Diving beetles of the world: Systematics and biology of the dytiscidae
Abstract
Among the hundreds of thousands of species of beetles, there is one family, containing some 4,300 species, that stands out as one of the most diverse and important groups of aquatic predatory insects. This is the Dytiscidae, whose species are commonly known as diving beetles. No comprehensive treatment of this group has been compiled in over 130 years, a period during which a great many changes in classification and a near quadrupling of known species has occurred. In Diving Beetles of the World, Kelly B. Miller and Johannes Bergsten provide the only full treatments of all 186 Dytiscid genera ever assembled. Entomologists, systematists, limnologists, ecologists, and others with an interest in aquatic systems or insect diversity will find these extensively illustrated keys and taxon accounts immensely helpful. The keys make it possible to identify all taxa from subfamily to genera, and each key and taxon treatment is accompanied by both photographs and detailed pen-and-ink drawings of diagnostic features. Every genus account covers body length, diagnostic characters, classification, species diversity, a review of known natural history, and world distribution. Each account is also accompanied by a range map and at least one high-resolution habitus image of a specimen. Diving beetles are fast becoming important models for aquatic ecology, world biogeography, population ecology, and animal sexual evolution and, with this book, the diversity of the group is finally accessible.
... In addition, brightly colored species of Hydroporus or Nebrioporus are found in trout ponds and streams (Galewski 1971). In addition, disruptive color patterns of predaceous diving beetles of genera Thermonectus (Fig. 6.17d), Sandracottus (Fig. 6.17e), Hydaticus, and Prodaticus (now subgenus of Hydaticus) in Africa, America, and Australia were reported from exposed habitats with clear opened water with mainly mineral substrates (Larson 1996;Miller and Bergsten 2016). Within New Guinea there was found an unusually high portion of dytiscids (e.g., Laccophilus) with dark or melanistic forms (Balke et al. 1997). ...
... All developmental stages of Dytiscidae may be associated with other organisms ranging from bacteria and fungi to microsporidia, gregarines, nematodes, mites, and parasitoid insects (Blunck 1923b;Franciscolo 1979;Miller and Bergsten 2016;Poinar and Petersen 1978). In this chapter, there are especially considered microorganisms (bacteria and fungi) which can be localized on the internal or external body surfaces of eggs, larvae, pupae, and adults of Dytiscidae. ...
... 6.4.2.1.2, moreover literature is compiled in Miller and Bergsten (2016). In an interesting study, Goldmann and Weir (2012) described the position specifity of Chitonomyces on Laccophilus-beetles and concluded that sexual contacts and transmissions of Laboulbeniales are responsible for position specificities of these ectoparasites. ...
The chapter deals with chemical mechanisms that help to control intra- und inter-specific interactions with respect to predaceous diving beetles. Apart from chemical receptors and senses within Dytiscidae there are described intraspecific (pheromones) and especially interspecific interactions with respect to this water beetle family. The last group of behavioral modifying compounds includes kairomones and allomones. Allomone constituents from pygidial glands, prothoracic defensive glands, and pupal glands are compiled for a large group of predaceous diving beetles. With respect to the natural compounds, their chemistry, distribution within Hydradephaga, biological activities, and especially their significance for dytiscids are discussed. In addition, further secondary compounds from these beetles are presented, including epicuticular lipids or pigments that may be responsible for the coloration of the adult beetles and their larvae. Finally, the microorganisms including fungi and their secondary metabolites that are associated with predaceous diving beetles are presented. The described microorganisms range from culturable to non-culturable taxa. The role of hemolymph with respect to internal defense, hemostasis, and regeneration is briefly reviewed.
... Identification was performed through introductory genus-level keys (White and Roughley 2008;Archangelsky et al. 2009;Miller and Bergsten 2016;Benetti et al. 2018;Passos et al. 2018), and subsequently with specialized revisions and original species descriptions. ...
... This cosmopolitan genus is the largest of the subfamily Laccophilinae, with 285 species (Nilsson and Hákej 2020) Genus Neoclypeodytes Young, 1967 Note. This genus is present from southwestern Canada south through western United States and Mexico, with a few species in Panama and one in Jamaica (Miller and Bergsten 2016;Nilsson and Hájek 2020). It comprises 27 species (Nilsson and Hájek 2020), 15 of which are present in Mexico (Arce-Pérez and Roughley 1999; Arce-Pérez and Novelo-Gutiérrez 2015; Nilsson and Hájek 2020). ...
... Note. This genus is distributed in the Nearctic, Neotropical, Palearctic, and Oriental regions, with 67 species (Miller and Bergsten 2016;Nilsson and Hájek 2020), six of which are recorded from Mexico (Arce-Pérez and Roughley 1999; Nilsson and Hájek 2020). ...
Results of an aquatic beetle survey at Volcán Tacaná, Mexico, are presented with five altitudinal levels in a monthly sampling regime, aiming to estimate both diversity and altitudinal distribution patterns of the aquatic beetle fauna. The first list of aquatic beetle species from this mountain is presented, comprising 40 species in 32 genera and nine families, with four species recorded for the first time from Mexico and six recorded for the first time from Chiapas. The aquatic beetle fauna is characterized by Elmidae with 20 species, Dytiscidae with eleven species, Dryopidae with three, and Epimetopidae, Hydraenidae, Hydrophilidae, Gyrinidae, Lutrochidae, and Noteridae with one species each. The species composition through the sampled altitudinal gradient (670–1,776 m) was not homogeneous, with the elmid genera Macrelmis , Heterelmis , Microcylloepus , and Austrolimnius present at all levels, while Hexanchorus , Neoelmis , and Onychelmis were present at levels 1–3 (673–1,214 m); dytiscids were mostly present at levels 4 and 5 (1,619–1,776 m), and dryopids were present only at levels 1–3. A Parsimony Analysis of Endemicity supports a general partition between altitudinal levels 1–3 and levels 4 + 5.
... Identification was performed through introductory genus-level keys (White and Roughley 2008;Archangelsky et al. 2009;Miller and Bergsten 2016;Benetti et al. 2018;Passos et al. 2018), and subsequently with specialized revisions and original species descriptions. ...
... This cosmopolitan genus is the largest of the subfamily Laccophilinae, with 285 species (Nilsson and Hákej 2020) Genus Neoclypeodytes Young, 1967 Note. This genus is present from southwestern Canada south through western United States and Mexico, with a few species in Panama and one in Jamaica (Miller and Bergsten 2016;Nilsson and Hájek 2020). It comprises 27 species (Nilsson and Hájek 2020), 15 of which are present in Mexico (Arce-Pérez and Roughley 1999; Arce-Pérez and Novelo-Gutiérrez 2015; Nilsson and Hájek 2020). ...
... Note. This genus is distributed in the Nearctic, Neotropical, Palearctic, and Oriental regions, with 67 species (Miller and Bergsten 2016;Nilsson and Hájek 2020), six of which are recorded from Mexico (Arce-Pérez and Roughley 1999; Nilsson and Hájek 2020). ...
Results of an aquatic beetle survey at Volcán Tacaná, Mexico, are presented with five altitudinal levels in a monthly sampling regime, aiming to estimate both diversity and altitudinal distribution patterns of the aquatic beetle fauna. The first list of aquatic beetle species from this mountain is presented, comprising 40 species in 32 genera and nine families, with four species recorded for the first time from Mexico and six recorded for the first time from Chiapas. The aquatic beetle fauna is characterized by Elmidae with 20 species, Dytiscidae with eleven species, Dryopidae with three, and Epimetopidae, Hydraenidae, Hydrophilidae, Gyrinidae, Lutrochidae, and Noteridae with one species each. The species composition through the sampled altitudinal gradient (670-1,776 m) was not homogeneous, with the elmid genera Macrelmis, Heterelmis, Microcylloepus, and Austrolimnius present at all levels, while Hexanchorus, Neoelmis, and Onychelmis were present at levels 1-3 (673-1,214 m); dytiscids were mostly present at levels 4 and 5 (1,619-1,776 m), and dryopids were present only at levels 1-3. A Parsimony Analysis of Endemicity supports a general partition between altitudinal levels 1-3 and levels 4 + 5.
... Previous authors noticed the morphological resemblance of Neoporus and Heterosternuta (e.g. Larson et al., 2000;Miller and Bergsten, 2016), considering them as closely related genera with overlapping distributions (Larson et al., 2000) and similar habitat preferences (Table S2). The main morphological character separating both genera is the apex of the aedeagus (bifid in Heterosternuta), and our samples were identified based on this character. ...
... Miller et al. (2013) reported a similar result, with a clade including Haideoporus, Heterosternuta and Neoporus. Another novel result was the ascription of Lioporeus to subtribe Siettitiina, formerly considered to be part of the Hydroporus pulcher-undulatus group by Fall (1923) (see also Miller and Bergsten, 2016 interpretation. The paraphyly of Hydroporus was also not surprising, as Hydrocolus was erected for the former Hydroporus oblitus group (Larson et al., 2000). ...
... Tiporus is a homogeneous group of species inhabiting lotic environments in northern Australia (Miller and Bergsten, 2016). The low support for its monophyly (pp = 0.85) may be due to the inclusion of Sekaliporus in some of the topologies of the Bayesian analysis. ...
