The aim of this research was to assess the larval instar number of Pissodes castaneus (De Geer) and to facilitate the study of its biology by identifying a reliable method to determine the instar of individual larvae. The larvae of this weevil were collected in central Italy in 2004, and their head capsules were measured by means of a binocular microscope. Head capsule width and length data were analyzed using Hcap, a computer program that use the distribution of size measures to determine instar separation rules. To determine instar number, the Gaines and Campbell method, which represents the perfect geometric progression of size measures (Dyar’s rule) by a regression line, was also used. This study identified four larval instars of P. castaneus and found that head capsule widths and lengths followed Dyar’s rule and reliably distinguished instars.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.