NOTES ON THE BIOLOGY OF THE LEAFHOPPER APHRODES BICINCTA (HOMOPTERA: CICADELLIDAE) IN THE OTTAWA AREA

Abstract Nymphs of the leafhopper Aphrodes bicincta (Schrank) first appeared in the field at the end of May or early June. Emergence of nymphs was protracted over a long period with second and third instar nymphs still being found when adult males were already present. Early instar nymphs were found on strawberry, Trifolium pratense L., T . hybridum L., Plantago major L., Taraxacum officinale Weber, Capsella bursa-pastoris (L.) Medic., Erigeron canadensis L., and a species of Brassica . There was only one generation per year, the winter being spent in the egg stage. Eggs deposited in plants in the field hatched when brought into the greenhouse during the winter months.In greenhouse studies, eggs were most often found oviposited on the surface of the soil or completely embedded in the petioles of leaves and in clumps of peat moss. Although eggs held at room temperature (70°–75°F) occasionally hatched, cold treatment (45°–50°F) of several weeks resulted in eggs hatching in as short a time as 14 days following their return to room temperature. There were five instars in the nymphal stage. The first four were relatively uniform in length but the fifth was at least 3 days longer than any other instar. Male insects completed the nymphal stage in 38.4 days and female insects in 41.3 days. Descriptions and measurements of the five nymphal instars and male and female adult insects are given. Adult male insects survived well for about 4 weeks and then declined rapidly. Female survival remained relatively high for at least 8 weeks. Some females have lived for up to 20 weeks. Fecundity varied with one female producing 51 offspring and others producing 1.