Crawling water beetlesRolf Georg Beutel
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The Haliplidae or crawling water beetles are a comparatively small group of inconspicuous, small water dwelling insects. They belong to the coleopterous suborder Adephaga but differ from all other groups of this taxon in several important characters. The strictly algophagous habit of haliplid larvae is a feature not found in any other taxon of the almost exclusively carnivorous Adephaga. The extremely enlarged hind coxal plates of adults are also a highly unusual feature of Haliplidae. They function as an accessory breathing air storage and physical lung.
The family contains 5 genera in current classifications (Lawrence & Newton 1995) and about 200 species world wide. Adults live among aquatic vegetation along the edges of ponds, lakes, creeks or streams. They prefer a mixed diet of chironomid eggs, oligochaet worms, small crustaceans, hydrozoans and algae. The relative amount of algae is usually less than 50%. The swimming abilities are rather poor. Middle and hind tibiae are not flattened but equiped with a fringe of swimming hairs. The legs move alternately in contrast to predacious diving water beetles or most whirligig beetles. The English name of the group refers to their habit of crawling along different water plants. Larvae are mostly found among masses of algae. They move slowly and are very easily overlooked in their preferred habitat. Haliplid larvae suck the contents of single cells of algae with their highly specialized mandibles. They breathe by means of dorsal tracheal gills or microtracheal gills.
Adults: The body is 2.5-4.5 mm in length, strongly convex dorsally, and boat-shaped. Most species are testaceous with more or less distinct rows of black punctures on the elytra. The eyes are distinctly protruding. The 11-segmented antennae are devoid of pubescence and filiform. The basal antennomere (scapus) is unusually short. The prosternal process is broadened, truncate apically and adjacent with the metasternal process posteriorly. The metasternal transverse ridge is complete. The metacoxae are immobilized but not fused medially (Belkaceme 1986). The metacoxal plates conceal the basal abdominal segments and the trochanters and femorae of the hind legs.
Enlarged metacoxal plates of Haliplus.
All legs are slender and not flattened. A protibial antenna cleaning organ is absent. Swimming hairs are present on the tibiae and tarsi. The hind wings are rolled apically and not folded as in other groups of Adephaga.
Larvae: The body is elongated, narrow, and strongly sclerotized. The head is small and equipped with highly specialized mandibles with a conspicuous sucking channel (Seeger 1971; Beutel 1986). Maxillae and labium are adapted to handle algae during the feeding process. The short legs have a single claw. Different climbing devices are present on the fore legs (Jaboulet 1960). 1-3 long filamentous gills or short microtracheal gills are present on the thoracic terga and on the abdominal terga I-IX (Jaboulet 1960; Seeger 1971). Urogomphi are absent. Segment X is either reduced or elongated, tapering caudally, and sometimes bifid at the apex. Functional spiracles are present in third instar larvae on the mesothorax and the abdominal segments I-VII.
Five genera are recognized in the recent classification of Coleoptera presented by Lawrence & Newton (1995). The monotypic genera Apteraliplus Chandler (Northern California) and Algophilus Zimmermann (Southern Africa) were erected on the basis of conspicuous autapomorphous features (e.g. absence of wings: Apteraliplus). They are probably closely related with a subgroup of the largest genus Haliplus Latreille (Beutel & Ruhnau 1990). Therefore, the generic status is not appropriate, leaving three genera:
Haliplidae are the second offshoot of Adephaga according to Beutel (1993, 1995) and the second group which acquired aquatic habits. The monophyly of Adephaga excl. Gyrinidae and Haliplidae (=Trachypachidae, Dytiscoidea, Caraboidea) is supported by several apomorphic features of larvae: cephalic egg bursters are present (Arndt 1993), the maxillary groove is completely reduced, M. tentoriolacinialis is attached to the mesal stipital base.
An alternative hypothesis is a sistergroup relationship between Dytiscoidea (=Noteridae, Amphizoidae, Hygrobiidae, Dytiscidae) and Haliplidae. It is discussed in Beutel & Haas (1996) (computer analysis of 38 taxa and 80 characters of Adephaga).
