Category Archives: ants

Please Don’t Poison Me or Take Away My Food

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Pileated Woodpecker
(Dryocopus pileatus) Pileated Woodpecker
(Dryocopus pileatus) Pileated Woodpecker

This post is for the folks living on San Juan Island and in San Juan County, but also for the wider PNW area.  After seeing multiple posts this morning about Carpenter Ants showing up, and I personally have seen three or four Carpenter Ants in our house this past week (Camponotus vicinus), I felt compelled to do a write-up that can be shared more easily into social media groups and read by those who aren’t on social media sites.

It is the time of year when you may see activity in your own home.  Don’t freak out.  Their appearance does not mean you have an infestation, but if you see one crawling around on the floor or wall, you should use this as a sign to check around your home carefully.  Annual inspections are an important part of caring for your home and investment.

Once upon a time, we found issues in our own home. There were carpenter ants in the wood trim around our skylight. Our roof had been leaking for some time and that rotted the wood. I told my husband one morning that I could HEAR them chewing. I could. They were up there munching away. He got a ladder, removed the wood trim, and then danced like he was at a rave. I’m surprised, and thankful, he didn’t fall off the ladder. The entire colony dumped out onto his head. They were biting him and spraying him with formic acid. Fortunately, I had the shop vac handy. Once we vacuumed them up and he replaced the wood and fixed the roof leak, we have been ant-free (almost 10 years now).

Camponotus vicinus carpenter ant
Camponotus vicinus carpenter ant
Camponotus vicinus carpenter ant
Camponotus vicinus carpenter ant

In your home, I recommend inspecting for water leaks, repairing them, and replacing any rotten or damp wood.  If you have trees or vegetation overhanging and touching your home, trim this back.  Avoid leaving stacks of firewood near or against your home.  Also, avoid mulching near your foundation.  Fix any areas near your yard where water is not draining properly and seeps back towards your foundation . Keep the humidity low in your home, especially in basement areas.  If you can’t do this yourself and you live in San Juan County, I do recommend calling Paul at San Juan Pest Control   (360) 378-2941- who can check all the things I just recommended. In my experience, Paul has been careful about minimizing use of pesticides or baits. Please, please, do not go to the home store and pick your poisons out and apply them yourself. If you won’t consider any alternatives I’ve suggested here, at least get a professional to help you with this.

You might ask, “Why are you so against toxic baits and chemicals?” Well, aside from the dangers of using pesticides in your home for yourself and your pets, they are highly toxic to wildlife. These toxic chemicals or baits go through the food chain, impacting non-target species.

For instance, the diet of our beautiful Pileated Woodpecker species is comprised of 54-60% carpenter ants.  They will be feeding nestlings soon, as will other bird species that utilize ants for food. Applying pesticides can impact these birds directly through the poisons going through the food chain or by removing their food source.  We want to protect our structures, but also need the reminder to protect our avian neighbors.  Just as you don’t want to go hungry and starve, neither do they.

Violet Green Tree Swallow with Camponotus modoc Carpenter Ant

I guess I should go a bit further here in my ecology connection. If we are feeding the birds, why do we need to worry about ants or other bugs in the first place? Bird seed and suet cakes, and even sugar water solution for hummingbirds, provides them with a supplementary food source when they need extra energy. Supplementing with feed can help birds before leaving, or after arriving from a long migration, after a winter season when food sources decline or are scarce or harder to access. Supplementing with feeders can also provide them with extra calories before they begin nesting, or if they are compromised in some other way.

Feeding birds, however, is primarily for our entertainment. We feed them because we appreciate nature and bird watching. Suet, seeds, and sugar water are not their main diet components though. Especially not for baby birds that need protein sources.

Birds need BUGS. Even hummingbirds feed their baby birds bugs. Spiders are a favorite because baby birds need taurine, an amino acid necessary for brain development. Spiders are a source of taurine.

All birds need essential minerals, amino acids, and vitamins that aren’t found in bird seed, suet, and sugars. They will visit sources of sap, nectar, and forage in tree stumps, standing dead snags, under rocks, in the soil, and all through the leaves and twigs of our trees. I’ve seen hummingbirds taking small insects and spiders from beneath the eaves of our home. The “environment,” or what little remains that has not been altered, degraded, or poisoned by humans, is literally the “grocery store” for wildlife. Wildlife, including birds and even other insects or spiders are nature’s best pest control. Let’s make sure we protect them and acknowledge their value in choosing how we live.

