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- Title
APHID PREDATION BY HARPALUS RUFIPES (DEGEER) (COLEOPTERA: CARABIDAE) IN THE LABORATORY AND FIELD.
- Authors
Loughridge, A. H.; Luff, M. L.
- Abstract
(1) The ability of Harpalus rufipes (Degeer) to feed on aphids was tested in laboratory experiments, and compared with evidence of aphid feeding on cereals and other crops in small outdoor plots. (2) In the laboratory, adult H. rufipes ate up to 130 Myzus persicae Sulz. per day. There was no apparent preference for any instar but more apterae were eaten than alatae. (3) Functional response curves were derived using both the disc equation and the random predator equation. A typical type II curve was obtained for H. rufipes. Actual feeding time on each aphid was just over one minute, and comprised about half the estimated total handling time (1.63--204 min). Feeding time increased when the beetle had already fed on many aphids. (4) H. rufipes was observed in the laboratory to be active on oat plants infested with Rhopalosiphum padi L. This activity increased with aphid density and males were not seen on plants at densities below fifty aphids per plant. Activity on plants also increased with temperature, with a lower threshold of below 10 °C. (5) Up to 35% of H. rufipes caught weekly in the field in dry pitfall traps had fed on aphids. but the mean percentage overall was only 1.24%. The percentage which had fed on aphids increased with increasing aphid density; 34% of H. rufipes caught in a formalin-filled time-sorting trap had fed on aphids. (6) H. rufipes was swept from cereal plants at night above a threshold minimum temperature of about 6 &degC: 35% of swept specimens had fed on aphids. (7) It is concluded that H. rufipes has potential as an aphid predator, but the aphid density and temperature thresholds limit its usefulness at the time of year when predation would be of most benefit.
- Subjects
PREDATION; HARPALUS; APHIDS; ANIMAL nutrition; BEETLES; GROUND beetles; BIOLOGICAL control of aphids; PREDATORY animals
- Publication
Journal of Applied Ecology, 1983, Vol 20, Issue 2, p451
- ISSN
0021-8901
- Publication type
Article
- DOI
10.2307/2403519