Interaction between flight, reproductive development and oviposition in the pine weevil Hylobius abietis

Abstract

1 The development of reproductive and flight capacity of pine weevils Hylobius abietis during the spring and their dispersal to, and subsequent development at, new clearfell oviposition sites comprise key phases in their life cycle in managed forests. At an old clearfell site where autumn-emerging weevils had overwintered, weevils were trapped as they re-emerged in the spring and tested for their ability to fly and then dissected to determine the degree of wing muscle and egg development. 2 Re-emerging weevils were most abundant in pine growing at the edge of the clearfell and, over most of the trapping period (April to June), their capacity for flight (proportion flying and wing muscle width) was more advanced than in weevils from the clearfell itself, with a similar trend in the degree of reproductive development (proportion with mature eggs and egg volume). 3 In weevils from the clearfell, flight capacity and reproductive development increased concurrently to a peak around mid-May. In weevils from pine, wing muscles were already well developed at the start of trapping, although few of them flew. Their more advanced development was attributed to the increased opportunities for maturation feeding after emergence in the previous autumn. 4 In the spring, weevils reached the canopy of trees for maturation feeding by walking and, to a lesser extent, by flight. Weevils dispersed by flight to oviposition sites in mid-May when most of them were reproductively mature. After arrival, flight ability and wing muscle size declined rapidly but egg production was maintained until most weevils had stopped flying. When wing muscles reached their minimum size, there was a marked decline in egg size, suggesting that wing muscle breakdown is important in maintaining egg production at oviposition sites. Prospects for further wing muscle and reproductive development are discussed.

Inducibility of Plant Secondary Metabolites in the Stem Predicts Genetic Variation in Resistance Against a Key Insect Herbivore in Maritime Pine

“…The success in the regeneration of conifer forests is highly contingent on this insect ( Langström and Day, 2004 ), which causes important economic losses in large part of Europe ( Leather et al, 1999 ). Larval stages feed on stump roots of recently cut trees ( Nordenhem and Nordlander, 1994 ), and newly emerged adults migrate in massive numbers to fresh clear-cuts in spring ( Solbreck and Gyldberg, 1979 ; Tan et al, 2011 ). Generation times may vary from 1 to 3 years depending on the location in Europe ( Day et al, 2004 ; Wainhouse et al, 2014 ).…”

Regeneration of European boreal forests: Effectiveness of measures against seedling mortality caused by the pine weevil Hylobius abietis

“…Adult pine weevils migrate en masse to fresh clear-cuts 0378-1127/$ -see front matter Ó 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.foreco.2011.08.033 during their migratory flight in spring (Örlander et al, 2000;Solbreck and Gyldberg, 1979;Tan et al, 2011). They locate suitable stump roots for oviposition, remain on the site during the entire season, and then overwinter Örlander et al, 1997).…”

The large pine weevil Hylobius abietis (L.) as a potential vector of the pathogenic fungus Diplodia sapinea (Fr.) Fuckel

“…Diplodia sapinea is able to damage trees of different ages, including seedlings (Stanosz et al , ), and infection of D. sapinea affects trees that are wounded (Swart & Wingfield, ). The weevil feeding activity is increasing at the same time as the length of the overwintering period is reduced as a result of climate warming (Tan et al , , ; Wainhouse et al , ).…”

“…The adult weevils hibernate below ground in the soil and litter and emerge from hibernation in spring when temperatures reach 8–9 °C (Nordenhem, ; Leather et al , ). Before and after oviposition in spring, H. abietis adults feed on seedlings, on the bark of young transplants or branches of conifers, on the canopy of mature trees (Örlander et al , ) and on the bark of tree roots (Nordlander et al , ; Tan et al , ).…”