Peruvian Journal of Agronomy 4(1): 1-9 (2020) ISSN: 2616-4477 (Versión electrónica) DOI: http://dx.doi.org/10.21704/pja.v4i1.1438 http://revistas.lamolina.edu.pe/index.php/jpagronomy/index © The authors. Published by Universidad Nacional Agraria La Molina Received for publication: 13 November 2019 Accepted for publication: 20 January 2020 Soil arthropods associated with sweetpotato crop (Ipomoea batata L.) in La Molina, Lima, Peru Artrópodos de suelo asociado al cultivo de camote (Ipomoea batata L.) en La Molina, Lima, Perú Livia-Tacza, C.(1)*; Sánchez, G. (1) *Corresponding author: clivia@lamolina.edu.pe https://orcid.org/0000-0003-4456-322X Abstract Sweetpotato (Ipomoea batata L.) is an economically important crop grown in Peru. The present study aimed to determine the soil arthropods associated with sweetpotato and its relative abundance in sweetpotato production fields in La Molina, Lima, Peru. Evaluations were conducted at Universidad Nacional Agraria La Molina, from February to August 2017. Samples were collected using pitfall traps and examined at the Klaus Raven Büller Entomology Museum. Soil morphospecies were extracted and separated from collected samples and then counted, recorded and identified. They were also admitted to the Entomology Museum collection. Eighty morphospecies in the classes Collembola, Insecta, Malacostraca, Arachnida and Chilopoda of phylum Arthropoda were recorded. Within the Collembola class, Entomobryidae was the most abundant family; within Insecta, Gryllus spp. (Gryllidae); within Malacostraca, Porcellio laevis (Porcellionidae); within Arachnida, Theridion volubile (Theridiidae) of the order Aranea; and within Chilopoda, the order Lithobiomorpha. By understanding the diversity of arthropods, it may inform future measures and improve control of pests by taking into consideration the soil arthropods among which important beneficial natural enemies could be found. Keywords: Arthropods, sweetpotato, soil, pitfall traps Resumen En Perú, el camote es un cultivo económicamente importante. El presente trabajo se realizó con el fin de determinar la asociación de los artrópodos de suelo con el cultivo de camote y su abundancia relativa en los campos de producción de camote en La Molina, Lima, Perú. Se evaluó en el área agrícola de la Universidad Nacional Agraria La Molina, Lote ‘Pancal’, del 3 de febrero al 11 de agosto, 2017. Las muestras colectadas fueron examinadas en los Laboratorios del Museo de Entomología Klaus Raven Büller. Se instalaron seis trampas de caída las cuales se evaluaron semanalmente. De las muestras colectadas se extrajeron y separaron las morfoespecies de suelo, se contabilizaron, registraron e identificaron. Así mismo, fueron ingresadas a la colección del Museo de Entomología. Se registraron a las Clases Collembola, Insecta, Malacostraca, Arachnida y Chilopoda del Phyllum Arthropoda. De la Clase Collembola, la más abundante fue la Familia Entomobryidae; de Insecta, Gryllus spp. (Gryllidae); Malacostraca, Porcellio laevis (Porcellionidae); Arachnida, Theridion volubile (Theridiidae) del Orden Aranea; y Chilopoda, el Orden Lithobiomorpha. Se registraron 79 morfoespecies. Palabras clave: Artrópodos, camote, suelo, trampas de caída 1 Universidad Nacional Agraria La Molina. Faculty of Agronomy. Department of Entomology. Lima, Perú. Introduction Sweetpotato (Ipomoea batata L.) is one of the most widely sown crops in the world (Martin 1988), and it typically performs well in warm valleys. Native to Central America (Ishida et al., 2000), it has been cultivated in Peru since pre-Incan times (Fonseca, et al., 2002). In Peru, it is sown in coastal valleys (at sea level), inter-Andean valleys and jungle regions (500 to 2000 m altitude) (Fonseca et al., 2002). Between 2017 and 2018, a total of 6,000 hectares (ha) of sweetpotato were registered nationwide, 2,400 ha being grown in the Lima region, followed by Lambayeque (700 ha), Ica (700 ha), and Cajamarca (600 ha), reaching yields of up to 17.8 tonnes/ha (Sistema Integrado de Estadística Agraria, SIEA, 2017). Soil arthropods associated with sweetpotato crop (Ipomoea batata L.) in La Molina, Lima, Peru January - April 2020 2 The physical-chemical nature, structure and sources of organic matter in the soil allow for the development of a wide diversity of flora and fauna, which interact with and maintain functioning ecosystems through processes such as nutrient cycle, decomposition of organic matter, emission of greenhouse gases, modification of soil structure, water treatment and erosion (Cortet et al., 1999). Soil arthropods are individuals that play an important role in soil ecosystems. Behan-Pelletier (1993) considered the study of soil arthropods difficult to establish and define since most arthropods, with some exceptions, spend a certain stage of their life in the ground. In sweetpotato, Robles (2002) recorded the orders Dermaptera and Coleoptera of the class Insecta and the class Arachnida. Schuller (2003) documented the class Insecta with the families Staphylinidae and Carabidae of the order Coleoptera and the class Arachnida in Chancay near Lima in tomato (Solanum lycopersicum L.). In maize (Zea mays L.), the order Dermaptera occurs most abundantly, followed by the Coleoptera, which is dominated by the families Staphylinidae and Carabidae, and the class Arachnida. In artichoke (Cynara scolymus L.) grown in Huaura (Larco, 2018), three orders have been reported: Coleoptera with the family Carabidae as the most abundant, followed by the families Linyphiidae and Theridiidae within the order Aranea and the families Anisolabididae and Labiduridae within Dermaptera. In avocado (Persea americana Mill.), the families Sicariidae, Lycosidae and Dysderidae within the order Aranea have been observed as well as the orders Coleoptera and Dermaptera. Pyle et al. (1981) points out that agriculture is the main factor that disturbs the agroecosystem of soil arthropods. However, Altieri (1999) emphasises that the disturbance in the diversity and abundance of these systems will depend on the type, age, diversity, structure and management of the crop. For example, sweetpotato (Ipomoea batatas L.) requires less input and labour than other crops such as corn, and it tolerates marginal growth conditions (International Potato Center, 2020). Generally, it does not require many intensive agricultural practices, which has led to it becoming a refuge for many species of arthropods due to the favourable conditions for survival. For this reason, the objective was to determine the relative diversity and abundance of the arthropod inhabitants of the soil in the sweetpotato crop in La Molina, Lima, Peru. Materials and Methods Weekly collections of soil arthropods were made, by means of pitfall traps, of a 1.1 ha sweetpotato field planted with the variety ‘Jonathan’ that had previously been planted with maize. The field was located in a sector of the Fundo, called ‘Pancal’, in the agricultural area of the Universidad Nacional Agraria La Molina, located in the district of La Molina, St. La Molina SN (Lima, Peru). The evaluation periods were from February 3rd to August 11th, 2017, and a total of 27 samples were collected. Typical cultural practices were performed during the collection period, including fertilisation, irrigation and weeding. At 36 days after sowing, cultivation and pounding were performed. No insecticide applications were made. Field work Installation of pitfall traps Six pitfall traps consisting of 12.5-cm-high and 12-cm- diameter polyethylene poly-rap containers were installed. They were filled weekly with approximately 250 mL of a solution of water and formaldehyde and 2 mL of liquid soap. Formaldehyde was used to prevent the decomposition of the collected insects and liquid soap to break the surface tension. The field was divided into six sectors, and a pitfall trap was placed in each sector. They were located at the back of the furrow. A hole was excavated to a depth where the mouth of the container was flush with the surface of the soil. The location of each pitfall trap was flagged. Each time a cultural practice was performed in either field, the pitfall traps were removed and subsequently replaced. Traps were placed at least 5 m from the field perimeter so as to minimise edge effects. Sample collection