A new canopy-dwelling species of the genus Alloscopus Brner (Collembola: Orchesellidae: Heteromurinae) from Mt. Makiling, Philippines.

A new species of Alloscopus Brner, 1906 (Orchesellidae: Heteromurinae), A. arborealis sp. nov., is herein described from Mt. Makiling, Laguna, Philippines. The new species is distinct from its blind congeners by the combination of: 7+7 macrochaetae on head An series and 1+1 on M series; 13+13 macrochaetae on thorax II (vs. 912) and 7+7 central on thorax III (vs. 6+6); absence of the microsensilla on abdomen I; abdomen IV with four sensilla (vs. three); and ventral tube with a small number of chaetae on its posterior face (45 vs. 1123) and lateral flap (7 vs. 916). The complete body chaetotaxic pattern of the new species and a revised key to the world fauna of Alloscopus are also provided.

Direct sequencing of insect symbionts via nanopore adaptive sampling.

Insect symbionts can alter their host phenotype and their effects can range from beneficial to pathogenic. Moreover, many insects exhibit co-infections, making their study more challenging. Less than 1% of insect species have high-quality referenced genomes available and fewer still also have their symbionts sequenced. Two methods are commonly used to sequence symbionts: whole-genome sequencing to concomitantly capture the host and bacterial genomes, or isolation of the symbiont's genome before sequencing. These methods are limited when dealing with rare or poorly characterized symbionts. Long-read technology is an important tool to generate high-quality genomes as they can overcome high levels of heterozygosity, repeat content, and transposable elements that confound short-read methods. Oxford Nanopore (ONT) adaptive sampling allows a sequencing instrument to select or reject sequences in real time. We describe a method based on ONT adaptive sampling (subtractive) approach that readily permitted the sequencing of the complete genomes of mitochondria, Buchnera and its plasmids (pLeu, pTrp), and Wolbachia genomes in two aphid species, Aphis glycines and Pentalonia nigronervosa. Adaptive sampling is able to retrieve organelles such as mitochondria and symbionts that have high representation in their hosts such as Buchnera and Wolbachia, but is less successful at retrieving symbionts in low concentrations.

Patterns of asexual reproduction of the soybean aphid, Aphis glycines (Matsumura), with and without the secondary symbionts Wolbachia and Arsenophonus, on susceptible and resistant soybean genotypes.

Plant breeding is used to develop crops with host resistance to aphids, however, virulent biotypes often develop that overcome host resistance genes. We tested whether the symbionts, Arsenophonus (A) and Wolbachia (W), affect virulence and fecundity in soybean aphid biotypes Bt1 and Bt3 cultured on whole plants and detached leaves of three resistant, Rag1, Rag2 and Rag1 + 2, and one susceptible, W82, soybean genotypes. Whole plants and individual aphid experiments of A. glycines with and without Arsenophonus and Wolbachia did not show differences in overall fecundity. Differences were observed in peak fecundity, first day of deposition, and day of maximum nymph deposition of individual aphids on detached leaves. Bt3 had higher fecundity than Bt1 on detached leaves of all plant genotypes regardless of bacterial profile. Symbionts did not affect peak fecundity of Bt1 but increased it in Bt3 (A+W+) and all Bt3 strains began to deposit nymphs earlier than the Bt1 (A+W-). Arsenophonus in Bt1 delayed the first day of nymph deposition in comparison to aposymbiotic Bt1 except when reared on Rag1 + 2. For the Bt1 and Bt3 strains, symbionts did not result in a significant difference in the day they deposited the maximum number of nymphs nor was there a difference in survival or variability in number of nymphs deposited. Variability of number of aphids deposited was higher in aphids feeding on resistant plant genotypes. The impact of Arsenophonus on soybean aphid patterns of fecundity was dependent on the aphid biotype and plant genotype. Wolbachia alone had no detectable impact but may have contributed to the increased fecundity of Bt3 (A+W+). An individual based model, using data from the detached leaves experiment and with intraspecific competition removed, found patterns similar to those observed in the greenhouse and growth chamber experiments including a significant interaction between soybean genotype and aphid strain. Combining individual data with the individual based model of population growth isolated the impact of fecundity and host resistance from intraspecific competition and host health. Changes to patterns of fecundity, influenced by the composition and concentration of symbionts, may contribute to competitive interactions among aphid genotypes and influence selection on virulent aphid populations.

