TY  - JOUR
A1  - Ammunét, Tea
A1  - Heisswolf, Annette
A1  - Klemola, Netta
A1  - Klemola, Tero
T1  - Expansion of the winter moth outbreak range : no restrictive effects of competition with the resident autumnal moth
T2  - Ecological Entomology
N2  - 1. Both direct and indirect competition can have profound effects on species abundance and expansion rates, especially for a species trying to strengthen a foothold in new areas, such as the winter moth (Operophtera brumata) currently in northernmost Finland. There, winter moths have overlapping outbreak ranges with autumnal moths (Epirrita autumnata), who also share the same host, the mountain birch (Betula pubescens ssp. czerepanovii). Competitive interactions are also possible, but so far unstudied, are explanations for the observed 1–3 years phase lag between the population cycles of the two moth species. 2. In two field experiments, we studied host plant-mediated indirect inter-specific competition and direct interference/exploitation competition between autumnal and winter moths. The experimental larvae were grown either with the competing species or with the same number of conspecifics until pupation. Inter-specific competition was judged from differences in pupal mass (reflecting lifespan fecundity), larval development time and larval survival. 3. Larval performance measurements suggested that neither direct nor indirect interspecific competition with the autumnal moth reduce the growth rate of winter moth populations. Winter moths even had a higher probability of survival when reared together with autumnal moths. 4. Thus, we conclude that neither direct nor indirect inter-specific competition is capable of suppressing the spread of the winter moth outbreak range and that both are also an unlikely cause for the phase lag between the phase-locked population cycles of the two moth species.
KW  - climate change
KW  - direct competition
KW  - indirect competition
KW  - invasion
KW  - phase lag
KW  - Finland
Y1  - 2013
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/30112
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-301125
N1  - Postprint version. Original publication in: Ecological Entomology (2010) 35(1): 45-52; doi: 10.1111/j.1365-2311.2009.01154.x
VL  - 35
IS  - 1
SP  - 45
EP  - 52
ER  -