The long-term geological stability of aquatic habitats has been demonstrated to be a determinant in the evolution of macroinvertebrate fauna, with species in running (lotic) waters having lower dispersal abilities, smaller ranges and higher gene flow between populations than species in standing (lentic) environments. Lotic species have been hypothesized to be more specialised, but the diversification dynamics of both habitat types have not been studied in detail. Using a speciose lineage of water beetles we test here whether diversification rates are related to the habitat preference of the species and its consequences on turnover, which we expect to be higher for lotic taxa. Moreover, we tested whether life in lotic environments is acting as an evolutionary dead-end as it is considered as ecological specialisation. We built a comprehensive molecular phylogeny with 473 terminals representing 421 of the 689 known species of the tribe Hydroporini (Coleoptera, Dytiscidae), using a combination of sequences from four mitochondrial and two nuclear genes plus 69 mitogenomes obtained with NGS. We found a general pattern of gradual acceleration of diversification rate with time, with 2 to 3 significant diversification shifts. However, habitat is not the main factor driving diversification in Hydroporini based on SecSSE analyses. The most recent common ancestor of Hydroporini was reconstructed as a lotic species, with multiple shifts to lentic environments. Most frequent transitions were estimated from lentic and lotic habitats to the category “both”, followed by transitions from lotic to lentic and lentic to lotic respectively, although with very similar rates. Contrary to expectations, we found little evidence for differences in diversification dynamics between habitats, with lotic environments clearly not acting as evolutionary dead-ends in Hydroporini.
... Sandracottus species show variation in body colour pattern and structure of genitalia is important for species level identification. Identification of specimens was based on the description given by [9] and [7]. Species synonym given is only based on the original citation [11] and the latest citation on [3]. ...
... . In India, Tribe Aciliini Thomson, 1867 consist of only two genera namely Sandracottus Sharp, 1882 and Sharp, 1882 comprises of 17 described species distributed worldwide[7,3]. An adult Sandracottus is found in ponds, dams and at the edge of slow streams and even inside the caves. ...
The present study is based on some recent collections of 77 samples of genus Sandracottus Sharp, 1882 during the year 2019 to 2023 from various locations of Western Ghats of India. Six species of the genus Sandracottus Sharp, 1882 is reported from India with three species having distribution in the Western Ghats. The present study reports one additional species Sandracottus mixtus (Blanchard, 1843) to the Western Ghats of Maharashtra, Karnataka, Kerala and Tamil Nadu for the first time. The study also reports a new state record of Sandracottus dejeanii (Aubé, 1838) to Karnataka.
... More than 100 species of subterranean predaceous diving beetles have now been described from Australia, virtually all coming from the calcretes in the Yilgarn region of Western Australia and the Ngalia Basin of the Northern Territory . In other regions of Australia, which are mostly devoid of calcrete deposits, and other regions globally (i.e., U.S.A., Europe, Africa south-east Asia, Miller and Bergsten 2016), stygobiotic beetles are mostly found in river/stream gravels and cave systems and usually as small numbers of species. ...
... Respiration in stygobiotic larvae has not been investigated, though they likely use cutaneous respiration given their small size and that smaller larvae and early instars of epigean species use this form of respiration (Miller and Bergsten 2016). ...
The western half of the Australian arid zone harbours the richest diversity of obligate subterranean dytiscids in the world, which are found in isolated calcrete (carbonate) aquifers. Each calcrete usually supports from one to three beetle species that are locally endemic to a specific calcrete, and display the full array of adaptations to living in a permanently dark, aquatic environment. The origin of this dytiscid diversity likely dates back to the late Miocene to Pliocene when central and western Australia was dominated by a more benign, mesic environment. Subsequent aridification led to relictualisation of the fauna to the calcrete aquifers which, because of their physical isolation from each other, have been described as ‘islands under the desert’. Here we provide an overview of this remarkable fauna of dytiscids, and outline what is currently known about their diversity, life history, respiratory physiology, modes of speciation, population biology, and outline their conservation issues and areas for future research.
... Hydaticus belongs to the subfamily Dytiscinae and is the only genus in the tribe Hydaticini. It is mainly characterised by the anterolateral margin of the metaventrite (metasternal wing) straight (convex in other dytiscids), by the presence in males of a stridulatory apparatus on the dorsal surface of protarsomere II (absent in a few species), and in females of a sexual sculpture on the pronotum sides and humeral angle of the elytron, which consists of irregular grooves and/or pits (strongly reduced or absent in a few species) (Miller et al. 2009;Miller & Bergsten 2016). Hydaticus is well-supported as a monophyletic group (Miller et al. 2009) and each of the afore-mentioned diagnostic characters is also a synapomorphy of the genus and the tribe. ...
... The subgenus Hydaticus comprises only seven species, distributed in the temperate and cold parts of the Nearctic and Palearctic regions. The subgenus Prodaticus Sharp, 1882, mainly tropical and much more diversified (143 species), is characterised mainly by the anterior surfaces of metafemur and metatibia without fine punctation (present in subgenus Hydaticus), a basal brush of setae on the ventral surface of male mesotarsomere I which is small and linear (broad in subgenus Hydaticus) and the fused female gonocoxae apically broad (sharply acute and knife-like in subgenus Hydaticus) (Miller et al. 2009;Miller & Bergsten 2016). A recent comprehensive taxonomic revision of the genus Hydaticus is lacking, but important parts of it have received thorough treatment in the last decades (e.g. ...
Hydaticus (Prodaticus) mangamanga n. sp. is described from a single sampling site in the south-eastern part of Madagascar Central Highlands, near Ranomafana. The new species is unique among the known species of the genus Hydaticus in that the last visible abdominal ventrite is strongly modified and differentiated between sexes, and is also quite unusual in paramere configuration. Analysis of partial CO1 sequences revealed that H. mangamanga belongs to the leander-group and is genetically close to the Malagasy region endemic H. inconspicuus Régimbart, 1895 Régimbart M. 1895. Révision des Dytiscidae et Gyrinidae d’Afrique, Madagascar et îles voisines. Mémoires de la Société entomologique de Belgique. 4:1–244. [Google Scholar] stat. rev. with only around 1.5% of sequence divergence, providing the first instance of a sister-group relationship between two Hydaticus species endemic from the Malagasy region. However, morphologically these two species differ considerably. They are illustrated (habitus, structures, male genitalia) and compared in detail. Collecting circumstances for H. mangamanga are described and a map of its known distribution is provided. A lectotype is designated for H. inconspicuus; this name is re-established as valid for this species, and the name H. kolbei Branden, 1885 used in the recent literature is considered of doubtful identity. An identification key is provided for all Hydaticus (Prodaticus) species known from Madagascar, with accompanying illustrations of median lobes of aedeagus in lateral view.
... Diving beetles (Coleoptera: Dytiscidae) are well adapted for an aquatic lifestyle, as adults as well as all larval stages live in water (Miller & Bergsten 2016). Both larvae and adults are predaceous and active predators in freshwater environments (Yee 2014). ...
... The beetles of the genus Cybister are medium to large (body length 13.0-43.0 mm) and distributed in all major biogeographic regions of the world (Miller & Bergsten 2016). Seven Cybister species are distributed throughout Japan (Mori & Kitayama 2002;Nakajima et al. 2020). ...
The population of the diving beetle Cybister rugosus (Macleay, 1825) has been declining in recent years, and it is designated as “Vulnerable” (VU) in the Red List of Japan. However, there have been no quantitative studies on the feeding habits of the larval stage of this beetle. Revealing the feeding habits is indispensable for understanding the life history of C. rugosus. In the current study, we reared C. rugosus larvae on different prey taxa (Odonata nymph, fish, tadpole, and shrimp) and evaluated their growth and survival rates. Previous studies have shown that three congeneric Cybister species larvae feed mainly on invertebrates. However, all larval instars of C. rugosus were able to feed on invertebrates and vertebrates and grow. Thus, we considered C. rugosus to be a generalist compared to the other Cybister species. The larval periods were shorter for C. rugosus that fed on Odonata nymphs than on any other prey. Feeding different prey taxa had no significant effect on the body length of newly emerged adult males. However, the body length of newly emerged adult females was larger when the larvae fed on Odonata nymphs than when the larvae fed on fish. As in other Cybister species, we concluded that the Odonata nymph is an appropriate food from the viewpoint of increased growth rate in C. rugosus.
... Dytiscidae is currently the largest group of aquatic coleopterans (Jäch & Balke 2008;Yee 2014), with 4589 species known worldwide (Nilsson & H ajek 2021). Dytiscids inhabit most freshwater habitats, including stagnant, ground, and running water, as well as wet rock surfaces, flooded tree holes, and many other ephemeral and spontaneously appearing water sources (Balke & Hendrich 2016;Miller & Bergsten 2016). In aquatic habitats where fish are absent, Dytiscidae constitute the apex predator and play a central role in maintaining species compositions of other trophic levels (Foster & Bilton 2014). ...
... This predatory behavior is common to at least three species groups and is a likely characteristic of Copelatus larvae (Balke & Hendrich 2016). Miller and Bergsten (2016) also described Copelatinae larvae eating solid and not liquid food. The commonality of this foraging behavior is likely because these species are fast and active predators, and require rapid consumption of whole prey in order to move on to the next prey, as opposed to the extraintestinal digestion methods used in Cybister spp. ...
