Castilho et al. Zoological Studies (2015) 54:20 DOI 10.1186/s40555-014-0104-5 RESEARCH Open Access Life history and DNA barcode of Oxyurella longicaudis (Birgei, 1910) (Cladocera, Anomopoda, Chydoridae) Maria Carolina de Almeida Castilho1*, Maria José dos Santos Wisniewski2, Cínthia Bruno de Abreu2 and Tereza Cristina Orlando2 Abstract Background: Cladocera is an important group of freshwater zooplankton, and the species plays an important role in energy transfer and in aquatic food webs. Oxyurella longicaudis is a Chydoridae species that has been recorded in North and South America. The aim of this study is to investigate the life cycle aspects of parthenogenetic females of O. longicaudis cultured in laboratory under controlled conditions: temperature (23°C ± 05°C), photoperiod (12 h light/12 h dark), food supply, and reconstituted water. Results: Embryonic development duration (2.3 ± 0.5 days), post-embryonic development (5.2 ± 0.69 days), mean fecundity (two eggs female−1 brood−1), total egg production (22.55 ± 3.98 eggs), average longevity (58 days), and body growth of the species were recorded. We also report the first DNA barcode for O. longicaudis isolated in Brazil, which will allow for easy identification in future zooplankton community studies. The analysis shows a genetic divergence of around 7% between our Brazilian isolate and O. longicaudis isolates from Mexico. Conclusions: The time of embryonic and post-embryonic development of O. longicaudis was higher than that of the other species of the same family, which contributed to lower total egg production throughout its life cycle. The genetic divergence appears to be sufficient to classify the two isolates as different species. Keywords: Conservation-priority areas; Zooplankton; Bionomics; Cryptic speciation; COI Background Cladocerans participate in energy transfer and aquatic food webs. In lakes and ponds, they represent a link in the food chain by consuming phytoplankton and are preyed upon by other invertebrates and fish (Sarma et al. 2005; Rocha et al. 2011). Cladocerans may be filter feeders, such as family members of Sididae, Moinidae, and Daphnidae or scrapers like the Macrothricidae and Chydoridae (Elmoor- Loureiro 2004; Castilho-Noll et al. 2010). The latter family feeds by scraping surfaces of the macrophytes or sediment. Studies focusing on functional classification of Cladocera species are scarce, and its type of feeding is used for func- tional classification, so this gap in the literature needs to be addressed (Barnett et al. 2007). Studies have also shown * Correspondence: mariacarolcastilho@gmail.com 1Departamento de Zoologia, Instituto de Biociências, Universidade Estadual Paulista, CP. 510, CEP 18618-000, Botucatu, SP, Brazil Full list of author information is available at the end of the article © 2015 Castilho et al.; licensee Springer. This is Attribution License (http://creativecommons.or in any medium, provided the original work is p that cladocerans' fine mesh filtering apparatus allows them to feed on small protozoa and the microbial flora of aquatic environments or feed on bacteria associated with algae (Geller and Müller 1981; Ooms-Wilms et al. 1995). According to Frey (1980), representatives of the Chydoridae family are found in the littoral region of water bodies where they live associated with macrophytes, periphyton, and sediment. The distribution of the mem- bers of the Chydoridae family is directly related to the presence of macrophytes, most often occurring in specific association (Sacherová and Hebert 2003). Oxyurella longicaudis is a Chydoridae species recorded in North and South America. In Brazil, they have been recorded in the northeast (Ceará, Pernambuco, Bahia, and Maranhão states), central west (Mato Grosso, Mato Grosso do Sul, and Goiás states), and the southeast (Rio de Janeiro, São Paulo, and Minas Gerais states) an Open Access article distributed under the terms of the Creative Commons g/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction roperly credited. mailto:mariacarolcastilho@gmail.com http://creativecommons.org/licenses/by/4.0 Castilho et al. Zoological Studies (2015) 54:20 Page 2 of 7 (Elmoor-Loureiro 2007; Van Damme and Dumont 2010; Rocha et al. 2011; Castilho and Santos-Wisniewski 2013). This species is rare since it was found in only 3 of 40 