Australian Journal of Entomology (2001) 40, 371-375

Stephen L. Goldson, Mark R. McNeill, John R. Proffitt and David B. Baird (2001)
Seasonal variation in larval-instar head-capsule sizes of Argentine stem weevil, Listronotus bonariensis (Kuschel) (Coleoptera: Curculionidae)
Australian Journal of Entomology 40 (4), 371-375
Abstract: The distribution of head-capsule widths of larvae of the Argentine stem weevil, Listronotus bonariensis (Kuschel), was analysed using an extensive database and the results were compared to those in other publications. The study confirmed that there are four larval instars, but revealed that their size ranges can vary widely from season to season and/or generation to generation. Indications were that larval stage to larval stage first summer generation larvae tended to be larger than those in the second generation. Generally, Dyar's Rule applied to all data sets, although the third-to-fourth-instar ratio was sometimes below the mean value of 1.393; this was possibly related to observed sexual differences in size of L. bonariensis. The conformation to Dyar's Rule resulted in first-instar head-capsule size being a predictor of subsequent mean instar stadia sizes. Possible reasons for the observed differences in L. bonariensis head-capsule widths between seasons and generations 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): Stephen L. Goldson, Mark R. McNeill

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Listronotus bonariensis