Жук-скарабей Odontotaenius disjunctus: Экология и особенности вида.

Species of beetle

Odontotaenius disjunctus, the patent leather beetle or horned passalus, is a saproxylic beetle in the family Passalidae (bess beetles) which can grow to just over an inch and a half long, weigh 1 2 grams and are capable of pulling 50 times their own weight. They have been used to study several aspects of general family characteristics since the early 1900s but remain a relatively unknown species within the diverse Coleoptera order.

Odontotaenius disjunctus is most commonly found in climates with higher humidity, mainly in the warmer parts of both hemispheres, and also widely distributed in temperate North American forests. O. disjunctus beetles are usually found under, or inside, old logs or stumps and are rarely observed outside of their wooden habitats.

These beetles can be found in rotting logs, especially of oak and hickory. This specific locale offers unique benefits in regards to protection from predators and external abiotic factors such temperature and precipitation. There is a level of stability with the two factors mentioned, the water retention in the wood helps to keep temperatures stable while aiding in further decomposition of the log itself. Adults are only found outside of their log when they are searching for a new mate, or a new log in which to burrow.

These beetles are shiny black, and have many long grooves on their elytra. They have a small horn between their eyes, and clubbed antennae. Females and males are difficult to distinguish based on external appearances alone. Their large size may be in part a result of exploiting a niche that provides an unlimited food source of rotting wood material. A nematode parasite, Chondronema passali, inhabits the abdominal cavity has been shown to effect stress responses in these beetles, although the results are relatively small, they do show that O. disjunctus is not only infected by parasites but are negatively impacted by them. Interestingly, their ecology and approach to symbiotic digestion is similar to wood feeding cockroaches of the subfamily Panesthiinae, that also appear to rely on a similar contribution from their hindgut microbiomes. Burrowing within rotting logs offers the triturated wood that is a staple in the diet of these beetles, this wood is consumed widely by the males and then further broken down through the digestive tract, and eventually expelled for the eventual re consumption by all family members. These four general categories can be further examined into more specific signals and patterns. Offspring rely heavily on parental care for protection and nourishment, food is mixed with secretions by the parent before the larvae can feed. Reproduction appears to be affected by seasonality, with summer months being the time in which females lay majority of their eggs. O. disjunctus remain in monogamous pairs, during the breeding season (early spring until late summer) they will repeatedly copulate and produce anywhere from 20 to 35 eggs over the time period. Offspring remain in the parental tunnel for the rest of the year, overwinter, and then disperse in the following late spring. Infanticidal behavior has been observed, and is most likely to occur in the event of a burrow take over by a male or female that has not yet had the chance to mate due to limited access to an empty burrow.

The patent leather beetle is considered beneficial in its activities to decompose dead wood, and is harmless to humans. The increase in habitat loss due to deforestation for agriculture has caused a decline in populations as they do not react well to fragmentation. Studies reveal that a decrease in suitable habitat and increased open areas between forests have been the two leading causes of population decline and potential extirpation of some areas. Shrinking habitat would also cause an increase in competition and infanticidal behaviors, further straining reproductive success.