INTRODUCTION

Sawflies (Fig. SF-1) of the Mixedwood Plains Ecozone (MWPE) found in the sedimentary basin of southern Quebec and Ontario show a remarkable diversity. Generally, sawflies are regarded as insects of boreal regions, so it is impressive to discover that the temperate regions of eastern Canada have a similarly diverse fauna. Perhaps my perception of a lower diversity comes from the greater difficulties in locating specimens of sawflies in temperate regions of eastern Canada than in boreal regions. Moreover, the diversity of genera of MWPE is markedly greater than in the boreal zone.

Sawfly sampling has occured over 100 years. Sampling efforts were intensified in the 1950's and more so in the 1980's. I made a special effort in building our knowledge of sawflies for the Mixedwood Plains Ecozone because few amateurs and professionals have studied this group in this area. Since 1980, I have sampled for at least a complete season 44 sites in MWPE. The regions involved are Ottawa, southern Quebec, the St. Lawrence River area near Kingston, Ancaster and Rondeau Provincial Park. The range of habitats is exceptionally wide (e.g. primary deciduous forests, mixed forests of various ages, conifer forests, dry alvars, shore alvars, cattail marshes, Osmunda marshes, fens, sphagnum bogs, remnant prairies, open dunes and blowouts, old fields, backyards, blueberry meadows, open red cedar forests, creek and small river edges, large river forested flood plains, beaver ponds, floating button bush islands and hilltop meadows). Despite the above list of sites, the ranges of sawflies in the ecozone are incompletely known.

The following information on the sawfly biodiversity for MWPE is from the literature and the holdings at the Canadian National Collection of Insects and Arachnids. The sawfly taxonomy is generally excellent for most of the genera that occur in the MWPE (Gibson, 1980a, 1980b,Goulet, 1986, 1992, Middlekauff, 1984, Smith, 1969, 1971, 1979a, 1979b, 1986, Smith and Gibson, 1984, Wong, 1977). Though the territory extends only over the sedimentary basin of southern Quebec and Ontario, I have included data within 50 km from the sedimentary basin as I do not see much differences in sawfly composition.

Table of Contents

• CURRENT DIVERSITY OF SAWFLIES

• MAJOR DISTRIBUTION PATTERNS OF SAWFLIES

• SAWFLY LARVAL HOST SUMMARY

• CHANGES IN THE FAUNA THROUGH MAN MADE ACTIVITIES

• CHANGES IN RANGES AND POPULATION LEVELS

• DECLINES IN ABUNDANCE

• DISAPPEARANCE OF LARVAL HOST PLANTS

• CONTAMINATION OF ADULTS BY PESTICIDES

• INCREASE IN ABUNDANCE AND RANGES

• SUMMARY

• APPENDIX A: List of species of the Selandriinae (Symphyta: Tenthredinidae) recorded in the Mixedwood Plains Ecozone with status, type of distribution, provincial distribution, and Ecoregions of the Mixedwood Plains Ecozone.

• REFERENCES

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