Peltodytes is probably the sistergroup of the remaining genera. They are characterized by lateral tubercles of the head and microtracheal gills as larvae (Seeger 1971; Beutel 1995). A subulate labial palpomere II, partly reduced elytral sutural striae, asymmetric parameres, and specialized egg-laying habits are apomorphies of adults (Beutel 1995; Beier 1929; Galewski 1972).
Brychius is the sistergroup of Haliplus (including Algophilus and Apteraliplus). Sensory tubercles are present on the laciniae of larvae of Haliplus (Jaboulet 1960; Beutel 1995). Complete absence of the sutural striae, sternal bulges on abdominal sternites V-VII, and the rudimentary setal fringe on the left paramere are apomorphic features of adults (Beutel & Ruhnau 1990).
A monophylum comprising Algophilus, Apteraliplus, and the Haliplus-subgenus Liaphlus is supported by the presence of two posterolateral ridges on the head, the presence of a digitiform appendage on the left paramere, and strong, caudolaterally dilated apodems of the gonocoxae (Beutel & Ruhnau 1990).
Arndt, E. 1993. Phylogenetische Untersuchungen larvalmorphologischer Merkmale der Carabidae (Insecta: Coleoptera). Stuttgarter Beiträge zur Naturkunde (A), 488: 1-56.
Beier, M. (1929): Zur Kenntnis der Lebensweise von Haliplus wehnckei Gerh. Zeitschrift für Morphologie und Ökologie der Tiere, 14: 191-233.
Belkaceme, T. 1986. Skelet und Muskulatur der Hinterhüfte von Haliplus lineatocollis Mrsh. (Haliplidae, Coleoptera). Stuttgarter Beiträge für Naturkunde (A), 393: 1-12.
Beutel, R. G. 1993. Phylogenetic analysis of Adephaga (Coleoptera) based on characters of the larval head. Systematic Entomology, 18: 127-147.
---- 1995. The Adephaga (Coleoptera): phylogeny and evolutionary history. Pp. 173-217 in J. Pakaluk and S. A. Slipinski (eds.), Biology, Phylogeny, and Classification of Coleoptera: Papers Celebrating the 80th Birthday of Roy A. Crowson. Muzeum i Instytut PAN, Warszawa.
Beutel, R. G. & S. Ruhnau 1990. Phylogenetic analysis of the genera of Haliplidae (Coleoptera) based on characters of adults. Aquatic Insects 12 (1): 1-17.
Galewski, K. 1972). Significance of the mandible shape for the identification of females of the European species of Haliplidae (Coleoptera). Bulletin de l' Acadmie Polonaise des Sciences, Séries des Sciences Biologiques, 20 (12): 867-871. Warschau.
Jaboulet, M.C. 1960. Contribution a l'étude des larves d' Haliplides. Travaux du Laboratoire de Zoologie et de la Station Aquicole Grimaldi de la Faculté des Sciences de Dijon 31: 1-17..
Lawrence, J. F. and A. F. Newton, Jr. 1995. Families and subfamilies of Coleoptera (with selected genera, notes, references and data on family-group names). Pp. 779- 1006 in J. Pakaluk and S. A. Slipinski (eds.), Biology, Phylogeny, and Classification of Coleoptera: Papers Celebrating the 80th Birthday of Roy A. Crowson. Muzeum i Instytut Zoologii PAN, Warszawa.
Seeger, W. 1971a. Morphologie, Bionomie und Ethologie von Halipliden, unter besonderer Berücksichtigung funktionsmorphologischer Gesichtspunkte (Haliplidae; Coleoptera). Archiv für Hydrobiologie 68 (3): 400-435.
Seeger, W. 1971b. Autökologische Untersuchungen an Halipliden mit zoogeographischen Anmerkungen. Archiv für Hydrobiologie 68 (4): 528-574.
Institut f?r spezielle Zoologie und Evolutionsbiologie, FSU Jena, D-07743 Jena, FRG
Page copyright © 1996 Rolf G. Beutel
- First online 14 October 1996
Citing this page:
Beutel, Rolf Georg. 1996. Haliplidae. Crawling water beetles. Version 14 October 1996 (under construction). http://tolweb.org/Haliplidae/8884/1996.10.14 in The Tree of Life Web Project, http://tolweb.org/