An annotated catalog of the primary type material of Myriapoda deposited in the Florida State Collection of Arthropods in Gainesville, FL, USA.

The Florida State Collection of Arthropods (FSCA) is one of the top insect collections in the United States with in excess of eight million curated specimens and significant amounts of materials in bulk collections and other unprocessed samples. The subphylum Myriapoda currently comprises approximately 17,500 species in the four classes Diplopoda, Chilopoda, Symphyla, and Pauropoda. The FSCA houses type material in the Diplopoda orders Callipodida, Chordeumatida, Glomeridesmida, Julida, Polydesmida, Polyzoniida, Siphonophorida, Spirobolida, and Spirostreptida. This catalog documents the FSCA primary type material for 74 species in 45 genera in 25 families and nine orders within Diplopoda.

Description of a new species of Plutomurus Yosii (Collembola: Tomoceridae) from Georgia, Caucasus and notes on the morphology of Plutomurus birsteini Djanashvili amp; Barjadze.

Plutomurus jordanai sp. nov. from Zeda Kvilishori Cave (Tskaltubo Municipality, Imereti region, Western Georgia) is described, illustrated and differentiated from other morphologically similar species‒‒P. kelasuricus Martynova, 1969 and P. eristoi Barjadze, Baquero, Soto-Adames, Giordano Jordana, 2016. In addition, morphological characters omitted or erroneously provided in the original description of Plutomurus birsteini Djanashvili Barjadze, 2011 are described and illustrated from the specimen sampled in the type locality‒‒Sakishore Cave (Racha region, Western Georgia). An identification key to the species of the genus Plutomurus reported from the Caucasus is presented. A list of the invertebrate communities for Zeda Kvilishori and Sakishore caves is provided.

Checklist and distribution of Collembola from Greater Puerto Rico.

BACKGROUND: Springtails (Arthropoda, Hexapoda, Collembola) are small arthropods commonly found in soil, litter and other habitats all around the Globe. More than 9,000 species have been described worldwide, but knowledge about their diversity and distribution remains far from complete. Reports of springtail diversity in the Antilles are uneven, some islands are relatively well known, whereas others have not been explored at all. The fauna of Puerto Rico is reasonably well known, but many recent reports are scattered in published literature and unpublished theses. NEW INFORMATION: Here, we present a summary of all springtail species identified from the Bank of Puerto Rico, including unpublished records. As a result, we list 146 species including 43 unnamed, included in 65 genera and 17 families. Most species, 33, belong to Entomobryidae, but this possibly reflects the taxonomic expertise of specialists working in Puerto Rico rather than a real bias in the distribution of higher taxa in the islands. In addition to the new records, the database provides information on the world and local distribution of species listed. The dataset, presented here, is work in progress and will be updated as ongoing taxonomic inventories are completed.

Soybean aphid biotype 1 genome: Insights into the invasive biology and adaptive evolution of a major agricultural pest.

