Tag Archives: Art Evans

Megasemum asperum, a Cerambycid Beetle

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Megasemum asperum, a Cerambycid Beetle

Here is a new-to-me Cerambycid (longhorn) beetle. I haven’t added one of these to my photo collection in the 15 years I’ve lived on San Juan Island, so note here that they are “UNCOMMON” and not populous in number.

This species is the only one in its genus in North America. It is Megasemum asperum. I see in perusing iNaturalist.org that there have been 67 reported observations dating back to 2007.

Location: San Juan Island, WA

ID: Megasemum asperum

From Bugguide.net –

Size: 18-25mm

Season: July to August (this is when you could see an adult)

Numbers: a single species in the New World & in NE Asia

It was described by John Lawrence LeConte in 1854

From Beetles of Western North America – “Larvae mine Douglas-fir (Pseudotsuga menziesii) and fir (Abies). Adults are attracted to lights during the summer. Found in coniferous forests of western North America,” (Dr. Art Evans, entomologist, 2021).

Your take away message – NOT a pest. NOT a tree killer. NATIVE species! Performs important recycling of nutrients role in ecosystems allowing regeneration in our forests. Appreciate Biodiversity.

Thanks for reading!

Watch Me Take Off!

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It’s a short clip, and you’ll have to check out the end to see this little beetle take flight. I fished this one out of the pool and it’s the 2nd one I’ve seen this week, albeit a new one for me to observe. I believe this is Hylastes macer, but hoping a friend will take a look for me to confirm. I have tentatively based my ID on size (approx 5mm) and locale being under our Shore Pine trees, but I wasn’t confident using Wood’s key with only my photo and video in lieu of an actual specimen under the microscope. At minimum, Hylastes should be correct for Genus. These beetles are in the family Curculionidae and subfamily Scolytinae, one of the Bark and Ambrosia beetle species.  

As to their life history, they construct galleries in phloem tissues of roots and stumps of Pinus or Pine trees and occasionally Picea or Spruce trees. According to Atkinson (2024), there are six species of Hylastes known in Washington State. Some of the species in this genus range from BC to CA. For more on distribution, take a look at Wood, 1982.

While identifying a bug is part of the process, the most fun for me is observing their behaviors. I knew when I saw the march of those little front feet, that the launch was about to take place.

References and Further Reading: 

Atkinson, T.H.  2024. Regional Checklist: Bark and Ambrosia Beetles of Washington. Bark and Ambrosia Beetles of Washington.  U.S. Forest Service. https://www.barkbeetles.info/regional_chklist_condensed.php#hylastes

Bugguide.net. 2024. Halastes macer. https://bugguide.net/node/view/495026 

Evans, A. 2021. Beetles of Western North America. Princeton University Press.

Wood, S.L. 1982. The bark and ambrosia beetles of North and Central America (Coleoptera: Scolytidae), a taxonomic monograph. Great Basin Nat. Mem. 6: 1-1356.

A Minute Scavenger

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I found this very tiny (1mm) beetle on the rim of the pool outside yesterday (Dec. 8, 2023). In my investigational efforts to identify my specimen, I have concluded it should be one of the Minute Brown Scavenger Beetles in the family Latridiidae (pronounced la-trid-eye-i-dee). As to species, I think it is Cartodere bifasciata – based on the color pattern of elytra – black markings between 2nd and 5th stria in anteriour third and behind middle; lateral black spot in about middle. (Bugguide, 2014).

Cartodere bifasciata
Cartodere bifasciata
Cartodere bifasciata

This particular species is an Australian native and likely introduced to North America via international shipping. Records show this species in Nova Scotia about 1989 (Majka et al 2009). Looking on iNaturalist for observational reports of this species, I see a few (about 15 or so) in the box I drew. You can see in the attached screenshot the general area where they are turning up in the Western US. Again, likely introduced via international shipping cargo.

Reported observations of Cartodere bifasciata in the PNW Region

Adults of beetles in this family are generally known to feed on the reproductive structures of fungi, plant and animal materials, and slime molds (Evans, 2021). They are found in association with wet or damp habitats in open or forested areas, especially in leaf litter, decomposing wood, on trees, herbaceous vegetation, and in bird, mammalian, or hymenopteran nests (Majka, 2009).

Cartodere bifasciata
Cartodere bifasciata

References and Further Reading

Bugguide 2014. Cartodere bifasciata. Iowa State University. https://bugguide.net/node/view/108526

Evans, A. V. 2021. Beetles of Western North America. Princeton University Press, N.J.

Majka CG, Langor D, Rücker WH. 2009. Latridiidae (Coleoptera) of Atlantic Canada: new records, keys to identification, new synonyms, distribution, and zoogeography. The Canadian Entomologist. 141(4):317-370. doi:10.4039/n09-050.