Diving beetles (Dytiscidae) play an important ecological role in most aquatic water habitats. However, approximately 40% of dytiscids in Japan have been classified as threatened, and further knowledge on their life history is necessary to support conservation efforts. In this study, we collected adult Copelatus zimmermanni (Coleoptera: Dytiscidae) from an ephemeral rain pool and raised a generation under laboratory conditions. We then compared the larval period with two Copelatus species, C. parallelus and C. masculinus. Complete development (egg to adult) occurred in 39-61 days (n = 10) and comprised the following stages: egg (3-6 days, n = 20), first instar (3-8 days, n = 20), second instar (3-12 days, n = 15), third instar larvae (4-13 days, n = 14), and landing to escape (11-36 days, n = 10). The third instar and total larval periods of C. zimmermanni were significantly shorter than those of C. parallelus and C. masculinus. The differences in the duration of larval periods may be related to the permanence of water sources used as reproductive sites for each species. We suggest that the shorter developmental period of C. zimmermanni allows it to complete entire lifecycles even in highly ephemeral aquatic habitats. This is the first report on the immature stages of a species within the C. nigrolineatus species group.
... The geographic coordinates were recorded in the field using a GPS satellite app on a mobile phone. Morphological terminology used in the description follows Miller & Bergsten (2016) and Hendrich et al. (2018). ...
... Clypeodytes Régimbart, 1894 is a group of small-sized (1.5-2.5 mm) diving beetles which have a short and robust body and differ from other genera of Bidessini in the following combination of characters: (1) head with a transverse occipital line, (2) anterior clypeal margin with bead, (3) pronotum with basal striae, (4) elytra with basal striae and without sutural line (elytra without striae in the subgenus Hypoclypeus Guignot, 1950), (5) each elytron with a carina laterally, (6) epipleura with a transverse or oblique subhumeral carina, (7) metaventrite with a pair of serial punctures medially in most species, (8) parameres (lateral lobe) of aedeagus two-segmented (Biström 1988a(Biström , 1988bMiller & Bergsten 2016). Coloration. ...
The diving beetle Clypeodytes limpidus sp. nov. is described from western Yunnan, China. It is the second known species of the genus Clypeodytes Régimbart, 1894 from China and belongs to the subgenus Hypoclypeus Guignot, 1950. It can be distinguished from C. bufo (Sharp, 1890), the only other Chinese Clypeodytes species, by the shape of the median lobe, the more rounded body and the elytral pattern. A Chinese specimen of C. bufo is illustrated, and the species is recorded for the first time for Laos.
... The diving beetle subfamily Colymbetinae Erichson, 1837 comprises 11 genera worldwide (Miller and Bergsten 2016;Balke et al. 2017). In Australia, Colymbetinae are represented by the widespread genus Rhantus Dejean, 1833 (Balke et al. 2000;Miller and Bergsten 2016;Nilsson and Hájek 2017), with two species (Hendrich et al. 2019). ...
... The diving beetle subfamily Colymbetinae Erichson, 1837 comprises 11 genera worldwide (Miller and Bergsten 2016;Balke et al. 2017). In Australia, Colymbetinae are represented by the widespread genus Rhantus Dejean, 1833 (Balke et al. 2000;Miller and Bergsten 2016;Nilsson and Hájek 2017), with two species (Hendrich et al. 2019). One species, the so called "supertramp" Rhantus suturalis (Macleay, 1825) ( Fig. 1B) is distributed over almost all of Australia, except the tropical lowlands in the north, and recorded from all states but one. ...
New distributional records of the rarely collected diving beetle Rhantus simulans Régimbart, 1908, an endemic species of south-western Australia, are presented. We also summarize what is known about its habitat. The occurrence of R. simulans indicates a high conservation value of the sampled wetland. For easier identification, we provide photographs of the habitus and male genitalia of R. simulans and R. suturalis (Macleay, 1825). Rhantus simulans is now recorded from 17 localities along the coast of south-western Australia. Furthermore, data on the location of other 31 diving beetle species are provided.
... Therefore, while we might expect the observed mortality rates to be relatively consistent between both types of studies, we acknowledge that there could be potential issues with the lack of control and standardization in this study and present the results as illustrative of what can occur in this system. Furthermore, as the insects we study here are often found in shallow, temporary ponds (Miller & Bergsten, 2016;Wilbur, 1997), our mesocosms effectively replicate such a shallow habitat with often limited refuge or complexity. Characteristics of larger, deeper, and more complex lentic habitats may enable some taxa to use additional antipredator traits, such as diving deeper into the water and refuge use, but these habitat characteristics are not representative of our small temporary pond system or potentially characteristics that our species would have traits to take advantage of. ...
... As three of the most abundant aquatic insect species at UMFS, N. irrorata, C. glyphicus, and L. fasciatus are often found in temporary ponds (but especially C. glyphicus; (Miller & Bergsten, 2016) and coexist at the landscape scale despite the seemingly maladaptive habitat selection patterns. Due to this co-occurrence, it could theoretically be possible that N. irrorata serve as a proxy for fishless habitats, attracting C. glyphicus and L. fasciatus. ...
Predators are a particularly critical component of habitat quality, as they affect survival, morphology, behavior, population size, and community structure through both consumptive and non‐consumptive effects. Non‐consumptive effects can often exceed consumptive effects, but their relative importance is undetermined in many systems. Our objective was to determine the consumptive and non‐consumptive effects of a predaceous aquatic insect, Notonecta irrorata, on colonizing aquatic beetles. We tested how N. irrorata affected survival and habitat selection of colonizing aquatic beetles, how beetle traits contributed to their vulnerability to predation by N. irrorata, and how combined consumptive and non‐consumptive effects affected populations and community structure. Predation vulnerabilities ranged from 0% to 95% mortality, with size, swimming, and exoskeleton traits generating species‐specific vulnerabilities. Habitat selection ranged from predator avoidance to preferentially colonizing predator patches. Attraction of Dytiscidae to N. irrorata may be a natural ecological trap given similar cues produced by these taxa. Hence, species‐specific habitat selection by prey can be either predator‐avoidance responses that reduce consumptive effects, or responses that magnify predator effects. Notonecta irrorata had both strong consumptive and non‐consumptive effects on populations and communities, while combined effects predicted even more distinct communities and populations across patches with or without predators. Our results illustrate that an aquatic invertebrate predator can have functionally unique consumptive effects on prey, attracting and repelling prey, while prey have functionally unique responses to predators. Determining species‐specific consumptive and non‐consumptive effects is important to understand patterns of species diversity across landscapes.
... Thanks to this ability in some case they can move from permanent habitats to ephemerals one. Thus in field studies they could be found in unpredictable sites (Miller & Bergsten, 2016). Diving beetles are represented by 182 genera and approximately 4,600 species around the world (Nilsson & Hájek, 2023a). ...
This study was carried out between 2013 and 2019 in five provinces located in Eastern and South Eastern Anatolian Region of Turkey. The dytiscid specimens were collected from a total of 226 sampling sites that altitudes varied between 500 and 2,700 meters. The 226 sampling sites were classified into one of six altitudinal levels defined by semi open intervals with amplitude of 300 m. A total of 45 species belonging to the family Dytiscidae were identified. A detailed ecological analysis related to altitude is made by means of the distribution of 45 identified species. The richness of species was analyzed at different altitudinal levels. The indicator species were determined by establishing their altitude profile in terms of reciprocal species-factor information. The species density is highest in altitudinal level 2 (800-1100m) and is gradually decrease by increasing of altitudinal level. Ten representative species are placed into three groups: species occurring at high altitude; species present at low altitude and species occurring along the entire altitudinal gradient.
... The genus Neobidessodes (tribe Bidessini) has stygobiotic species in WA, which we also consider below for the generic placement. Adults of N. humphreysi have curved metatibia which are expanded towards the apex (Figure 3a,b) and have a spine in the spermatheca (Figure 3e), both characters defining the tribe Bidessini (Miller & Bergsten 2016). This would rule the species out of the tribe Hydroporini, and therefore of Paroster, the most species rich genus of stygobiotic Dytiscidae in the Ngalia Basin. ...
The largest diversity in the world of subterranean diving beetles (Dytiscidae) has been discovered in underground waters of the Australian arid zone. The majority of species are from the Dytiscidae genera Limbodessus Guignot, 1939 (Bidessini) and Paroster Sharp, 1882 (Hydroporini) and are distributed within two major regions: calcrete islands of central Western Australia and the Ngalia Basin of the Northern Territory. Here, we use an integrative approach based on morphological and molecular analyses to describe Ngaliadessus humphreysi gen. et sp. nov. Watts & Villastrigo representing a new genus and species of stygobiotic Bidessini collected from a single well in the Ngalia Basin. Phylogenetic analyses using whole mitochondrial genome, Histone 3 and 18S rRNA data, representing a comprehensive coverage of Bidessini genera, support the distinction of the genus and species as a separate evolutionary lineage sister to the Australasian genus Limbodessus and the widely distributed genus Allodessus Guignot, 1953. Our study further confirms that the Ngalia Basin, containing 13 subterranean dytiscid species from four distinct genera, is one of the most speciose areas within the world's most diverse hotspot of subterranean diving beetles.