The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae) is a serious pest of the soybean plant, Glycine max, a major world-wide agricultural crop. We assembled a de novo genome sequence of Ap. glycines Biotype 1, from a culture established shortly after this species invaded North America. 20.4% of the Ap. glycines proteome is duplicated. These in-paralogs are enriched with Gene Ontology (GO) categories mostly related to apoptosis, a possible adaptation to plant chemistry and other environmental stressors. Approximately one-third of these genes show parallel duplication in other aphids. But Ap. gossypii, its closest related species, has the lowest number of these duplicated genes. An Illumina GoldenGate assay of 2380 SNPs was used to determine the world-wide population structure of Ap. Glycines. China and South Korean aphids are the closest to those in North America. China is the likely origin of other Asian aphid populations. The most distantly related aphids to those in North America are from Australia. The diversity of Ap. glycines in North America has decreased over time since its arrival. The genetic diversity of Ap. glycines North American population sampled shortly after its first detection in 2001 up to 2012 does not appear to correlate with geography. However, aphids collected on soybean Rag experimental varieties in Minnesota (MN), Iowa (IA), and Wisconsin (WI), closer to high density Rhamnus cathartica stands, appear to have higher capacity to colonize resistant soybean plants than aphids sampled in Ohio (OH), North Dakota (ND), and South Dakota (SD). Samples from the former states have SNP alleles with high FST values and frequencies, that overlap with genes involved in iron metabolism, a crucial metabolic pathway that may be affected by the Rag-associated soybean plant response. The Ap. glycines Biotype 1 genome will provide needed information for future analyses of mechanisms of aphid virulence and pesticide resistance as well as facilitate comparative analyses between aphids with differing natural history and host plant range.

Fully automated sequence alignment methods are comparable to, and much faster than, traditional methods in large data sets: an example with hepatitis B virus.

Aligning sequences for phylogenetic analysis (multiple sequence alignment; MSA) is an important, but increasingly computationally expensive step with the recent surge in DNA sequence data. Much of this sequence data is publicly available, but can be extremely fragmentary (i.e., a combination of full genomes and genomic fragments), which can compound the computational issues related to MSA. Traditionally, alignments are produced with automated algorithms and then checked and/or corrected "by eye" prior to phylogenetic inference. However, this manual curation is inefficient at the data scales required of modern phylogenetics and results in alignments that are not reproducible. Recently, methods have been developed for fully automating alignments of large data sets, but it is unclear if these methods produce alignments that result in compatible phylogenies when compared to more traditional alignment approaches that combined automated and manual methods. Here we use approximately 33,000 publicly available sequences from the hepatitis B virus (HBV), a globally distributed and rapidly evolving virus, to compare different alignment approaches. Using one data set comprised exclusively of whole genomes and a second that also included sequence fragments, we compared three MSA methods: (1) a purely automated approach using traditional software, (2) an automated approach including by eye manual editing, and (3) more recent fully automated approaches. To understand how these methods affect phylogenetic results, we compared resulting tree topologies based on these different alignment methods using multiple metrics. We further determined if the monophyly of existing HBV genotypes was supported in phylogenies estimated from each alignment type and under different statistical support thresholds. Traditional and fully automated alignments produced similar HBV phylogenies. Although there was variability between branch support thresholds, allowing lower support thresholds tended to result in more differences among trees. Therefore, differences between the trees could be best explained by phylogenetic uncertainty unrelated to the MSA method used. Nevertheless, automated alignment approaches did not require human intervention and were therefore considerably less time-intensive than traditional approaches. Because of this, we conclude that fully automated algorithms for MSA are fully compatible with older methods even in extremely difficult to align data sets. Additionally, we found that most HBV diagnostic genotypes did not correspond to evolutionarily-sound groups, regardless of alignment type and support threshold. This suggests there may be errors in genotype classification in the database or that HBV genotypes may need a revision.

Two new species of Plutomurus Yosii (Collembola, Tomoceridae) from the Caucasus.

Two new species of Plutomurus, P. pichkhaiai sp. nov. from Garakha and Letsurtsume caves and P. shurubumuensis sp. nov. from Shurubumu Cave (Chkhorotsku district, Western Georgia) are described, and illustrated. The new species are very similar to P. kelasuricus from the Tsebelda karst massif formation in Apkhazeti, Georgia, but differ in having two inner spine-like chaetae on the inner edge of the hind tibiotarsus (only one in P. kelasuricus) and in occupying different, isolated cave formations separated by a geographic distance of nearly a 100 km. A key to the species of Plutomurus with 6 prelabral chaetae is provided.