References and Further Reading ***noting here that Carpenter Ants also provide valuable pest control for species of insects that defoliate our fruit and forest trees! ***

Akre, R. D., L. D. Hansen, and E. A. Myhre. 1995. My house or yours? The biology of carpenter ants. Am. Entomol. Soc. 41:221–226.

Bull, E. L. 1987. Ecology of the pileated woodpecker in northeastern Oregon. Journal of Wildlife Management 51: 472–481.

Bull, E. L., R. C. Beckwith, and R. S. Holthausen. 1992a. Arthropod diet of pileated woodpeckers in northeastern Oregon. Northwestern Naturalist 73: 42–45.

Bull, E. L., C. G. Parks, and T. R. Torgersen. 1997.  Trees and logs important to wildlife in the Interior Columbia River Basin. U.S. Forest Service General Technical Report PNW-GTR-391, Portland, Oregon, USA.

Campbell, R.W., and T.R.Torgersen.1982. Some effects of predaceous ants on western spruce budworm pupae in north central Washington.
Environ. Entomol. 11:111-114.

Cruz, A., and D.W. Johnston. 1979.  Occurrence and feeding ecology of the common flicker on Grand Cayman Island. Condor 81:370-375. 

Furniss, R. L., and V. M. Carolin. 1977.  Western forest insects. U.S. Forest Service Miscellaneous Publication number 1339, Washington, D.C., USA.

Hansen, L. D., and R. D. Akre. 1985.  Biology of carpenter ants in Washington State (Hymenoptera:Formicidae:Camponotus). Melanderia.  Volume 43. Washington State Entomological Society, Pullman, Washington, USA.

Hansen, L. D., and A. L. Antonelli. 2005.  Carpenter ants: their biology and control. Washington State University Extension Bulletin 0818, Pullman, Washington, USA.

Hansen, L. D., and J. H. Klotz. 2005. Carpenter Ants of the United States and Canada. Ithaca, N.Y.: Cornell University Press.

Mankowski, M. 2001.  Biology of the Carpenter Ants Camponotus vicinus (Mayr) and Camponotus modoc(Wheeler) in Western Oregon.  Ph.D. dissertation, Oregon State University, Corvallis.  

Mannan, R. W. 1984. Summer area requirements of pileated woodpeckers in western Oregon. Wildlife Society Bulletin 12: 265–268.

RALEY, C.M. and AUBRY, K.B. (2006), Foraging Ecology of Pileated Woodpeckers in Coastal Forests of Washington. The Journal of Wildlife Management, 70: 1266-1275. https://doi.org/10.2193/0022-541X(2006)70[1266:FEOPWI]2.0.CO;2

Ramsay, S.L. and Houston, D.C. (2003), Amino acid composition of some woodland arthropods and its implications for breeding tits and other passerines. Ibis, 145: 227-232. https://doi.org/10.1046/j.1474-919X.2003.00133.x

Torgersen, T. R., and E. L. Bull. 1995. Down logs as habitat for forest-dwelling ants—the primary prey of pileated woodpeckers in northeastern Oregon. Northwest Science 69: 294–303.

Torgersen, T.R., R. R. Mason, and H.G. Paul. 1983. Predation on pupae of Douglas-fir tussock moth, Orgyia pseudotsugata (McDunnough) (Lepidoptera: Lymantriidae). Environ. Entomol. 12:1678-1682.

University Of Glasgow. “Super Spiders Make Bolder Birds.” ScienceDaily. ScienceDaily, 29 August 2007. http://www.sciencedaily.com/releases/2007/08/070824220328.htm

Spiny Fungiculturists, a short species profile from my recent trip to Quintana Roo, MX

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Acromyrmex octospinosus scraping something off the railing that led down to the Cenote. I’m not sure what the bird species was in the background. Location: Tulum, Quintana Roo, MX

This is a Neotropical leaf cutter ant, Acromyrmex octospinosus, a taxonomically challenging species complex of fungus farming ants found ranging from Brazil to Northern Mexico, and including Cuba and the Lesser Antilles (Mera-Rodriguez et al.,2025).

I observed more than a few of these while we were visiting in Quintana Roo, MX in late January. This one was on the handrail of the steps leading down to a cenote in a shaded area in Tulum. I also found specimens daily in the swimming pool at the property where we lodged during our stay.

These spiky, dark-red leaf cutter ants practice what is known as fungiculture, meaning they utilize fresh vegetation, including flowers, to grow their obligate fungal symbionts. The spiny projections on the exoskeleton of the ant help it to maneuver vegetative material around on their backs. These fungus-farming ants provide their fungal cultivars with food, dispersal, waste management services, and protection.

