Description of the Third Instar Larva of Haliplus Variomaculatus Brigham & Sanderson with Notes on Larvae of Nearctic Haliplidae (Coleoptera)
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Description of the third instar larva of Haliplus variomaculatus Brigham & Sanderson with notes on larvae of Nearctic Haliplidae (Coleoptera) Bernhard J. van Vondel The third instar larva of Haliplus variomaculatus Brigham & Sanderson, 1973 is described and compared with earlier described larvae of Nearctic Haliplidae. A key to the known third stage larvae of Nearctic Haliplidae is given. The differences between the larvae of the subgenera Liaphlus and Paraliaphlus are discussed. Bernhard J. van Vondel, Natural History Museum Rotterdam, p/o Roestuin 78, 3343 CV Hendrik-Ido-Ambacht, The Netherlands. [email protected] Introduction impetus to this study, which aims at describing for The Haliplidae of the Nearctic region comprise the first time the third instar of Haliplus variomac- 67 species (Majka et al. 2009). Of these, for only ulatus and at comparing this species with those of 12 species the larvae have been described: Haliplus other Nearctic Haliplidae known as larvae. (Haliplus s.str.) immaculicollis Harris, 1828 (Math- General information on the morphology of Hali- eson 1912; Hickman 1930), H. (Haliplus s.str.) api- plidae larvae, specifically for Brychius, Haliplus and calis Thomson, 1868 (Bertrand 1942), H. (Liaphlus) Peltodytes are given in van Vondel (1997). fulvus (Fabricius, 1801) (Schiødte, 1864), Peltodytes edentulus (LeConte, 1863) (Matheson 1912; Hick- man 1930), P. muticus (LeConte, 1853) (Matheson Material and methods 1912), P. lengi Roberts, 1913 (Hickman 1930), The single larva used for this description was stored P. sexmaculatus Roberts, 1913 (Hickman 1930), in alcohol. After having it photographed the left Apteraliplus parvulus Roberts, 1913 (Leech & Chan- legs and the right mandible were separated from the dler 1956), Brychius hungerfordi Spangler, 1954 specimen. After about three hours in Euparal essence (Strand & Spangler 1994) and B. hornii Crotch, body and body parts were transferred to Euparal on a 1873 (Mousseau & Roughley 2007). microscope slide. Drawings were made using a Zeiss Recently I had the opportunity to study a small stereo-microscope with photo-tube; measurements collection of Haliplidae from Missouri, results of a were made using a micrometer eyepiece. For detailed project by Megan M. Zeller from the University of drawings a Swift universal microscope was used. Tax- Missouri. In that material were three adults of Hali- onomic terms are according to Jaboulet (1960) and plus variomaculatus Brigham & Sanderson together van Vondel (1997). All known third stage larvae can with a third instar Haliplus larva, all collected from be distinguished with the following key, except for the same locality at two different dates. It is postu- the species of the subgenus Haliplus s.str. as I was not lated that this larva is indeed the third instar larva able to find reliable distinguishing characters. of H. variomaculatus. Such finding provided the Tijdschrift voor Entomologie 154: 127–133, Table 1, Figs 1–29. [ISSN 0040–7496]. http://www.nev.nl/tve © 2011 Nederlandse Entomologische Vereniging. Published 1 June 2011. Downloaded from Brill.com09/24/2021 11:26:33PM via free access 128 Tijdschrift voor Entomologie, volume 154, 2011 2 3 4 5 6 7 8 9 10 1 11 12 13 14 15 16 17 Figs 1–17. Haliplidae, third instar larva details. –1, Dorsal view of Peltodytes caesus; 2, spine on dorsal projection of Peltodytes muticus; 3, spine on dorsal projection of Peltodytes sexmaculatus; 4, spine on dorsal projection of Peltodytes lengi; 5, spine on dorsal projection of Peltodytes edentulus; 6, antenna of Brychius; 7, antenna of Haliplus; 8, fore leg of Brychius; 9, fore leg of Haliplus subgenus Liaphlus; 10, fore leg of Haliplus subgenus Haliplus s.str.; 11, pronotum of Haliplus immaculicollis; 12, pronotum of Haliplus apicalis; 13, pronotum of Apteraliplus parvulus; 14, pronotum of Haliplus fulvus; 15, pronotum of Haliplus triopsis; 16, part of fore leg of Haliplus triopsis; 17, mandible of Haliplus triopsis. (Figs 1,6, 7, 8, 9, 10, 14 after van Vondel, 1997; Fig. 2 after Matheson 1912; Figs 3, 4, 5, 11, 15, 16, 17 redrawn from Hickman 1930; Figs 12, 13 original). Downloaded from Brill.com09/24/2021 11:26:33PM via free access Van Vondel: Description of larva of Haliplus variomaculatus 129 20 22 ? ? 