TWO UNUSUAL BUGS

THE IRONCLAD BEETLE

This flightless beetle is native to California and Baja California. It lives up to eight years (note: most beetles live for only a few weeks or months). It has a very hard flat carapace (shell) that is difficult to penetrate, even with a pin: hence, the name “ironclad”. This insect can play dead and go for long periods without food water. It eats rotten wood and any associated fungi in the wood. This beetle has smaller legs than non-boring insects, thus it is more easily burrows into wood.

  Classification

Kingdom Animalia

Phylum Arthropoda

Clade (only one)

Class Insecta

Order Coleoptera

Family Zopheridae

Genus Phloeodes

Type Species P. diabolicus

The adults of this beetle are up to inch long (25 mm). It moves fairly slowly. It spends most of its time living under the bark of a rotting tree. I discovered this beetle in late afternoon as it was slowly “walking” on a sidewalk next to where a partially rotten tree was recently removed by city workers. Ironclad beetles are crepuscular (active an hour or so before sunset).

It was a challenge to identify this insect, but I just kept looking online and in my small collection of “nature books.” I eventually concluded that it had to be a beetle, but there are so many of them! Eventually, via a process of elimination, I concluded that what I found was as “ironclad beetle.” 

Figure 1. Phloeodes diabolicus (about 10 mm long). Santa Clarita, Southern California.  

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MOTTLED STINK BUG

This insect is another species that I had never seen before. It is native to southern Europe. Finding a specimen clinging to the outer wall of my house was even more of a surprise to me, because this insect is supposedly not yet known to occur in the USA. Well, it can reported as definitely occurring there now! Shield bugs have sucking mouth parts that damage crops, thus, it and insects like it are considered to be pests Fichter (1966, p. 70).

The common name for this insect is a “shieldbug.” The large triangular area (or scutellum) at the posterior end of this insect is conspicuous and distinctive for this kind of insect.

Stink bugs do damage, both as nymphs and as adults, by sucking sap from plants and causing them to wilt, and/or to become pimpled or malformed. These bugs also give off a strong order. 

   Classification

Kingdom Animalia

Phylum Arthropoda

Family Pentatomidae

Clade (1 of them)

Class Insecta

Order Hemiptera

Family Pentatomidae

Genus Rhaphigaster

Type Species Rhaphigaster nebulosa

Reference

Fichter, G. S. 1966. Insect Pests. A Golden Nature Guide. Western Publishing Company, New York. 160 pp.

Figure 2. Rhaphigaster nebulosa, 16 mm length, from Santa Clarita, southern California. This specimen has an orange abdomen with tiny black dots on its outer surface.

References

Hogue, C.L. [revised by J.N. Hogue] 2015. Insects of the Los Angeles Basin, 3^rd ed. Natural History Museum of the Los Angeles Basin, 479 pp.

Wikipedia, 2026.