Annales de la Société Entomologique de France (2002) 38, 239-246
Christiane Nardon and Paul Nardon (2002)
Nouveaux caractères distinctifs des larves et adultes des deux espèces jumelles Sitophilus oryzae (L.) et S. zeamais Mots. (Coleoptera : Dryophthoridae)
[New characters to distinguish larvae and adults of the two sibling species Sitophilus oryzae (L.) and S. zeamais Mots. (Coleoptera, Dryophthoridae)]
Annales de la Société Entomologique de France 38 (3), 239-246
Abstract: Sitophilus oryzae and S. zeamais are recognized as sibling species, intersterile and difficult to distinguish. We have systematically searched for new morphological and non-destructive characters in order to facilitate their identification. We also revisited two already known characters: pigmentation and pronotum punctures, presenting or not, a smooth median line. In the larvae we discovered a small difference in mandible structure: the apical zone is more depressed in S. oryzae than in S. zeamais. In adults, four new distinctive features are described. i: structure of the metathoracic episternum (two rows of punctures in S. oryzae and three in S. zeamais), ii: the frontal groove (much more depressed in S. zeamais), iii: the complex setae bordering the frontal groove (bigger in S. oryzae than in S. zeamais) and iv: presence of a little structure called « rosette », at the base of the rostrum, easy to see in S. zeamais but less visible in S. oryzae. By the combination of these characters, it is easy to distinguish the insects of the two species. The presence, in several populations, of insects with intermediate features, leads us to consider that the divergence between the two species is still gradually working.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: French)
Research topic(s) for pests/diseases/weeds:
identification/taxonomy
general biology - morphology - evolution
Pest and/or beneficial records:
Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
---|---|---|---|---|
Sitophilus oryzae | ||||
Sitophilus zeamais |