent with those de- and larvae of L. impressus, because none was found in scribed for larvae of other members of Xenoscelinae. intact pods. However, there are other potential Similarities between larvae of L. impressus and the two sources of entry. I. hexagona pods disperse seeds by other described larvae of Loberini, H. prolixus and B. dehiscing, and many adult L. impressus were found in angulosus, include arrangement of granules into dis- pods that had begun to split open. Also, many pods tinct rows and/or symmetrical patterns, and absence showed evidence of entry by other insects, including of cranial sutures (Rymer Roberts 1939, Sen Gupta ants (Crematogaster sp.), and L. impressus adults and 1968). Both characters are diagnostic for Loberini larvae also were found in these. Ant entry was typi- (Sen Gupta and Crowson 1971). Loberus impressus cally indicated by small holes (Ϸ3 mm diameter) and B. angulosus have single, not paired, tarsungular chewed in the green pods. Many of the pods in which setae, and this may be an important character linking L. impressus were found contained an unidentiÞed the 2 genera phylogenetically. Other described lan- fungus both on seed coats and within the septum and guriid larvae have paired tarsugular setae, although integument of the pod. Adult beetles carried spores of Lawrence (1991) noted that 1 seta may be shorter than Fusarium and Cladosporium spp. on their integuments. the other in some genera, and this is the situation in Other beetle specimens found in I. hexagona pods Hapalips according to Rymer Roberts (1939). included Toramus sp. (Languriidae), Phalacridae, Sco- Sen Gupta and Crowson (1967) described “a clump lytinae (Curculionidae), Coccinelidae, Chrysomeli- of three short unequal setae” near the apex of the mala dae, Anthicidae, and Latridiidae. Most were present in in Z. brunneus (Xenoscelini). A similar character is small numbers or as single individuals. Only L. im- visible at the apex of the mala of L. impressus, but can pressus adults and ants were found within the pods be seen on SEMÕs to be either a single trifurcate seta consistently. or sensilla or a composite structure formed by the Frass deposited by L.impressus was in the form of fusion or near fusion of 3 (Fig. 4). This character needs long strands. We were unsure whether most of the to be reexamined on Z. brunneus and other languriid frass observed was produced by adults or larvae, but larvae to determine its systematic signiÞcance and the former were always more numerous in the sam- range of variation. The star-shaped or polygonal gran- ples. High magniÞcation revealed that most undi- ules (Fig. 5) have not been described or illustrated in gested material in frass appeared to consist of cell walls previous descriptions of larval languriids and also may of fungal hyphae and several kinds of spores (Fig. 8). be phylogenetically informative. The general habitus Cultures of this frass produced hyphae and spores of and granulate integument of L. impressus are similar to Cladosporium sp. the larva of Pharaxonotha kirschii Reitter (Xenosce- lini) illustrated by Bo¨ving and Craighead (1931) and of P. floridana Casey described by Rymer Roberts Acknowledgments (1939) under the junior synonym P. zamiae Blake. But We thank Meredith Blackwell (Louisiana State Univer- these species possess well-deÞned cranial sutures, a sity) for identiÞcation of fungi associated with beetles and iris different setal pattern on the mala, and, at least for P. seed pods. We thank Richard Leschen (Landcare Research, floridana, equally developed dual tarsungular claws. New Zealand) for helpful suggestions about the project and These characters set them apart from Loberus and its for providing pertinent literature. Reviews of the manuscript allies. were provided by Richard Leschen, Margaret McMichael, May 2000 CARLTON ET AL.: LARVA OF L. impressus 361

Victoria Moseley, Dorothy Prowell, Alexey Tishechkin, and Leschen, R.A.B., and P. Weˆgrzynowicz. 1998. Generic cat- 2 anonymous reviewers. This research was supported by alogue and taxonomic status of Languriidae (Cucu- University of Southwestern Louisiana Fellowships to P.V.Z. joidea). Ann. Zool. (Warsaw) 48: 221Ð243. and V.R.T., and by National Science Foundation Grant Nos. Nation, J. L. 1983. A new method for using hexamethyld- DEB-96Ð32302, DEB-97Ð43938, and INT-97Ð29521 to S.M. isilazane for preparation of soft insect tissue for scanning electron microscopy. Stain Technol. 58: 347Ð351. References Cited Rymer Roberts, A. W. 1939. On the taxonomy of Erotylidae (Coleoptera), with special reference to the morpholog- Iris fulva Bennett, B. D. 1989. Habitat differentiation of Ker ical characters of the larvae. Trans. R. Entomol. Soc. Gawler, Iris hexagona Walter, and their hybrids. Ph.D. Lond. 88: 89Ð117. dissertation, Louisiana State University, Baton Rouge. Sen Gupta, T. 1968. Revision of the genera of the tribe Bo¨ving, A. G., and F. C. Craighead. 1931. An illustrated synopsis of the larval forms of the order Coleoptera. Loberini (Coleoptera: Languriidae). Breviora 303: 1Ð27. Entomol. Am. 11: 1Ð351. Sen Gupta, T., and R. A. Crowson. 1967. The systematic Crowson, R. A. 1955. The natural classiÞcation of the fam- position of Eicolyctus Sahlberg (Coleoptera: Languri- ilies of Coleoptera. Nathanial Lloyd, London. idae). Proc. R. Entomol. Soc. Lond. Ser. B Taxon. 36: Karnovsky, M. J. 1965. A formaldehyde-glutaraldehyde Þx- 87Ð93. ative of high osmotility for use in electron microscopy. Sen Gupta, T., and R. A. Crowson. 1971. A review of the J. Cell. Biol. 27: 137a. classiÞcation of the Languriidae (Coleoptera: Clavicor- Lawrence, J. F. 1991. Languriidae (Cucujoidea) (including nia) and the place of Languriidae in the natural system of Cryptophilidae), pp. 471Ð473. In F. W. Stehr [ed.], Im- Clavicornia. Mem. Zool. Surv. India 15: 1Ð42. mature insects, vol. 2. Kendall Hunt, Dubuque, IA. Viosca P. Jr. 1935. The irises of southeastern Louisiana: a LeConte, J. L. 1861. ClassiÞcation of the Coleoptera of North taxonomic and ecological interpretation. J. Am. Iris Soc. America. Part I. Smithsonian Miscellaneous Collection, 57: 3Ð56. Washington, DC. LeConte, J. L. 1863. New species of North American Co- leoptera. Part I. Smithson. Misc. Collect.167[1863Ð1866]: Received for publication 26 May 1999; accepted 25 October 1Ð86. 1999.