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Javier E. Mercado

Javier Mercado

Research Entomologist

240 West Prospect Road
Fort Collins, CO 80526-2098
Contact Javier E. Mercado

Current Research

I study complex interactions between mountain pine beetle and the associated organisms it carries. Attacking mountain pine beetles carry several organisms (called phoretic) such as mites, nematodes, fungi, and bacteria. During their establishment into a tree, some of these organisms may affect mountain pine beetle success which ultimately may influence to the effect of this important disturbance agent on trees. My current research will allow a better understanding of the different phoretic organisms carried by the beetle across multiple hosts and the landscape and their effect on the fitness of this ecologically important forest insect.

Research Interests

I am exploring the relationships of phoretic organisms in other ecological important bark beetles in western forests, and how their relationship varies on different populations of the insects. Other topics of interests include: investigating the effects of forest insect disturbances on western forest dynamics. I consider forest insects to be an instrumental part of healthy forests and plan to investigate ways of utilizing them to help manage the next forest that has resulted from current and past decades of disturbances.

Why This Research is Important

My current research is important to increase our understanding about strategies used by mountain pine beetle populations to move across different tree hosts and landscapes. I want to help understand whether phoretic organisms facilitate or hamper these movements. My findings can serve as a venue for developing new ways of controlling insects that are affecting ecologically and economically important areas. My future research is needed since we need a more comprehensive understanding of phoretic associates of our important forest insects, since we could derive a better understanding about unexplored regulatory mechanisms. It is also very important to increase our understanding about the effects of ecologically important forest insects on forest dynamics since land administrators will need to manage increasing areas of disturbance where current management practices might be too expensive or impractical to use and new approaches are desired. Altogether, we are faced with the challenge of managing a developing forest that needs to be more resilient not only to insects but to a potentially changing climate, I hope to bring new ideas and approaches to improve the health of our forests and contribute to improving the way we do it.

Featured Publications


Malesky, Danielle M.; Bentz, Barbara J.; Brown, Gary R.; Brunelle, Andrea R.; Buffington, John M.; Chappell, Linda M.; ; Guyon, John C. II; Jorgensen, Carl L.; Loehman, Rachel A.; Lowrey, Laura L.; Lynch, Ann M.; Matyjasik, Marek; McMillin, Joel D.; Mercado, Javier E.; Morris, Jesse L.; Negron, Jose; Padgett, Wayne G.; Progar, Robert A.; Randall, Carol B., 2018. Effects of climate change on ecological disturbances [Chapter 8]
Mercado, Javier E.; Ortiz-Santana, Beatriz; Kay, Shannon L., 2018. Fungal frequency and mite load trends interact with a declining mountain pine beetle population
Martins, Thaynara S.; Moreira, Felipe F. F.; Mercado, Javier E.; Santiago-Blay, Jorge A., 2016. Lecto- and Paralectotype Designations and Redescription of Arachnocoris alboannulatus Costa Lima, 1927 (Hemiptera: Heteroptera: Nabidae)
Mercado, Javier E.; Hofstetter, Richard W.; Reboletti, Danielle M.; Negron, Jose, 2014. Phoretic symbionts of the mountain pine beetle (Dendroctonus ponderosae Hopkins)
Close view of sap tubes on pine bark, evidence of Dendroctonus attacking lodgepole pine
Lodgepole pine growing above 9,000 feet have been under attack by a Dendroctonus insect other than the mountain pine beetle for several years. Trees are not dying as fast as expected. Identifying this beetle species required a new approach.
The mountain pine beetle has its very own microbiome, or community of organism that share its space. Scientists studied the fungal and mite aspects of the mountain pine beetle microbiome as the beetles attacked host trees ranging in elevations of 1800 to 3000 meters in the Roosevelt Forest in Colorado. Gaining a better understanding of the mountain pine beetle microbiome at different beetle population levels will help scientists understand the factors affecting fluctuations in beetle populations.  
Image 1. A group of Arachnocoris feeding on spider trap prey.
Worldwide insect diversity is underestimated due in part to decreasing taxonomic expertise. The genus Arachnocoris represents fascinating, but poorly-studied insects that evolved to live in the dangerous ecological niche of a spiders’ web. An RMRS scientist has discovered two new species of bugs.  
There is minimal knowledge of phoretic processes (where one species transports another) of mountain pine beetles. This is important so we can later compare it to endemic populations, which might help us understand potential causes of fluctuations in the beetle populations. Researchers found that like the beetles, phoretic mites are important vectors of pathogenic blue-stain fungi in northern Colorado. These findings set a base line of information of the blue-stain fungi and its carriers present during a mountain pine beetle epidemic.
This project focused on understanding the fungal biome of an endemic level population of Jeffrey’s pine beetle (JPB) in northern California. The authors of this study found a fungus on the JPB, which is often associated with mountain pine beetles (a species that is closely related to JPB). The researchers theorize that the fungi associated with the beetle could determine if the population of the beetle remains at an endemic (normal) level or rises to an epidemic (outbreak) level.  
Since 1996, bark beetles and fires have affected 155 million forested acres across the West. Homogenous forest conditions resulting from the widespread outbreak could set the stage for similar events about 80 years from now. New management techniques are needed to create more resilient future forests. RMRS scientist explores the controlled use of native forest insects to alter forest structure and promote more resilient forest conditions.
Factors influencing population dynamics of the mountain pine beetle are not well understood. Researchers are studying the variation of mite and fungal communities on different population stages of the mountain pine beetle throughout the western United States. This research seeks to determine if more subtle environmental fluctuations in the beetle’s associates (e.g., mites) and symbionts (e.g., blue-stain fungi) may drive indirect population changes in the beetles.

RMRS Science Program Areas: 
Forest and Woodland Ecosystems