Red-Shouldered Bug

Question:

How do you feel about those bugs that hang around golden rain trees?

- Sandoval County

Answer:

I don’t mind them! Red-shouldered or golden rain tree bugs (Jadera haematoloma) are some of the earliest bugs I see in my garden, and they remind me that spring is here, even while I’m still bundled up.

Every year I see these little characters under my golden rain tree in Albuquerque. Photo credit: Bethany Abrahamson.

In fact, I started this article thinking they were boxelder bugs, but the two are in different genera. Boxelder bugs and red-shouldered bugs have pretty similar life habits and effects on the landscape.

So that you can tell them apart: Both boxelder bugs and red-shouldered bugs are red and black with red eyes, but boxelder bugs are found on boxelder (Acer negundo), maple and ash, and have more red in their coloration. Red-shouldered bugs only have red shoulders, and are found on or near golden rain trees (Koelreuteria paniculata). They both can leave a red stain when squished, but compared to boxelder bugs, they are less foul-smelling.

Here's a size comparison of some Jadera nymphs. Photo credit: Marisa Thompson.

I’m probably so tolerant of these bugs because I’ve never had them get inside my home. Boxelder bugs seek warm places to shelter, and have been known to move inside homes for the winter. Red-shouldered bugs may do this as well, though not as much. The best way to get rid of them if you see a lot indoors is to use a vacuum. Check your home for any places where they might be getting in—broken window screens, gaps at the bottoms of doors, etc., which is good practice for excluding other unwelcome guests. You can sweep up those golden rain tree seeds if there is concern about finding them outside in certain areas such as patios, but it really is unnecessary to apply any kind of pesticide to control these insects. They don’t harm the plants they feed on, and don’t bite.

If you let them be, you can observe interesting behaviors such as mating:

Photo credit: Rebekah D. Wallace, University of Georgia, Bugwood.org, CC BY-NC 3.0 US.

...And congregating (a little scary, but harmless):

Photo credit: Judy Gallagher, Wikimedia Commons, CC BY-NC 3.0 US.

Adored by red-shouldered bugs everywhere, the golden rain tree (this one planted at the University of New Mexico):

Golden rain trees grow well in central New Mexico, as they're known to be fairly drought- and heat-tolerant, though some may consider the fruit to be a potential problem—however I love the papery lanterns that this tree produces.

Photo credit: Bethany Abrahamson.

Sources:

• Red Shouldered Bug - Baker, J. PDIC Factsheets. North Carolina State University, Cooperative Extension. (2013, reviewed 2023).
• Boxelder, Red-Shouldered and Scentless Plant Bugs - Missouri Botanical Garden. (n.d., updated 2024).
• Love Story - Mitchell, R. University of Florida Blog, UF/IFAS Extension. (2017).
• Boxelder Bugs - National Pesticide Information Center (NPIC). (2021).
• SWYG March 31, 2007 Article - Smith, C. Southwest Yard and Garden (SWYG). New Mexico State University. (2007).
• Guide H-426: Shade Trees for New Mexico - Smith, C. New Mexico State University. (2009).
• O & T Guide O-4: Boxelder Bugs - Sutherland, C. New Mexico State University. (Oct. 2006).

Bethany Abrahamson is the Cooperative Extension Agriculture Agent for Sandoval County.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

Links:

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook page.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!