Cis bilamellatus (Wood, 1884)

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POLYPHAGA Emery, 1886

TENEBRIONOIDEA Latreille, 1802

CIIDAE Leach, 1819

CIINAE Leach, 1819

CIINI Leach, 1819

Cis Latreille, 1796

This is our only non-native member of the family, it was described from specimens found at West Wickham (south of London) in 1884 and over the next few decades it became common and spread slowly over the surrounding area but it was not until 1934 that the species started to become widespread and generally common, and there are records from Woking (1935), Oxon (1936), Nottinghamshire (138), Cheshire (1940), Cambridge (1949) and Hampshire (1950). In 1910 C.G. Champion discovered that it was synonymous with the widespread Australian C. munitus Blackburn, 1888, and it is now supposed that the species was imported from Australia either with timber or with herbarium specimens destined for Kew Gardens. The modern distribution includes all of England and Wales, Anglesey, Man and the Isle of Wight, and there are records from southern Scotland and Ireland, it was discovered on the channel Islands in 1999 and since that time it has occurred in northwest France on several occasions, this represents the European extent of the distribution but this is very likely to change in the future. Through much of England and Wales it is now our most common ciid and this success has been attributed to its ability to use a range of fungal hosts, often alongside other ciids and fungivorous beetles, among known hosts are Laetiporus sulphureus (Bull.) Murrill (1920), Pleurotus sapidus Quélet, 1883, Cerioporus squamosus (Huds.) Quélet (1886), Fomitopsis betulina (Bull.) Cui, Han & Dai (2016), Inonotus dryadeus (Pers. : Fr.) Murr., Polyporus adustus (Willd.) Fr., Ganoderma applanatum (Pers.) Pat., Irpex Fr. sp., G. resinaceum Boud., Trametes versicolor (L.) Lloyd (1920) and T. hirsuta (Wulfen) Lioyd (1924) but adults are likely to occur on other species, they may also occasionally occur under bark or among samples of decaying wood with no obvious fungal associations, and they very occasionally visit flowers of lime and possibly other trees. All life stages have been recorded throughout the year and the species seems to be continuously breeding throughout its range; adults generally occur in small numbers during the winter and increase in abundance in the spring when hundreds, along with numerous larvae and pupae, may occur in a single sporophore, they will continue breeding until the fungus is reduced to an empty shell, sometimes remaining over several seasons, and in the meantime disperse to other sporophores. Populations will breed and are easy to keep indoors in containers, they will produce adults year-round and these tend to emerge synchronously and will readily infest most fungus samples offered to them although they should be kept protected as parasites will otherwise soon appear. Sampling from the wild is simply a matter or tapping sporophores over a net but adults sometimes fall out in large numbers, especially at night when they are active on the surface, and so will need to be released safely, they are generally common in woodland and wooded parkland but will occur on a wide range of deciduous trees wherever suitable hosts are fruiting e.g. beside busy roads, pathways and in gardens.

Cis bilamellatus 1

Cis bilamellatus 1

© Dave Hodges

Cis bilamellatus 2

Cis bilamellatus 2

© Dave Hodges

1.5-2.0 mm. Males may be identified by the broad erect plates on the clypeus and the anterior margin of the pronotum, these vary greatly in size and are not proportional to the size of the specimen, sometimes they are only weakly developed but they are always obvious. The clypeal plate is flat and straight while the pronotal plate is convex and weakly recurved, the apical margin varies from being weakly sinuate to strongly incurved. No other ciid has these plates although males of some species e.g. Cis bidentatus Ol. have the anterior margins of the clypeus and pronotum produced into blunt teeth. Females will soon become familiar by association. Long-oval and almost cylindrical in form, entirely dark brown, legs pale brown, antennae pale with the club darkened. Dorsal surface with short, pale semi-erect scale-like pubescence. Head with short temples and convex, protruding eyes, vertex flat; distinctly punctured and microsculptured in the female and more finely so in the male, antennae 10-segmented; the two basal segments long and broad, 3 elongate, 4-7 quadrate and 8-10 forming a loose club. Pronotum slightly transverse, broadest across the base and narrowed to a rounded anterior margin, the anterior angles not visible from above, surface variably uneven and finely punctured, anterior margin produced in the male, finely bordered in the female. Elytra gently curved from weakly-angled shoulders to a continuously rounded apical margin which covers the abdomen, relatively short, at most twice the pronotal length, surface without striae; rugose with fine and quite dense punctation which becomes obscure towards the apex. Legs short and robust, the femora and tibiae about equal in length, front tibiae gradually widened to a sharp (in fresh specimens) external apical tooth. Tarsi 4-segmented; 1-3 short and the terminal segment long and curved, longer than the others combined. Claws smooth and weakly appendiculate.

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