Yves Alarie

Association of insect life stages using DNA sequences: the larvae of Philodytes umbrinus (Motschulsky) (Coleoptera: Dytiscidae)

Abstract.  Insect life stages are known imperfectly in many cases, and classifications are based often on only one or a few semaphoronts of a species. This is unfortunate as information in alternative life stages often is useful for scientific study. Although recent examples of DNA in taxonomy have emphasized the identification of indistinguishable species, such sequence data facilitate the association of life history stages and hold considerable promise in phylogenetic analysis, evolutionary studies, diagnostics, etc. These concepts are discussed here and an example is provided from diving beetles (Dytiscidae: Coleoptera). Three unknown larval specimens of an apparent species of Laccophilinae collected in Namibia were associated with the species Philodytes umbrinus (Motschulsky) using DNA sequence data. An 806‐bp portion of the gene cytochrome oxidase I was sequenced from the unknown larvae. Several identified adult specimens of species of Laccophilinae from Namibia were also sequenced, including two P. umbrinus specimens and specimens from four Laccophilus Leach species. Additional species of Laccophilus from other areas of the world also were sequenced, as were specimens of Agabetes acuductus (Harris), Australphilus saltus Watts, Neptosternus boukali Hendrich & Balke and a species of Laccodytes Régimbart. Parsimony analysis resulted in two most parsimonious trees with the unknown larva unambiguously resolved in a group with both adult specimens of P. umbrinus (bootstrap value = 100%). The average pairwise p‐distance between the unknown larva and adult P. umbrinus specimens averaged 0.09% (0–0.14%), compared with an average divergence between other conspecifics in the analysis of 0.24% (0–0.82%) and an overall average divergence between species of 13.49% (1.90–19.86%). Based on this, the unknown larvae were assigned to P. umbrinus. The larvae are diagnosed and described and their relationship with other Laccophilinae is discussed.

Molecular phylogeny of Pacific Island Colymbetinae: radiation of New Caledonian and Fijian species (Coleoptera, Dytiscidae)

We present a molecular phylogeny and taxonomic review of the Pacific island colymbetine diving beetles, focusing on the Fijian and New Caledonian faunas. Four new species are described: Rhantus monteithi and R. poellerbauerae from New Caledonia, and R. kini and R. bula from Fiji. We also describe the 3rd instar larvae of R. monteithi and R. poellerbauerae spp. nov., assigned to adults using mtDNA sequence data and discuss larval characters in the light of phylogeny. The phylogenetic hypotheses derived from both parsimony and Bayesian inference based on 3508 aligned nucleotides from a combination of mitochondrial (cox1, cob and rrnL‐tRNALeu‐Nad1) and nuclear genes (18S rRNA and H3) reveal a clade comprising R. novaecaledoniae, R. alutaceus, R. pseudopacificus, R. monteithi sp. nov. and R. poellerbauerae sp. nov., which agrees with the R. pacificus group sensu Balke (1993). Carabdytes upin was included within this clade, possibly indicating paraphyly of the genus Rhantus. Rhantus annectens, R. bacchusi, R. supranubicus, R. suturalis, R. simulans, and the Palearctic R. exsoletus, R. latitans and R. bistriatus formed a clade corresponding to the R. suturalis group sensu Balke (2001). Rhantus vitiensis, previously assigned to the R. pacificus group, was included in the R. suturalis clade. We find some support for a scenario where the Pacific was colonized out of the Northern hemisphere only during the past c. 12 million years, rejecting a Gondwanan origin of the morphologically isolated endemics. The new species are all characterized by mtDNA haplotype clusters, the degree of divergence between sister species pairs ranging from 1.3 to 7%, while R. novaecaledoniae individuals from all over New Caledonia apparently form one morphospecies, with moderate genetic diversity (up to 2.3% mtDNA divergence between populations). The sisters R. pollerbauerae sp. nov. + R. monteithi sp. nov. occur sympatrically on Mont Panié but appear ecologically segregated, while the sisters R. vitiensis + R. bula sp. nov. were encountered syntopically on Viti Levu. Comparing genetic and morphological data of Fijian Rhantus and Copelatus diving beetles, we here show that even in island radiations it is not per se possible to know if mitochondrial DNA barcoding would perform well (Rhantus: YES, Copelatus: NO). At the same time we show that fixed cutoff values, as sometimes used to discriminate between barcodes, thus species, might be meaningless. We underpin the importance of morphology for sustainable exploration of global diversity.