... Acilius Leach, 1817 is a Holarctic genus, which currently includes 13 species (Nilsson & Hájek 2023). Members of this group are most often collected in lentic habitats with considerable vegetation (Miller & Bergsten 2016). The genus is included in the tribe Aciliini, subfamily Dytiscinae, along with Aethionectes Sharp, 1882, Graphoderus Dejean, 1833, Rhantaticus Sharp, 1882, Sandracottus Sharp 1882, Thermonectus Dejean, 1833, and Tikoloshanes Omer-Cooper, 1956. ...
Adults and larvae of the very rare Chinese endemic species Acilius sinensis Peschet, 1915 are newly reported from three localities in western Yunnan, which indicates the presence of viable populations in this area. Based on the available data, the rarity of the species in collections is more caused by collecting bias than actual threat of its habitat loss. All larval instars of A. sinensis are for the first time described according to the now generalized larval descriptive format of Dytiscidae, which incorporates detailed chaetotaxic and morphometric analyses. Like other known Acilius Leach, 1817 larvae, A. sinensis is characterized by the typical Y-shaped median process of prementum. So far as the third instar larva is considered, A. sinensis shares with A. fraternus (Harris, 1828), A. kishii Nakane 1963, A. semisulcatus Aubé, 1838, and A. sulcatus (Linnaeus, 1758) the median process of prementum invaginated at nearly 75% of its length compared to less than 35% in A. abbreviatus Aubé, 1838, A. duvergeri Gobert, 1874, and A. canaliculatus (Nicolai, 1822). As far as chaetotaxy is concerned, A. sinensis is distinguished by the presence of the primary pore PAo located on the ventral face of the parietal. The habitat of the species is briefly commented. Acilius sinensis is here newly proposed for inclusion in the IUCN red list in the category Vulnerable.
... Larval studies (Alarie et al. 2000;Michat et al. 2017) as well as most recent molecular analyses (Miller & Bergsten 2023) postulated a sister relationship of Agabetini and Laccophilini. The phylogenetic relationships of J. niponensis with other Laccophilini, however, remain unclear (Miller & Bergsten 2016), although the fact that this species was originally described by Kamiya (1939) in the genus Neptosternus Sharp, 1882 may suggest that it is related to this group. ...
The three larval instars of Japanolaccophilus niponensis (Kamiya, 1939) (Coleoptera: Adephaga, Laccophilinae) are described for the first time according to the now genevralized larval descriptive format of Dytiscidae (Coleoptera: Adephaga), which incorporates detailed chaetotaxic and morphometric analyses. A parsimony analysis based on larval characteristics of 14 Laccophilini species in seven genera was conducted using the program TNT. One of the main results is that Japanolaccophilus Satô, 1972, which so far was treated as being related to Neptosternus Sharp, 1882 now stands out as sister to Laccophilus Leach, 1815, and Philodytes J. Balfour-Browne, 1938 with strong support. Additionally, Laccomimus Toledo & Michat, 2015, and Africophilus Guignot, 1948 are resolved as monophyletic and sister to a clade which itself is subdivided into two well supported clades: Neptosternus + Australphilus Watts, 1978, and Japanolaccophilus + (Laccophilus, Philodytes). Philodytes is here newly accepted as junior synonym of Laccophilus.
... The genus Laccophilus Leach belongs to the subfamily Laccophilinae and is known to be the second largest genus in the family Dytiscidae, with 289 species distributed across most zoogeographical regions (Miller and Bergsten 2016;Nilsson and Hájek 2022). In Japan, recent taxonomical studies by the first author revealed the occurrence of several new species Kamite 2018, 2020), and ecological studies have gradually unraveled their life cycle in detail (Watanabe 2019(Watanabe , 2020(Watanabe , 2021a(Watanabe , b, 2022Watanabe and Kamite 2020). ...
The larva of Laccophilus yoshitomii Watanabe and Kamite, 2018 from Japan is described for the first time, with an emphasis on the chaetotaxy analysis of the cephalic capsule, head appendages, legs, last abdominal segment, and urogomphi. The larva of L. yoshitomii is characterized as follows: setae MX5 and MX6 curved posteriorly, seta FE5 longer than FE6, setae TI1 and TI7 approximately the same length, seta AB11 longer than AB15, setae UR2–4, 7 long (instar I), and each posterolateral margin of PA with 2 secondary setae (instar II–III). Wild individuals tend to be darker than reared individuals, probably owing to the lightness and color of the surrounding environment.
... Collected insects were immediately sorted and preserved in a 4% formalin solution. They were identified using a Labomed stereozoom microscope following standard keys Nieser, 2002;Subramanian and Sivaramakrishnan, 2007b;Merritt and Cummins, 2008;Gosh and Hegde, 2013;Jaiswal, 2013;Jehamalar and Chandra, 2013;Thirumalai, 2013;Sundar et al., 2014;Holzenthal, 2015;Basu et al., 2016;Miller and Bergsten, 2016;Prommi, 2016;Bird et al., 2017;Bezděk and Hájek, 2017;Basu et al., 2018;Saha and Gupta, 2018). Data processing was done using Microsoft excel 2010 (Microsoft corporation) and diversity indices were worked using PAST software. ...
A study on aquatic insects biodiversity and abundance along with physicochemical parameters of two lentic water bodies (Varuna and Dalvoy) of Mysore district was carried out on monthly basis from October 2018 to March 2019. A total of 31 species belonging to 19 families and 6 orders were recorded during the study period. At order level, Coleoptera showed maximum relative abundance (57%) followed by Hemiptera (13%) in Varuna Lake, while in Dalvoy Lake, the order Hemiptera (66%) was most abundant, followed by Coleoptera (16%). Computation of dominant status of different species of aquatic insects in lakes based on Engelmann's scale revealed that Canthydrus laetabilis and Gyrinus distinctus, from the order Coleoptera, were dominant in Varuna Lake, while two Hemipteran species, Diplonychus rusticus and Anisops sp., were dominant in Dalvoy Lake. The highest Shannon diversity index (2.803) and evenness values (0.66) were recorded in Varuna Lake, which was slightly greater than Dalvoy Lake (2.028 and 0.45). Similarly, the Biological Working Party Score (BMWP) and Average Score Per Taxon (ASPT) values were 80 and 5.33 in Varuna Lake and 53 and 4.08 in Dalvoy Lake. This indicates Varuna Lake is less polluted and has higher species diversity than Dalvoy Lake. In terms of the physico-chemical properties of water, a significant difference was noted in electrical conductivity, total dissolved solids, free carbon dioxide, dissolved oxygen, total alkalinity, hardness, nitrate, sulphate, and chloride concentrations between Dalvoy Lake and Varuna Lake. The results of physicochemical analysis and diversity indices suggest stressed and disturbed water quality conditions at Dalvoy Lake.
... S. optatus is a small Hydroporinae distributed in the West-Europe; Sc. halensis is a little bit larger species with a larger geographic distribution, recorded in Europe and North-Africa. Both species belong to the tribe Hydroporini and to two different subtribes (Miller and Bergsten, 2016). ...
The structure of the male genital organs and spermiogenesis of two diving beetles, Stictonectes optatus and Scarodytes halensis were studied for the first time. S. optatus shows unifollicular testes consisting of a long tubule apically forming a globular structure. The deferent duct epithelia show a secretory activity involved in the spermatostyle organization. They are connected with two very large accessory glands. Sc. halensis has a more common structure of the male genital apparatus with unifollicular cylindrical testes and very long deferent ducts. Sc. halensis accessory glands are smaller than those of S. optatus. The sperm structure in both species is characterized by a small acrosome, a flattened nucleus with a lateral extension containing a centriole from which a long flagellum originates. Both species exhibit sperm conjugation with long sperm bundles showing nuclei orderly arranged in sperm-heads stacks and free flagella. In addition, S. optatus has a thick layer of secretion surrounds these sperm-head stacks. Such a secretion is considered a spermatostyle. This finding represents the first record about the presence of this structure among Dytiscidae. In the flagellum, a typical axoneme with a 9 + 9 + 2 microtubular complex, and two mitochondrial derivatives are present in both species. Those of S. optatus have a peculiar shape with the apical side, in cross-section, displaying pointed corners. Two small accessory bodies are located between the axoneme and the two mitochondrial derivatives.
... The genus Laccophilus Leach, 1815 is by far the largest genus in this subfamily, including 105 species in Africa (Biström et al. 2015). It is the second most diverse genus of diving beetles in the world with currently 282 species (Miller & Bergsten, 2016;Nilsson, 2001Nilsson, , 2016. On a worldwide level, the most complete work on Laccophilus were written by Sharp (1882) and since then authors like Régimbart (1895), Guignot (1959), Zimmerman (1970), Brancucci (1983) and Biström et al (2015) have revised the Laccophilus fauna of separate geographical regions. ...