On each evaluation date, the pitfall traps were removed, and the contents were emptied into airtight 6 × 4 cm polyethylene containers previously marked with indelible ink with the trap number and date. Then, the traps were washed and again filled with the solution (water, formaldehyde and detergent) and reinstalled. The pitfall traps were removed once to prevent them from being damaged due to the hilling and subsequently relocated to the same place. When trap containers were damaged, they were changed and reinstalled. Sample processing in the laboratory Taxonomic separation and counting of the collected soil arthropods was performed in the research laboratory at the Klauss Raven Büller Entomology Museum of the Entomology Department of the Universidad Nacional Agraria La Molina. The contents of the 6 x 4 cm polyethylene container were screened with an organza cloth placed in a strainer, and the sample was washed with tap water and then with distilled water. The washed sample was placed in 25-cm-diameter glass Petri dishes. The separation and grouping of soil arthropods based on morphological characteristics, called morphospecies (Oliver & Beattie, 1993, 1996a, 1996b), was done using fine tweezers. Selected individuals were counted and kept in small glass bottles with 30 mL of 75% alcohol and labelled with their corresponding code. The code consisted of 1) the first letter of the crop, 2) the abbreviation of the order of the sample and 3) the number of the sample. Livia-Tacza, C.; Sánchez, G. Peruvian Journal of Agronomy 4(1): 1-9 (2020) 3 For example, a recorded individual belonging to the order Hymenoptera (HYM) and being the first identified individual ‘1’ was coded as HYM1, the second individual of the same order as ‘HYM2’ and so on. Those samples where an order could not be identified were classified as Morpho1, Morpho2, etc. One or a group of individuals of each species, depending on the number of individuals collected during the evaluation, were mounted on entomological pins and/or stored in alcohol, labelled and registered in the Entomology Museum of the Universidad Nacional Agraria La Molina. Taxonomic identification Collected individuals were identified in the laboratory using identification keys, with the support of specialists and by comparison with samples from the collection of the Klaus Raven Büller Entomology Museum of the Universidad Nacional Agraria La Molina. These were counted and evaluated for class, order, family, genus and/ or, in some cases, due to its abundance and/or importance, even species. Results During the entire evaluation period, 22,822 individuals were recorded in 5 classes, 15 orders and 28 families. The arthropods identified and counted are shown in Table 1. Classes represented included Chilopoda, Arachnida, Malacostraca, Collembola and Insecta. In descending order of number of individuals counted, the class Collembola was the most abundant (18,592), followed by Insecta (2,161), Malacostraca, Arachnida and Chilopoda. With respect to the number of morphospecies, the class Insecta was the most predominant, followed by the classes Arachnida, Collembola, Chilopoda and Malacostraca (Fig. 1). CLASS INSECTA 2161 CLASS COLLEMBOLA 18592 Order Coleoptera 357 Order Entomobryomorpha 18499 Family Carabidae 210 Family Entomobryidae 18499 Blennidus peruvianus (Dejean, 1828) 190 Seira sp. Calleida sp. 1 Lepidocyrtus sp. Carab1. sp. 1 Entomobrya sp. Carab2. sp. 5 Order Poduromorpha 53 Tetracha chilensis (Laporte, 1834) 4 Family Brachystomellidae 53 Tetragonoderus sp2. 9 Brachystomella sp. Family Elateridae 3 Order Symphypleona 40 Conoderus sp. 1 Family Bourletiellidae 40 Heteroderes sp. 2 Rastriopes sp. Family Scarabaeidae 8 Aphodius sp. 3 Ataenius sp. 2 CLASS MALACOSTRACA 1124 Paranomala undulata (Melsheimer, 1845) 3 Order Isopoda 1124 Family Staphylinidae 54 Family Porcellionidae 1124 Subfamily Aleocharinae 35 Porcellio laevis (Latreille 1804) (adults) 377 Aleoc. sp1. 25 Porcellio laevis (Latreille 1804) (nymphs) 747 Aleoc. sp2. 1 Aleoc. sp3. 