TY - JOUR
T1 - Interspecific competition between Sitophilus zeamais and Sitotroga cerealella in a patchy environment
AU - Nykjær Larsen, Marie
AU - Nachman, Gösta Støger
AU - Skovgaard, Henrik
N1 - KEYWORDS
stored product pests • maize weevil • Angoumois grain moth • IPM • spatial ecology • population dynamics • simulation models • coexistence • competitive exclusion • Coleoptera • Curculionidae • Lepidoptera • Gelechiidae
PY - 2005
Y1 - 2005
N2 - The maize weevil, Sitophilus zeamais (Motchulsky) (Coleoptera: Curculionidae), and the Angoumois grain moth, Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae), are important insect pests of stored products. The coexistence in nature of the two species on maize has been difficult to explain from laboratory set-ups, as the moth is inevitably eliminated by S. zeamais. However, early laboratory experiments ignored the spatial dimension, while several studies have lately revealed that two competing species may coexist in a spatially divided environment even though one of the species is competitively superior in a simpler universe. Two hypotheses for coexistence were examined by studying the interactions in a system where the resources were spatially divided. It was found that spatial subdivision in the current experiment was insufficient to ensure coexistence between the two species, so neither of the hypotheses could be confirmed. A simple model describing the population dynamics of S. zeamais was fitted to the data. Its parameters provide important information about how resource depletion influences the per capita growth rate. Finally, the study indicates that the mechanism responsible for S. zeamais's rapid elimination of S. cerealella is the superiority of the former species to colonize and monopolize new patches. The design of this study may serve as a template for further laboratory experiments revealing the effect of a spatially divided environment on competitive interactions. However, the present study also indicates that choosing the appropriate spatial scale may be critical for relating the results to natural environments.
AB - The maize weevil, Sitophilus zeamais (Motchulsky) (Coleoptera: Curculionidae), and the Angoumois grain moth, Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae), are important insect pests of stored products. The coexistence in nature of the two species on maize has been difficult to explain from laboratory set-ups, as the moth is inevitably eliminated by S. zeamais. However, early laboratory experiments ignored the spatial dimension, while several studies have lately revealed that two competing species may coexist in a spatially divided environment even though one of the species is competitively superior in a simpler universe. Two hypotheses for coexistence were examined by studying the interactions in a system where the resources were spatially divided. It was found that spatial subdivision in the current experiment was insufficient to ensure coexistence between the two species, so neither of the hypotheses could be confirmed. A simple model describing the population dynamics of S. zeamais was fitted to the data. Its parameters provide important information about how resource depletion influences the per capita growth rate. Finally, the study indicates that the mechanism responsible for S. zeamais's rapid elimination of S. cerealella is the superiority of the former species to colonize and monopolize new patches. The design of this study may serve as a template for further laboratory experiments revealing the effect of a spatially divided environment on competitive interactions. However, the present study also indicates that choosing the appropriate spatial scale may be critical for relating the results to natural environments.
U2 - 10.1111/j.1570-7458.2005.00313.x
DO - 10.1111/j.1570-7458.2005.00313.x
M3 - Journal article
SN - 0013-8703
VL - 116
SP - 115
EP - 126
JO - Entomologia Experimentalis et Applicata
JF - Entomologia Experimentalis et Applicata
IS - 2
ER -