Spring colonisation of orchards by Anthonomus pomorum from adjacent forest borders

Abstract

The early‐season dispersal of the overwintered apple blossom weevil, Anthonomus pomorum (L.) (Coleoptera: Curculionidae), is a crucial stage in the colonisation of dwarf apple orchards adjacent to forests. We have conducted release‐recapture studies with 1700 to 4000 marked weevils at two orchard sites in Switzerland over 2 years to characterise the spatial and temporal pattern of the dispersal process. The dispersal and colonisation of orchards in spring by overwintered weevils is dependent upon the prevailing temperature. An orientated dispersal from the forest border to the centre of the orchard was observed consistently, irrespective of the angle of the apple tree rows with respect to the forest border or of climatic conditions. The average dispersal distance of the weevils was 19 m. Approximately one third of the weevil population remained on the first tree encountered, the remainder of the population moved over short distances mainly along the tree rows. This dispersal pattern led to a strong ’edge effect‘ with higher numbers of weevils occurring at the edges adjoining the forests as compared to the centre of orchards. The relevance of these findings to population dynamics and management of the pest is discussed.

Response of Plum Curculio (Coleoptera: Curculionidae) to Odor-Baited Traps Near Woods

“…Other studies (Dixon et al 1999, Prokopy et al 1999b) have attempted to correlate the inßuence of weather on plum curculio cap- tures by traps. In our study, periodic peaks of adult captures by traps seemed to coincide with rises in temperature suggesting that, in early spring, temperature may be the most important factor favoring adult dispersal and orchard colonization, as suggested by Smith and Flessel (1968) for plum curculio and by Duan et al (1996) and Toepfer et al (1999) for the apple blossom weevil. In fact, when captures of adults by traps were studied in association with the Þve weather factors evaluated here (temperature, relative humidity, barometric pressure, rainfall, and wind speed), we found that temperature was positively and signiÞcantly correlated with plum curculio captures by both trap types, except for male and female captures by pyramid traps baited with benzaldehyde plus pheromone, which were weather-independent.…”

Are landscape structures insurmountable barriers for foraging bees? A mark-recapture study with two solitary pollen specialist species

“…While recapture rates found in the present study are well within the range of recaptures measured for species of other insect groups in search of their key resources (Toepfer et al, 1999(Toepfer et al, , 2000Haddad et al, 2008), they are lower than those reported in other studies with pollen specialist bee species (Bischoff, 2003;Franzen et al, 2009).…”

Host recognition in a pollen-specialist bee: evidence for a genetic basis

“…Newly emerged adults were marked individually on the thorax with enamel paint, using a code consisting of six different colours (Toepfer et al, 1999). To mark the bees, they were first immobilized in the cold room at 4…”