7 Table 1: Morphospecies of soil arthropods captured with pitfall traps in sweetpotato from February to August 2017 Figure 1. Number of individuals and morphospecies (percentages) by Arthropod class in sweetpotato from February to August 2017, in Lima, Peru Chilopoda Arachnida Malacostraca Collembola Insecta % Individuals 0.07 4.06 4.93 81.47 9.47 % Morphospecies 3.75 33.75 1.25 3.75 57.5 0 10 20 30 40 50 60 70 80 90 P e r c e n t a g e ( % ) Soil arthropods associated with sweetpotato crop (Ipomoea batata L.) in La Molina, Lima, Peru January - April 2020 4 Aleoc. sp4. 1 CLASS ARACHNIDA 928 Aleoc. sp5. 1 Subclass Scorpiones 5 Subfamily Oxytelinae 1 Subclass Acari 267 Oxyt. sp1. 1 Order Mesostigmata 1 Subfamily Paederinae 6 Mesostigmata1 1 Paederus sp. 4 Order Oribatida 100 Paederi. sp1. 2 Oribatida1 100 Subfamily Staphylininae 11 Order Prostigmata 166 Platydracus notatus 5 Prostigmata1 77 Staphy. sp1. 2 Prostigmata2 89 Staphy. sp2. 4 Order Aranea 656 Staphylinidae1 1 Family Gnaphosidae 216 Family Tenebrionidae 82 Family Linyphiidae 71 Blapstinus cisteloides (Erichson, 1847) 17 Family Lycosidae 54 Blapstinus holosericius (Laporte, 1840) 48 Family Mysmenidae 1 Epitragopsis olivaceus (Erichson, 1847) 2 Family Oxyopidae 7 Parepitragus pulverulentus (Erichson, 1847) 5 Family Salticidae 1 Order Hymenoptera 383 Family Scytodidae 11 Family Formicidae 119 Family Sicariidae 1 Dolichoderinae 34 Family Theridiidae 289 Linepithema sp. 34 Family Thomisidae 3 Formicinae 18 Family Trachelidae 2 Brachymyrmex sp. 18 Myrmicinae 12 Solenopsis sp. 12 CLASS CHILOPODA 17 MorfoL1 sp. 1 Order Geophilomorpha 6 MorfoL2 sp. 1 Family Geophilidae 6 MorfoL3 sp. 2 Geophilidae1 3 MorfoL4 sp. 1 Geophilidae2 3 MorfoL5 sp. 3 Order Lithobiomorpha 11 MorfoL6 sp. 43 Family Henicopidae 11 MorfoL7 sp. 2 MorfoL8 sp. 2 Family Scelionidae 264 Baeus sp. 251 Trimorus sp. 13 Order Orthoptera 1396 Family Acrididae 3 Family Gryllidae 1393 Gryllus sp. adult 564 Gryllus sp. nymph 829 Order Dermaptera 24 Family Anisolabididae 24 Euborellia annulipes (Lucas, HF, 1847) 24 Order Blattodea 1 Family Blattellidae 1 TOTAL 22822 Livia-Tacza, C.; Sánchez, G. Peruvian Journal of Agronomy 4(1): 1-9 (2020) 5 Classes of arthropods that were recorded consistently throughout the evaluation period were Collembola, Insecta, Malacostraca and Arachnida. Class Collembola A total of 18,592 individuals were recorded throughout the evaluation belonging to the orders Entomobryomorpha, Poduromorpha and Symphypleona according to the taxonomic classification of Bellinger et al. (2012). Entomobryomorpha was the most abundant with 99.5%, followed by Poduromorpha with 0.3% and Symphypleona with 0.2%. From the order Entomobryomorpha, 18,499 individuals of the family Entomobryidae were identified, among which were the genera Seira sp., Lepidocyrtus sp. and Entomobrya sp.; from the order Poduromorpha, 53 individuals of the genus Brachystomella sp. of the family Brachystomellidae; and from the order Symphypleona, 40 individuals of the genus Rastriopes sp. of the family Bourletiellidae. The Bourletiellidae (Symphypleona) and Brachystomellidae (Poduromorpha) were collected on 10 evaluation dates. However, neither family was consistently captured, and on several evaluation dates, they were not recorded at all. Conversely, the Entomobryidae (Entomobryomorpha) were the most abundant and constant throughout the evaluation period. Figure 2 illustrates that during the period of vegetative development fewer individuals were collected compared to the period of root filling. Irrigation and weeding may have influenced the decrease in the number of individuals registered in June (928 individuals) and July (642 individuals), respectively. The highest number of recorded individuals occurred on May 12th (1,699) and June 23rd (1,702). Class Insecta Of this class, 2,161 individuals were collected throughout the evaluation, among which individuals of the order Orthoptera (64.6%), Coleoptera (17.72%), Hymenoptera (16.52%), Dermaptera and Blattodea were identified, the first three being more abundant (Fig. 3). From the order Orthoptera, Gryllus spp. was the morphospecies recorded in greater abundance at both adult (564 individuals) and nymphal (829) forms. Figure 4 illustrates, in adults, a decrease in the number of