Category Archives: coleoptera

Your Garden’s Guardian: A Soldier in Miniature (Silis sp.)

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Soldier Beetle (Genus Silis)
Soldier Beetle (Genus Silis)

This tiny little friend (approx. 6mm) sporting a red collar is a soldier beetle in the family Cantharidae. It is in the Genus Silis, but there are so many species, that I will just leave it at the genus level for now.

Soldier Beetle (Genus Silis)

Silis beetles are quite cosmopolitan in distribution, associated with wooded areas and leaf litter, and active daytime fliers in early summer.

Adults are typically found on foliage and flowers. Primarily, they are pest predators, feeding on insects, but also serve as pollinators, feeding on nectar and pollen. Silis species are known to prey on aphid populations infesting trees, plants, and shrubs, so gardeners can appreciate them as a “friend.”

Silis beetles can also attack other groups of invertebrates, feeding on small soft-bodied specimens or consuming their eggs. However, the ecology of some species is remains to be investigated. While Fender (1973) found the larvae would eat earthworms and are mostly carnivorous in the soil, little else is known about the feeding habits in this stage. (Pelletier and Hébert , 2014).

The etymology of the nomenclature for the genus (Silis) comes from Σίλας in Greek. It is derived from the Latin name Silvanus, meaning “forest” or “wood,” and a contraction of the Greek form Silouanos, a transliteration of Silvanus. Silis or Silas is also associated with the Roman god of the countryside, Silvanus, a god who was worshipped by those who lived in wooded areas or worked with wood. Even older than the etymology is this tidbit. Silis beetles are quite ancient. Fairly recent research has identified specimens of the genus discovered in Baltic Amber (Parisi and Fanti, 2019).

Soldier Beetle (Genus Silis)

While I have now scooped a few out of our pool, thankfully in time to save them from drowning, some of them (perhaps the ones I’ve rescued) are also finding me. I have had them on my clothing and peeping in the door at me!

Thanks for reading!

Soldier Beetle (Genus Silis) looking in our door at me!

References

Bugguide 2025. Genus Silis. Iowa State University. https://bugguide.net/node/view/11961

Green, John Wagener. 1966. Revision of the Nearctic species of Silis (Cantharidae: Coleoptera). Proceedings of the California Academy of Sciences, 4th Series, 32, 447–513. https://www.biodiversitylibrary.org/part/52839

Pelletier, G., Hébert, C. 2014. The Cantharidae of Eastern Canada and Northeastern United States. Canadian Journal of Arthropod Identification No. 25. February 28, 2014. Available online doi: 10.3752/cjai.2014.25

Parisi, F. and Fanti, F. 2019. On the first Silis Charpentier, 1825 from Baltic amber (Coleoptera, Cantharidae), Foss. Rec., 22, 119–123, https://doi.org/10.5194/fr-22-119-2019

Counting Bugs: What’s at the light in the night? April 20, 2025

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Egira rubrica moth

Here’s a quick rundown of what I spied at my bug light when I checked this morning. I did move the bucket and light to a new location across from our house in our open air barn.

There were nine species of moths (31 individuals), two species of Coleoptera (beetles), and one wasp that I believe is Ophion sp.

Moths:

Egira perlubens = 1

Egira (either E. simplex or E. crucialis) = 3

Egira rubrica = 1

Orthosia transparens = 5

Orthosia hibisci = 8

Orthosia praeses = 8

Feralia comstocki = 2

Eupithecia graefii = 2

Melanolophia imitata = 1

Beetles:

Diplotaxis sp. = 2

Strophosoma melanogrammum = 1

Wasps:

Ophion sp. = 1

Melanolophia imitata
Strophosoma melanogrammum
Feralia comstocki
Eupithecia graefii
Egira sp. (Either E. simplex or E. crucialis)
Orthosia transparens
Ophion sp. I believe
Egira rubrica
Orthosia transparens
Orthosia preses
Orthosia hibisci
Feralia comstocki
Orthosia praeses
Diplotaxis sp. beetle with Orthosia praeses
Orthosia hibisici
Egira perlubens
Egira sp.
Eupithecia graefii

If I may, I’d like to leave you with something to consider. When you rake your leaves and clean your yard – especially if you are burning, chipping, or bagging and removing all those things that fall onto the ground, you are eliminating habitat for native species. If you can refrain the urge to spring clean around your property, you can help support life.

