Circulating hemocytes from larvae and adults of Carabus (Chaetocarabus) lefebvrei Dejean 1826 (Coleoptera, Carabidae): Cell types and their role in phagocytosis after in vivo artificial non-self-challenge Anita Giglio a , Silvia Battistella b , Federica Fabia Talarico a , Tullia Zetto Brandmayr a , Piero Giulio Giulianini b, * a Department of Ecology, University of Calabria, via P. Bucci 4B, I-87036 Rende (CS), Italy b Department of Biology, University of Trieste, via L. Giorgieri 9, I-34127 Trieste (TS), Italy Received 9 March 2007; received in revised form 23 July 2007; accepted 24 July 2007 Abstract Carabus lefebvrei Dejean 1826 is an helicophagous Italian endemic ground beetle that lives in central and south Apennines mountain forests, from lower altitudes to about 1500 m. In ground beetles, no morphofunctional data about immune system is available, even though they are well known both taxonomically and ecologically and they have been often used as indicators of the habitat quality due to their specificity to certain habitat types. In the current investigation the cellular population in the hemolymph of adult and third instar larvae of C. lefebvrei has been characterized by means of light and electron microscopy analysis and phagocytosis assays were performed in vivo by injection of 0.9 mm carboxylate-modified polystyrene latex beads in order to identify the hemocyte types involved in phagocytosis. Four morphotypes of circulating hemocytes were found both in larvae and in adults: prohemocytes, granulocytes, oenocytoids and plasmatocytes. After in vivo artificial non-self- challenge treatments, C. lefebvrei showed a non-specific immune response involving phagocytosis performed by plasmatocytes, both in adults and in larvae and by oenocitoids in larvae. In untreated animals, the hemocyte type presenting a firm phagocytic activity, the plasmatocytes, presented a percentage significantly higher in larvae than in adults, and after latex beads injections in larvae there was a tendency of significant difference in plasmatocyte percentage compared to controls injected with phosphate saline buffer. We think that these differences could be correlated with the peculiar morphology (less chitinization) and ecology of larval stages that are more sensitive to pathogens than adults. # 2007 Elsevier Ltd. All rights reserved. Keywords: Hemocytes; Ultrastructure; Latex beads; Phagocytosis; Cellular immunity; Carabus lefebvrei (Coleoptera) 1. Introduction Phagocytosis is a membrane-driven process by which cells include particulate materials in phagosomes. It is involved in multiple cell functions, as nutrition in unicellular organisms, embryogenesis and host–pathogen interaction in immunity in multicellular organism (Lavine and Strand, 2002). Cellular response of insect immune system to pathogens has been shown to be an important determinant to stop the infection progress (Hoffmann, 1995). Different categories of immune cells participate in phagocytosis of small invaders or encapsulation if the foreign object is too large to be phagocytosed (Chapman, 1998; Schmidt et al., 2001). Several classes of hemocytes have been morphologically and functionally characterized in insects (Brehelin et al., 1978; Brehelin, 1982; Hoffmann and Hoffmann, 1990; Hoffmann et al., 1996; Lavine and Strand, 2002). However, their relative contributions to phagocytosis process, which vary between insect species, have not been extensively known. Lepidoptera and Dipteran’s species have been used as main model systems in phagocytic populations hemocytes studies (Brehelin, 1982; Hoffmann, 1995; Hoff- mann et al., 1996; Tzou et al., 2002; Meister and Lagueux, 2003; Au et al., 2004; Costa et al., 2005). Such as to identify two main hemocyte types that perform these defence responses: granulocytes and plasmatocytes. Yet, little is know about morphofunctional data on coleopteran’s species (Brehelin et al., 1978; Giulianini et al., 2003). www.elsevier.com/locate/micron Micron 39 (2008) 552–558 * Corresponding author. Tel.: +39 040 558 3560; fax: +39 040 575079. E-mail address: giuliani@units.it (P.G. Giulianini). 0968-4328/$ – see front matter # 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.micron.2007.07.004