Tytthaspis sedecimpunctata (Linnaeus, 1760)
16-spot Ladybird
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POLYPHAGA Emery, 1886
CUCUJOIDEA Latreille, 1802
COCCINELLINAE Latreille, 1807
Tytthaspis Crotch, 1874
Our only U.K. species of Tytthaspis is widespread and common in Europe. In the U.K. a generally common and often abundant species throughout England north to Lincolnshire and west to Somerset. Further north there are records scattered to the Clyde. There are very occasional records from Wales, mostly coastal, and it is apparently absent from Ireland and Man. They occur in grassland in a wide variety of situations although they seem to prefer drier habitats; arable borders, parkland, woodland, gardens and also salt marshes and dunes. Locally the first specimens are seen in early spring but adults are also seen during mild winter spells on vegetation. By April they are generally abundant and they remain so until September or October. They are surprisingly cryptic in the field and are best sampled by sweeping. Both larvae and adults are widely polyphagous feeding on pollen, nectar and various fungi but the main food is Conidia of Erysiphales (Powdery Mildews). As soon as the adults are active they may be observed on flowers, and sometimes in very large numbers, those most favoured include umbels (Apiaceae), deadnettles, reeds, buttercups, knapweed and dandelion. Pollen and nectar are an important food source in the absence of mildew for both adults and larvae. It may be adequate for the survival of adult beetles but not necessarily so for egg development. Adults overwinter and prior to doing so may be found in numbers feeding up before finding a suitable site. In general the same site will be used year after year while it remains suitable. Sometimes adults will overwinter among aggregations of other species e.g. Psyllobora and sometimes other species are found among Tytthaspis aggregations. The largest coccinellid aggregation recorded was for this species with more than 10,000 individuals. There are two distinct types of overwintering site. Firstly, aggregations may be found in exposed positions, on trunks, posts, gorse, stems or walls. The second type is among dead herbage or in hedges. Grass tussocks have been found to accommodate numbers of adults in the winter. Mating has been observed in the spring prior to dispersal. We have also observed them mating on flowers etc. in late spring. As stated above the adults occur in a wide range of habitats; in 2006 we found them in abundance during May and June on oak foliage in a local park. The drab grey larvae are a common sight in the sweep net in late May and June.
The overall appearance will soon become familiar so that any variation will be recognized. The number of spots varies between 16 and 18; the three lateral spots are usually fused and there is a very rare melanic form, f. poweri.
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2.5-3.0mm. Body round and slightly oval; almost hemispherical when set ‘closed’. Ground colour yellow but pale grey and almost white specimens are not uncommon later in the year. Head finely punctured and pubescent. Centre of head and labrum black. Clypeus contracted in front of eyes, almost right angled, front margin incurved. Palps and antennae darkened towards apex. Antennae longer than head width, terminal segment truncate. Pronotum transverse and widest at rounded hind angles. Usually with six dark marks but these may be variously fused. Lateral margins very weakly bordered. Front angles produced. Hind margin strongly sinuate. Surface finely punctured and microsculptured. Scutellum small and hidden when the elytra are closed. Elytra typically with 8 dark marks and a black sutural stripe-a character shared only with Propylea. Side margins very weakly edged and not explanate. Surface punctured and microsculptured as the pronotum. Underside mostly black; prosternal and elytral epipleura orange and meso- and metepimera conspicuously white. Entire underside with fine, pale pubescence. Prosternal process with a raised ridge either side so that it appears to be furrowed. Front margin of the first abdominal sternite, between the hind coxae, not margined, the lateral edges are rather strongly margined. Front margin of metasternum strongly bordered between mid coxae. Coxae and femora black, trocanters, tibiae and tarsi mostly orange. Meso- and metatibiae with a fine black spine on the inside at apex. Claws black; smooth and with a weak tooth at base.
Larval characteristics:
-Meso- and metathoracic segments each with two seta-bearing tubercles low down on either side.
-Six rows of tubercles along the abdomen, wide and weakly domed, and topped with black bristles. Each tubercle darker than the surrounding cuticle.
-Body pale grey-brown with head and legs darker.
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Tytthaspis Crotch, 1874
A small genus of four species contained within two subgenera; Tytthaspis gebleri (Mulsant, 1850) in Barovskia Iablokoff-Khnzorian, 1979 and T. phalerata (Costa, 1849), T. Sedecempunctata (Linnaeus, 1758) and T. novemdecemguttata (Linnaeus, 1761) in Tytthaspis (s.str.). They are small, drab ladybirds which live among grass etc. and feed primarily on fungi. The mandibles are specialized in having a fine comb-like structure along the inner margin with which they gather fungal spores. They occur in the Palaearctic and Oriental regions.