Vol. 109, No. 4, September & October, 1998 285 EASTWARD RANGE EXTENSION IN CANADA OF THE ALDERFLY SIALIS VELATA (MEGALOPTERA: SIALIDAE), AND THE POTENTIAL OF THE GENUS AS A CONTAMINANT MONITOR 1 Isabelle Roy2, Landis Hare^ ABSTRACT: We report on a range extension for Sialis velata (Megaloptera: Sialidae) in eastern Canada and assess the potential of the genus as a metal biomonitor. Sialis velata Ross is reported from the province of Quebec for the first time since its original collections (Ross 1937). Ours is the first record of any Sialis species from the province since 1937. All previous collections of the five Sialis species known from the province (S. velata, S. iola, S. itasca, S. mohri and S. vagans) were from the extreme southwestern corner near the city of Montreal ( 44N, 73W) (Ross 1937; Whiting 1991). It is now possible to extend the range of 5. velata, north to the 47th parallel, and east to the Quebec City region (71W). Ours is the most easterly record for S. velata in Canada. Only two Sialis species are known to occur in Canada east of Quebec City, i.e., 5. mohri (New Brunswick) and S. vagans (New Brunswick and Nova Scotia) (Ross 1 937, Whiting 1 99 1 ). Because we have found Sialis larvae in the major-ity of the Quebec lakes that we have visited, the lack of collection records in eastern Canada is likely a consequence of a lack of effort in collecting adults and rearing larvae rather than the rarity of the genus in eastern Canada. Adults of S. velata (five males, three females) were reared from a large number of larvae collected on May 1 8 1 997, from soft mud at a depth of 5 m in a Shield lake (Lake St-Joseph; 4655'N, 7140'W). Sialis larvae for rearing were held individually in small plastic containers, in 50 ml of water that was renewed weekly, and fed live chironomid larvae. Gut content analysis indi-cated that larvae in the field fed largely on chironomids and oligochaetes, as has been reported by previous investigators (Azam and Anderson 1969, Pritchard and Leischner 1973, Canterbury 1978). When individual larvae ex-hibited agitated swimming behavior at the water surface they were transferred to a small plastic container filled with a mixture of sand and soil for pupation. In the laboratory, pupation and adult emergence were highly successful at room temperature (10% mortality), but not at 10C (100% mortality). Our results are consistent with those of Elliott (1996), who found that pupation success could be described by a quadratic equation with a threshold at approximately C and an optimum at 15. 7 1 Received October 20, 1997. Accepted January 21, 1988. 2 INRS-Eau, Universite du Quebec, C./P. 7500, Sainte-Foy, Quebec, Canada GIV 4C7. 3 Author to whom correspondence should be addressed. ENT. NEWS 109(4) 285-287, September & October, 1998
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