Weevils, weevils, weevils everywhere *
Author
Oberprieler, Rolf G.
Author
Marvaldi, Adriana E.
Author
Anderson, Robert S.
text
Zootaxa
2007
1668
491
520
journal article
37514
10.5281/zenodo.274039
2d13c1a2-0d8f-4031-986a-3900e879582c
1175-5326
274039
Nemonychidae
This family of weevils (fig. 1) retains numerous primitive traits, both in structure and in habits. It is a relict group of the ancient past, today comprising only about 76 known species (71 described) in 21 genera but with a rich fossil record of about 60 species from Upper Jurassic and Lower Cretaceous deposits largely in the northern hemisphere. The extant fauna shows a highly disjunct distribution mainly in temperate northern and southern regions but with some species also in the tropics. It is most diverse in the Australian and Neotropical regions, which harbour about 70% of the fauna, fewer species occurring in the Nearctic and Palaearctic regions.
Nemonychidae
are predominantly associated with conifers, especially the family
Araucariaceae
, which hosts half of all the species, while
Pinaceae
provide the common hosts in the northern hemisphere. Only two genera live on angiosperm hosts,
Rhynchitomacer
on
Nothofagus
(Nothofagaceae)
in South
America
and
Nemonyx
on
Consolida
and
Delphinium
(Ranunculaceae)
in the western Palaearctic. The association with conifers (especially
Araucariaceae
) is likely the ancestral one and the angiosperm associations to represent secondary host shifts. The
Nemonychidae
are presumed to retain the ancestral life style of weevils, their mobile larvae living freely (ectophytically) among the sporophylls inside dehiscing male conifer strobili (cones), feeding on pollen in the open sporangia (pollen sacs) and moving between cones. Eggs are laid openly between the sporangia by means of the ovipositor (
Howden 1995
), but the females of some species may use their elongated rostrum to separate sporophylls before the cope ripens, allowing them to lay their eggs inside the cone against the sporangia. A few forms, however, such as
Bunyaeus
and
Eutactobius
in
Australia
and
Brarus
in South
America
, have a short to very short rostrum, and
Nemonyx
females use their hard, piercing ovipositor to drill holes into the follicles of the host fruits, in which their larvae feed on the developing seeds. Adult nemonychids also feed mainly on pollen.
FIGURES 1–8.
1—
Mecomacer scambus
(
Nemonychidae
:
Rhinorhynchinae
), developing in male cones of
Araucaria
(Araucariaceae)
in southern South America (Chile and Argentina). 2—
Mecocerinopis
sp. (
Anthribidae
:
Anthribinae
) from northern Australia. 3—
Cyrotyphus vestitus
(
Belidae
:
Belinae
), a rare Australian agnesiotidine from
Callitris
(Cupressaceae)
. 4—
Hydnorobius hydnorae
(
Belidae
:
Oxycoryninae
), an Argentine oxycorynine associated with the root-parasitic
Prosopanche
(Hydnoraceae)
. 5—a female of the Australian
Euops falcatus
(
Attelabidae
:
Attelabinae
) showing abdominal brushes used for inoculating her leaf rolls with fungal spores 6—the Australian
Car pini
(Caridae)
on its hostplant,
Callitris endlicheri
(Cupressaceae)
. 7—
Orapaeus cretaceus
(
Brentidae
:
Eurhynchinae
), an early Upper Cretaceous brentid fossil from Botswana. 8—the Australian
Aporhina australis
(
Brentidae
:
Eurhynchinae
), whose larva develops in stem galls of
Litsea leefiana
(Lauraceae)
. (all photos R. Oberprieler except 1, 4 (A. Marvaldi) and 8 (J. Hasenpusch))
The
Nemonychidae
are classified into three subfamilies,
Nemonychinae
(for
Nemonyx
only),
Rhinorhynchinae
and
Cimberidinae
.
Nemonyx
differs from all other genera in a number of characters, many of them plesiomorphic (
Kuschel 1995
), which prompted
Crowson (1985)
to argue for placing it in a family of its own. However, Kuschel (1994, 1995) and
May (1994)
identified pertinent imaginal and preimaginal synapomorphic characters that hold all nemonychids together as a single family.
Nemonyx
nonetheless shows the greatest number of plesiomorphic traits of all extant weevils.