Abstract

BARDI, Christian  and  LANGE, Carlos E.. Geographic distribution, prevalence, and infection intensity of Gregarina ronderosi (Eugregarinorida: Gregarinidae) in Dichroplus elongatus (Orthoptera: Acrididae). Rev. Soc. Entomol. Argent. [online]. 2016, vol.75, n.1-2, pp.3-9. ISSN 0373-5680.

Gregarina ronderosi is an obligate parasite of the digestive tract of the pest grasshopper Dichroplus elongatus. It is one of only two eugregarines of Argentine grasshoppers described with their complete life cycles. Given the lack of knowledge regarding fundamental epizootiologic aspects of eugregarine infections in Argentine grasshoppers, the objective was to initiate the recording of the geographic distribution of G. ronderosi in the Pampas region, its natural prevalence, and the intensity of infections under natural conditions. To this end, 4084 individuals of D. elongatus were collected at 42 localities in the Pampas region between 2008 and 2012. Mean prevalence of G. ronderosi for all localities with presence (17 localities) was 29.7 ± SE 6.6% (n = 1071). Infected individuals (n = 396) were categorized according to infection intensity: three (0.8%) had very heavy infections, 80 (20%) showed heavy infections, 210 (53%) moderate, and 103 (26%) light ones. The known geographic distribution of G. ronderosi was expanded, high prevalence events suggesting the occurrence of epizootics were recorded, and intense infections categorized as very heavy and heavy were detected under natural conditions for the first time.

Keywords : Melanoplinae; Biocontrol; Grasshopper; Apicomplexa; Pest.