Ambrosiodmus

Taxonomy

Ambrosiodmus Hopkins, 1915a: 55.

Synonyms

Phloeotrogus Motschulsky, 1863: 512. Wood, 1969: 113.

Brownia Nunberg, 1963: 37. Wood, 1980: 96.

Diagnosis

2.5−4.8 mm long, 1.7−2.8 times as long as wide, body usually stout and darkly colored. Ambrosiodmus can be distinguished by the pronotumpronotum:
the dorsal surface of the thorax
short, rounded; pronotal discdisc:
the flat central upper surface of any body part (e.g. pronotum and elytra)
entirely asperateasperate:
covered in asperities
; pronotum anterioranterior:
the front or forward; opposite of posterior
margin without a carinacarina:
an elevated ridge or keel, not necessarily high or acute
or serrations; elytral discdisc:
the flat central upper surface of any body part (e.g. pronotum and elytra)
convexconvex:
appearing rounded
; elytral declivitydeclivity:
downward slope of either the pronotum or elytra
rounded and steep at apexapex:
point or edge furthest from the body; opposite of base
; scutellum flat, flush with elytra; mycangial tufts absent; and procoxae contiguous.

May be confused with

Ambrosiophilus, Beaverium, and Immanus

Distribution

temperate and tropical regions of the world

Gallery system

This consists of a radial entrance tunnel leading to branched tunnels. These usually lie predominantly in one horizontal plane, but may extend into three dimensions. They lack enlarged brood chambers. Many gallery systems are often started in a small area of the tree. Unlike many xyleborines, the galleries of different individuals often interconnect so that beetles can move between galleries (Beeson 1961Beeson 1961:
Beeson CFC. 1961. The ecology and control of the forest insects of India and the neighbouring countries. 2nd edition. Government of India, New Delhi, 767 pp., Kasson et al. 2016Kasson et al. 2016:
Kasson MT, Wickert KL, Stauder CM, Macias AM, Berger MC, Simmons DR, Short DPG, DeVallance DB, Hulcr J. 2016. Mutualism with aggressive wood-degrading Flavodon ambrosius (Polyporales) facilitates niche expansion and communal social structure in Ambrosiophilus ambrosia beetles. Fungal Ecology 23: 86-96. https://doi.org/10.1016/j.funeco.2016.07.002).

Remarks

Recent studies suggest that all the species in Ambrosiodmus and Ambrosiophilus Hulcr and Cognato are associated with a single species of polypore basidiomycete ambrosia fungus (Flavodon ambrosius) (Kasson et al. 2016Kasson et al. 2016:
Kasson MT, Wickert KL, Stauder CM, Macias AM, Berger MC, Simmons DR, Short DPG, DeVallance DB, Hulcr J. 2016. Mutualism with aggressive wood-degrading Flavodon ambrosius (Polyporales) facilitates niche expansion and communal social structure in Ambrosiophilus ambrosia beetles. Fungal Ecology 23: 86-96. https://doi.org/10.1016/j.funeco.2016.07.002; Li et al. 2017Li et al. 2017:
Li Y, Bateman CC, Skelton J, Jusino MA, Nolen ZJ, Simmons DR, Hulcr J. 2017. Wood decay fungus Flavodon ambrosius (Basidiomycota: Polyporales) is widely farmed by two genera of ambrosia beetles. Fungal Biology 121: 984-989. https://doi.org/10.1016/j.funbio.2017.08.004). This fungus has greater ability to break down lignocellulose than most ambrosia fungi. This enables the beetles to colonize wood at a more advanced state of decay than most ambrosia beetles, and to persist in the same tree over several generations (Kasson et al. 2016Kasson et al. 2016:
Kasson MT, Wickert KL, Stauder CM, Macias AM, Berger MC, Simmons DR, Short DPG, DeVallance DB, Hulcr J. 2016. Mutualism with aggressive wood-degrading Flavodon ambrosius (Polyporales) facilitates niche expansion and communal social structure in Ambrosiophilus ambrosia beetles. Fungal Ecology 23: 86-96. https://doi.org/10.1016/j.funeco.2016.07.002; Li et al. 2017Li et al. 2017:
Li Y, Bateman CC, Skelton J, Jusino MA, Nolen ZJ, Simmons DR, Hulcr J. 2017. Wood decay fungus Flavodon ambrosius (Basidiomycota: Polyporales) is widely farmed by two genera of ambrosia beetles. Fungal Biology 121: 984-989. https://doi.org/10.1016/j.funbio.2017.08.004).