This fungus farming practice is extraordinarily sophisticated and the ants’ investment in labor even includes “weeding” their food garden. The ants even have their own sanitizing and pharmacy tools on hand. They have special infrabuccal pockets https://sci-hub.su/10.1016/j.asd.2022.101154 to filter the material they collect for their fungus gardens, screening out spores of fungal contaminants that might interfere with the ants’ specialized garden (Quinlan, 1978). They are also able to produce antimicrobials to protect their fungi from pathogens. The ant farmers utilize the fungi they cultivate as their main food source for themselves and their larvae.

Leaf Cutter Ant in Tulum, MX

I don’t have time to go into an extensive write-up about them, but did link some interesting papers and websites for your review in case you’re interested in learning more.

Thanks for reading! 🙂

References

AntWiki. 2026. Acromyrmex octospinosus. https://www.antwiki.org/wiki/Acromyrmex_octospinosus#Life_History_Traits
Barke, J., Seipke, R. F., Grüschow, S., Heavens, D., Drou, N., Bibb, M. J., … & Hutchings, M. I. 2010. A mixed community of actinomycetes produce multiple antibiotics for the fungus farming ant Acromyrmex octospinosus. BMC biology, 8(1), 109.

iNaturalist. 2026. Acromyrmex. https://www.inaturalist.org/taxa/50162-Acromyrmex#articles-tab

Mera‐Rodríguez, D., Fernández‐Marín, H., & Rabeling, C. 2025. Phylogenomic approach to integrative taxonomy resolves a century‐old taxonomic puzzle and the evolutionary history of the Acromyrmex octospinosus species complex. Systematic Entomology, 50(3), 469-494.

Quinlan, R.J., Cherrett, J.M. 1978. Studies on the role of the infrabuccal pocket of the leaf-cutting ant Acromyrmex octospinosus (Reich) (Hym., Formicidae). Ins. Soc 25, 237–245 . https://doi.org/10.1007/BF02224744

Quinlan, R.J. and Cherrett, J.M. 1978, Aspects of the symbiosis of the leaf-cutting ant Acromyrmex octospinosus (Reich) and its food fungus. Ecological Entomology, 3: 221-230. https://doi.org/10.1111/j.1365-2311.1978.tb00922.x

Therrien, P. 1986. Behavioral ecology of the leaf-cutting ant, Acromyrmex octospinosus (Reich), in Guadeloupe, F.W.I. (T). University of British Columbia. Retrieved from https://open.library.ubc.ca/collections/ubctheses/831/items/1.0097339

Wang, Chu, Alessio Cocco, Chung-Chi Lin, Johan Billen. 2022. Morphology and ultrastructure of the infrabuccal pocket in Strumigenys ants. Arthropod Structure & Development. Volume 68, 101154. ISSN 1467-8039.
https://doi.org/10.1016/j.asd.2022.101154. https://www.sciencedirect.com/science/article/pii/S1467803922000159

Wetterer, James. 1991. Foraging Ecology of the Leaf-Cutting Ant Acromyrmex Octospinosus in a Costa Rican Rain Forest. Psyche. 98. 361-371. 10.1155/1991/46737.

Western Thatching Ants (Formica obscuripes)

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Formica obscuripes, Western Thatching Ant

I went for a walk yesterday on Three Corner Lake Road just to get out of the house. Springtime on San Juan Island has been cold and dreary, but sometimes there’s a moment or two when the sun peeks out, giving a bit of hope that the winter doldrums are coming to an end. Don’t get me wrong, I love the Pacific Northwest, but the Visitor Center’s claim that San Juan gets 247 days of sunshine a year is a stretch. I think they actually count the days when it is overcast and rainy as long as the sun peeks out for just a minute before the clouds darken the day again.

It was cold and I wasn’t expecting to see any insect activity, so I was surprised to find this long time ant colony with a mass of individuals near the top of the nest. The sun had been out intermittently, so I believe what was happening was the workers were at the surface to warm themselves (thermoregulating). There were a few straggling workers carrying thatch debris (conifer needles) to the nest from the forest. If the weather had been nicer, I would have enjoyed plopping myself into a chair to ant watch for an hour or so. They are quite pretty when you see them up close.