These may be somewhat drab colored moths and you may not even like them, but they sustain other organisms, including plants, because moths are also nighttime pollinators. Each species has a niche, and a role in the ecosystem (and ultimately the food web).

Please take note of nature around you. It’s actually beautiful and mysterious. Whether you like it or not though, nature is life. Nature matters. Little things like leaving the leaves can make a difference. Care.

Thanks for reading.

Green Ostomid beetle

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I found this gorgeous BENEFICIAL Green Ostomid beetle yesterday on the floor of our barn in the sand. Moved him over to some alder logs we have stacked as wildlife habitat and discovered he appeared to be quite thirsty. Yes, I did actually bring him some more water to drink from our outdoor above ground “pond.” More in the video description. Also want to add that if you have Alders on your property – please don’t grind them up or burn them. They are extremely important resources for many species of wildlife. They hold water even as dead trees, and they are full of insects that feed many birds (and other insects and spiders).

Headless Gnasher

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Matthew’s Angry Gnashing Beetle (Zacotus matthewsii)

Boy was I disappointed today when I found this beetle on the path near my home and it was HEADLESS!

This is one of my favorite San Juan Island beetles. It is the ground beetle Zacotus matthewsii, also known by the common name Matthew’s Angry Gnashing Beetle. “Zacotus” translates from Greek into “Very Angry” in English. I’m certain I’ve never seen one angry, but this one may indeed have been angry right before it lost its head. Or perhaps the predator that removed it took this beetle entirely by surprise.

I can tell you the EXACT date I last saw one of these beetles. They are reported as “rare.” It was February 16, 2020. Also in roughly the same spot. The beetles are associated with conifer forests and believed to prefer old-growth areas. There are some old trees near our home, but I believe San Juan is losing many, many trees. Lots to new home construction (happening at a rate that I never imagined), and some to the impact of a warming climate – likely accelerated by all the land use changes in the region. Many times I feel extremely saddened by the loss of nature. It is happening so fast. We are becoming suburbia.

If you would like to see a photo of this beetle intact, meaning a non-headless version. Check out my previous blog post from 2020 here – https://buggingyoufromsanjuanisland.com/2020/02/17/forest-co-habitating-microfauna/

Thanks for reading!

Matthew’s Angry Gnashing Beetle (Zacotus matthewsii)

Living Jewels of San Juan

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Buprestis aurulenta or Golden Buprestid Beetle

I found this little green beetle (and another sad little black and yellow beetle missing its antennae) in the pool yesterday. The black and yellow beetle is alive and… well, sort of living in a special habitat right now because of those missing antennae.

The green one was completely waterlogged and lifeless. I had left it on the table next to Drago’s enclosure last night, thinking I’d pin it and keep it in my collection. I am SO GLAD I DIDN’T stick it with a pin! This morning, I found it moving those little legs around at me. It was alive! RIP woke up.  

Golden Buprestid beetle (Buprestis aurulenta)

Golden Buprestid beetle (Buprestis aurulenta


This is a Golden Buprestid Beetle (Buprestis aurulenta). They are a native species in the Pacific Northwest. I have referred to them often as the Rip Van Winkle beetle because they take such a long time to develop from egg to adult. In fact, the record is 51 years!  


Why so long? Well, the developmental time depends a lot on the quality of what they’re eating (they develop in dead or dying trees) and miscellaneous environmental factors. When they come out as an adult, they leave behind a little oval hole. I think it adds character to your wood trim if you have them “sleeping” in timber used to build your house.

We had one in our door trim that didn’t make it all the way out and probably had been stuck for awhile before I noticed. It became a fascinating object to show anyone who came to visit our home.

Golden Buprestid stuck in door trim (March 20, 2016)

I’m not sure what gives them this beautiful iridescence, but they are undeniably one of nature’s jewels, thus the name “Jewel” Beetle. 

Golden Buprestid Beetle – San Juan Island 07.27.2022
Golden buprestid set free to fly away in the forest.

