Second and third instars tentatively identified as Liodessus noviaffinis Miller have six dorsolateral stemmata near the origin of each antenna. However, each stemma lacks a corneal (cuticular) lens on the surface exterior to its internal sensory pigmented components

Barman, E. H.

Binkowski, J.

Shepley-James, T. A

Treat, A.

White, B. P

English

Digital Commons @ the Georgia Academy of Science

Georgia Journal of ScienceVolume 67 No. 2 Scholarly Contributions from theMembership and Others Article 72009Variation in Stemmatal Morphology of Larvae ofLiodessus noviaffinis Miller (Dytiscidae:Hydroporinae: Bidessini)T. A. Shepley-JamesB. P. WhiteE. H. BarmanGeorgia College and State University, e.barman@gcsu.eduJ. BinkowskiA. TreatFollow this and additional works at: https://digitalcommons.gaacademy.org/gjsPart of the Life Sciences CommonsThis Research Articles is brought to you for free and open access by Digital Commons @ the Georgia Academy of Science. It has been accepted forinclusion in Georgia Journal of Science by an authorized editor of Digital Commons @ the Georgia Academy of Science.Recommended CitationShepley-James, T. A.; White, B. P.; Barman, E. H.; Binkowski, J.; and Treat, A. (2009) "Variation in Stemmatal Morphology of Larvaeof Liodessus noviaffinis Miller (Dytiscidae: Hydroporinae: Bidessini)," Georgia Journal of Science, Vol. 67, No. 2, Article 7.Available at: https://digitalcommons.gaacademy.org/gjs/vol67/iss2/772VARIATION IN STEMMATAL MORPHOLOGy OF LARVAE  OF Liodessus NoviaffiNis MILLER  (DyTISCIDAE: HyDROPORINAE: BIDESSINI)T. A. Shepley-James, B. P. WhiteNatural Science DepartmentGeorgia Military CollegeWarner Robins, Ga 31093E. H. Barman, J. Binkowski and A. TreatDepartment of Biological & Environmental SciencesGeorgia College & State UniversityMilledgeville, Ga 31061Address Correspondence To:E. H. BarmanDepartment of Biological & Environmental SciencesGeorgia College & State UniversityMilledgeviLle, Ga 31061e.barman@gcsu.eduABSTRACTSecond and third instars tentatively identified as Liodessus noviaffinis Miller have six dorsolateral stemmata near the origin of each antenna. However, each stemma lacks a corneal (cuticular) lens on the surface exterior to its internal sensory pigmented components.Key words: Dytiscidae, Liodessus, larva, stemmata, corneal lenses. Bidessine larvae collected on 26 October 2007 from a small drainage ditch in Bibb County, Georgia, USA (N32°52.813'; W083° 45.425') were identified tentatively as Liodessus noviaffinis Miller. The identification was based on distribution records (1, 2) and co-occurrence of adults identified as L. noviaffinis. The morphology of third instars in this cohort also corre-sponded, in general, to that attributed to Liodessus (3, 4) with the exception of the stemmata. Larvae of most dytiscid species have six stemmata located on and in the cranium posterior to the origin of each antenna (1). The cuticle above each stemma usually forms a biconvex corneal (cuticular) lens exterior to the crystalline cone and the various stemmatal sensory components of the cranial interior (5, 6). Although complete stemmata were expected based on previous descriptions (3, 4), there were no indications of corneal lenses on exuviae of second instars in this cohort.Our analysis of intact second and third instars that had been preserved and stored in 70% glycerated alcohol revealed six moderately pigmented 1Shepley-James et al.: Stemmatal Morphology of Larvae of Liodessus noviaffinisPublished by Digital Commons @ the Georgia Academy of Science, 2009 73dorsolateral stemmata defining stemmatal regions posterior to the origin of each antenna. However, corneal lenses were not observed (Meiji, ML2000; 400x) on the cranial exteriors although the pigmented interior stemmatal components tended to obscure our observations. The absence of a corneal lens on each stemma was readily apparent when non-sclerotized internal material was removed with 15% KOH. Thus, on these second and third instar bidessine