Western Thatching Ants (Formica obscuripes) are native to our region. They seem to like forest edge habitat, and you’ll find the nests situated in areas where there is some clearing to take advantage of the sun’s warmth. These ants are considered general omnivore-predators. They scavenge or prey upon insects and other arthropods for food. Foraging activity takes place both on the ground and on vegetation, including high in trees. Thatch ants also harvest honeydew from aphids and other homopterans as well as from extrafloral nectaries. You can read more about extrafloral nectaries or EFN’s (little nectar producing glands on plants) here https://bygl.osu.edu/node/1774 or check out one of my earlier blog posts about them here https://buggingyoufromsanjuanisland.com/2022/05/17/what-are-extra-floral-nectaries%EF%BF%BC/

Extrafloral nectary on Fruitless Cherry Tree

The ant workers are considered weakly polymorphic, which means they have only slight variations in size and shape within the worker caste as opposed to other species where workers may be monomorphic (all the same size and shape), or strongly polymorphic (a high degree of variability between worker sizes and shapes). You can read more about polymorphism in ants here https://www.antwiki.org/wiki/images/1/1c/Wheeler_1908f.pdf .

Given all the information you’ll find from pest control companies online about these ants and others, you might ask, why or if there is any benefit to having these ants around. The answer is YES! Western Thatching ants are beneficial in ecosystems because they not only aerate the soil with their burrowing practices in nest construction, but they also provide FREE pest control, helping regulate populations of other insects that defoliate forests, fruit trees, and even our vegetable gardens. They also help clean up the environment through scavenging dead animals. There is no need to eradicate these nests and if you get into ant watching, they might provide a bit of intriguing summer entertainment. Pull up your lawn chairs and sit and watch with your friends. As long as you aren’t poking the nest, they are not inclined to bother you at all.

Thanks for reading!

References:

Formica obsuripes. 2025. Bugguide.net. https://bugguide.net/node/view/31269

Formica obscuripes. 2025. AntWiki. https://www.antwiki.org/wiki/Formica_obscuripes

McIver, J.D., Torolf, T.R., Cimon, N.J. 1997. A supercolony of the thatch ant Formica obscuripes forel (Hymenoptera: Formicidae) from the Blue Mountains of Oregon. Northwest science., Vol.71(1), pp.18-29. https://rex.libraries.wsu.edu/esploro/outputs/journalArticle/A-supercolony-of-the-thatch-ant/99900502747101842

Bird notes 🎶

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Something happened in the yard yesterday afternoon. We have a fruitless cherry tree in a cage that I didn’t plant. At least I think it’s a fruitless cherry tree. It sort of popped up on its own.

In the beginning, I didn’t really want it there, so I cut it down – a few times. It kept coming back, intent on sticking around. A couple of years ago, I just stopped trying to get rid of it. I even put a little cage around it. That was actually for the juncos that built a nest in the grass below that little tree though, to keep them safe from the mower.

Aside from me personally whacking it down a few times, the little tree has suffered other adversities. It has been attacked by cherry slugs (sawfly larvae). They ate its leaves.

Sawfly larva or Cherry Slug

It has had a few tent caterpillars munching too. One year that it was super dry, it lost its leaves and I thought it was dead. Only it came back again. I started to pay more attention to this little tree, even watering it in the summer. It’s not very tall, but this year it looks more healthy than ever before.

Last year, I noticed in the spring that it put out these cool little red bumps on the stem just above the leaf.

extrafloral nectaries
Formica ascerva ant at extrafloral nectaries

Those little bumps soon had little red and black ants visiting. I learned the red bumps are extrafloral nectaries. They produce nectar that attracts pollinators to the tree. I haven’t seen any flowers, so I’m not sure what would be pollinated. Maybe the tree isn’t old enough yet. I’m still learning. I sure need to figure out if I’m right that it’s a fruitless cherry.

Well, the other thing that is interesting is shortly after the little red bumps attract the red and black ants, there are little black aphids. I’ve seen this for 2 years in a row now. The ants tend those little aphid flocks like sheep. They are guarding them in exchange for the sugary honey dew the aphids produce.

The aphids and the ants seem to multiply. I have seen 2 or 3 ants per leaf with aphids. Not all the leaves have aphids, but maybe 1/3 of the tree does, and each guarded by the ants. The ants are Formica ascerva species.

They are interesting in their own right because aside from guarding the “sheep,” they also are fierce warriors, driving away (and killing) the large Camponotus sp. carpenter ants that try to invade every spring.

This colony of Formica ants lives under a bedroom of our home. They are welcome to stay since they don’t eat wood.

Today, when I looked out the window though, I saw something challenging the fearsome Formica ants. There were birds inside the tree caging and they were hungrily pecking and even tearing at the leaves with aphids. I grabbed and clumsily set up my camera to video the scene.

Birds attacking aphids farmed by Formica ascerva ants

I saw finches first, then there was a chickadee, and even a hummingbird. I thought I saw bumble bees, but they wouldn’t have been eating the aphids. Perhaps they were visiting the extrafloral nectaries or maybe even sipping honeydew produced by the aphids, but I wasn’t close enough to be certain.