individuals recorded in the evaluation of May 26th, which likely may have been due to irrigation realised on May 21st. Likewise, weeding and irrigation could have affected the capture of these individuals during subsequent evaluations. With respect to the nymphs, 135 individuals were collected on May 19th, and irrigation occurred on May 21st. Furthermore, adult individuals collected likely decreased close to harvest. Given the previous results with the adults collected, the number of individuals was expected to decrease in the subsequent evaluation. However, agricultural practices performed before the evaluation of June 16th (121 individuals) did not seem to have much influence. It could not be determined if weeding influenced the number of nymphs collected. From the order Coleoptera, the families Carabidae, Elateridae, Scarabaeidae, Staphylinidae and Tenebrionidae were recorded. The family Carabidae was the most Figure 2: Seasonal occurrence of Entomobryidae (Order Entomobryomorpha) captured in sweetpotato from February to August 2017, in Lima, Peru. 64.6 1.11 0.05 16.52 17.72 Orthoptera Dermaptera Blattodea Coleoptera Hymenoptera Figure 3: Percentage of Orders of the Class Insecta registered in the sweetpotato from February to August 2017, in Lima, Peru. Figure 4: Seasonal occurrence of Gryllus spp. (Orthoptera: Gryllidae) captured in sweetpotato from February to August 2017, in Lima, Peru.. Soil arthropods associated with sweetpotato crop (Ipomoea batata L.) in La Molina, Lima, Peru January - April 2020 6 abundant with 210 individuals in total, followed by Tenebrionidae (82), Staphylinidae (54), Scarabaeidae (8) and Elateridae with 3 individuals (Fig. 5). However, with respect to the number of morphospecies registered, the family Staphylinidae was predominant. Blennidus peruvianus (family Carabidae) was the most abundant species, and its presence was almost constant throughout the evaluation period. Figure 6 illustrates how the different agricultural practices influence collection rate. Within the order Hymenoptera, Baeus sp. was the most abundant genus. In Figure 7, the ascending presence can be observed from June 9th (1 individual) to the last evaluation date, having the highest record on July 28th with 78 individuals. Class Malacostraca Throughout the evaluation, 1,124 individuals belonging to the Porcellio laevis Latreille 1804 species (order Isopoda: family Porcellionidae) were counted. Individuals in adult and juvenile stages were registered with juveniles (747 individuals) more abundant than adults (377 individuals). Figure 8 shows the increase in the population of Porcellio adults during the first three evaluations. As with other species, the cultivation practices and field management seemed to have strong influence on the number of individuals captured during each collection. Regarding juveniles, the juvenile curve had a tendency almost similar to that of adults; however, the number of juveniles captured in a given evaluation was usually higher. Class Arachnida Of this class, 928 individuals were registered throughout the evaluation, among which subclasses Acari and Scorpiones from the order Aranea were identified. The order Aranea was the most abundant with 656 individuals and, in turn, the one that presented the highest number of morphospecies (Fig. 9). Within the order Aranea, 11 families were identified: Gnaphosidae, Linyphiidae, Lycosidae, Mysmenidae, Oxyopidae, Salticidae, Scytodidae, Sicariidae, Theridiidae, Thomisidae and Trachelidae. The most abundant families were Gnaphosidae and Theridiidae. In the subclass Acari, the order Oribatida predominates. Figure 5: Percentage of individuals and morphospecies of the families within the Order Coleoptera registered in sweetpotato from February to August 2017, in Lima, Peru. Figure 6: Seasonal occurrence of Blennidus peruvianus (Dejean, 1828) (Coleoptera: Carabidae) in sweetpotato from February to August 2017, in Lima, Peru. Figure 7: Seasonal occurrence of Baeus sp. (Hymenoptera: Scelionidae) in sweetpotato from February to August 2017, in Lima, Peru. Figure 8: Seasonal occurrence of Porcellio laevis Latreille 1804 (Porcellionidae) captured