Madagascar is recognized as a global hotspot of freshwater diversity and is well known as one of the most diverse places in the world. Furthermore, the relevance of freshwater ecosystems to human wellbeing has progressively been recognized and in the last decade the scientific knowledge of aquatic insects on the island has improved dramatically. To preserve and manage freshwater diversity is vital. In this work I study the diversity and distribution of the endemic Laccophilus alluaudi group of diving beetles (Dytiscidae) from Madagascar as a contribution to the better understanding of these organisms. Based on taxonomical work, nuclear (H3) and mitochondrial (CO1) gene fragments I perform species delimitation analyses and revise the group taxonomically. A total of five new species are described, Laccophilus angustiphallus sp. n., Laccophilus robustus sp. n., Laccophilus nosybei sp. n., Laccophilus pseudocomes sp. n. and Laccophilus ornithopterus sp. n. As a result, the total number of species in this group doubles. Furthermore, I provide an identification key to all species in the group, distribution maps, descriptions, and photographs of each species including male genitalia in dorsal and lateral views.
... Whereas the monophyly of Copelatinae seems well supported on the basis of adult (Miller 2001) and larval characters (Michat et al. 2017), molecular data were contradictory and favoured either the monophyly of the group (Balke et al. 2004) or its para-or polyphyly (Ribera et al. 2002(Ribera et al. , 2008. Since their exclusion from the Colymbetinae, the phylogenetic position of Copelatinae has remained contentious (Miller & Bergsten 2016). ...
The larvae of 12 species of Copelatinae, Liopterus haemorrhoidalis (Fabricius, 1787) are described or redescribed, including for the first time a detailed chaetotaxy analysis of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. A provisional parsimony analysis based on larval characteristics of 13 copelatine species was conducted using the program TNT, which reinforces the monophyletic origin of the Copelatinae. Copelatinae larvae stand out from the remaining Dytiscidae based on several synapomorphies, including the unusual shorter length of the mesothoracic legs. Legs and urogomphi morphology suggest that Copelatinae larvae studied evolved a creeping way of life. The provisional phylogenetic analysis presented in this study provides some arguments for the validity of the taxonomic status of the genera Liopterus Dejean, 1833 and Exocelina Broun, 1886.
... Miller (2000), on its part, suggested that Brachyvatus, Clypeodytes, Leiodytes Guignot, 1936, Neoclypeodytes Young, 1967, Pachynectes, and Platydytes Biström, 1988 may be closely related to Hemibidessus based on similarity in the transverse epipleural carina and in the modified anterior clypeal margin. Finally, Miller & Bergsten (2016) indicated that Hemibidessus is closely related to Brachyvatus. ...
We describe for the first time the larva of the diving-beetle genus Hemibidessus Zimmermann, 1921, based on instars II and III of H. conicus (Zimmermann, 1921). We include detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi in order to discover useful characters for distinguishing Hemibidessus larvae from those of other known Bidessini. Hemibidessus larvae characteristically have elongate legs armed with natatory setae and elongate urogomphi that bear numerous secondary setae, features commonly associated with an increased swimming ability. These characters are shared with Brachyvatus Zimmermann, 1921, suggesting a close phylogenetic relationship between these two genera. The primary seta UR8 is inserted apically on urogomphomere 2 in Hemibidessus larvae, a feature so far only shared with the mature larva of Yola Gozis, 1886. Other characters that combined with those previously mentioned are useful to distinguish Hemibidessus from other bidessines are the absence of a ventroapical spinula on antennomere 3 and the presence of secondary dorsal setae on protarsus.
... Insect biodiversity has declined globally due to habitat loss as a result of agriculture and urbanisation, pesticide application, and biological factors, including pathogens and introduced species (S anchez-Bayo and Wyckhuys 2019). Aquatic insects have also been reported to be at risk of becoming endangered (Saunders, Meeuwig, and Vincent 2002;Miller and Bergsten 2016). Therefore, efforts at in situ and ex situ conservation of endangered species have been conducted to reduce the risk of extinction (Vahru sevs 2011; Foster and Bilton 2014;Watanabe, Suda, and Fukutomi 2017). ...
Water beetles are holometabolous, which have a pupal period in their ontogeny. When rearing water beetles in a laboratory, both aquatic and land environments should be provided. We designed and created a new system for rearing water beetles, and tested it with five species. Seven parts of three-dimensional printed objects were assembled to make two containers for a larva and a pupa. The assembled container was half submerged in an aquarium filled with water. When the larva had grown enough for pupation, it spontaneously crossed a bridge to reach land and made a pupal chamber in the soil. The newly emerged adult then left the soil and went back to the container with water. The growth process from larva to adult can be achieved sequentially without human assistance. Most larvae could succeed in landing on the soil and returning to water using this system.
... Cette variété en espèces provient de la formidable plasticité génétique de l'ordre des coléoptères et de sa faculté à coloniser divers milieux naturels. Les environnements aquatiques, en exerçant une pression de sélection constante sur ces insectes, les ont amenés à s'adapter au fil du temps, à l'exploitation de différentes ressources et habitats d'où la forte variabilité présente dans leur mode de vie et leur régime alimentaire (Miller & BergsTen, 2016). ...
An IndVal analysis allows to establish a typology of lentic habitats for
the Rhône-Alpes region by studying the communities of aquatic beetles. The classification
distinguishes five types of environments and allows the definition of indicator beetle species
for each of them.
... The genus Hyphydrus Illiger, 1802 includes 139 described species, distributed in Afrotropical, Australian, Oriental and Palaearctic Regions (Biström 1982;Nilsson & Hájek, 2019). The species in the genus are mainly found in ponds and pools with vegetation (Miller & Bergsten, 2016). Biström (1982) revised the genus and divided into 19 species groups. ...
Hyphydrus biswasi Ghosh, sp. nov. (Coleoptera: Dytiscidae: Hyphydrini), is described in H. signatus species group from
Namdapha National Park, Arunachal Pradesh, India. An identification key to the Indian species of genus Hyphydrus Illiger,
is also provided.
Keywords: Himalaya, Identification Key, Male Genitalia, Taxonomy
... Laccophilus is the second most diverse genus of diving beetles (Dytiscidae), with a worldwide distribution [30]. Members inhabit both running and standing water bodies and are found over a large altitudinal and habitat range. ...
The Laccophilus alluaudi species group is an interesting case of an endemic species radiation of Madagascar and the Comoros. To date, a single species, Laccophilus tigrinus Guignot, 1959 (Anjouan), is known from the Comoro Islands, with eight other species known from Madagascar. Here we review the Laccophilus alluaudi species group from the Comoro Islands based on partly new material. We recognize five species, out of which four are here described as new: L. mohelicus n. sp. (Mohéli), L. denticulatus n. sp. (Grande Comore), L. michaelbalkei n. sp. (Mayotte) and L. mayottei n. sp. (Mayotte). Based on morphology of male genitalia, we hypothesize that the five species form a monophyletic group and originated from a single colonization event from Madagascar. If confirmed, this would constitute one of the few examples of intra-archipelago diversification in the Comoros. The knowledge of species limits in relation to their distribution in the Comoros archipelago is also urgently needed in the face of rapid habitat degradation.
... The Holarctic genus Laccornis Gozis, 1914 has eight species in the Nearctic region and two in the western Palearctic region (Miller and Bergsten 2016; Hájek 2021) and was last revised by Wolfe and Roughley (1990). Laccornis oblongus was classified as Holarctic, but its reporting from North America is only based on a single individual from northwestern Canada and a few unverified records from Alaska (Wolfe and Roughley 1990;Larson et al. 2000). ...
The diving beetle Laccornis oblongus (Stephens, 1835) is recorded for the first time from Bavaria, southern Germany, which marks the most south-westerly record of the species known to date. Three specimens were collected in the Murnauer Moos nature reserve in Upper Bavaria. We summarize what is known about the species habitat in Germany and provide photographs of the sampling site and habitus, median lobe of aedeagus, and paramere of the species. We provide a checklist of the 20 other diving beetle species we found syntopic with L. oblongus.
... Most species of diving beetles (Coleoptera: Dytiscidae) spend the majority of their lives in water, but they are known to inhabit land during their pupal stages (Miller and Bergsten 2016;Yee 2014). Nevertheless, it is often physically difficult to locate pupation sites and pupating individuals in the field (Yee 2014), and only a few observations have been recorded, such as of Cybister chinensis Motschulsky, 1854 and Oreodytes kanoi (Kamiya, 1938) (Ichikawa 2004;Okada and Alarie 2020). ...
... However, even females of these two big species can be easily separated by the shape of their posterior metatibial spur the apex of which is distinctly bifurcate. Another character of Megadytes species is the presence of only one series of setae near the apical margin (posteroventrally; not posterodorsally as given in Miller & Bergsten 2016: 104)-in females on pro-and mesotarsomeres I-IV, in males only on the mesotarsomeres. The other three members of genus Cybister known to occur in North America are C. fimbriolatus, C. explanatus and C. occidentalis, which do not exceed a total length of 34 mm and are thus considerably smaller than the new species. ...