Afterwards, I went out to survey the damage. I saw one leaf with lots of shreds. Aphid parts scattered about. Ants wandering somewhat aimlessly. Another leaf had an ant that died courageously in battle protecting his little flock.

I wanted to share my observations with you because a lot of folks really dislike aphids. Others also dislike ants and don’t understand their role in nature’s ecosystems. Maybe this will help others to understand there are a lot of hungry birds that eat aphids (and ants). Without them, the birds might not find enough food to feed their nestlings. It’s all part of the cycle of life.

If you see aphids your garden that you are worried about, you can mitigate some of their feeding damage by hanging a hummingbird feeder nearby. The hummingbirds have to have protein along with all that carbohydrate sugar water and they will most certainly find your aphids delicious. In fact, insects and spiders make up about 85 % of the diet of hummingbirds. Birds need bugs. And not all ants are pests. Some are extremely beneficial. I challenge you to take up bird and bug watching. You will not be disappointed!

Thanks for reading!

Below are more images of the birds feeding on the aphids inside the caged tree.

References and further reading

Bentley, B. L. (1977). Extrafloral Nectaries and Protection by Pugnacious Bodyguards. Annual Review of Ecology and Systematics, 8, 407–427. http://www.jstor.org/stable/2096735

Bugguide. 2024. Formica Ascerva. https://bugguide.net/node/view/497956

What are extrafloral nectaries?

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Ants (Lasius sp.) on Big Leaf Maple Extra-Floral Nectary – May 17, 2022, San Juan Island, WA

When you study insects, or even birds for that matter, you start to understand you have to get to know plants a bit too.  It’s all connected.  

Plants (including trees and shrubs) provide food and shelter for many different species of animals.  Admittedly, I just don’t know a lot about the parts of plants, beyond things like a tree trunk, bark, limbs, branches, leaves, or stems or flowers, nuts, fruit.  The obvious parts.  

There are some not so obvious parts.  Like these extrafloral nectaries.  Huh? Sounds weird.  Keep reading. 

Extrafloral nectaries (EFN’s) are glands occurring on more than 2000 plant species in 64 families.  Extrafloral literally means outside of the flower. When we think of nectar, we usually think of little bees and hummingbirds flying around, visiting pretty flowers to sip nectar and in the process, pollinate all of our plants.  It’s just that plants are a bit more complex.  These glands are located in various places on plants (including trees and shrubs), and may be found on the laminae of leaves, petioles, rachids, bracts, stipules, pedices, fruit, etc.  (Mizell, 2019).  

These glandular secretions are a fascinating part of how plants attract and sustain a diverse, ecological community, providing sustenance for a multitude of species, including both pests and predators.  You can find ants, aphids, beetles (including ladybugs), bees, wasps, and possibly even birds utilizing this excretory faucet to sip what consists of mostly carbohydrate-rich sugar, but also comprised of a wide array of amino acids and other nutrients.  

Why are these important? Well, scientists are still trying to fully understand all of the diverse relationships around extra-floral nectaries. It is thought perhaps, beyond attracting organisms to a food source, they play a role in orchestrating a plant’s defense strategy against predators. They also are believed to provide a source of food and/or beneficial nutrients for various organisms during the off-season – when flowering and pollen sources are not available. They may also reduce conflict between ants and other pollinators by partitioning resources (Villamil & Stone, 2019).

Lasius sp. Ants at Extra-floral nectaries on Big Leaf Maple, 05.17.2022, San Juan Island, WA

Ant and aphid hanging out on extrafloral nectaries on Cherry Tree, San Juan Island, 05.17.2022

References

Bentley, B. L. (1977). Extrafloral nectaries and protection by pugnacious bodyguards. Annual Review of Ecology and Systematics, 8(1), 407-427.

Holopainen JK, Blande JD, Sorvari J. Functional Role of Extrafloral Nectar in Boreal Forest Ecosystems under Climate Change. Forests. 2020; 11(1):67. https://doi.org/10.3390/f11010067

Mizell, R. 2019. MANY PLANTS HAVE EXTRAFLORAL NECTARIES HELPFUL TO BENEFICIALS.  UF IFAS Extension Bulletin. https://edis.ifas.ufl.edu/publication/IN175

Villamil, N., Boege, K., & Stone, G. N. (2019). Testing the Distraction Hypothesis: Do extrafloral nectaries reduce ant-pollinator conflict?. The Journal of ecology, 107(3), 1377–1391. https://doi.org/10.1111/1365-2745.13135