New diagnosis for species of Plutomurus Yosii (Collembola, Tomoceridae), with descriptions of two new species from Georgian caves.

Two new species of the genus Plutomurus, P. revazi sp. nov. from Prometheus and Satsurblia caves and P. eristoi sp. nov. from Satevzia Cave are described, illustrated and differentiated from other morphologically closely related species. A high variability in the number of teeth in the claw, unguiculus and mucro of P. revazi sp. nov. demonstrate that these characters are not useful for species diagnosis. However, dorsal chaetotaxy was shown to be stable character for this purpose. Analysis of DNA sequences for the COI and 28S genes is congruent with species-level groups delimited by chaetotaxy, and provide additional support for chaetotaxy as the most reliable morphological character system to distinguish species in Plutomurus. A key to species of the genus Plutomurus found in Georgia is provided, which for the first time includes characters of the macrochaetotaxy.

The dorsal chaetotaxy of first instar Trogolaphysa jataca, with description of twelve new species of Neotropical Trogolaphysa (Hexapoda: Collembola: Paronellidae).

Adult members of tribe Paronellini are characterized by a substantially reduced idiochaetotaxy and as a result chaeta homology determination is often ambiguous. To evaluate previous hypotheses of chaetae homology in adult Trogolaphysa, a complete description of the dorsal chaetotaxy of first instar Trogolaphysa jataca (Wray, 1953b), supplemented with observations on first instar Trogolaphysa paracarpenteri sp. nov., is presented. It is showed that first instar Trogolaphysa carries an almost complete set of dorsal chaetae and that the reduction in adult idiochaetotaxy is secondary. In addition, the organization of primary chaetae in T. jataca points to a closer relationship with genera in subfamily Entomobryinae than to Orchesellinae. Based on chaetae correspondence between first instar and adult T. jataca it is established that the inner median chaetae on adult head corresponds to M1 instead of S1, the mesothorax p3 complex includes chaetae p1-p4, and on the fourth abdominal segment, anterior macrochaeta on column A corresponds to A3, and the secondary bothriotrix corresponds to D3p. In addition, T. relicta (Palacios-Vargas, Ojeda & Christiansen, 1985) is re-described based on a paratype, and 12 new species are described: from Mexico, T. stannardi sp. nov., T. dimorphica sp. nov., T. laterolineata sp. nov., T. marieloiseae sp. nov., T. clarencei sp. nov., T. ocellata sp. nov., T. paracarpenteri sp. nov., T. palaciosi sp. nov., T. octosetosa sp. nov., and T. trioculata sp. nov.; from Jamaica, T. balteata sp. nov.; and from Argentina, T. entreriosensis sp. nov.

Taxonomic review and phylogenetic analysis of fifteen North American Entomobrya (Collembola, Entomobryidae), including four new species.

The chaetotaxy of 15 species of eastern North American Entomobrya is redescribed in order to determine potential characters for the diagnosis of cryptic lineages and evaluate the diagnostic and phylogenetic utility of chaetotaxy. As a result, four new species (Entomobrya citrensis Katz & Soto-Adames, sp. n., Entomobrya jubata Katz & Soto-Adames, sp. n., Entomobrya neotenica Katz & Soto-Adames, sp. n. and Entomobrya unifasciata Katz & Soto-Adames, sp. n.) are described, and new diagnoses are provided for Entomobrya assuta Folsom, Entomobrya atrocincta Schött, Entomobrya decemfasciata (Packard), Entomobrya ligata Folsom, Entomobrya multifasciata (Tullberg), and Entomobrya quadrilineata (Bueker). Furthermore, previously undocumented levels of intraspecific variation in macrosetal pattern are reported, tempering the exclusive use of chaetotaxy for species delimitation. Phylogenetic relationships, estimated using both morphological and molecular data, indicate that Entomobrya is likely paraphyletic. The phylogenies also suggest that unreliable character homology, likely fostered by Entomobrya's profusion of macrosetae, may limit the phylogenetic utility of chaetotaxy in groups characterized by an abundance of dorsal macrosetae.

