Instar‐dependent hemocyte changes in Pieris brassicae after parasitization by Cotesia glomerata

Abstract

Cotesia glomerata L. (Hymenoptera: Braconidae) is a parasitoid of early instar larvae of Pieris brassicae L. (Lepidoptera: Pieridae). Late instars of P. brassicae can more often overcome parasitization by hemocytic encapsulation of C. glomerata eggs. Short-term hemocyte responses to parasitization were examined in third and fourth instar larvae of P. brassicae. Total and differential hemocyte counts did not differ between parasitized and unparasitized host larvae. A rapid, but temporary decrease of total hemocyte as well as plasmatocyte numbers was observed immediately after oviposition. Numbers of hemocytes adhering to tissues were shown to be the same in untreated, wounded and parasitized P. brassicae larvae by tracing hemocytes with monoclonal antibodies as markers. The in vitro spreading ability of hemocytes from unparasitized third and fourth instar larvae was lower than that of the last instar's; parasitization, however, had no influence on hemocyte spreading. We therefore suggest that the higher parasitization success of C. glomerata in earlier instars of P. brassicae is mainly due to the low spreading ability of the hemocytes.

Compatibility between the endoparasitoid Hyposoter didymator and the entomopathogenic fungus Metarhizium brunneum: a laboratory simulation for the simultaneous use to control Spodoptera littoralis

“…In general, THC increases with the larval age reaching a maximum in pre‐pupae although THC also tends to increase prior to each molt, decrease at molting, and then increase again . Other studies have reported the same effect of parasitism on THC . When comparing both scenarios, we observed that parasitism was the factor which has most contributed to S. littoralis total mortality.…”

Hemocyte quantitative changes in Anticarsia gemmatalis (Lepidoptera: Noctuidae) larvae infected by AgMNPV

“…1992), D. saccharalis (Barduco et al 1988;Bombonato and Gregorio, 1995;Falleiros et al, 2003), Lacanobia oleracea (Richards and Edwards, 1999). Our results are similar to those observed by Silva et al (2002), who reported the absence of quantitative alterations of OE in response to pathogens in the hemocoel of A. obliqua larvae and are discordant to Bauer et al (1998), who reported the increase of this cellular type in larvae of P. brassicae parasited by Cotesia glomerata. However, this species is a parasitoid and we worked with a virus that might have led to the different results.…”

Calcium dynamics of hemocytes of the gastropod Biomphalaria glabrata: effects of digenetic trematodes and selected bioactive compounds

“…Hemocyte spreading defects are believed to reflect parasitemediated immunosuppression (Noda & Loker 1989;Loker et al 1992;Loker 1994). Parasitoid larvae also alter the spreading ability of hemocytes of their insect hosts (Bauer et al 1998;Beckage 1998;Stettler et al 1998). Of the hemocytes of B. glabratn observed to round, most (81%) first showed at least one calcium transient.…”