water bodies sampled in priority regions for conservation in southern Minas Gerais State (Castilho and Santos- Wisniewski 2013). This species has been identified in oligotrophic environments and is probably sensitive to en- vironmental changes. O. longicaudis individuals are found in low densities on plankton and have restricted occur- rence in coastal regions, where they play a significant role in ecosystem productivity and nutrient cycling (Kotov 2006), serving as a food source for other animals. Consid- ering studies of the coastal region, we may assume that this species may have a wider distribution, demonstrating their role in the aquatic environment. Studies of the Cladocera life cycle are important be- cause they provide a deeper understanding of the biology of these animals, in addition to providing information on secondary production, population dynamics, and in- teractions in the food chain in aquatic environments. Ecotoxicology studies aim to control the environmental quality and the ability of zooplankton organisms to swim against a gradient of turbulence (Seuront et al. 2004; Santos-Wisniewski et al. 2002; Freitas and Rocha 2006; Castilho et al. 2012). In Brazil, studies on the life cycle of Chydoridae have been done on species such as Chydorus dentifer and Acroperus harpae, Chydorus pubescens, Coronatella rectangula, and Alona iheringula by Melão (1997), Santos-Wisniewski et al. (2006), Viti et al. (2013), and Silva et al. (2014), respectively. High variation was observed in their life cycle, with a duration average varying between 9 and 46 days, with the greatest longevity recor- ded for A. iheringula cultured at 25°C. Although the num- ber of studies has been increasing recently, the knowledge of the taxonomic diversity of Cladocera remains insufficient due to morphological differentiation, phenotypic variation, and historical factors. Nowadays, molecular identification such as the DNA barcoding has been useful for ecological studies as it allows for precise identification and determination of cryptic species. The DNA barcode includes an analysis of partial sequences of the mitochondrial gene cytochrome oxidase I (COI). Its diversity has been used to identify and detect new species in many animal groups (Hebert et al. 2003), including the Crustacea (Costa et al. 2007; Young et al. 2012). For the Chydoridae, DNA barcoding has already been used to determine some species (Sacherová and Hebert 2003; Gutiérrez et al. 2008; Gutiérrez and Valdez–Moreno 2008; Jeffery et al. 2011; Silva et al. 2014). The aim of this study is to investigate the aspects of the life cycle of parthenogenic females of O. longicaudis cultured in a laboratory under controlled conditions and characterize its DNA barcode in order to allow for easy identification in future ecological studies. Methods Study area and sampling date Sampling was carried out on July 7, 2010 in the Epamig Pond (21° 56′ 33″ S 45° 18′ 56″ W) situated in a prior- ity area for conservation in Serra da Mantiqueira, Minas Gerais State, Brazil. This pond is oligotrophic, with water which has slightly acidic pH (5.7), high concentra- tion of dissolved oxygen (9.1 mg.L−1), and low electrical conductivity (31 μs.cm−1). The pond is shallow and small in size (approximately 60 × 30 m), with an extensive macrophyte stand. The Epamig Pond is located next to the Parque Estadual de Nova Baden. The pond is com- prised of a large forest fragment and located near a rice cultivation. Sampling and acclimatization Organisms for starting cultures were collected close to macrophyte stands in the littoral region of the Epamig Pond by horizontal hauls using a zooplankton 68-μm mesh size net. In the laboratory, parthenogenetic females of O. longicaudis (Figure 1) were isolated and placed in 2-L beakers containing reconstituted water. This culture me- dium had pH 7.6, conductivity 140 μs.cm−1 and hardness of 46 mg.L−1 CaCO3. Experimental cultures were main- tained in germination chambers (model 347-CDG) at a constant temperature of 23.0°C ± 0.5°C and 12 h-light/ 12 h-dark photoperiod. O. longicaudis was fed a suspen- sion of the small chlorophycean Raphidocelis subcapitata, cultured in Chu 12 medium and cropped in the expo- nential phase, at a concentration of 105 cells.mL−1, and 0.02 mL of a mixed suspension of yeast, and fish ration