First Record of Pulvinaria urbicola (Hemiptera: Coccomorpha: Coccidae) on Dysphania ambrosioides (Amaranthaceae) Associated with Ant and Parasitoid in Guerrero, Mexico¹

The order Hemiptera includes of a variety of insects that have a detrimental effect on the plant epazote Dysphania ambrosioides ([L.] Mosyakin and Clemants) (Amaranthaceae), principally several species from the suborders Sternorrhyncha and Auchenorrhyncha. These insects maintain various biotic interactions with ants (Hymenoptera: Formicidae), forming mutualistic relationships on the basis of trophobiosis (Delabie and Fernández 2003, Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Bogotá, Colombia). Also, there is a wide range of entomophages associated with the soft scale, acting as predators and parasitoids. The representative families of parasitoids are Aphelinidae, Encyrtidae, Pteromalidae, and Eulophidae (Hymenoptera) (Ben-Dov and Hodgs 1997, World Crop Pests, Elsevier, Amsterdam, 7B, 442 p.; García et al. 2016, ScaleNet: A literature-based model of scale insect biology and systematics, http://scalenet.info).

Between February 2024 and March 2024, the soft scales, ants, and parasitoids associated with Dysphania ambrosioides were collected from a home garden in the municipality of Petatlán in the state of Guerrero, Mexico (17°32′50.0″N, 101°16′31.0″W, at an elevation of 41 m). The adult scales were mounted using the methodology of Kosztarab (1963, Bull. Ohio Biol. Surv. 2: 1–120) and identified with the taxonomic keys of Williams and Watson (1990, The Scale Insects of the Tropical South Pacific Region, Part 3: The Soft Scales (Coccidae) and Other Families, CAB International, Wallingford, Oxon, United Kingdom) and Hodgson (1994, The Scale Insect Family Coccidae: An Identification Manual to Genera, CAB International, Wallingford, Oxon, United Kingdom). The ants were identified using the taxonomic keys of Fernández (2003, Instituto de Investigación de Recursos Biológicos Alexander von Humboldt. Vol. 26. Bogotá, Colombia. 398 pp.) and the AntWiki database (2022, The Ants. Key to Dorymyrmex of SE United States Workers, https://www.antwiki.org/wiki/Key_to_Dorymyrmex_of_SE_United_States_workers). The parasitoids were identified using the procedure outlined by Myartseva et al. (2011, Acta Zool. Mex. 27: 583–590) and the keys of Fernández and Sharkey (2006, Sociedad Colombiana de Entomología y Universidad Nacional de Colombia, Editora Guadalupe Ltda, Bogotá, Colombia) and Myartseva et al. (2012, Serie avispas parasíticas de plagas y otros insectos, Departamento de Fomento Editorial de la Univ. Autonoma de Tamaulipas (UAT), Ciudad, Victoria, Tamaulipas, México).

The soft scale Pulvinaria urbicola (Cockerell) (Hemiptera: Coccoidea) was identified as the species associated with the epazote plant (Fig. 1A). According to García et al. (2016), P. urbicola infests hosts in 45 botanical families and 91 genera worldwide. Dorymyrmex smithi (Cole) (Hymenoptera: Formicidae) was also recorded as the ant associated with the P. urbicola scale colony (Fig. 1B). To the best of our knowledge, no such association has been documented at the global scale. In Mexico, this species of ant is associated with the papaya mealybug, Paracoccus marginatus (Williams & Granara de Willink) and the citrus snow scale, Unaspis citri (Comstock), a pest observed on grapefruit (Citrus paradisi Macfad.) (Hernández 2017, Escamas (Hemiptera: Coccoidea), sus enemigos naturales y hormigas asociadas con frutales de Guerrero. PhD Tesis. Colegio de Postgraduados, Montecillo-Texcoco, Estado de México, México). The natural enemy Coccophagus lycimnia (Walker) (Hymenoptera: Aphelinidae) (Fig. 1C) was identified as the parasitoid of the soft scale P. urbicola. Worldwide, 138 species of coccoids hosting C. lycimnia have been recorded (Noyes 2019, Universal Chalcidoidea Database, https://www.nhm.ac.uk/ourscience/data/chalcidoids/database/detail.dsml?). This parasitoid was introduced to Mexico in 1954 to control Saissetia oleae (Olivier) and became established in the states of Chihuahua, Durango, Guanajuato, Guerrero, Morelos, Sonora, Tamaulipas, and Veracruz, parasitizing various soft scales such as Philephedra lutea (Cockerell), Coccus hesperidum Linnaeus, Saissetia spp., and Pulvinaria spp. (Myartseva et al. 2012). This is the first time that the association of the ant Dorymyrmex smithi with a soft scale species has been reported.

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