Primary Setae and Pores on the Maxilla of Larvae of the Subfamily Hydroporinae (Coleoptera: Adephaga: Dytiscidae): Ground Plan Pattern Reconsidered

Abstract Through an analysis of the primary setae and pores of first-instar larvae of 31 genera of Hydroporinae, and 22 genera belonging to other dytiscid subfamilies, the ancestral system of primary setae and pores of the maxilla of the Hydroporinae is reconsidered. Fourteen setae and seven pores have been assigned to the ground plan pattern of the hydroporine maxilla. Larvae of Hydroporinae differ from those of other Dytiscidae in the absence of the primary pores MXa, MXb, MXc and MXd, and in the presence of the primary pore MXk.

Larval morphology of the diving beetle Celina and the phylogeny of ancestral hydroporines (Coleoptera : Dytiscidae : Hydroporinae)

Phylogenetic relationships within diving beetles (Dytiscidae) are imperfectly known. In particular, some authors have considered that the tribe Methlini is included in the subfamily Hydroporinae (a large group including about half of the dytiscid species worldwide), whereas others have argued in favour of excluding Methlini from the Hydroporinae and giving it subfamilial rank. Larval characters have been underutilised in phylogenetic studies, mainly because the larvae of many taxa within the family are still unknown. The larval morphology of the dytiscid tribe Methlini, in particular, remains poorly known. In this study, the phylogenetic relationships among ancestral lineages of the Hydroporinae are investigated based on a cladistic analysis of 34 taxa and 127 morphological larval characters. For this purpose, larvae of the Methlini (Celina parallela (Babington, 1841)) and C. imitatrix Young, 1979) are described and illustrated in detail for the first time, with particular emphasis on morphometry and chaetotaxy. The results show high support for a monophyletic origin of the Hydroporinae, including Methlini, based on eight unique character states. Giving Methlini subfamily rank would leave Hydroporinae with a single unique larval apomorphy. This supports the inclusion of Methlini as a tribe of Hydroporinae. Other interesting but less well supported results include: 1, the clade Laccornini + Hydrovatini + Canthyporus Zimmermann, 1919 (Hydroporini) resolved as the sister-group to the other Hydroporinae minus Methlini; and 2, Hydrovatini and Canthyporus resolved as sister-groups. The presence of a galea, albeit in a reduced form, in larvae of Methlini, Laccornini and Hydrovatini is of the utmost interest. The putative hypothesis of an ancestral position for these genera within Hydroporinae suggests that hydroporines lost the galea secondarily.

Larval Morphology of Agabetes Crotch (Coleoptera: Adephaga: Dytiscidae): The Hypothesis of Sister-Group Relationship with the Subfamily Laccophilinae Revisited

Abstract Description of all larval instars of Agabetes acuductus (Harris) is presented including a detailed chaetotaxic and porotaxic analysis of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. A parsimony analysis based on the 43 informative larval characteristics was conducted with PAUP. Boostrap values indicate strong support for the monophyly of the clade containing the genus Agabetes Crotch and members of the subfamily Laccophilinae. This is supported by five synapomorphies: (i) egg bursters positioned posteriorly, contiguous to the coronal suture, (ii) presence of two lamellae clypeales in instar I, (iii) absence of the primary setae LA10 and LA12, (iv) absence of a ventroapical spinula on antennomere 3, and (v) abdominal venter 6 sclerotized.