added in equal proportions (1:1) (USEPA 1994; ABNT 2009). Life cycle Individuals were acclimated for about ten generations (30 days). Ten females were isolated and maintained until the production of neonates. A total of 30 neonates less than 24 h old were placed in 50-mL polypropylene bottles and kept in a germination chamber with the tem- perature, light, and feeding conditions specified above. These organisms were observed to obtain the parameters of the life cycle. Culture media and food suspensions were completely renewed daily with a fresh suspension at the same temperature, once or twice a day. The animals were observed under a stereomicroscope to determine the number of eggs produced per brood and the longevity. The body growth of each individual was measured daily under an optical microscope, using a micrometric grid and × 50 magnification. DNA barcode For the DNA barcode analysis, the specimens were fixed with 95% EtOH and placed in pure water for 12 h for A B Figure 1 Oxyurella longicaudis from Epamig Pond in Lambari, Minas Gerais state, Brazil. (A) Female, general view (×200). (B) Post-abdomen (×400). Table 1 Life cycle parameters of Oxyurella longicaudis (Cladocera: Chydoridae) Life cycle parameters Values Adult mean size (μm) 883.7 ± 27.75 Maximum adult size (μm) 940 Neonate mean size (μm) 503.85 ± 52.77 Primipara mean size (μm) 654.61 ± 45.09 Minimum size of primipara (μm) 580 Number of instars between neonate and primipara 1.88 ± 0.65 Maximum number of instars in the whole life cycle 8.92 ± 1.23 Mean number of eggs in the whole life cycle 22.55 ± 3.98 Mean fecundity (eggs female−1 brood−1) 2 Maximum longevity (days) 58 Mean longevity (days) 46.96 ± 9.00 Mean embryonic development time (days) 2.30 ± 0.5 Primipara age (days) 5.20 ± 0.69 Cultured at 23.0°C ± 0.5°C in a 12-h light/dark photoperiod, fed on a mixed suspension of Raphidocelis subcapitata (at 105 cells.mL−1) and yeast, and fish ration added in equal proportions. Castilho et al. Zoological Studies (2015) 54:20 Page 3 of 7 cleaning. Genomic DNA was extracted using phenol extraction and ethanol precipitation (Bucklin 2000). To amplify the mitochondrial COI gene, the universal primers, LCO 1490 and HCO2198 (Folmer et al. 1994) were used. PCR reactions had a total volume of 25 μl and were performed according to Ivanova et al. (2009) using Platinum Taq (Invitrogen, Carlsbad, CA, USA) as the enzyme. The PCR conditions were 94°C for 2 min as initial denaturation and 40 cycles of 94°C for 40s, 55°C for 40s, and 72°C for 1 min. DNA sequencing was done by direct sequencing of PCR amplification products, carried out in a 3130xl Genetic Analyzer automated DNA sequencer, following the manufactur- er's instructions (Applied Biosystems, Foster City, CA, USA). The sequences were obtained bi-directionally two times for accurate reading. The O. longicaudis COI was aligned in MEGA 6 (Tamura et al. 2013) with other COI sequences that show high sequence similarity using the BLAST tool at Genbank (http://www.ncbi.nlm.nih.gov/pubmed/). The Kimura 2- parameter (K2P) distance model (Kimura 1980) was used to calculate sequence divergences. Neighbor-joining (NJ) trees using the K2P method were generated by MEGA 6 (Tamura et al. 2013) facilities. Nonparametric bootstrap- ping was performed using 1,000 replicates. Results Life cycle The mean duration of embryonic development was 2.3 days, and the time of post-embryonic development was 5.2 days for O. longicaudis. Throughout the life cycle of the species, a mean of 12 broods per female and 22 eggs female−1 were produced and the fecund- ity rate was 2 eggs female−1 brood−1. The mean lon- gevity was 47 days, and maximum longevity was 58 days (Table 1). Figure 2 shows mean individual growth curve of the species as a function of time (days). The neonate of O. longicaudis had an average size of 504 μm and reached maturity with approximately 655 μm. On average, two juvenile instars and nine instars were re- corded throughout the life cycle of the species. DNA barcode The sequence region of the COI gene (barcode region) was 658 bp in length and was deposited as accession number JX501501 in the Genbank. The base compos- ition for O. longicaudis COI sequence was as follows: T = 41.33%, C = 13.82%, A = 23.1%, and G = 21.73%. The calculated A-T content was 64.4 %. A genetic divergence