Cybister (s. str.) poblanus sp. n. is described from the Puebla state in Mexico. The species belongs to a group of members of the genus Cybister Curtis, 1827, which occur only in North America (including the Caribbean Islands) and are characterised by having several distinct ridges on the metacoxae (stridulatory organ) in males. The new species is the third of the genus reported for Mexico and the fourth for North America. It can easily be separated from its congeners by its great size and the shape of the male aedeagus. The habitus, the male genitalia and other details of C. poblanus sp. n. are illustrated and photographs of the male genitalia of the other three Cybister are given for comparison. Megadytes (Bifurcitus) lherminieri (Guérin-Méneville, 1829) and M. (B.) magnus Trémouilles & Bachmann, 1980 are the only other big species of subfamily Cybistrinae which occur in North America. They are externally similar to the new species and can easily be confused with it, hence the illustrations of their aedeagi to facilitate identification. A key to species is given for all species of Cybistrinae occurring in America north of Belize and Guatemala, including Cuba and the Bahamas. Lectotypes are designated for Cybister flavocinctus Aubé, 1838, Cybister explanatus var. fusculus Zimmermann, 1919, and Cybister (Megadytes) aubei Wilke, 1920. Notes are given on material of some Neotropical and Nearctic species of Cybister and Megadytes stored in different museums.
... They plant Taro in the field without using pesticides and keep the environment friendly and beneficial for biodiversity, especially for the invertebrates. The stem of Taro provides the substratum for oviposition in Cybister sugillatus and Hydaticus vittatus (Wang unpublished field and laboratory data) and probably for Hydrovatus, too (Miller and Bergsten 2016). ...
We provide the first records of the diving beetles Hydrovatus subrotundatus Motschulsky, 1859 and Hydrovatus pu-dicus (Clark, 1863) from Taiwan. They are otherwise widespread in Southeast Asia. The habitats of both species and the associated diving beetle fauna are briefly described. Altogether eight species of the genus Hydrovatus are now recorded from Taiwan, raising the number of Taiwanese dytiscid species to 68.
... ( Calosi et al., 2008a ;Calosi et al., 2008b ;Sánchez-Fernández et al., 2010 ;Sánchez-Fernández et al., 2012 ;Bilton and Foster, 2016 ;Verberk et al., 2018 ). However, while adults of epigean dytiscids usually come out of water, either for dispersal or secretion grooming, stygobiotic species never or rarely do ( Dettner, 1985 ;Miller and Bergsten, 2016 ;Jones et al., 2019 ). ...
Thermal tolerance limits in animals are often thought to be related to temperature and thermal variation in their environment. Recently, there has been a focus on studying upper thermal limits due to the likelihood for climate change to expose more animals to higher temperatures and potentially extinction. Organisms living in underground environments experience reduced temperatures and thermal variation in comparison to species living in surface habitats, but how these impact their thermal tolerance limits are unclear. In this study, we compare the thermal critical maximum (CTmax) of two subterranean diving beetles (Dytiscidae) to that of three related surface-dwelling species. Our results show that subterranean species have a lower CTmax (38.3-39.0°C) than surface species (42.0-44.5°C). The CTmax of subterranean species is ∼10°C higher than the highest temperature recorded within the aquifer. Groundwater temperature varied between 18.4°C and 28.8°C, and changes with time, depth and distance across the aquifer. Seasonal temperature fluctuations were 0.5°C at a single point, with the maximum heating rate being ∼1000x lower (0.008°C/hour) than that recorded in surface habitats (7.98°C/hour). For surface species, CTmax was 7-10°C higher than the maximum temperature in their habitats, with daily fluctuations from ∼1°C to 16°C and extremes of 6.9°C and 34.9°C. These findings suggest that subterranean dytiscid beetles are unlikely to reach their CTmax with a predicted warming of 1.3-5.1°C in the region by 2090. However, the impacts of long-term elevated temperatures on fitness, different life stages and other species in the beetle's trophic food web are unknown.
... Elytral surface between lateral outline and actual margin of elytra (alongside epipleura, where sides of elytra projecting over rimmed margin; see Fig. 1c) with only very few punctures except a line of small punctures alongside actual margin of elytra (Fig. 2b). Notes: According to Miller & Bergsten (2016: 219) most genera of Bidessini have the metacoxae fused to the first visible abdominal ventrite; this character was not checked as it would have damaged a specimen. We can, however, state that the suture between the two structures is easily visible (see Figs 1c, 2b). ...
Bidessus anatolicus adiyaman ssp. n. is described from the Adıyaman province in southern Turkey. The taxon belongs to the unistriatus-group of the genus and can be separated from the nominotypical subspecies of Bidessus anatolicus Wewalka, 1972 by the broader body and the different shape of the male genitalia. The new taxon is illustrated in detail and photographs of the type locality and the surrounding area are given.
... Once the O 2 level becomes too low or gas volume too small, the insect returns to the surface. These dive variables are important as they affect an insect's allocation of time and energy to foraging and reproduction, and their exposure to predators and parasites (Aiken, 1985;Calosi et al., 2007;Miller and Bergsten, 2016). Dive duration is expected to decrease with greater activity or higher temperature, due to increased O 2 demand, and would be expected to increase with more gas volume stored or increased O 2 diffusion from the water. ...
Many aquatic insects use bubbles on the body surface to store and supply O2 for their dives. There are two types of bubbles: air stores, which store O2 gained from air at the surface, and gas gills that allow passive extraction of O2 from water. Many insects using air stores and gas gills return to the surface to replenish their bubbles and, therefore, their requirement for O2 influences dive behaviour. In this study, we investigate gas exchange and dive behaviour in the diving beetle Platynectes decempunctatus that uses a sub-elytral air store and a small compressible gas gill. We measure the PO2 within the air store during tethered dives, as well as the amount of O2 exchanged during surfacing events. Buoyancy experiments monitor the volume of gas in the gas gill and how it changes during dives. We also directly link O2-consumption rate at three temperatures (10, 15 and 20°C) with dive duration, surfacing frequency and movement activity. These data are incorporated in a gas exchange model, which shows that the small gas gill of P. decempunctatus contributes less than 10% of the total O2 used during the dive, while up to 10% is supplied by cutaneous uptake.
... Hydrovatus Motschulsky, 1853 is a large genus of small diving beetles distributed worldwide but most diverse in lower latitudes (Miller & Bergsten 2016). The genus currently includes 214 species arranged in 17 species groups (Nilsson & Hájek 2021), and is therefore one of the largest genera of diving beetles. ...
The second- and third-instar larvae of the diving-beetle species Hydrovatus crassulus Sharp, 1882 are described and illustrated, including detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. Larvae of this species lack the parietal pore PAo, the premental seta LA3 and the urogomphal seta UR8, and have the sensillum MN2 shaped as a short hair-like seta and the ventral surface of the abdominal segments II–V sclerotized. All these characteristics are shared with the other species of Hydrovatus Motschulsky, 1853 known in detail (H. caraibus Sharp, 1882) and therefore are considered diagnostic for the genus. Hydrovatus crassulus also characterizes by the presence of a small galea, which reinforces the hypothesis that this structure is part of the ancestral condition of Hydrovatus. Larvae of H. crassulus differ from those of H. caraibus in having a smaller size, a smaller ratio U/LAS, and a larger ratio U1/U2, and also in the presence (in most cases) of a secondary seta on the anteroventral surface of femur.
... Metatrochanters and -femora not distinctly modified (Biström 1987(Biström , 1988. A genus with 28 species in Africa, Southeast Asia, New Guinea and Australia (Miller & Bergsten 2016;Hendrich et al. 2019;Nilsson & Hájek 2021). The larvae are still unknown. ...
Bidessus migrator Sharp, 1882, so far assigned to Clypeodytes Régimbart, 1894, and widely distributed in Australia and New Guinea, is re-described. Based on morphological and molecular evidence, it is here transferred to Leiodytes Guignot, 1936. Bidessus loriae Régimbart, 1892 is found to be a junior subjective synonym of L. migrator. We describe the following new species: Leiodytes surianiae sp. nov. (eastern New Guinea, northeast coast of Queensland), and Leiodytes wattsi sp. nov. (southern New Guinea and Darwin area to northern Queensland). We delineate the species using characters such as male genital structure and beetle size, shape and color pattern. Mitochondrial Cox1 data for 27 individuals, representing all three Australasian species, were generated and revealed clusters congruent with the morphological evidence. In Australia Leiodytes only occurs in the tropical and subtropical northern part of the continent. None of the species is endemic to Australia. The species are mainly lentic, occurring in seasonal swamps, flooded meadows and pools of intermittent rivers and temporary creeks.
... There are more than 4,500 known species (Nilsson and Hájek 2021), occupying a large variety of aquatic habitats including ground water, rivers and streams, peat bogs, hypersaline as well as hygropetric habitats, ponds, puddles and lakes. In general, they can easily be collected and are often used as a study group for ecological, conservation, biogeographic and evolutionary research (Balke and Hendrich 2016;Miller and Bergsten 2016). The diving beetle genus Neobidessodes Hendrich & Balke, 2009 belongs to the tribe Bidessini of the subfamily Hydroporinae-the tribe comprising one of the world's smallest known dytiscids (body length 0.9-4.8 ...
The diving beetle genus Neobidessodes Hendrich & Balke, 2009 contains 10 species. Nine of them were considered endemic to Australia, one of them to the Trans Fly Savanna and Grasslands Ecoregion of New Guinea island. Here, we provide the first report of one of the Australian species, Neobidessodes mjobergi (Zimmermann, 1922), from the same region of New Guinea. We suggest that more focused research will reveal the occurrence of far more Australian diving beetle species in that region of New Guinea.
