Hyperparasitoids (Hymenoptera: Encyrtidae and Signiphoridae) of Hypogeococcus spp. mealybugs (Hemiptera: Pseudococcidae) in Argentina and Paraguay

Authors: TRIAPITSYN, SERGUEL - University Of California; AGUIRRE, MARIA - Fuedei; LOGARZO, GUILLERMO - Fuedei; Hight, Stephen

Submitted to: Acta zoologica Academiae Scientiarum Hungaricae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2020
Publication Date: 12/7/2020
Citation: Triapitsyn, S.V., Aguirre, M.B., Logarzo, G.A., Hight, S.D. 2020. Hyperparasitoids (Hymenoptera: Encyrtidae and Signiphoridae) of Hypogeococcus spp. mealybugs (Hemiptera: Pseudococcidae) in Argentina and Paraguay. Acta Zoologica Lilloana. 64(2):76-93. https://doi.org/10.30550/j.azl/2020.64.2/5.
DOI: https://doi.org/10.30550/j.azl/2020.64.2/5

Interpretive Summary: The South American cactus-feeding mealybug was accidently introduced into Puerto Rico and is devastating native cactus species. Two parasitoid wasps that attack this mealybug in South America are being evaluated in a Puerto Rican quarantine facility to ensure they can be safely released into the environment as control agents. However, hyperparasitoids (parasitizing insects that specialize on other parasitic insects) can disrupt the success of controlling the pest by reducing the population of the deployed biocontrol parasitoid. To identify hyperparasitoids of the two biocontrol parasitoids for the South American cactus-feeding mealybug, surveys, collections, and identifications were made in Argentina and Paraguay by scientists with USDA, Agricultural Research Service, Center for Medical, Agricultural and Veterinary Entomology, Tallahassee, Florida, in collaboration with the University of California and the Argentine Foundation for the Study of Invasive Species. Seven species of hyperparasitoids were collected and identified in Argentina and Paraguay. Taxonomic review validated their characterization and clarified their relationship with biocontrol parasitoids. Central to determining the importance that a biocontrol agent may have on its host in the country of origin as well as its introduced area is a thorough understanding of the role played by hyperparasitoids that attack the biocontrol agent. This study provided identities and information on hyperparasitoids in the country of origin as a first step in assessing their potential negative impacts on the biocontrol agents.

Technical Abstract: Identified and reviewed taxonomically are the hyperparasitoids (Hymenoptera: Chalcidoidea) in Argentina and Paraguay associated with Hypogeococcus spp. (Hemiptera: Pseudococcidae), mealybugs that feed on various native cacti (Cactaceae) as well as some Amaranthaceae and Portulacaceae. The following genera and species were collected and reared in the course of surveys conducted in Argentina during 2010–2019 and in Paraguay during 2016–2019: Chartocerus argentinus (Brèthes) stat. rev. [(reinstated as a valid species from the previous synonymy with Chartocerus niger (Ashmead)]) and Chartocerus axillaris De Santis from Argentina (Signiphoridae), an undescribed Cheiloneurus sp. from Paraguay and Prochiloneurus argentinensis (De Santis) from Argentina (Encyrtidae). These are secondary parasitoids via Encyrtidae primary parasitoids of Hypogeococcus spp., which are candidate biological control agents against a Hypogeococcus sp. (commonly called the Harrisia cactus mealybug) that is devastatinges the native columnar cacti in Puerto Rico. The previously unknown male of Chartocerus argentinus is described, and a lectotype is designated for Signiphora argentina Brèthes. Taxonomic notes are provided for Ablerus platensis (Brèthes) (Hymenoptera: Azotidae), for which a lectotype is designated (for Dimacrocerus platensis Brèthes); it is newly recorded from Paraguay. Hyperparasitoids can be detrimental to biological control programs, but their impact has been often beeneither unknown or underestimated. Taxonomic identification of the hyperparasitoids is the first step in assessing theis potential negative impact to the natural control of Hypogeococcus spp. in South America.