from other O. longicaudis from the GenBank was found ranging from 7.0% to 7.2% (Table 2). With other Chydoridae species including Oxyurella sp., Kauralona penuelasi, Alona sp., and Alona setulosa, the genetic divergence ranged from 16.8% to 20.1%. The NJ tree with 14 COI analyzed sequences shows O. longicaudis from Brazil as closely related to seven other O. longicaudis from Mexico (100% bootstrap support) (Figure 3). For Oxyurella sp., a bootstrap support of 86% was found with all O. longicaudis and, Alona sp., and A. setulosa were separated as another clade (Figure 3). http://www.ncbi.nlm.nih.gov/pubmed/ 0 200 400 600 800 1000 0 10 20 30 40 50 60 S iz e (µ m ) Time (days) Size = 516 + 99 * ln(X) Figure 2 Mean individual growth curve of Oxyurella longicaudis (Cladocera, Chydoridae). Grown in the laboratory at 23.0°C, in a 12 h-light/ 12 h-dark photoperiod, fed on a mixed suspension of Raphidocelis subcapitata (at 105 cells.mL− 1) and yeast, and fish ration added in equal proportions. Castilho et al. Zoological Studies (2015) 54:20 Page 4 of 7 Discussion Life cycle of O. longicaudis O. longicaudis occurred more abundantly in preserved environments, shallow oligotrophic water bodies, with low electrical conductivity, well-oxygenated concentra- tion, and pH from neutral to alkaline (Rocha et al. 2011; Van Damme and Dumont 2010; Castilho and Santos- Wisniewski 2013). Temperature is more important for determining the time of embryonic and post-embryonic development and genetic factors, such species size and size of the egg also influence these parameters. High temperatures promote quick development, while larger eggs take longer time to develop (Melão 1999). The embryonic development time observed for O. longicaudis at 23°C (2.3 days) is greater than that of the other Chydoridae species (Table 3): A. iheringula (510 μm) has an embryonic development time Table 2 K2P Genetic distance between COI sequences of Oxyu Alona species 1 2 3 4 5 1. O. longicaudis (JX501501) 2. O. longicaudis (KC617722) 0.072 3. O. longicaudis (KC617723) 0.070 0.002 4. O. longicaudis (KC617724) 0.072 0.000 0.002 5. O. longicaudis (KC617725) 0.072 0.000 0.002 0.000 6. Oxyurella sp.(KC617135) 0.168 0.153 0.151 0.153 0.153 7. O. longicaudis (KC617136) 0.072 0.000 0.002 0.000 0.000 8. O. longicaudis (KC617138) 0.072 0.000 0.002 0.000 0.000 9. O. longicaudis (KC617139) 0.070 0.002 0.000 0.002 0.002 10. K. penuelasi (KC617020) 0.188 0.192 0.190 0.192 0.192 11. K. penuelasi (KC617021) 0.188 0.192 0.190 0.192 0.192 12. K. penuelasi (KC617022) 0.188 0.192 0.190 0.192 0.192 13. Alona sp.(KC617433) 0.181 0.197 0.195 0.197 0.197 14. Alona setulosa (EU701997) 0.201 0.209 0.206 0.209 0.209 Genbank access numbers are located after each species name. greater than O. longicaudis (940 μm) at the same temperature (23°C). In addition, C. rectangula (468 μm) was less than O. longicaudis at 25°C, which, at this tem- perature, reduced the time of embryonic development. A. harpae at a higher temperature (25°C) (Melão 1997) has a shorter embryonic development time and at a lower temperature (20°C) takes longer in embryonic develop- ment (Bottrell 1975). The post-embryonic development of O. longicaudis (5.2 days) was longer than that observed for other represen- tatives of the Chydoridae family. A. harpae, Alonella excisa, Leydigia acanthocercoides, and A. iheringula reached ma- turity on the third day of life (Melão 1997; Sharma and Sharma 1998; Murugan and Job 1982; Silva et al. 2014), and C. rectangula reaches primipara age on the second day of life (Viti et al. 2013) (Table 3). By the fifth day of life, O. longicaudis began to show exponential body rella longicaudis and other Oxyurella, Kauralona and 6 7 8 9 10 11 12 13 14 0.153 0.153 0.000 0.151 0.002 0.002 0.217 0.192 0.192 0.190 0.217 0.192 0.192 0.190 0.000 0.217 0.192 0.192 0.190 0.000 0.000 0.184 0.197 0.197 0.195 0.208 0.208 0.208 0.227 0.209 0.209 0.206 0.204 0.204 0.204 0.198 Figure 3 Identification COI tree of Oxyurella and other Oxyurella, Kauralona, and Alona species. Using a 658-bp COI fragment inferred by NJ. Numbers in each node designate percentage of bootstrap support (for 1,000 replicates). The bar shows the number of substitutions per site. Genbank access number and locality are located after each species name. Castilho et al. Zoological Studies (2015) 54:20 Page 5 of 7 growth (Figure 2). Therefore, the species began to allocate energy for reproduction only from this period on- ward, which is indicated by the increase of O. longicaudis' body, being larger than most representatives of the Chy- doridae family. According to Lynch (1980), larger body species invest almost all of their energy and reproduction after reaching maturity. Additionally, the time duration for post-embryonic development is higher for the Cladocera species with larger bodies under the same feeding conditions (Hardy and Duncan 1994). The fecundity rate (two eggs brood−1) found for O. long- icaudis is common in representatives of the Chydoridae family (Bottrell 1975; Murugan and Job 1982; Robertson, 1988; Sharma and Sharma 1998; Santos-Wisniewski et al. Table 3 Comparison of life cycle parameters of Chydoridae sp Species EDD PA F Oxyurella longicaudis 2.30 5.20 2 Chydorus pubescens 1.96 2.37 2 Chydorus dentifer 2.20 5.73 2 Chydorus sphaericus 3.10 2 Acroperus harpae 1.56 3.70 1.59 Acroperus harpae 3.18 Pleuroxus uncinatus 3.16 2 Alonella excisa 3.17 2 Leydigia acanthocercoides 3.00 2 Leydigia ciliata 2 Euryalona orientalis 2 Coronatella rectangula 1.68 2.48 1.98 Alona iheringula 1.79 3.24 2 EDD embryonic development duration (days), PA primiparous age (days), F fecundit female−1), L longevity (days), and T temperature (°C). 2006; Silva et al. 2014). This rate is the lowest fecundity rate between the families of Cladocera. The flat body of Chydoridae members prevents a higher yield of eggs per brood, as occurs with the representatives of other Cladocera families. For example, the Daphnidae Sca- pholeberis armata freyi produce up to 16 eggs brood−1 (Castilho et al. 2012) and the Sididae Pseudosida ramosa produces on average 3.4 eggs brood−1 when cultured at 25°C (Freitas and Rocha 2006). Moreover, the low fecundity rate of Chydoridae is related to the low levels of popula- tion growth of species (Martínez-Jerónimo and Gómez- Díaz 2011). Among the cladocerans, small species such as Chy- dorus and Alona produce 20 eggs female−1 on average ecies (data from the present study and the literature) CF L T (°C) Author 22 46.96 23 Present study 22.3 25.44 23.6 Santos-Wisniewski et al. 2006 11.39 25 Melão 1997 74 20 Bottrell 1975 9.79 25 Melão 1997 74 20 Bottrell 1975 Bottrell 1975 46 73.4 19-23 Sharma and Sharma 1998 20 23.2 28-30 Murugan and Job 1982 50 46 28-30 Venkataraman 1990 20 23.8 28-30 Venkataraman 1990 27.8 28.04 23.6 Viti et al. 2013 47.6 46 25 Silva et al. 2014 y (eggs female−1 brood−1), CF cumulative fecundity (total number of eggs Castilho et al. Zoological Studies (2015) 54:20 Page 6 of 7 during their whole life cycle (Muro-Cruz et al. 2002). The total production of eggs of O. longicaudis over the course of its life cycle (22 eggs female−1) was low compared to other Chydoridae, since it has a longer embryonic devel- opment time, and a later primipara. Similar production of eggs has been observed by Santos-Wisniewski et al. (2006) to C. pubescens (22.3 eggs female−1), by Murugan and Job (1982) to L. acanthocercoides (20 eggs female−1), and in Euryalona orientalis (20 eggs female−1) by Venkataraman (1990), and longevity of these species ranged from 23 to 25 days. Longer-lived species such as A. excisa (73.4 days) (Sharma and Sharma 1998) and Leydigia ciliata (46 days) (Venkataraman 1990) produced 46 and 50 eggs female−1 in their whole life cycle, respectively. A. excisa had a shorter embryonic development time, and L. ciliate, grown at a higher temperature by increasing the metabolism of organ- isms, probably lead to a shorter embryonic development. O. longicaudis stopped producing eggs near the end of its life cycle, contributing to lower total fertility. The mean size of neonate of O. longicaudis was about 50% less than the maximum size of adults. Smaller species tend to produce offspring with a hatching length closer to their adult size than the larger species (Lynch 1980). DNA barcode of O. longicaudis This study established the first barcode region of COI for the Cladocera species O. longicaudis isolated in Brazil. The percentage found for A-T (64.4%) is consistent with the data range previously described for the 60% A-T per- centage for COI of Chydoridae (Sacherová and Hebert 2003; Belyaeva and Taylor 2009). One value to consider is