Lynn K. Carta

Phoretic mites and nematode associates of Scolytus multistriatus and Scolytus pygmaeus (Coleoptera: Scolytidae) in Austria

Abstract  1 The species assemblages and abundance of phoretic mites and nematodes associated with the elm bark beetles, Scolytus multistriatus and Scolytus pygmaeus, were studied in Austria.

Morphological and molecular characterisation of Pratylenchus arlingtoni n. sp., P. convallariae and P. fallax (Nematoda: Pratylenchidae)

Pratylenchus arlingtoni n. sp. from the rhizosphere of grasses Poa pratensis and Festuca arundinacea at Arlington National Cemetery, VA, USA is characterised by six to eight lines in the lateral field, and pyriform to slightly overlapping pharyngeal glands. Morphological comparisons are made with lesion nematodes having similar morphometrics, six lateral lines, or crenate tail tips. Molecular sequences of the LS 28S rDNA were generated for the new species as well as P.fallax and P.convallariae. The new species differs by only 1% from identical sequences found in P.fallax and P.convallariae.

Rhabditis rainai n. sp. (Nematoda: Rhabditida) associated with the Formosan subterranean termite, Coptotermes formosanus (Isoptera: Rhinotermitidae).

Rhabditis rainai n. sp. is described from the gut and head of sick Formosan subterranean termites (Coptotermes formosanus) collected in New Orleans, LA, USA (isolate LKC20). Rhabditis rainai n. sp. is a hermaphroditic species with an unusual prerectum, four denticles per glottoid swelling, enlarged posterior stoma, three paired lip sectors, protruding posterior anal lip, and five ridges in the hermaphrodite lateral field. Males generated from starved bacterial cultures have three lateral field ridges and a notched peloderan bursa with only eight rays. Male spicules are distinctive with a round but truncated head, constricted neck, narrow shoulders, nearly straight blade with distal tenth upturned, and rounded tips supporting a curved ventral arch. Males of LKC20 were mated successfully with hermaphrodites cultured from a Fiji Islands soil (isolate PS1191). In subsequent crosses, male progeny were fertile as expected for conspecific populations. Differences in morphometrics of cultured specimens that were heat-killed or fixed is demonstrated. Rhabditis rainai n. sp. was compared to R. blumi and R. adenobia, but does not fit clearly within the current subgenera of Rhabditis or genera of Rhabditidae. Nematode-termite relationships and possible origin of R. rainai n. sp. with Formosan subterranean termites from Southeast Asia are discussed.

Multiple displacement amplification (MDA) of total genomic DNA from Meloidogyne spp. and comparison to crude DNA extracts in PCR of ITS1, 28S D2-D3 rDNA and Hsp90

Summary ‐ Because the quantity of nematode specimens available for molecular analysis is often limited, the number of analyses possible is constrained by the availability of DNA. Multiple displacement amplification (MDA) was assessed for whole genome amplification of crude DNA from several Meloidogyne species. MDA produced microgram quantities of template that resulted in successful amplification of the ribosomal internal transcribed spacer (ITS1) and 28S D2-D3 expansion regions, producing PCR results that were comparable to template generated by the single nematode smash method. MDA greatly improved degenerate primer PCR of single-copy Hsp90, a gene which is more sensitive than multi-copy ribosomal genes to limited DNA template. MDA should expand the number of molecular analyses possible for single nematodes. MDA will also be useful for archiving DNA from valuable specimens and provide a way for laboratories to share identical genetic material for nematode diagnosis.

Taxonomy, Morphology and Phylogenetics of Coffee-Associated Root-Lesion Nematodes, Pratylenchus spp

This review includes a synthesis of information on eight species of root-lesion nematodes (Pratylenchus spp.) that parasitize coffee or inhabit its rhizosphere. It includes a table of important morphological characters, a diagnostic key, photographs of anterior ends and tails of specimens from the USDA nematode collection, and a phylogenetic tree based on ribosomal DNA with drawings of scanning electron microscopic face-patterns. Information sources are evaluated and future research needs are outlined.

Detection of Rhynchophorus palmarum (Coleoptera: Curculionidae) and Identification of Associated Nematodes in South Texas

Abstract This study reports a survey conducted to find the South American palm weevil Rhynchophorus palmarum (L.) and the red palm weevil R. ferrugineus (Olivier) (Coleoptera: Curculionidae), 2 invasive species of palm trees. The study was performed in the Rio Grande Valley of south Texas and near the border with Tamaulipas state, Mexico. A total of 40 traps were inspected biweekly from 26 Sep 2011 to 20 Sep 2012 and 4 traps were inspected from 20 Sep 2012 to 4 Sep 2013. To attract R. palmarum and R. ferrugineus, the lures 2-methylhept-5-en- 4-ol and 4-methyl-5-nonanol were used, respectively. We used these lures in combination with sugar and the ethyl acetate aggregation kairomone for both species, plus an ethylene glycol kill solution. Two specimens of R. palmarum were found and identified next to a commercial palm plantation on 11 Mar and 5 May 2012 near the city of Alamo, Texas, but no R. ferrugineus was detected during the entire study. Nematodes found in the 2 R. palmarum specimens were dauer juveniles of the order Rhabditida, and in one of these weevils only 1 nematode of an undetermined species within the family Aphelenchoididae was found. It is of great importance that Bursaphelenchus cocophilus Cobb Baujard (Nematoda: Parasitaphelenchinae), the nematode causal agent of coconut red ring disease, was not found within these insects. This is the first detection of R. palmarum in Texas, and the second in the United States.

