A survey was conducted in 2004 and 2005* to assess the relative
abundance of native and non-native coccinellids in different habitats in Maine.
From May to October, coccinellids were sampled by yellow sticky trap, sweep
net, beating sheet, and visual observation in apple, potato, grain, mixed
organic crops, deciduous forest, coniferous forest, mixed forest, field, shrub,
and riparian habitats situated within close proximity to each other in five
locations in Orono, Presque Isle, Monticello, and
Fryeburg, Maine. In 2004, a total of
3735 coccinellids were collected. Propylea quatuorodecimpuncata
(1359), Coleomegilla maculata
(503), Harmonia axyridis
(181), and Coccinella septempunctata
(167) were the most numerous non-native species. Three other non-native species were also
collected, but in very small numbers: Coccinella hieroglyphica (2), Epilachna verivestris (6), and Hippodamia variegata (5). Among species collected that are native to
the region were Psyllobora vigintimaculata
(1190), Coccinella trifasciata
(80), Hippodamia parenthesis (47), Hippodamia tredecimpuncata (25), Mulsantina hudsonica
(7), Adalia bipunctata
(6), Anisosticta bitriangularis
(3), Coccinella transversoguttata
(2), Hippodamia convergens
(1), and Anatis quindecimpunctata
(1). Propylea quatuorodecimpunctata was the dominant
species in field, potato, and mixed organic habitats; Psyllobora vigintimaculata in shrub, riparian,
coniferous forest, and mixed forest; and Harmonia axyridis in apple. In deciduous forest, Psyllobora vigintimaculata
and Propylea quatuorodecimpuncata
shared dominance. In grain, Propylea quatuorodecimpuncata
was dominant in Presque Isle, but Coleomegilla maculata was dominant at the more southern, Orono location. *2005
results will be incorporated at the end of the field season.