Evidence of Protaphorura fimata (Collembola: Poduromorpha: Onychiuridae) feeding on germinating lettuce in the Salinas Valley of California.

A series of experiments were conducted to determine the impact of Protaphorura fimata Gisin (Family: Onychiuridae) feeding on seeds and germinating seedlings of lettuce, Lactuca sativa L. (Asteraceae). First, various densities of P. fimata were incubated with 25 lettuce seeds for 7 d and feeding injury was evaluated in three soilless arena experiments. As a second step, 100 P. fimata were incubated with 25 lettuce seeds in three arena experiments with soil media. Finally, in a commercial field the incidence and impact of P. fimata on recently planted lettuce was assessed following applications of pyrethroid-insecticides: 2 d before planting, at planting, and 20 d later. In experiments without soil, the number of ungerminated seeds, feeding injury sites, and plants with injury were significantly greater in arenas with P. fimata than without. Similarly, the number of germinated seedlings, shoot fresh, and dry weights, and the length and width of fully opened-leaves were greater in arenas without than with P. fimata in assays with soil. In the field, P. fimata densities were significantly lower in beds that received insecticides at 2 d before and at planting than in untreated beds. Also, the fresh and dry weights of lettuce plants were significantly greater in the beds that received insecticide than in untreated. The results clearly show that P. fimata is a pest of lettuce and can cause severe feeding injury to germinating seeds or seedlings, thereby reducing their growth rate. The potential implications of P. fimata feeding and feeding injury characteristics are discussed.

Quantitative phase imaging of arthropods.

Classification of arthropods is performed by characterization of fine features such as setae and cuticles. An unstained whole arthropod specimen mounted on a slide can be preserved for many decades, but is difficult to study since current methods require sample manipulation or tedious image processing. Spatial light interference microscopy (SLIM) is a quantitative phase imaging (QPI) technique that is an add-on module to a commercial phase contrast microscope. We use SLIM to image a whole organism springtail Ceratophysella denticulata mounted on a slide. This is the first time, to our knowledge, that an entire organism has been imaged using QPI. We also demonstrate the ability of SLIM to image fine structures in addition to providing quantitative data that cannot be obtained by traditional bright field microscopy.

Collembola of Rapa Nui (Easter Island) with descriptions of five endemic cave-restricted species.

Eight species of Collembola are reported from recent collections made in caves on the Polynesian island of Rapa Nui (Easter Island). Five of these species are new to science and apparently endemic to the island: Coecobrya aitorererere n. sp., Cyphoderus manuneru n. sp., Entomobrya manuhoko n. sp., Pseudosinella hahoteana n. sp. and Seira manukio n. sp. The Hawaiian species Lepidocyrtus olena Christiansen & Bellinger and the cosmopolitan species Folsomia candida Willem also were collected from one or more caves. Coecobrya kennethi Jordana & Baquero, recently described from Rapa Nui and identified as endemic, was collected in sympatric association with C. aitorererere n.sp. With the exception of F. candida, all species are endemic to Rapa Nui or greater Polynesia and appear to be restricted to the cave environment on Rapa Nui. A key is provided to separate Collembola species reported from Rapa Nui. We provide recommendations to aid in the conservation and management of these new Collembola, as well as the other presumed cave-restricted arthropods.

Comparative analysis of the dorsal chaetotaxy of Troglopedetes, Trogolaphysa, and Campylothorax supports the synonymization of tribes Paronellini and Troglopedetini (Collembola: Paronellidae).