... The generic delimitation of Liodessus remains fuzzy, relying on a set of diagnostic rather than apomorphic characters (Miller & Bergsten 2016). We assembled a multigene dataset of global Hydroporinae (Balke, work in progress), where we recovered the species treated here in one clade including the Nearctic and Neotropical Liodessus affinis (Say, 1823). ...
We describe the larvae of the diving-beetle genus Sandracottus Sharp, 1882 based on S. femoralis Heller, 1934 and S. mixtus (Blanchard, 1843). We include detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, terminal abdominal segment and urogomphi in order to discover useful characters for distinguishing Sandracottus larvae from those of other known Aciliini (Coleoptera: Dytiscidae, Dytiscinae). A provisional parsimony analysis based on larval characteristics of seven Aciliini species in four genera (Acilius Leach, 1817, Graphoderus Dejean, 1833, Sandracottus, Thermonectus Dejean, 1833) was conducted using the program TNT. A clade grouping Eretini and Aciliini stands out as the most strongly supported in this analysis. The tribe Aciliini finds itself monophyletic with also very good support. Our analysis, however, failed to depict any clear phylogenetic relationships within the Aciliini although each of the four genera studied emerged from our study as morphologically distinct.
The classification of highly adapted species in well-studied clades may be obscured by convergent character evolution. This is for example the case in aquatic lineages adapted to subterranean (and shallow subterranean) habitats, in which species usually possess reduced eyes and wings as well as translucent cuticles. In 1985, the terrestrial diving beetle genus and species Typhlodessus monteithi Brancucci (Coleoptera: Dytiscidae) was described from a shallow subterranean habitat in New Caledonia. Until now, the systematic classification of Typhlodessus remains unclear, as it could not be assigned to any of the known tribes of the subfamily Hydroporinae. Here, we reveal this species' phylogenetic position and evolutionary history. We obtained molecular data from an almost 30 years old museum specimen and performed phylogenetic analyses using complete mitochondrial genomes and nuclear markers, which resulted in the placement of Typhlodessus monteithi within the subtribe Sternopriscina, as a junior synonym of the genus Paroster. The genus Paroster contains epigean, stygobitic as well as two other terrestrial Australian species. Our finding extends the geographical distribution of Paroster to New Caledonia. Adaptation to terrestrial habitats in Paroster species may be a way to survive in hyper humid environments that however might lack suitable lentic habitats.
Predaceous diving beetles (Dytiscidae) are a highly speciose group of insects occurring in a large variety of habitat types, where they often form multispecies assemblages, due to their high diversity and large variation in the degree of habitat specificity. While most species have broad habitat preferences, some are specialized for life under extreme habitat conditions. In this chapter, we provide an overview of the main habitats in which dytiscids occur and summarize some of the habitat variables that contribute most to shaping the distribution of dytiscids across habitats and landscapes. These include a range of abiotic conditions and plant–beetle relationships, which act as major habitat selection factors. We discuss how a variety of habitats in agricultural and urban landscapes can contribute to maintain high dytiscid diversity. We then describe some of the most peculiar habitats where dytiscids occur, including phytotelmata, subterranean and interstitial habitats, rock pools, and terrestrial habitats. Over the past couple of decades, examination of habitats that had been typically underexplored for dytiscids has led to the discovery of new species and even new genera. These studies suggest that further exploration of these habitats and the increasing availability of phylogenetic data will provide important insights into the ecology and evolutionary history of species colonizing extreme habitats. This is in turn critical to improve our understanding of the vulnerability of dytiscids to global environmental changes associated with changes in habitat characteristics and availability.
The phylogenetics and higher (family-group) classification of extant members of the beetle family Dytiscidae (Coleoptera), or predaceous diving beetles, is reviewed and reassessed. A phylogenetic analysis of the family is presented based on 168 species of diving beetles and 9 outgroup taxa from Gyrinidae, Noteridae, Amphizoidae, and Paelobiidae. All currently recognized dytiscid subfamilies and tribes are represented, most by multiple genera and species. Data include 104 morphological characters and approximately 6700 aligned bases from 9 DNA sequence fragments from cytochrome c oxidase I (COI) and II (COII), histone III (H3), 16S rRNA (16S), 12S rRNA (12S), arginine kinase (argkin), RNA polymerase II (RNA pol II), elongation factor 1 alpha (Ef1α), and wingless (wnt). Parsimony and Bayesian analyses were conducted. The topology of the parsimony tree (consensus of 13 equally-parsimonious solutions) exhibits numerous anomalies inconsistent with convincing morphological features and the Bayesian results and has, generally, relatively poor bootstrap support for major clades. The Bayesian topology is more consistent with major morphological features and has strong support for most clades, and conclusions are based primarily on this estimate. Major higher-level phylogenetic relationships with strong support include: (1) monophyly of Dytiscidae Leach, (2) Matinae Branden sister to the rest of Dytiscidae, (3) Agabinae Thomson + Colymbetinae Erichson, (4) Hydrodytinae Miller + Hydroporinae Aubé, (5) Dytiscinae Leach + Laccophilinae Gistel + Cybistrini Sharp + Copelatinae Branden, (6) monophyly of the subfamilies Matinae, Colymbetinae, Copelatinae, Coptotominae Branden, Lancetinae Branden, Laccophilinae (including Agabetes Crotch), Agabinae (support weaker than in other subfamilies) and Hydroporinae (monophyly of Hydrodytinae not tested), (7) paraphyly of Dytiscinae with Cybistrini sister to Laccophilinae (with strong support) and this clade sister to other Dytiscinae, and (8) monophyly of both Agabini (Agabus-group of genera) and Hydrotrupini Roughley (Hydrotrupes Sharp and the Platynectes-group of genera). Major conclusions regarding tribes within Hydroporinae include: (1) monophyly of the tribes Vatellini Sharp, Methlini Branden, Hydrovatini Sharp, Hygrotini Portevin, Hyphydrini Gistel (without Pachydrus Sharp) and Bidessini Sharp (including Peschetius Guignot, Hydrodessus J. Balfour-Browne and Amarodytes Régimbart) (monophyly of Laccornini Wolfe and Roughley and Pachydrini Biström, Nilsson and Wewalka not tested), (2) Pachydrini is a problematic, long-branched taxa resolved here as sister to Hydrovatini but with weak support, (3) Hydroporini monophyletic except for Laccornellus Roughley and Wolfe and Canthyporus Zimmermann, (4) Laccornellus and Canthyporus together monophyletic and sister to Hydroporinae except Laccornini. Four groups are resolved within Hydroporini exclusive of Laccornellus + Canthyporus corresponding to the Deronectes-, the Graptodytes-, the Necterosoma- and the Hydroporus-groups of genera. The classification of Dytiscidae is revised with the following taxonomic changes [2014]: (1) Hydrotrupini is recognized as a tribe of Agabinae including the genus Hydrotrupes and the Platynectes-group of genera, (2) the genus Rugosus García is moved from Colymbetinae to Copelatinae, (3) Cybistrini is elevated from tribe rank within Dytiscinae to subfamily of Dytiscidae, (4) Hyderodini Miller is placed as a junior synonym of Dytiscini, (5) Laccornellus and Canthyporus are removed from Hydroporini and placed in their own tribe, Laccornellini, (6) the following family-group names are resurrected from synonymy with Hydroporini and placed as subtribes within Hydroporini, Deronectina Galewski (for the Deronectes-group of genera), Siettitiina Smrž (for the Graptodytes-group of genera), Sternopriscina Branden (for the Necterosoma-group of genera), and Hydroporina (for the Hydroporus-group of genera), (7) Carabhydrini Watts is placed as a junior synonym of Sternopriscina, and (8) Hydrodessus, formerly incerta sedis with respect to tribe, is placed in Bidessini. Each subfamily, tribe and subtribe is diagnosed and its taxonomic history discussed.
Aspects of the conservation of Dytiscidae are discussed with particular reference to the benefits, potential and realized, associated with ways of conserving species threatened internationally and nationally. Examples are drawn on a global basis, but inevitably with some bias to the predaceous diving beetles of Western Europe endangered by a history of intensification of agriculture, industrialisation and urban sprawl.
Aquatic beetles belong to the suborders Adephaga and Polyphaga. The suborder Adephaga contains five families of water-related species. A characteristic behaviour of their representatives is taking air reserves under the water surface. In well-oxygenated streaming waters this air bubble also functions as a physical gill being capable of absorbing dissolved oxygen from the surrounding water via diffusion.
We use molecular phylogenomic as well as morphological data to provide a taxonomic update on New Guinea endemic Philaccolilus diving beetles. In these lotic beetles, we find cryptic diversity that highlights the need for geographically denser sampling combined with the use of an intergrative taxonomic approach to unravel the true diversity and biogeography of these beetles. We describe three new species: P. intania sp. nov. from the northern Bird’s Head Peninsula, P. kirana sp. nov. from the southern Bird’s Head as well as P. febrina sp. nov. which is more widespread on the Bird’s Head. Philaccolilus ameliae weylandensis is elevated to species rank, as Philaccolilus weylandensis stat. nov.
