Procladius Skuse

Saether, Ole A., 2010, Procladius Skuse from Lake Winnipeg, Manitoba, Canada, with keys to some females and immature stages of the genus (Diptera: Chironomidae), Zootaxa 2726, pp. 34-58 : 36

Procladius Skuse

Seven species of Procladius were found in the light traps from Lake Winnipeg. Of these, however, two species were never caught with certainty in the bottom samples. The other five belonged to the most common species of the benthos ( Fig. 1 ).

Adults of all five common species were caught from the beginning of June to the middle of September ( Figs. 3 , 5 , 7 , 9 , 11 ). Pupae or first and second instars of P. culiciformis were present from early June to early October ( Fig. 5 ), in early June to early September for P. freemani ( Fig. 9 ), from early June to end of August for P. denticulatus ( Fig. 7 ), in June and July for P. sublettei ( Fig. 11 ), and in July for P. bellus ( Fig. 3 ).

The individual species within the genus Procladius are among the most difficult to determine within the Tanypodinae both as imagines and as immatures. Kobayashi (1998) showed that body size and male genital structures varied seasonally in Procladius choreus (Meigen) . The smallest imagines, which were observed in summer, were reduced to about 60 % of the largest ones in wing length, while the gonostylus had a longer posterior heel in spring and fall. Since the length and shape of the gonostylus heel is used as one of the important genital characters in discriminating species of Procladius the separation of several species becomes doubtful. About 20 species of Procladius are known from the Nearctic region and more than 60 from the Palaearctic region many of them likely synonyms. The genus is in urgent need of taxonomic revision especially of species outside the Nearctic region.

Figures

FIGURE 1. Larval distribution of the five most common species of Procladius Skuse in the benthos of Lake Winnipeg.

FIGURE 3. Procladius (Ps.) bellus (Loew). Numbers of adults caught in light traps and emergence traps in 1969 and 1971, and numbers of immatures in benthic samples from June to November 1969 and in March 1970. (LT = light traps, ET = emergence traps, vertical lines = 1 – 25 specimens, 3 = third instar larvae, 4 = fourth instar larvae, P = pupae.)

FIGURE 5. Procladius (H.) culiciformis (L.). Numbers of adults caught in light traps and emergence traps in 1969 and 1971, and numbers of immatures in benthic samples from June to November 1969 and in March 1970. (LT = light traps, ET = emergence traps, short vertical lines = 1 – 25 specimens, longer line = 51 – 100 specimens, 2 = second instar larvae, 3 = third instar larvae, 4 = fourth instar larvae, P = pupae.)

FIGURE 7. Procladius (H.) denticulatus Sublette. Numbers of adults caught in light traps and emergence traps in 1969 and 1971, and numbers of immatures in benthic samples from June to November 1969 and in March 1970. (LT = light traps, ET = emergence traps, short vertical lines = 1 – 25 specimens, medium long lines = 26 – 50 specimens, longest vertical lines = 201 – 400 specimens, 2 = second instar larvae, 3 = third instar larvae, 4 = fourth instar larvae, P = pupae.

FIGURE 9. Procladius (Holotanypus) freemani Sublette. Numbers of adults caught in light traps and emergence traps in 1969 and 1971, and numbers of immatures in benthic samples from June to November 1969 and in March 1970. (LT = light traps, ET = emergence traps, short vertical lines = 1 – 25 specimens, medium long lines = 26 – 50 specimens, longest vertical lines = 201 – 400 specimens, 1 = first instar larvae, 2 = second instar larvae, 3 = third instar larvae, 4 = fourth instar larvae, P = pupae.)

FIGURE 11. Procladius (Holotanypus) sublettei Roback. Numbers of adults caught in light traps and emergence traps in 1969 and 1971, and numbers of immatures in benthic samples from June to November 1969 and in March 1970. (LT = light traps, ET = emergence traps, vertical lines = 1 – 25 specimens, 2 = second instar larvae, 3 = third instar larvae, 4 = fourth instar larvae, P = pupae.)