Genera in subfamily Paronellinae have been grouped into five tribes, in part based on chaetotaxy. Tribes Bromacanthini, Paronellini, and Troglopedetini are characterized by having rounded scales and reduced or no macrochaetae, and although Bromacanthini harbors two well-differentiated genera, the core genera in tribes Paronellini and Troglopedetini form a homogeneous group where even generic diagnoses were, until recently, unclear. The genera assigned to Troglopedetini (Troglopedetes Absolon, Trogolaphysa Mills, and Cyphoderopsis Carpenter) harbor many species with reduced eyes number, whereas the tribe Paronellini (genera Paronella Schött, Dicranocentruga Wray and Campylothorax Schött) includes species with 6-8 eyes. Recent analyses of the chaetotaxy of Trogolaphysa and Cyphoderopsis suggest that these genera represent specialized forms related to species in Paronellini. The taxonomy of Troglopedetes, the type genus of Troglopedetini, is based almost exclusively on claw and mucro shape and dorsal macrochaetae pattern, and few details of the complete dorsal chaetotaxy of the species are known. This contribution presents a comparative analysis of the complete dorsal chaetotaxy of two species of Troglopedetes from Spain (one new to science), two new species of Trogolaphysa from the Dominican Republic and Martinique, and Campylothorax sabanus with the purpose of identifying aspects of the chaetotaxy that could provide diagnostic characters for the separation of Trogolaphysa and Troglopedetes, and a new diagnosis for tribe Troglopedetini. The analysis shows that neither the number of chaetae nor its organization or pattern of macrochaeta provides diagnostic differences between Trogolaphysa and Troglopedetes. It is also concluded that the separation of Paronellini and Troglopedetini is not justified. Troglopedetini is here synonymized with Paronellini, and a new diagnosis of Paronellini is provided.

Invertebrates associated with a horizontal-flow, subsurface constructed wetland in a northern climate.

Wetlands function as buffers between terrestrial and aquatic ecosystems, filtering pollutants generated by human activity. Constructed wetlands were developed to mimic the physical and biological filtering functions of natural systems for the treatment of human and animal waste under controlled conditions. Previous studies on the effect of constructed wetlands on native invertebrate populations have concentrated almost exclusively on mosquitoes. Here, we present the first study investigating the relationship between vegetation cover and aeration regime, and the diversity and abundance of nematodes and springtails (Collembola) in a constructed wetland designed to treat dairy farm wastewater in northwestern Vermont. We investigated four treatment cells differing in aeration regime and vegetation cover, but equally overlaid by a layer of compost to provide insulation. Analysis showed that nematodes were most abundant in the nonplanted and nonaerated cells, and that bacterivorous nematodes dominated the community in all cells. Springtails were found to be most numerous in the planted and nonaerated cells. We hypothesize that the vegetation provided differing environmental niches that supported a more diverse system of bacteria and fungi, as well as offering protection from predators and inclement weather. Nematodes were likely imported with the original compost material, while springtails migrated into the cells either via air, water, or direct locomotion.

An evolutionary analysis of flightin reveals a conserved motif unique and widespread in Pancrustacea.

