Bulletin of Entomological Research (1998) 88, 527-536
M.R. McNeill, D.B. Baird and S.L. Goldson (1998)
Evidence of density-dependent oviposition behaviour by Listronotus bonariensis (Coleoptera : Curculionidae) in Canterbury pasture
Bulletin of Entomological Research 88 (5), 527-536
Abstract: Argentine stem weevil (Listronotus bonariensis) (Kuschel) is a pasture pest of Lolium spp. in New Zealand and is the target of a classical biological control programme using the parasitoid Microctonus hyperodae Loan. However, laboratory experiments have indicated a strong density-dependent egg laying response which may have important implications for the biological control effort. Two field experiments were conducted using a manipulated range of weevil densities within 2.0-2.4 m-2 field enclosures and oviposition activity measured by weekly sampling of grass tillers within the enclosures. In both experiments, density had no effect on general oviposition behaviour although the percentage of tillers found to be infested with eggs increased significantly at higher densities. In experiment 1, L. bonariensis exhibited strong density-dependent oviposition with a significant decline in eggs/tiller/female with increasing adult density. An initial population of five L. bonariensis m-2 oviposited 32 times more eggs/tiller/female than 200 L. bonariensis m-2. By comparison, density-dependent oviposition was absent in experiment 2 with eggs/tiller/female comparable for all densities. The dramatic difference between the two experiments in the expression of density-dependent oviposition was attributed to prevailing spring temperatures during the sampling interval, which in the second experiment were much cooler and delayed the onset of egg laying. It is probable that in experiment 2, oviposition was not regulated by density-dependent cues but limited by temperature and age related mortality in the adult population. The mechanism for density-dependent oviposition, its occurrence in the field and impact on the effectiveness of the parasitoid M. hyperodae are discussed.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Mark R. McNeill, Stephen L. Goldson
Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation
general biology - morphology - evolution
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Listronotus bonariensis | Lolium (crop) | New Zealand | ||
| Microctonus hyperodae (parasitoid) | Listronotus bonariensis | Lolium (crop) | New Zealand |