18 19 21 23 Figs 18–23. Haliplus variomaculatus,larva third instar. –18, dorsal view; 19, lateral view; 20, head and thoracic seg- ments in dorsal view; 21, seventh to ninth abdominal segment in dorsal view; 22, antenna; 23, mandible. Scale lines for Figs 18–21 = 1.0 mm, for Figs 22, 23 = 0.1 mm. Downloaded from Brill.com09/24/2021 11:26:33PM via free access 130 Tijdschrift voor Entomologie, volume 154, 2011 Key to the known third instar larvae of Nearctic Haliplidae between dorsoposterior extensions (Fig. 15) . Haliplus (Liaphlus) cribrarius 1. Body with long filamentous dorsal processes – Distance between lateroposterior extensions (Fig. 1) . Peltodytes.2 of thoracic segments about 3.5 distance – Body without (Fig. 13), with short (Figs 11, between dorsoposterior extensions (Fig. 14) 12, 20) or with long (but not filamentous) . Haliplus (Liaphlus) fulvus dorsal processes (Fig. 14) . 5 11. Ventral side of tibia and tarsus of all legs 2. Length of spine on dorsal projections greater weakly serrate (Fig. 16). Inner face of mandi- than diameter of projections (Figs 2, 3) . 3 ble with three pointed projections (Fig. 17) – Length of spine on dorsal projections not . Haliplus (Paraliaphlus) triopsis greater than or equal to diameter of projec- – Ventral side of tibia and tarsus of all legs tions (Figs 4, 5) . 4 smooth or with small hairs. Inner face of man- 3. Length of spine on dorsal projections about dible with a few tiny dull denticles (Fig. 23) . 1.3–1.4 diameter of projections (Fig. 3) . Haliplus (Paraliaphlus) variomaculatus . Peltodytes sexmaculatus – Length of spine on dorsal projections about Haliplus variomaculatus Brigham & Sanderson 2.0 diameter of projections (Fig. 2) . Figs 18–23 . Peltodytes muticus 4. Length of spine on dorsal projections equal Haliplus variomaculatus Brigham & Sanderson, 1972: 157 to about two thirds of diameter of projec- (original description of adult) tions (Fig. 5) . Peltodytes edentulus Material examined. 1?, 1/, USA, Missouri, Craw- – Length of spine on dorsal projections about ford Co., Onondaga Cave SP, Onondaga Spring, equal to diameter of projections (Fig. 4) . 10 May 2007, M. Hedrick coll., orifice large pool, . Peltodytes lengi vegetation; 1/ and 1 third instar larva from same 5. Antenna with segments 2 and 3 of about the locality, 6 August 2008, M. Zeller coll. (2/ in same length (Fig. 6). Profemur with ventro- Univ. of Missouri coll., 1? and larva in authors distal lobe (Fig. 8) . Brychius.6 coll.). – Antenna with segment 3 twice as long as or longer than segment 2 (Fig. 7). Profemur Description of third instar larva without ventrodistal lobe (Figs 9, 10) . 7 Body. Total length 8.6 mm (urogomphi incomplete). 6. Head including mandibles about as wide as Elongate and subcylindrical (Figs 18, 19). Dorsal long . Brychius hornii and ventral surface covered with small tubercles – Head including mandibles 1.4 wide as (micro tracheal gills). long . Brychius hungerfordi Color. Pale yellowish to yellow, tubercles slightly 7. Protibia distally dilated (Fig. 10) . darkened, tip of backward directed extensions of tho- . Haliplus s. str.: H. apicalis or H. immaculicollis racic and abdominal segments dark brown; cephalic – Protibia distally not dilated (Fig. 9) . 8 capsule light brown to brown on vertex. 8. Dorsal posterior edge of thoracic and ab- Ratios and measurements aimed at characterizing dominal segments without backward di- the body shape are shown in Table 1. rected processes, but with a sparse row of Head. About circular in dorsal view, widest across the single tubercles (Fig. 13). Prothorax sparsely ocelli (Fig. 20). Anterior margin straight to slightly covered with small tubercles (Fig. 13) . convex. Dorsal surface with dense microsculpture . Apteraliplus (1 species: A. parvulus) and about 12 sensilla. Behind eyes laterally two – Dorsal posterior edge of thoracic and ab- tubercles with sensilla. Antenna with four segments, dominal segments with backward directed fourth segment distally bears a bristle and has a par- processes consisting of three or more tu- allel segment attached to third segment (Fig. 22). bercles (Fig. 20), prothorax densely covered Mandible with a darkened narrow pointed tip, suc- with tubercles (Fig. 20) . 9 tion channel running to the tip with an oval opening 9. Lateroposterior extensions of thoracic and on ventral side, a few tiny dull denticles on inner abdominal segments strong (Fig. 14) . 10 margin, two (probably more) setae on outer margin – Lateroposterior extensions of thoracic and (Fig. 23). abdominal segments weak (Fig. 20) . 11 Thorax. Thoracic segments laterally with a weak 10. Distance between lateroposterior extensions backward directed extension, dorsally with 4 weak of thoracic segments about 2.5 distance extensions on hind margin (Fig. 20). Prothorax Downloaded from Brill.com09/24/2021 11:26:33PM via free access Van Vondel: Description of larva of Haliplus variomaculatus 131 24 25 26 27 28 29 Figs 24–29. Haliplus variomaculatus, larva third instar. –24, front leg in anterior view; 25, front leg in posterior view; 26, mid leg in anterior view; 27, mid leg in posterior view; 28, hind leg in anterior view; 29, hind leg in pos- terior view. Scale line = 0.1 mm. Downloaded from Brill.com09/24/2021 11:26:33PM via free access 132 Tijdschrift voor