As a major component of freshwater ecosystems, insect species play an important role in nutrient cycling and are often used as bioindicators of water pollution. Although extensive studies have characterized insects from freshwater habitats, little is known about the distribution of these species along the Lower Sector of the Danube River. Therefore, this survey conducted in the Danube section within the Romanian territory aimed to identify insect larvae belonging to seven different species of Odonata, Trichoptera, Ephemeroptera, Lepidoptera and Megaloptera by DNA barcoding and to investigate their distribution, density and frequency. A total of 41 quantitative macrozoobenthic samples were collected during two consecutive years (2019 and 2020). Species showed large differences in the distribution and density along different sections, and an overall tendency to populate downstream areas, except for Sialis morio. On the other hand, only Hydropsyche bulgaromanorum, Triaenodes bicolor and S. morio larvae were identified in the upstream section (Sulina branch). These data provide baseline information on the larger range of some of the most common aquatic insects in the Romanian Danube section in relation to several environmental parameters based on the first molecular identification of these species using COI gene sequencing.
Belladessus Miller and Short, 2015 is reported from Brazil for the first time. Two new species in the genus are described: Belladessus espinhasso, new species is described from the state of Minas Gerais, while Belladessus minutopunctatus, new species is described from the Federal District. Belladessus femineus Miller and Short, 2015 is reported from the northern Brazilian state of Roraima. The new species were collected in the Brazilian Shield, expanding the geographic distribution of the genus that until now was limited to the Andean and the Guiana Shield regions of South America
To facilitate ex-situ conservation of predaceous endangered insect species large numbers of live prey organisms are typically collected from the natural environment, potentially exacerbating biodiversity decline. To address this issue, two endangered beetle species (Cybister chinensis Motschulsky, 1854 and Cybister lewisianus Sharp, 1873) were reared using only laboratory-bred food. The beetle larvae were provided with laboratory-bred two-spotted cricket (Gryllus bimaculatus DeGeer; Orthoptera: Gryllidae) larvae as prey. The survival rates of the beetle larvae were as follows: C. chinensis, first instar larvae, 100% (n = 25), second instar larvae, 100% (n = 25), and third instar larvae, 92% (n = 23); C. lewisianus, first instar larvae 96% (n = 24), second instar larvae 92% (n = 23), and third instar larvae 92% (n = 23). The body length of adult insects fed laboratory-bred crickets did not significantly differ compared to the body length of field-collected adults.
The first stygobiontic diving beetle known from Laos, Laodytes lapiei n. gen., n. sp., is described from a cave located in the Vientiane province. Its morphological characters lead to its placement, among Hydroporinae, in Hydroporini. Inside these, the new species could not be assigned to an existing genus. As a result, a new genus has been defined without it being possible, at the present stage, to assign it to one of the currently recognized subtribes. Résumé.-Nouveaux genre et espèce de Coléoptère aquatique souterrain du Laos (Coleoptera, Dytiscidae, Hydroporinae, Hydroporini). Le premier Dytiscidae stygobie connu du Laos, Laodytes lapiei n. gen., n. sp., est décrit d'une grotte de la province de Vientiane. Ses caractères morphologiques conduisent à le placer, parmi les Hydroporinae, dans les Hydroporini. À l'intérieur de ceux-ci, la nouvelle espèce n'a pu trouver place dans aucun genre existant. En conséquence, un nouveau genre a été défini, sans qu'il soit possible, à ce stade, de le rattacher à l'une des sous-tribus actuellement reconnues.
Larvae of aquatic mites are common ectoparasites of aquatic beetles. A population of Dytiscus alaskanus (Coleoptera: Dytiscidae) studied in a central Alberta lake was parasitized by members of the genus Eylais (Acari: Hydrachnellae). Mites attached preferentially in the costal–subcostal region of the ventral surface of the hindwings. Afferent blood flow in the costa and subcosta and the numerous blood sinuses in this region provide an abundant food source. The smallest (= youngest) larvae were taken on the first beetles caught in early spring, indicating that some mite larvae overwinter on the host. Mites grow rapidly, reach maximum size in late June and July, and then enter the nonparasitic phase of the life cycle. Rates of parasitism (proportion of beetles with parasites) was highest in early spring, declined throughout the summer, and rose again in the fall. In this way, the parasitic phase of the mites life cycle occurs at the same time as the peak in the population of adult beetles. There was constant recruitment throughout the year into the population of larval mites indicating asynchronous cohorts or more than one mite species.
The New Zealand diving beetle Rhantus plantaris Sharp, 1882 (Coleoptera: Dytiscidae), although comparatively large (10.0–10.5 mm), has not been reported since its description. Until this publication, only the male holotype was known. It has been questioned whether this species was a part of the New Zealand fauna. The rediscovery of the species is reported, based on a small series collected from near Christchurch. The specimens were taken from a roadside pond at about sea level. Collection details and distributional notes are given for the rare south western Australian species Rhantus simulans Régimbart, 1908 which appears to be a peatland swamp specialist. An illustrated key to the New Zealand and Australian Rhantus species is included.
The small beetle described below is probably classified in many
collections as either Desmopachria grana (Aubé) or Desmopachria
nitida Babington. However, the male external genitalia (Fig. 1) are
unique among the species of the typical subgenus of Desmopachria.
The species is closest to Desmopachria glabricula Sharp, but the
genitalia are distinctive (Fig. 2).
Rectal expansion appears to be a mechanism that increases the body specific gravity and permits buoyancy control. -from Authors
Up to 96% of all individuals in a sample carried marks. With one exception (H. incognitus) the relation between the "rate of recapture' and the "sum of marked individuals' could be described by a straight regression line. Using two methods the number of all H. tristis adults living in a bog pool was estimated. -from English summary
Hyphydrus hiekei n. sp. belonging to the species group H. schoutedeni is described from Equatorial Guinea, based on seven specimens. New faunistic records are H. caryerus GUIGNOT from Togo and H. maculatus BABINGTON from Guinea Bissau.
Hyphydrus hiekei n. sp. wird aus Equatorial Guinea beschrieben. Neue faunistische Funde sind H. caryeus GUIGNOT aus Togo und H. maculatus BABINGTON aus Guinea Bissau.
Hyphydrus dani n. sp. is described from the highlands of West New Guinea. This species is probably the sister species of H. elegans (Montrouzier 1860). In addition, collecting notes on H. dani and H. lyratus Swartz 1808 are provided. The latter is reported from Bali, Lombok, Flores and Ceram for the first time, and the Balinese locality represents the first report of the species from paddy field waters. Faunistic data on H. decemmaculatus Wehncke 1877 and H. elegans as well as notes on the type material of H. curvipes Régimbart 1892 and of H. gibbicollis Régimbart 1892 are reported.
Two of three species of the genus Rhantus studied were found to produce sounds while in water. Sound production by both sexes of R. gutticollis and R. binotatus occurs in a behavioral context of emigration, while R. atricolor does not produce waterborne sounds. Elevated temperature, absence of suitable bottom substrate, and high densities were effective stimuli for sound production by’ the two acoustically active species. The sounds were analyzed and a mechanism previously described as being involved in preflight warm-up of the thoracic musculature was found responsible for sound production in water. Possible functions of acoustical behavior are discussed, and new information on some aspects of the habitat ecology and general behavior of adults of the three species is provided.
Paraprosalpia dytisci
new species is described from a larva, puparia, and adults reared from a dead larva of
Dytiscus fasciventris
Say, collected in southern Ontario.
Yola counselli n. sp. is described on the basis of seven adult specimens from Cameroon. Distinguishing character states are given for the new species, which is probably closest related to Y. grandicollis Peschet 1921 and Y. darfurensis Balfour-Browne 1947. The bidessine species, Uvarus retiarius Guignot 1939, is recorded for the first time in Cameroon.
Members of the pulcher–undulatus species group of Hydroporus Clairville (sensu Fall 1923) were rearranged as follows by Wolfe and Matta (1981): (1) H. pulcher LeConte and 12 other species (each with a bifurcate aedeagal apex) were assigned to the subgenus Heterosternuta E. Strand; (2) H. pilatei Fall and H. triangularis Fall were revised and assigned to a new genus, Falloporus ; (3) and the remaining approximately 35 species were placed in the subgenus Neoporus Guignot.
Three species of water beetles, 2 dytiscids and 1 hydrophilid, from Mt. Roraima and Ptari‐tepui in the state of Bolivar, Venezuela, are discussed. One dytiscid, Tepuídessus breweri n. gen., n. sp., and the hydrophilid Tropisternus jolyi n. sp., are described and distinguishing characters are illustrated. The new taxa are compared to related ones and their habitats are discussed. Also, a collection of Rhantus elegans Waterhouse is reported for the first time since the species was described in 1895. The male genitalia of R. elegans is illustrated for the first time and its habitat also is described.
Aglymbus bimaculatus sp. n., is described based on a large series of adults collected from the leaf axils of three species of bromeliads, in Salcsopolis, State of São Paulo, Brazil. The habitus and the male genitalia are illustrated. Comparisons with other similar species are provided. The available biological data are summarized.