in sweetpotato from February to August 2017, in Lima, Peru.. 0 10 20 30 40 50 60 70 Carabidae Elateridae Scarabaeidae Staphylinidae Tenebrionidae P e rc e n ta g e ( % ) Families of Order Coleoptera % Individuals % Morphospecies 0 20 40 60 80 100 120 3 -F 1 0 -F 1 7 -F 2 4 -F 3 -M 1 0 -M 1 7 -M 3 1 -M 7 -A 1 4 -A 2 1 -A 2 8 -A 5 -M y 1 2 -M y 1 9 -M y 2 6 -M y 2 -J n 9 -J n 1 6 -J n 2 3 -J n 3 0 -J n 7 -J L 1 4 -J L 2 1 -J L 2 8 -J L 4 -A g 1 1 -A g N º IN D IV ID U A LS / 6 P IT F A LL T R A P S EVALUATION DATE Adult Nymph Vegetative development Root filling period Beginning Ending Irrigation Fertilization, earth up Weeded Livia-Tacza, C.; Sánchez, G. Peruvian Journal of Agronomy 4(1): 1-9 (2020) 7 Discussion Some of the agricultural practices performed in the sweetpotato crop likely influenced the dynamics of the different arthropods identified due to the alteration of habitats that it generates. The field was subjected to practices such as fertilisation, cultivation, harvesting, hilling, irrigation and manual weeding, but not pesticide applications which should allow for a large number of arthropods to establish in the crop. Class Collembola Individuals within the class Collembola (Entomobryidae) were the most abundant. In a study carried out in Cañete, another town in the region Costa, Rondón (1999) recorded a large number of individuals of this class, registering 38,197 individuals, in sweetpotato. In the present investigation of the three families identified, Entomobryidae predominated, with the genera Seira sp., Lepidocyrtus sp. and Entomobrya sp. During the period of crop vegetative growth, a small number of individuals were recorded. In this period, the soil was more exposed to the environment. During the period of starch accumulation in the root closer to harvest, the plants almost entirely covered the soil, and the number of individuals captured began to increase. Based on capture data, lush vegetation conditions generate a favourable microclimate for the establishment of individuals in this group. Class Insecta Of this class, only morphospecies predominantly living in the soil were considered. Hence, within this group, the families Gryllidae and Acrididae of the order Orthoptera; Anisolabididae of Dermaptera; Blattellidae of Blattodea; Carabidae, Staphylinidae, Elateridae, Scarabaeidae and Tenebrionidae of Coleoptera; and Formicidae and Scelionidae of Hymenoptera were registered. From the order Orthoptera, more nymphs than adults were captured. The evaluation period was carried out between the months of February and July, months that covered the entire summer, autumn and early winter seasons at the evaluation site. The time of the year was likely favourable for the development of Gryllus spp., and the number of individuals recorded increased until the onset of autumn and early winter. Furthermore, minimum soil disturbance from reduced agricultural practices and not applying pesticides likely allowed for a greater number of individuals to establish. It should also be noted that the largest record of individuals, both adult and nymphal, occurred when the plants almost completely covered the soil, which provided refuge area, food sources and favourable oviposition conditions. Due to the greater number of individuals in the nymphal state registered in this period, conditions favouring reproduction likely occurred, especially for oviposition, which permits a greater number of generations to establish. From Hymenoptera, members of the family Formicidae were considered due to their characteristic of mainly establishing their nests in different types of soil (Kaspari 2003). In addition, individuals from the family Scelionidae were also considered due to the behaviour of the identified morphospecies. The most representative and abundant individuals were females of the genus Baeus sp. and endoparasitoids of spider Ootheques (Araujo et al., 2013). Baeus females are small ‘wingless’ wasps with a highly fusiform body (Stevens & Austin, 2007). Because of these characteristics, they are frequently found in the soil. Loiácono and Margaría (2004) indicate that they parasitise eggs of some