Трансформация экосистем Ecosystem Transformation www.ecosysttrans.com Beetles of the family Heteroceridae (Insecta: Coleoptera) in extreme environments Alexey S. Sazhnev I.D. Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok 109, Nekouz District, Yaroslavl Region, 152742 Russia [email protected] Received: 23.03.2020 Heterocerid beetles (Heteroceridae) are morphologically and Accepted: 09.04.2020 ecologically uniform (all members of the family are burrowing Published online: 06.05.2020 stratobionts). Nevertheless, some groups are obviously in an active and dynamic stage of evolution, and some species have DOI: 10.23859/estr-200323a a high ecological valency. This has allowed Heteroceridae to UDC 574.43; 574.38 colonize semiaquatic environments almost globally and to inhabit ISSN 2619-094X Print some extreme and adverse biotopes. ISSN 2619-0931 Online Keywords: ecology, life form, Heteroceridae, variegated mud- Translated by S.V. Nikolaeva loving beetles, ecotone, ecological niche, distribution. Sazhnev, A.S., 2020. Beetles of the family Heteroceridae (Insecta: Coleoptera) in extreme environments. Ecosystem Transformation 3 (2), 22–31. Introduction family Heteroceridae MacLeay, 1825 is among the The natural and anthropogenic transformation most successful members of this group; heterocerids of semiaquatic ecosystems is extremely rapid, due have evolved in the unstable habitats of water-land to a range of hydrological environmental factors and ecotones and show high taxonomic diversity and natural and climatic conditions, as well as increasing abundance in semiaquatic communities. human impact. Terrestrial semiaquatic ecosystems The world fauna of variegated mud-loving beetles have an intrazonal character, directly dependent (Heteroceridae), totals 349 extant and four extinct on channel and hydrological processes of basins, species (pers. data); previous estimates ranged from resulting in their natural volatility and instability. 320–370 species (Mascagni, 2014; Skalický and Such semiaquatic ecosystems can be considered Ezer, 2014), because the fauna has not been revised. as ecotonic, located in the contact zone of two and/ Moreover, new taxa are being described annually. or more ecosystems (aquatic, terrestrial, air), the Adults and larva of burrowing stratobionts communities of which under such conditions are not (including Heteroceridae) construct branched fully complete and thus not quite stable. Semiaquatic networks of tunnels and chambers in a moist soft ecosystems are characterized by external dis tur ban- substrate, which are used for feeding, egg laying and ces (floods, surges, changes in water level), which pupation. A similar lifestyle is characteristic of many counteract the internal direction of succession, retur- inhabitants of water – land structures (supralittoral, ning formed communities to earlier stages, which aeropelal zone – a community characteristic of silted leads to successional process cycling. Therefore, sand saturated with water just above the water edge unique heterotrophic communities are formed in (Chertoprud, 2011)). At high densities, Heteroceridae, the water-land ecotones, in which coleopteran in- together with similar burrowing stratobionts, give the sects (Coleoptera) play a significant role. Among substrate a specific microrelief that forms accessible the co leopterans in semiaquatic communities, the microniches for other burrowing stratobionts and stenotopic ecomorphological group of semi-aquatic other organisms. Many types of heterocerids live beetles plays an important role (Jäch, 1998). The syntopically (up to four species), populating a single Sazhnev, A.S., 2020. Ecosystem Transformation 3 (2), 22–31. 23 biotope (Sazhnev, 2016). Heteroceridae use acoustic Heteroceridae species. As mentioned above, Hetero- communication by stridulation. Adults and larvae ceridae are indiscriminate algo-detritophages. When of Heteroceridae obtain nutrition as indiscriminate choosing a habitat, they avoid frequently flushed areas detritophages and/or microphytophages (algo det- of the margin of the water body, where detritus does ritophages), collectors that absorb organic detritus, not accumulate, as well as steep edges, preferring microorganisms, diatoms, and other types of algae the second type of waterline zone (Przhiboro, 2001), together with the substrate (Sazhnev, 2018a). Being a meter-wide coastal zone, usually with sediments of detritophages, Heteroceridae are involved in the pro- plant debris and away from the influence of waves. cessing of organics included in detrital food webs, In addition to the trophic component of the ecological and therefore in the transfer of matter and energy in niche, organisms (in particular, Coleoptera) that are the transition zone