the 7.2% and 7.0% value of gen- etic divergence among O. longicaudis from Brazil and the other seven isolates from Mexico. For the Branchiopoda group, a genetic divergence of 3% in the COI sequence is considered a parameter for distinguishing species at the molecular level. From 3% to 5%, the species is considered provisional, and its taxonomic status should be confirmed. Above 5%, the specimens are considered different species (Jeffery et al. 2011). From this view, a genetic divergence of around 7% found between our O. longicaudis and the specimens from Mexico should be sufficient to classify them as different species. In order to confirm this and cre- ate a new species name, it will be necessary to perform additional morphological detailed studies combined with other molecular markers. However, among all O. longicau- dis from Mexico, the genetic divergence ranged from 0 to 0.2% (Table 2), emphasizing that they represent the same species names. COI analysis represents an interesting approach to new studies of taxonomy and species recognition of Brazilian isolates as new species, including cryptic species. Also, COI can be used to analyze a zooplankton community to estimate species richness of an entire zooplankton community as already proposed by Machida et al. (2009) and for further phylogeographic studies and gene flow for subpopulations as recently described for copepods (Young et al. 2014). Also, our results using COI markers strengthen the continental endemism idea for Cladocera (Forró et al. 2008; Belyaeva and Taylor 2009) and the monopolization hypothesis for aquatic organisms such as cladocerans (De Meester et al. 2002). Conclusions The embryonic and post-embryonic development times of O. longicaudis were higher than those of the other species of the same family, which contributed to lower total egg production throughout its life cycle. For the DNA barcoding, the roughly 7% genetic diver- gence found between our O. longicaudis and the specimens from Mexico highlights the possibility of a cryptic speci- ation for this species and the urgent necessity to clarify the taxonomic position. Competing interests The authors declare that they have no competing interests. Authors' contributions MCAC, TCO, and MJSW conceived and designed the experiments. MCAC and TCO performed the experiments. MCAC, CBA, TCO, and MJSW analyzed the data and wrote the paper. All authors read and approved the final manuscript. Acknowledgments This research was funded by Eletrobrás Furnas (Programa de P&D Aneel) and FAPEMIG (Biota Minas APQ-03549-09 and Universal APQ 01518–09) grants and a graduate fellowship to C.B.A. (CAPES Program). Author details 1Departamento de Zoologia, Instituto de Biociências, Universidade Estadual Paulista, CP. 510, CEP 18618-000, Botucatu, SP, Brazil. 2Instituto de Ciências da Natureza, Universidade Federal de Alfenas-MG, CEP 37130-000, Alfenas, MG, Brazil. Received: 3 September 2014 Accepted: 30 December 2014 References ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS – ABNT (2009) NBR 12713: Ecotoxicologia aquática – toxicidade aguda- método de ensaio com Daphnia spp. (Cladocera, Crustacea). ABNT, Rio de Janeiro, p 23 Barnett AJ, Finlay K, Beisner BE (2007) Functional diversity of crustacean zooplankton communities: towards a trait-based classification. 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Zoological Studies 51(2):222–231 Young SS, Lee YY, Liu MY (2014) Genetic variability and divergence of Neutrodiaptomus tumidus Kiefer 1937 (Copepoda: Calonida) among 10 subpopulations in the high mountain range of Taiwan and their phylogeographical relationships indicated by mtDNA COI gene. Zool Stud 53:22 Submit your manuscript to a journal and benefi t from: 7 Convenient online submission 7 Rigorous peer review 7 Immediate publication on acceptance 7 Open access: articles freely available online 7 High visibility within the fi eld 7 Retaining the copyright to your article Submit your next manuscript at 7 springeropen.com Abstract Background Results Conclusions Background Methods Study area and sampling date Sampling and acclimatization Life cycle DNA barcode Results Life cycle DNA barcode Discussion Life cycle of O. longicaudis DNA barcode of O. longicaudis Conclusions Competing interests Authors' contributions Acknowledgments Author details References