World Catalogue of Insects, volume 3: Dytiscidae (Coleoptera)

WITH THE GROWING INTEREST in global biodiversity, the need for modern catalogues of all groups of organisms increase. Anders NilssonÕs Þrst installment of his awaited catalogue of world Dytiscidae does not disappoint! This is the third volume of the seriesWorld Catalogue of Insects (now comprised of seven volumes) which aims at compiling updated authoritative catalogues of insects. Like earlier volumes of the series, this volume is amazingly thorough and covers 3,792 valid species. In this book, the family Dytiscidae is organized into 10 subfamilies following the subfamily concepts of Miller (2001). The volume begins with a 5-page introduction aiming at providing basic information on the organization of the catalogue. The plan and execution of the catalogue is excellent. All taxa of the same rank are listed alphabetically instead of systematically which facilitates fast retrieval of names without explicit knowledge of current views on relationships. For each taxon name an outline of the modern distribution is given which refers to major zoogeographical regions only. For each taxon a reference is given to the original description (author, year of publication, and page). For each genus-name is also given: 1) type species, 2) reference to how and where the type species were designated, and 3) gender. Only the current and the original combinations of species names are given. All synonyms are listed in chronological order under the valid name along with a reference to the Þrst publication in which the synonym was established and the type locality. Following the main section of the catalogue is an appendix containing lists of fossil taxa, nomina nuda that could not be referred as synonyms to any dytiscid species, and species that were originally described under dytiscid genera, but are now excluded from the family. This is followed by a 52-page bibliography with titles and journal names written out in full. Taxonomic research depend to a much higher degree than other research on availability of old often rare publications, which must be seen only for checking certain formal data, such as correct spelling and authorship of name, year of publication, etc. In this regard, this bibliography is an invaluable source of information. This volume closes with a comprehensive index to taxa which combines familygenusand species-group names as well as synonyms and not available names. An obvious limitation in the preparation of a complete world catalogue of such a diversiÞed group of insects is that it is a perennial project. NilssonÕs catalogue includes names published up to September 30, 2001. Updates (Nilsson 2003, 2004) have been published, however, which aim at correcting the errors found in the published version and at including new taxa and other taxonomic acts. The number of recent species of Dytiscidae is now 3892. NilssonÕs catalogue is a great achievement for dytiscid systematics. Well produced on good paper and solidly bound, it is a must for anyone working on this diverse family. That publication is a necessity for every entomological library and every aquatic coleopterist. I recommend this book highly.

North American Stygobiontic Diving Beetles (Coleoptera: Dytiscidae: Hydroporinae) with Description of Ereboporus naturaconservatus Miller, Gibson and Alarie, New Genus and Species, from Texas, U.S.A

Abstract Ereboporus naturaconservatus Miller, Gibson and Alarie, new genus and new species (Coleoptera: Dytiscidae) is described from specimens collected from Caroline Springs, Independence Creek, Terrel County, Texas, U.S.A. Specimens were collected using drift nets placed at the head of the spring, suggesting the species is subterranean and occurs in nearby areas of the Edwards-Trinity Aquifer. In addition, the new taxon is characteristic of subterranean diving beetles in having adults depigmented, relatively soft, and lacking metathoracic wings and compound eyes. In addition, the taxon is diagnosed among all adult Dytiscidae in having: 1) the head extremely large relative to the rest of the body, 2) the pronotum short and cordate; 3) the prosternal process small, short and not extending to the mesosternum; 4) the elytra fused along the suture; 5) the elytron and elytral epipleuron extending ventromedially, concealing large lateral portions of the abdominal sterna; 6) the female internal genitalia with a large, elongate, ring-shaped structure on the bursa. The species is placed in the tribe Hydroporini (Hydroporinae) based on the character states: 1) pro- and mesotarsi pseudotetramerous; 2) male genitalia bilaterally symmetrical; 3) scutellum not visible with the elytra closed; 4) prosternum in lateral aspect declivous; 5) metatarsal claws the same length; 6) apices of elytra evenly rounded; 7) metepisternum extending to mesocoxal cavity externally; 8) male lateral lobe with one segment; 9) metacoxal process with well-developed lobes; 10) anterior margin of metafemur distinctly separated from the lobes of the metacoxal process. Three additional subterranean species are known from North America, Comaldessus stygius Spangler and Barr, 1995, Stygoporus oregonensis Larson and Labonte, 1994, and Haideoporus texanus Young and Longley, 1976. Each of these species is figured and discussed.