Flightin is a thick filament protein that in Drosophila melanogaster is uniquely expressed in the asynchronous, indirect flight muscles (IFM). Flightin is required for the structure and function of the IFM and is indispensable for flight in Drosophila. Given the importance of flight acquisition in the evolutionary history of insects, here we study the phylogeny and distribution of flightin. Flightin was identified in 69 species of hexapods in classes Collembola (springtails), Protura, Diplura, and insect orders Thysanura (silverfish), Dictyoptera (roaches), Orthoptera (grasshoppers), Pthiraptera (lice), Hemiptera (true bugs), Coleoptera (beetles), Neuroptera (green lacewing), Hymenoptera (bees, ants, and wasps), Lepidoptera (moths), and Diptera (flies and mosquitoes). Flightin was also found in 14 species of crustaceans in orders Anostraca (water flea), Cladocera (brine shrimp), Isopoda (pill bugs), Amphipoda (scuds, sideswimmers), and Decapoda (lobsters, crabs, and shrimps). Flightin was not identified in representatives of chelicerates, myriapods, or any species outside Pancrustacea (Tetraconata, sensu Dohle). Alignment of amino acid sequences revealed a conserved region of 52 amino acids, referred herein as WYR, that is bound by strictly conserved tryptophan (W) and arginine (R) and an intervening sequence with a high content of tyrosines (Y). This motif has no homologs in GenBank or PROSITE and is unique to flightin and paraflightin, a putative flightin paralog identified in decapods. A third motif of unclear affinities to pancrustacean WYR was observed in chelicerates. Phylogenetic analysis of amino acid sequences of the conserved motif suggests that paraflightin originated before the divergence of amphipods, isopods, and decapods. We conclude that flightin originated de novo in the ancestor of Pancrustacea > 500 MYA, well before the divergence of insects (~400 MYA) and the origin of flight (~325 MYA), and that its IFM-specific function in Drosophila is a more recent adaptation. Furthermore, we propose that WYR represents a novel myosin coiled-coil binding motif.

The dorsal chaetotaxy of Trogolaphysa (Collembola, Paronellidae), with descriptions of two new species from caves in Belize.

Species diagnosis in Trogolaphysa has been based, until now, almost exclusively on number of eyes and shape of claws and mucro. Chaetotaxy, a character system important to diagnose species in other genera of scaled Entomobryoidea, has been described only for a few Trogolaphysa species. Here the complete dorsal chaetotaxy of six species of Trogolaphysa is described using the AMS and Szeptycki's systems for head and body, respectively. A morphology-based parsimony analysis was performed to evaluate whether chaetotaxic characters overcome the influence of putatively cave adaptive convergent characters to resolve species level relationships, and to evaluate the evolution of the dorsal macrochaetae of the head. Phylogenetic analysis using only putative cave-adaptive characters support clades of unrelated taxa, but the addition of chaetotaxy overcomes the influence of convergent characters. A phylogeny based on all characters supports a trend towards reduced head macrochaetae number. Head macrochaetae are lost beginning with A3 and followed, in order, by S5, S3 and M3. In addition, a checklist of New World Trogolaphysa is provided and two new species, Trogolaphysa giordanoae sp. n. and Trogolaphysa jacobyi sp. n., are described on the basis of material collected in six caves in southern Belize.

The common ecotoxicology laboratory strain of Hyalella azteca is genetically distinct from most wild strains sampled in eastern North America.

The amphipod Hyalella azteca is commonly used as a model for determining safe concentrations of contaminants in freshwaters. The authors sequenced the mitochondrial cytochrome c oxidase subunit I (COI) gene for representatives of 38 populations of this species complex from US and Canadian toxicology research laboratories and eastern North American field sites to determine their genetic relationships. With 1 exception, all US and Canadian laboratory cultures sampled were identified as conspecific. In 22 wild populations spanning 5 US states and 1 Canadian province, the commonly occurring laboratory species was found only in northern Florida, USA. Therefore, the diversity of the H. azteca species complex detected in the wild is not accurately represented in North American laboratories, questioning the reliability of H. azteca cultures currently in use to accurately predict the responses of wild populations in ecotoxicological assays. The authors also examined the utility of different COI nucleotide fragments presently in use to determine phylogenetic relationships in this group and concluded that saturation in DNA sequences leads to inconsistent relationships between clades. Amino acid sequences for COI were not saturated and may allow a more accurate phylogeny estimate. Hyalella azteca is crucial for developing water-quality regulations; therefore, laboratories should know and standardize the strain(s) they use to confidently compare toxicity tests across laboratories and determine whether they are an appropriate surrogate for their regions.