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Adult Odontotaenius disjunctus
Larva of Odontotaenius disjunctus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Superfamily: Scarabaeoidea
Family: Passalidae
Leach, 1815


many more
> 500 species

Passalidae is a family of beetles known variously as "bessbugs",[1] "bess beetles",[1] "betsy beetles"[1] or "horned passalus beetles". Nearly all of the 500-odd species are tropical; species found in North America are notable for their size, ranging from 20–43 mm, for having a single "horn" on the head, and for a form of social behavior unusual among beetles.

Bodies elongate-cylindrical and black overall; ventral surfaces may be covered with yellow setae. The head is narrower than the thorax, with antennae consisting of 10 antennomeres with a three-segment club. The elytra are elongate with parallel sides, and heavily striated.

They are subsocial (brood caring) beetles living in groups in rotting logs. They care for their young by preparing food for them and helping the larvae construct the pupal case. Both adults and larvae must consume adult feces which have been further digested by microflora for a time; an arrangement that might be described as a sort of external rumen.

In addition, they are also able to produce fourteen acoustical signals, more than many vertebrates. Adults produce the sounds by rubbing the upper surface of the abdomen against the hind wings. The larvae produce the sounds by rubbing the third leg against a striated area on the coxa of the second leg.

While the taxonomy of Nearctic species is well-known (four species in the US, and 90 in Mexico), bess beetles in other parts of the world need further study.

Of North American species, Odontotaenius disjunctus (synonym: Popilius disjunctus) is the familiar bessbug found throughout the eastern US and Canada, while O. floridanus has only been found in Florida on sand hills that used to be islands when Florida was flooded thousands of years ago. Ptichopus angulatus was recently discovered near the border of Mexico in Arizona. Its habitat is south to Colombia and it is commonly associated with the detritus chambers of leafcutter ant nests (Atta spp.). Two other species were reported from Arizona at the beginning of the 20th century, but have not been seen there since that time; they may have been brought from Mexico by a train hauling firewood.

Selected species[edit]

Aceraius grandis
Ceracupes arrowi
Chondrocephalus debilis
Chondrocephalus granulifrons
Cylindrocaulus patalis
Heliscus tropicus
Leptaulax bicolor
Odontotaenius disjunctus (patent-leather beetle)
Odontotaenius floridanus
Odontotaenius striatopunctatus
Ogyges laevior
Oileus rimator
Passalus affinis
Passalus caelatus
Passalus elfriedae
Passalus inops
Passalus interruptus
Passalus interstitialis
Passalus jansoni
Passalus latifrons
Passalus pugionifer
Passalus punctatostriatus
Passalus punctiger
Passalus spiniger
Passalus unicornis
Paxillus leachi
Paxillus pentataphylloides
Pentalobus barbatus
Petrejoides orizabae
Popilius eclipticus
Proculus burmeisteri
Proculus mniszechi
Ptichopus angulatus
Publius agassizi
Spasalus crenatus
Spurius bicornis
Verres corticicola
Verres hageni
Veturius transversus



External links[edit]

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