Ecological niche modeling to calculate ideal sites to introduce a natural enemy: The case of Apanteles opuntiarum (Hymenoptera: Braconidae) to control Cactoblastis cactorum (Lepidoptera: Pyralidae) in North America

Authors: PEREZ-DE LA O, NIDIA BELIGCA - Autonomous University Of Chiapas; SPINOSA-ZARAGOZA, SAUL - Autonomous University Of Chiapas; LOPEZ-MARTINEZ, VICTOR - Autonomous University Of The State Of Morelos; Hight, Stephen; VARONE, LAURA - Fuedei

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/17/2020
Publication Date: 7/19/2020
Citation: Perez-De La O, N., Spinosa-Zaragoza, S., Lopez-Martinez, V., Hight, S.D., Varone, L. 2020. Ecological niche modeling to calculate ideal sites to introduce a natural enemy: The case of Apanteles opuntiarum (Hymenoptera: Braconidae) to control Cactoblastis cactorum (Lepidoptera: Pyralidae) in North America. Insects. 11(7):454. https://doi.org/10.3390/insects11070454.
DOI: https://doi.org/10.3390/insects11070454

Interpretive Summary: Biological control agents are host specific, non-native, natural enemies intentionally introduced into a new region to control a pest. To be successful, the agents must have the capacity to establish, survive, and multiply under their new climatic conditions. Ecological niche modeling is a tool used for predicting specific geographic areas where the environmental conditions are suitable for organisms. Scientists at USDA, Agricultural Research Service, Center for Medical, Agricultural and Veterinary Entomology, Tallahassee, Florida, collaborated with scientists at Universities in Mexico and the Argentine Foundation for the Study of Invasive Species to calculate ecological niche models of the invasive cactus pest Argentine cactus moth, established in the USA, and its potential biological control agent, a braconid wasp from Argentina. Models were created that defined regions of environmental suitability for each insect and determined where both insects shared the same niche and would geographically overlap. With this knowledge, liberations of the braconid wasp on the cactus moth will be focused at locations where both insects are expected to survive, increasing the likelihood of the wasps’ establishment, dispersal, and success in managing this invasive cactus pest.

Technical Abstract: The cactus moth, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae), is an invasive species in North America where it threatens Opuntia native populations. The insect is expanding its distribution along the United States Gulf Coast. In the search for alternative strategies to reduce its impact, the introduction of a natural enemy, Apanteles opuntiarum Martínez and Berta (Hymenoptera: Braconidae), is being pursued as a biological control option. To identify promising areas to intentionally introduce A. opuntiarum for the control of C. cactorum, we estimated the overlap of fundamental ecological niches of the two species to predict their common geographic distributions using the BAM diagram. Models were based on native distributional data for both species, 19 bioclimatic variables, and the Maxent algorithm to calculate the environmental suitability of both species in North America. The environmental suitability of C. cactorum in North America was projected from Florida to Texas (United States) along the Gulf coastal areas, reaching Mexico in northern regions. Apanteles opuntiarum environmental suitability showed a substantial similarity with the calculations for C. cactorum in the United States. Intentional introductions of A. opuntiarum in the actual distribution areas of the cactus moth are predicted to be successful; A. opuntiarum will find its host in an environment conducive to its survival and dispersal.