References and further reading:

Zeng, Y. 1995. University of Florida Book of Insect Records, Chapter 12 Longest Life Cycle. Department of Entomology & Nematology University of Florida, Gainesville, Florida 32611-0620 https://entnemdept.ufl.edu/walker/ufbir/files/pdf/UFBIR_Chapter12.pdf

Bugguide.net https://bugguide.net/node/view/74029

Nelson, D. 2021. Buprestis aurulenta (Golden Buprestid) 10,000 Things of the Pacific Northwest http://10000thingsofthepnw.com/2021/05/19/buprestis-aurulenta-golden-buprestid/

Radar Love

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Hello Everyone!  Meet my new bug friend, Radar Love ❤️  He must have crashed the wrong party.  Radar gone wrong!  I found him floating in our pool, in the midst of those raucous “dippers” (the Diplotaxis beetles).  Radar Love was so happy I didn’t let him drown, and even happier that I didn’t stick him with a pin and add him to the bug equivalent of a stamp collection.  We hung out together for a bit and I took some photos and video to remember him by.  Radar Love was released into the forest so he can make more of his kind.  

Odonteus obesus
Odonteus obesus

Odonteus obesus
Odonteus obesus
Odonteus obesus

Location:  San Juan Island

ID: Geotruipidae (Odonteus obsesus)

Special thanks to my friend, Michelle Sloan Bos and Tyler Hedlund for ID assistance with this.  I was rushing to get ready for my special spider outing.  More about that later.  For now, enjoy this rare and exciting  sighting of a most special little beetle that calls San Juan Island his home.  

More Info: https://bugguide.net/node/view/160586

Odonteus obesus

A Little Weevil House

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Key Words: masting, Curculio, Quercus, mast seeding, acorn weevil, diapause

I picked up these acorns (Quercus sp.) when I visited my folks recently in Texas. They have several oak trees on their property and there was an abundance of acorns all over the ground this year, so I brought a few home with me in a ziplock bag. I like acorns. My mom used to draw little faces on them and I had acorn “people” to play with when I was a child.

Acorn “person”

I also found a very cool bug under one of those oak trees while I was there. This strange looking creature is one of the Nut and Acorn Weevils (Curculio sp). It has an extremely long snout. When you find out how this weevil uses it to DRILL, you may be amazed. The adult female weevil will use this drill on her very long snout to make a hole in those acorns!

Nut and Acorn Weevil (Curculio sp).
Nut and Acorn Weevil (Curculio sp).
Nut and Acorn Weevil (Curculio sp).

Keep reading. It really is amazing.

A female weevil will make a hole in the acorn so she can put her eggs inside it!

Hole drilled by Nut and Acorn Weevil

Because I like word games, I thought I’d point out to you that rearranging the letters in the word weevil will make the words “we live?” Well, those eggs hatch into baby weevils who LIVE in a little house that is an acorn (and sometimes in other nuts too). Some folks call them grubs or worms. They are actually the larvae of the adult weevil mom who selected the acorn for her nursery.

If you are assessing this situation from an agricultural perspective (say that nut is a pecan), invested in harvesting a profitable crop, you might be feeling very worried. Sometimes the worry may indeed be justified, but in many cases, like with these acorns, the tree has evolved a strategy to deal with occasional waves of weevils and other insects we consider pests. In actuality, they are just utilizing the resources of the tree like we do when WE (the humans) eat the nut or fruit.

Larvae of Nut and Acorn Weevil (Curculio sp).

I’m going to name the trees’ strategy of dealing with this bug FEAR NO WEEVIL. However, the actual scientific moniker for this strategy (and it applies to other pests and adverse weather stressors as well) is MASTING. The word mast has been used since way back in the Middle Ages to refer to the acorns and seeds of forest trees that drop and accumulate on the ground. It comes from Old English, mæst. Essentially, masting is an ecological term referring to the highly variable and often synchronized periodic cycles of fruiting/seeding in the reproductive processes of trees (both forest and fruit trees).

How is it a strategy for circumventing the deleterious affects of pests? Well, the idea is that in some years, bumper crops of nuts and seeds are produced in order to satiate the predators, so some are left to germinate and continue new generations. In this particular case, you could think of it as the oak trees sacrificing some of their offspring to the weevil gods. When there are more acorns than there are adult female weevils, some of those acorns will escape the weevil drill and makeover into little bug nurseries.