Evaluation of Some Vulval Appendages in Nematode Taxonomy

Abstract A survey of the nature and phylogenetic distribution of nematode vulval appendages revealed 3 major classes based on composition, position, and orientation that included membranes, flaps, and epiptygmata. Minor classes included cuticular inflations, protruding vulvar appendages of extruded gonadal tissues, vulval ridges, and peri-vulval pits. Vulval membranes were found in Mermithida, Triplonchida, Chromadorida, Rhabditidae, Panagrolaimidae, Tylenchida, and Trichostrongylidae. Vulval flaps were found in Desmodoroidea, Mermithida, Oxyuroidea, Tylenchida, Rhabditida, and Trichostrongyloidea. Epiptygmata were present within Aphelenchida, Tylenchida, Rhabditida, including the diverged Steinernematidae, and Enoplida. Within the Rhabditida, vulval ridges occurred in Cervidellus, peri-vulval pits in Strongyloides, cuticular inflations in Trichostrongylidae, and vulval cuticular sacs in Myolaimus and Deleyia. Vulval membranes have been confused with persistent copulatory sacs deposited by males, and some putative appendages may be artifactual. Vulval appendages occurred almost exclusively in commensal or parasitic nematode taxa. Appendages were discussed based on their relative taxonomic reliability, ecological associations, and distribution in the context of recent 18S ribosomal DNA molecular phylogenetic trees for the nematodes. Characters were found to be distributed across subsets of terminal and phylogenetically distant taxa, demonstrating considerable homoplasy. Accurate definitions, terminology, and documentation of the taxonomic distribution of vulval appendages are important in evaluations of hypotheses for either parallelism and developmental constraint or convergence and adaptation.

Nematode specific gravity profiles and applications to flotation extraction and taxonomy

A technique is described that refines the standard sugar flotation procedure used to isolate nematodes from their surroundings. By centrifuging nematodes in a number of increasing specific gravity solutions and plotting the fraction floating, the cumulative probability distribution of the population’s specific gravity is generated. By assuming normality, the population mean, μ, and standard deviation, σ, are found by a nonlinear least squares procedure. These density parameters along with their error covariance matrix may be used as a taxonomic physical character. A chi-squared test is derived for comparing populations. Mean and standard deviation pairs (μ, σ) were found for the specific gravities of the adult stage of the plant parasites Pratylenchus agilis (1.068, 0.017), P. scribneri (1.073, 0.028), P. penetrans (1.058, 0.008) and the bacterial-feeder Caenorhabditis elegans (1.091, 0.016). La technique exposee affine le procedure standard par flottation au sucre utilisee pour separer les nematodes de leur milieu. La centrifugation des nematodes dans une serie de solutions de densites specifiques et la mise en diagramme de la valeur de la fraction surnageante permettent de connaitre le repartition de la probabilite cumulee de la densite specifique de la population en cause. La normalite etant supposee, la moyenne de la population, μ, et la deviation standard, σ, sont calculees par la methode des moindres carres non lineaires. Ces parametres relatifs a la densite ainsi que leur matrice de co-variance d’erreur peuvent etre utilises en taxinomie comme caractere physique. Un test chi2 en est derive pour comparer les populations entre elles. Des donnees en paires — moyenne (μ) et ecart-type (σ) — ont ete definies pour les densites des adultes des especes phytoparasites Pratylenchus agilis (1,068; 0,017), P. scribneri (1,073; 0,028), P. penetrans (1,058; 0,008), ainsi que pour l’espece bacterivore Caenorhabditis elegans (1,091; 0,016).

Supplemental description of Paraphelenchus acontioides (Tylenchida: Aphelenchidae, Paraphelenchinae), with ribosomal DNA trees and a morphometric compendium of female Paraphelenchus

Summary – Nematodes were isolated from surface-sterilised stems of cheatgrass, Bromus tectorum (Poaceae), in Colorado, grown on Fusarium (Hypocreaceae) fungus culture, and identified as Paraphelenchus acontioides. Morphometrics and micrographic morphology of this species are given to supplement the original description and expand the comparative species diagnosis. A tabular morphometric compendium of the females of the 23 species of Paraphelenchus is provided as the last diagnostic compilation was in 1984. Variations in the oviduct within the genus are reviewed to evaluate the taxonomic assignment of P. deckeri , a morphologically transitional species between Aphelenchus and Paraphelenchus. Sequences were generated for both 18S and 28S ribosomal DNA, representing the first identified species within Paraphelenchus so characterised. These sequences were incorporated into phylogenetic trees with related species of Aphelenchidae and Tylenchidae. Aphelenchus avenae isolates formed a well supported monophyletic sister group to Paraphelenchus. The ecology of Paraphelenchus, cheat grass and Fusarium is also discussed.

List of Type Specimens Deposited Since 1998 in the United States Department of Agriculture Nematode Collection, Beltsville, Maryland

The United States Department of Agriculture Nematode Collection (USDANC) is one of the largest and most valuable in existence and includes millions of specimens housed in over 39,800 permanent slides and 9,300 vials. This collection preserves type specimens of nematodes to serve as a reference for identifications and future taxonomic revisions. Also, the collection provides useful information on nematode hosts, occurrence, and distribution. The present list includes type specimens added to the USDANC since 1998. Since that time, the collection has expanded, with 474 type species mounted and preserved on 2,564 glass slides and 180 vials. We encourage nematologists throughout the world to deposit type specimens in the USDANC for use by future generations.