between the two media. associated with substrates are no less important than Despite their relative stenotopicity, Heteroceridae the method of using the medium as a resource (Kash- are distributed around the world (except for Antarctica) cheev, 1999); this is manifested morphologically. At all and populate the marginal zone of diverse water stages of ontogenesis, Heteroceridae are closely as- bodies in a wide range of environmental conditions, sociated with the substrate, and imagoes are the most including extreme ones. The purpose of this work is to distinctive of semiaquatic burrowing stratobiont Coleo- give an overview of Heteroceridae living in conditions ptera. Specialization for digging includes a cylindrical generally atypical for the group. body shape with a well-defined shape, tapering at the prothorax and mesothorax boundary, which gives mo- Materials and methods bility to the front of the body when digging, a spatulate This review is based on analysis of the available head with mandibles, and the presence of teeth on the literature on the fauna, biology, and ecology of the tibiae, especially the front tibiae (fossorial legs). Some family Heteroceridae, as well as my own observations psammophilic species, for example, Heterocerus faus- and studied collection material from different climatic ti Reitter, 1879, show ecomorphological adaptations to zones and subzones of the Palearctic and Oriental sandy substrate conditions (psammophilia) in the form region. of an increase in the length of the tarsal claws (Sazh- The map was created using the online project nev, 2018b). Individual species of Heteroceridae, in Simplemappr (http://www.simplemappr.net). The some cases, can fit the role of niche carriers, due to dendrogram (Jaccard coefficient, single linkage their life form and morphological adaptations. based on qualitative data) was created using the Species of the family Heteroceridae prefer finely STATISTICA 6.1 software package. The classification dispersed clay and sand types of soil with sufficient of habitats and the division of the Palearctic is given moisture, on which colonies are often formed with according to Emelyanov (1974). pronounced biotopic sympatry (cohabitation of spe- cies). They less frequently inhabit pebble beaches, Results choosing microstations between the stones when they do. In these environments, heterocerid occur- Main Trends for Habitat Selection rences are irregular. Heteroceridae are not recorded in Heteroceridae in wetlands and semiaquatic areas with dense vege- In general, species of the family Heteroceridae oc- tation that forms sod. cur in temperate, subtropical, and tropical latitudes, but The highest population density of Heteroceridae due to their high plasticity and vagility, some of them was recorded in southern Brazil, on the sandy beach- have colonized areas remote from their main range. es of the Atlantic Ocean (Heterocerus freudei (Pa- The following factors are of decisive importance for checo, 1973) – 162 spec./m2 (Vanin et al., 1995)). In Heteroceridae habitat choice: the hydrological regime southern Siberia, in the salt marshes, the population of the water body, the humidity of the substrate, the density of Heterocerus parallelus Gebler, 1830 reach- nature of the soil, the presence of a food supply and es 110 spec./m2 (Mordkovich and Lyubechanskii, the type of waterline zone (Sazhnev, 2016). 2017). In our studies (May–June), the average pop- The properties of individual populations in speci- ulation density of heterocerids on sandy substrates, fic local conditions are usually considered as a rea- the most populated ones, was 72.0 ± 5.2 spec./m2 lized niche (the ecological equivalent of a population) for adults, 27.5 ± 2.6 spec./m2 for adults (Sazhnev, (Hutchinson, 1957). The number of niche dimensions 2018a). It should be noted that the density of colonies (“licenses” (Levchenko, 1993)) can be reduced to is also related to the strategy of sexual behavior of dif- three generalized ones: 1) resources; 2) non-resource ferent species, which was shown for the North Ame- limiting factors; 3) organization of the niche carrier. The rican Heterocerus pallidus Say, 1823 and Augyles term “niche” is equally applicable to both the organism auromicans Kiesenwetter, 1851 (Kaufmann, 1987). and the population or species (Pianka, 1981). The main non-resource limiting environmental The forage base and a certain substrate structure factors that affect Heteroceridae are temperature, hu- are used as a resource measurement of a niche for midity, predators and parasites. 24 Sazhnev, A.S., 2020. Ecosystem Transformation 3 (2), 22–31. In poikilothermic animals, the external tempera- Influence of predators and parasites is a biotic fac- ture directly affects the biochemical and