larvae corneal lenses are absent, but the internal stemmatal sensory components appear to be present defining a rather typical stem-matal region. Assessments of stemmatal morphology included in many descriptive studies of dytiscid larvae may provide useful information for systematic evalu-ations. Areas of corneal lenses, volumes of cellular sacs (7) and orientation of individual stemma (8) may vary within stemmatal regions of individual taxa. Some species of Dytiscinae have a seventh stemmatal-like pair of structures on larvae in addition to the usual six (1). Stemmata are reportedly absent on the mature larva of the subterranean hydroporine genus Haideoporus Young and Longley (9) and on first and second instars of Hydrocolus Roughley and Larson (10, as Hydroporus paugus Fall). The absence of corneal lenses on these bidessine larvae presents systematists with an additional source of stemmatal variation that may be evaluated objectively with no more difficulty than assessments of cranial sensilla. However, pigmented internal sensory components may obscure the absence of the corneal lenses and the absence of lenses does not necessarily mean that stemmata are absent. ACKNOWLEDGEMENTSWe appreciate the assistance and comments generously provided by Dr. M.C. Michat of the University of Buenos Aires, Argentina and the identifica-tion of adult material by Dr. G. William Wolfe of this University. This project was supported in part by Faculty Research Grants awarded by the Office of Research Services, Georgia College & State University. Aquatic Coleoptera Laboratory Contribution Number 76. LITERATURE CITED 1. Larson DL, Alarie Y, and Roughley RE: Predaceous diving beetles (Coleoptera: Dytiscidae) of the Nearctic Region, with emphasis on the fauna of Canada and Alaska. NRC Research Press, Ottawa, Ontario, Canada, 982 pp, 2000. 2. Turnbow RH and Smith CL: An annotated checklist of the Hy-dradephaga (Coleoptera) of Georgia. J Ga Ent Soc 18: 429-443, 1983. 3. Alarie Y, Michat MC, Archangelsky M, and Barber-James HM: Larval morphology of Liodessus Guignot 1939: generic characteristics, descriptions of five species and comparisons with other members of the tribe Bidessini (Coleoptera: Dytiscidae: Hydroporinae). Zootaxa 1516: 1-21, 2007.2Georgia Journal of Science, Vol. 67 [2009], Art. 7https://digitalcommons.gaacademy.org/gjs/vol67/iss2/774 4. Matta JF: Description of the larva of Uvarus granarius (Aubé) (Co-leoptera: Dytiscidae) with a key to the Nearctic Hydroporinae larvae. Coleopts Bull 37: 203-207, 1983. 5. Snodgrass RE: Principles of Insect Morphology. McGraw-Hill, NY, 667 pp, 1935. 6. Gilbert C: Form and function of stemmata of holometabolous insects. Ann Rev Entomol 39: 323-349, 1994. 7. Barman EH, Wall WP, Mouton A, and Fenn TR: Changes in man-dibular musculature and morphology in response to stemmatal en-largement in larvae of Thermonectus basillaris (Harris) and Acilius mediatus (Say) (Coleoptera: Dytiscidae: Dytiscinae). Coleopts Bull 62: 279-286, 2008. 8. Schöne H: Optish Gesteuerte Lageänderungen (Versuche an Dy-tiscidenlarven zur Vertikalorientierung). Zeits ver Physiol 45: 590-604, 1962. 9. Longley G and Spangler PJ: The larva of a new subterranean water beetle, Haideoporus texanus (Coleoptera: Dytiscidae: Hydropori-nae). Proc Biol Soc Wash 90: 532-535, 1977. 10. Alarie Y: Description of larvae of 17 Nearctic species of Hydroporus Clairville (Coleoptera: Dytiscidae: Hydroporinae) with an analysis of their phylogenetic relationships. Canad Entomol 123: 627-704, 1991.3Shepley-James et al.: Stemmatal Morphology of Larvae of Liodessus noviaffinisPublished by Digital Commons @ the Georgia Academy of Science, 2009

Variation in Stemmatal Morphology of Larvae of Liodessus noviaffinis Miller (Dytiscidae: Hydroporinae: Bidessini)

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Variation in Stemmatal Morphology of Larvae of Liodessus noviaffinis Miller (Dytiscidae: Hydroporinae: Bidessini)

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