|scientific name Lixus |
Mesic (moist), semi-aquatic and aquatic habitats (Anderson, 2002).
In general, adults are most common within the late summer and fall (Essig, 1958).
Members of Lixus are relatively large weevils (near 1 cm in length, with some species well in excess of 1 cm), bearing fine pubescence in variable patterns and colours across their exoskeleton. They have a comparatively elongate and narrow rostrum (snout) and overall body shape (Anderson, 1987; Kissinger, 1964). Their rostrum lacks the inflation seen in the tips of some other genera, has no prominent dorsal furrow, and generally lacks carinae (ridges). The antennae are thin, with the first joint of the funicle (antennal segments between basal scape and clubbed tip) thicker than the second joint, and the second segment of the funicle generally equal to or greater than the length of the next two segments combined. Their thorax varies in relative length and width, but generally tapers forward, and has pronounced posterior notches for accepting the leading edges of the elytra, with a variable (but generally small) medial angle (backwards prominence) between. In this genus, the foot is broad, has a deeply bilobed tarsal segment 3, and is 'spongy' (bearing many fine hairs on its pad) (Kissinger, 1964). Many species in this genus have a pollen-like coating of yellowish powder that is rubbed off with handling (Blatchley and Leng, 1916), and this may give them a slightly different appearance in natural settings from that seen in the museum specimens presented here.
Females oviposit individual eggs into the notches that they create in stems (Milne and Milne, 1980). The larvae burrow into stems and roots, forming gall-like galleries where they then pupate (Blatchley and Leng, 1916). The adults emerge to feed on the soft tissues of various plants - often different plants from those used by larvae (Anderson, 1987). There appears to be only one generation per year within most species of Lixus. Adults of some species have been known to over-winter within stem cavities (Essig, 1958).
Not of concern.
Anderson (1987) stated that larvae mine stems or roots, while a minority feed on flower heads and seeds (these are generally members of other, closely related genera). He noted that adults inhabit a large range of shrubs and herbs, including the Compositae, Leguminosae, Rosacea, Cruciferae, Chenopodiacea, and Polygonaceae, with the bulk of Lixus species associated with Asteracea (thistles and knapweeds in particular) and Polygonaceae (largely water smartweeds) (Anderson, 2002).
The distribution includes most of Canada and the United States (Anderson, 2002), with concentrations in southern Canadian provinces, and northern US states. Alonso-Zarazaga and Lyal (1999) listed this genus as having fossil occurrences in both the Lower Oligocene (of France), and the Upper Miocene (of Switzerland).
Some species within Lixinae have been used as weed control taxa, but Lixus is not among them. Authors such as Milne and Milne (1980) have stated that Lixus contains pest species such as the pine weevil (a weevil that causes bent leader branches on conifers, reducing their value), but this pest species is actually a member of the Pissodini (Molytinae), a totally different tribe and subfamily (Anderson, 2002).
Taxonomically, Lixus was revised from its original definition by Champion 1902; Petri 1928 (as cited in O'Brien and Wibmer, 1982), but numerous authors have stated that it is in need of further taxonomic revision because it is difficult to demarcate from closely related genera. Strickland Museum specimens reinforce this general similarity, but also show that the characters discussed here serve to distinguish this genus from members of closely allied genera with reasonable consistency and accuracy.
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