In reality, this relationship is much more complicated. In some cases, acorns parasitized by only a few weevil larvae will germinate, while those acorns with many larvae will not. The trees’ bumper crops of seeds and nuts will also cycle with years of low production, where resources are scarce for the weevil (and other organisms). Nature is incredibly dynamic though. Studies show some species of weevils have adapted a counter mechanism to circumvent the trees’ strategy of masting. It’s called prolonged diapause. This means these weevils are able to sleep longer (more than one year) as they develop in order to synchronize adult emergence with years when the trees’ seed/nut production is high.

If you are interested in reading more about the history and MYSTERY of masting, I encourage you to delve into the literature I’ve listed in the references below. It’s quite fascinating – especially going back in history to the link between masting and pannage. Way more than I can cover here. Check it out.

References

Baldwin, M. 2021. Pigging out in the forest: the Common of Mast (Pannage) in Britain https://www.wildlifeonline.me.uk/blog/post/pigging-out-in-the-forest-the-common-of-mast-in-britain

Bugguide 2021. Curculio. https://bugguide.net/node/view/6682

Higaki M (2016) Prolonged diapause and seed predation by the acorn weevil, Curculio robustus, in relation to masting of the deciduous oak Quercus acutissima. Entomol Exp Appl 159:338–346. https://doi.org/10.1111/eea.12444

Jefferson, R. 2006. Why Are More Acorns Falling? Excessive Drops of Nuts from Oak Trees Is Part of Normal ‘Mast Year’ Phenomenon. Scientific Times. https://www.sciencetimes.com/articles/33795/20211006/why-more-acorns-falling-excessive-drops-nuts-oak-trees-part.htm and https://youtu.be/EQ748TZcuqs

Jesse, L. No date. The dark side of collecting acorns. Plant and Insect Diagnostic Clinic. Iowa State University Extension and Outreach. https://www.extension.iastate.edu/news/2007/sep/072107.htm

Koenig WD. 2021 A brief history of masting research. Phil. Trans. R. Soc. B 376: 20200423. https://doi.org/10.1098/rstb.2020.0423 Koenig, W. D., & Knops, J. M. H. (2005). The Mystery of Masting in Trees: Some trees reproduce synchronously over large areas, with widespread ecological effects, but how and why? American Scientist, 93(4), 340–347. http://www.jstor.org/stable/27858609

Nut Leaf Weevil

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I found a’nutter weevil! They’ve been everywhere this week! Looks like this may be the Nut Leaf Weevil (Strophosoma melanogrammum). These weevils feed on the leaves of broad leafed shrubs. I saw it on a chunk of rotting alder. It was pretty small and tough to photograph in low light. Probably about 3.2 mm in size. San Juan Island, WA October 13, 2021.

Strophosoma melanogrammum 

Twenty-spotted Lady Beetle (Psyllobora vigintimaculata)

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Twenty-spotted Lady Beetle (Psyllobora vigintimaculata) on daisy. This tiny ladybug almost went unnoticed when I was watering flowers the other day. It wasn’t easy to get a photo and she crawled down headfirst into the flower bud. I suppose she was feeling shy!

After reading a bit more about these, I discovered the best place to look for them is at the base of skunk cabbage in early spring. AND, this is the best part. Later in the season, these little beetles switch to plants that have powdery mildew. They eat it. Definitely a garden friend!

Twenty-spotted Lady Beetle (Psyllobora vigintimaculata) on Daisy – May 30, 2021 San Juan Island, WA
Twenty-spotted Lady Beetle (Psyllobora vigintimaculata) on Daisy – May 30, 2021 San Juan Island, WA

References/Further Reading

https://bugguide.net/node/view/39631

https://www.researchgate.net/publication/233687670_Biology_and_Co-Occurrence_of_Psyllobora_vigintimaculata_taedata_Coleoptera_Coccinellidae_and_Powdery_Mildews_in_an_Urban_Landscape_of_California

Northern Carrion Beetle – Thanatophilus lapponicus

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This is a Northern Carrion Beetle – Thanatophilus lapponicus, one of the carrion beetles in the family Silphidae. The origin of the name Thanatophilus is from Greek thanatos (θανατος)- “death” + philos (φιλος)- “loving, liking” (Bugguide.net, 2003-2021).