spider species of the family Theridiidae and Araneidae. The fact that there is a great abundance and diversity of spiders in this crop probably allowed Baeus sp. to become well established. Of Coleoptera, B. peruvianus (family Carabidae) was the most abundant. The number of individuals captured markedly increased during the latter half of the crop production. Plants should reach an adequate size to generate a favourable microclimate and facilitate the establishment of a greater number of arthropods, which then provides ample food source for B. peruvianus. Furthermore, the microclimate may have also been favourable for its establishment. However, research on the developmental cycle and/or any description on a favourable temperature of this species is lacking. Class Malacostraca Porcellio laevis was registered at both adult and juvenile stages, and the juveniles were more abundant than the adults. The conditions of the sweetpotato agroecosystem were likely favourable, allowing its establishment. The presence of these individuals is important, because, as noted by Leistikow and Wägele (1999), they are involved in the synthesis of nutrients and in maintaining energy flow in the soil (biochemical cycles). Order Aranea Subclass Acari Subclass Scorpiones % Individuals 69.57 29.9 0.53 % Morphospecies 77.8 14.8 7.4 0 10 20 30 40 50 60 70 80 90 P e rc e n ta g e ( % ) Figure 9: Percentage of Orders of the Class Arachnida registered in the sweetpotato from February to August 2017, in Lima, Peru. Soil arthropods associated with sweetpotato crop (Ipomoea batata L.) in La Molina, Lima, Peru January - April 2020 8 Class Arachnida The order Aranea was abundant and diverse with Zelotes laetus (family Gnaphosidae) and Theridion volubile (family Theridiidae) as the most frequently occurring species; individuals of the subclass Scorpiones and Acari were also recorded. Coddington et al. (2004) noted that it is the only taxon entirely composed of predators. As with the other groups of arthropods, the field conditions with reduced agricultural practices and lack of pesticide application likely allowed for the survival of a large number and diversity of individuals of this class. Class Chilopoda Chilopoda are considered important terrestrial predators (Prado-Sepúlveda et al., 2016). However, the number of individuals captured was the lowest with respect to the other arthropods. It is unknown whether conditions were favourable or not for these individuals, but it is likely that there are other more efficient capture methods for these individuals. Conclusion In this study, the classes Collembola, Insecta, Malacostraca, Arachnida and Chilopoda were recorded. The class Collembola had the greatest number of individuals, and the class Insecta had the most identified morphospecies. Seira sp., Lepidocyrtus sp. and Entomobrya sp. (order Entomobryomorpha: family Entomobryidae) were the genera belonging to the most abundant family registered in the class Collembola. Gryllus sp. (Orthoptera: Gryllidae), Baeus sp. (Hymenoptera: Scelionidae) and B. peruvianus (Coleoptera: Carabidae) were the most abundant morphospecies of the class Insecta. In Malacostraca, P. laevis (Isopoda: Porcellionidae) was the only registered species. Zelotes laetus (family Gnaphosidae) and T. volubile (family Theridiidae) were the most abundant morphospecies in the class Arachnida. Geophilidae (order Geophilomorpha) and Henicopidae (order Lithobiomorpha) were the only families registered in the class Chilopoda. Through capturing, identifying and cataloguing the rich diversity of soil arthropods that occur in sweetpotato agroecosystems of Peru, fundamental knowledge is established. The specimens collected and preserved may be of use for future research not only taxonomically but also as a snapshot of the number of species occurring in this region at this time. Acknowledgments The authors would like to thank Dr. José Palacios Vargas, for the identification of the morphospecies of the class Collembola. To Bach. Manuel Andia Navarro, for the identification of spider morphospecies. To the Biol., Mg. Sc. 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