Larvae of the genus Antiporus (Coleoptera : Dytiscidae) and phylogenetic implications

The larvae of Antiporus blakeii (Clark), A. femoralis (Boheman), A. gilbertii (Clark), A. hollingsworthi Watts, A. jenniferae Watts, A. uncifer Sharp and A. willyamsi Watts are described with an emphasis on chaetotaxy of the head capsule, head appendages, legs, last abdominal segment and urogomphi. A parsimony analysis based on 17 informative larval characteristics was conducted using the program PAUP*. The 11 most parsimonious trees support a monophyletic origin of the genera Antiporus Sharp, Nebrioporus Regimbart, Scarodytes Gozis, and Stictotarsus Zimmermann. Unambiguous synapomorphies supporting this clade are the presence of natatory setae on the femur, tibia and tarsus and the presence of a very elongate urogomphomere 1. It is postulated that these features evolved as swimming devices. The genus Oreodytes Seidlitz is postulated to represent the sister-taxon of Antiporus + Nebrioporus + Stictotarsus + Scarodytes and this clade is characterised by the absence of the maxillary cardo and insertion of the primary seta MX1 on the maxillary stipes.

Morphology and chaetotaxy of larval Hypodessus cruciatus (Régimbart) (Coleoptera: Dytiscidae: Hydroporinae), and analysis of the phylogenetic relationships of the Bidessini based on larval characters

The phylogenetic relationships of members of the hydroporine tribe Bidessini are investigated based on a cladistic analysis of 30 taxa and 43 characters from larval morphology. For this purpose, the three larval instars of Hypodessus cruciatus (Régimbart) are described and illustrated for the first time, with particular emphasis on the morphometry and chaetotaxy. The consensus cladogram supports a monophyletic origin of the Bidessini based on the absence of the primary pore ABc, a unique feature within Hydroporinae. Amarodytes Régimbart is sister to the other Bidessini genera studied, being characterized by the presence of secondary setae on the first urogomphomere and the presence of an occipital suture in first‐instar larva. Liodessus Guignot and Anodocheilus Babington are a monophyletic group and share the absence of a ventroapical spinula on the third antennomere. Hypodessus, Glareadessus Wewalka & Biström and the clade Liodessus + Anodocheilus form a polytomy. Bidessini is resolved as derived within Hydroporinae, as part of a clade along with Hygrotini, Vatellini, Hyphydrini and Hydroporini (excluding Laccornellus Roughley & Wolfe). Members of this clade share the absence of a galea and of setae MX8 and MX9. Within this grouping, Bidessini shares a common origin with Vatellini, Hyphydrini and part of Hydroporini, all these taxa being characterized by a cardo fused to the stipes.

Sexual Size and Shape Dimorphism in Dineutus nigrior (Coleoptera: Gyrinidae)

Abstract Sexual size and shape dimorphism was quantified in the whirligig beetle Dineutus nigrior Roberts. Females were larger in terms of body length, elytra length, body height, profemur width, and mass. Males had longer heads, longer and wider protarsi, longer and wider protibiae, and longer profemora. Discriminant function analysis identified 80.5% of individuals as the correct sex based on measurements of body size. Males and females also differed in terms of body shape. Potential causes of the dimorphism are discussed.