Northern Carrion Beetle (Thanatophilus lapponicus)

Death is part of a biological process that can be unsettling for many of us. That said, death makes way for new life. This past February, a small fawn died on our property.

February 17, 2021

We left the body where it lay. First the eagles came, then a pair of ravens. I believe a fox visited too (tracks in the snow).

Bald Eagle 2.18.2021

Fox (?) tracks in snow

Over the course of the past 12 weeks, I’ve found some very cool bugs developing in the carcass, even now in the bits of hide and bones that remain.

Did you know?

There is actually an entire field of scientific study (Forensic Entomology) where time of death of a body can be estimated by the presence and developmental stage of certain insects involved in the decomposition process. This is called determining the Post Mortem Interval or PMI. Forensic entomologists can aid law enforcement in crime investigations by surveying for species of arthropods on a corpse, and determining stages of development and feeding behavior of the arthropods present (Barnes, 2000).

Carrion beetles in the family Silphidae fall into two subfamilies: the Nicrophorinae and Silphinae. While both feed on the remains of animals, the Nicrophorinae or Burying Beetles are associated with smaller corpses like birds, mice, voles, etc., weighing under 300g, while the Silphinae utilize larger cadavers (Watson & Carlton, 2005). This preference or niche, makes them ideal for investigations related to human death or death of larger species of wildlife (as in poaching or other crimes against animals).

Northern Carrion Beetle (Thanatophilus lapponicus)
Northern Carrion Beetle (Thanatophilus lapponicus)
Northern Carrion Beetle (Thanatophilus lapponicus)

From Ratcliffe, 1996.

Distribution. Thanatophilus lapponicus ranges broadly throughout Canada and Alaska, across the norther United States from coast to coast, and south to Southern California, Arizona, and New Mexico (Anderson and Peck 1985, Peck and Kaulbars 1987). It is also found in Northern Europe and Asia (Hatch 1928, Schwaller 1982).

Remarks. Thanatophilus lapponicus is readily identified because of the presence of a row of small tubercles on each of the elytra intervals (Figs. 31-32, 62); it is the only silphid in North America with this distinctive form of elytra sculpturing.

https://museum.unl.edu/file_download/inline/1bde566e-27c3-4c55-9345-59057400e350

The larval stage was described by Dorsey (1940) , and a brief synopsis was given by Anderson and Peck (1985). The larva of this species is characterized by a dark brown to black color on the dorsal surface, urogomphi that are about two times the length of the 10th abdominal segment, and antennae with a large sense cone on the second segment (as in Fig. 40).

Anderson and Peck (1985) reported that individual females lay about ten eggs in the soil surrounding a carcass. The egg stage lasts 5-6 days, the first instar about 7 days, the second instar 8-10 days, and the third instar 10-12 days. While Anderson and Peck did not observe pupae, they did note that T. lapponicus is a cold-adapted species that occurs at higher elevations in the western Mountains of North America. It is often the only silphid present in some of these areas. Thanatophilus lapponicus shows a strong preference for open areas (Anderson 1982c).

Clark (1895) observed extensive predation on fly larvae by adult beetles.

Size. 9-14mm

Time of Year Seen. March-October

References:

Anderson, R.S. and Peck, S.B. (1985) The carrion beetles of Canada and Alaska. The insects and arachnids of Canada, part 13, 1–121.

Barnes, S. 2000. Forensic entomological case study and comparison of burned and unburned Sus scrofa specimens in the biogeoclimatic zone of northwestern Montana. Graduate Student Theses, Dissertations, & Professional Papers. 4655. https://scholarworks.umt.edu/etd/4655/?utm_source=scholarworks.umt.edu/etd/4655&utm_medium=PDF&utm_campaign=PDFCoverPages

Bugguide.net. https://bugguide.net/node/view/37875

Ratcliffe, B.C. 1996. The Carrion Beetles (Coleoptera: Silphidae) of Nebraska. Bull Univ. Nebr State Mus 13:1-100 https://museum.unl.edu/file_download/inline/1bde566e-27c3-4c55-9345-59057400e350

Watson, E., & Carlton, C. 2005. Succession of Forensically Significant Carrion Beetle Larvae on Large Carcasses (Coleoptera: Silphidae). Southeastern Naturalist, 4(2), 335-346. Retrieved April 27, 2021, from http://www.jstor.org/stable/3877967

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