Action of Andiroba Oil (Carapa guianensis) on Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) Semi-engorged Females: Morphophysiological Evaluation of Reproductive System MARIA CLA ´ UDIA RAMALHO VENDRAMINI, 1 MARIA IZABEL CAMARGO MATHIAS, 1 ADRIANO UEMURA DE FARIA, 1 KARIM CHRISTINA SCOPINHO FURQUIM, 2 LEONARDO PERES DE SOUZA, 1 GERVA ´ SIO HENRIQUE BECHARA, 2 AND GISLAINE CRISTINA ROMA 1 * 1 UNESP, Univ. Estadual Paulista, Avenida 24 A, 1515, 13506-900, Rio Claro, Sa ˜ o Paulo, CP 199, Brazil 2 UNESP, Univ. Estadual Paulista, Via de acesso Prof. Paulo Castellane, s/n, 14884-900, Jaboticabal, Sa ˜ o Paulo, Brazil KEY WORDS ticks; natural product; germ cells; cytotoxicity; reproductive efficiency index ABSTRACT Because of the increasing medical-veterinary importance of ticks, the development of alternative control methods, less aggressive to the host and the environment has become the tar- get of several researches. In this sense, the present study analyzed the action of different concen- trations (5, 10, and 20%) of andiroba seed oil (Carapa guianensis) on the reproductive system of Rhipicephalus sanguineus females, through histochemical techniques and the quantification of the reproductive efficiency index. The results showed that andiroba oil is a potent natural agent, able to cause several changes in the oocytes of this species, impairing the reproductive success, once this natural product induces great physiological changes in the oocytes in all development stages, such as drastic reduction in proteins, polysaccharides, and lipids in these cells, and these compo- nents are essential for the viability of the embryo. In addition, it was observed that this product stimulate the oviposition, mainly at the concentration of 20%. This higher production of eggs repre- sents a defense mechanism developed by the organism in order to ensure the reproductive success of the species, even in the presence of the toxic agent. However, the results obtained suggested that the laid eggs would not be viable, due to the great changes undergone by the oocytes. Thus, the present study showed that the use of this vegetal product would be an alternative way to control the ticks, bringing benefits similar to the ones obtained through the use of synthetic acaricides; however, with less damage to nontarget organisms and the environment as well. Microsc. Res. Tech. 00:000–000, 2012. V V C 2012 Wiley Periodicals, Inc. INTRODUCTION The ticks constitute one of the most important groups of arthropods from the medical and veterinary points of view, once they cause lesions on the hosts dur- ing the process of blood feeding, in addition to being vectors of pathogenic agents, affecting animals, includ- ing the human being (Walker, 1994). The group comprises animals belonging to Acari order, subclass Arachnida, being classified in three families: Ixodidae, Argasidae, and Nutalliellidae (Anderson and Magnarelli, 2008). R. sanguineus (Latreille, 1806) species is found within Ixodidae fam- ily, which is distributed throughout all the continents of the planet, mainly parasitizing the domestic dog. In addition to causing significant blood loss in the hosts, this species is also a vector of viruses, bacteria, and protozoa, which cause diseases such as Babesia canis, protozoa that acts on the erythrocytes causing babesiosis or ‘‘nambiuvu’’ (Flechtmann, 1973), Hepato- zoon canis, biopathogen of hepatozoonosis in dogs in Latin America (O’dwyer and Massard, 2001; Vicent- Johnson et al., 1997) and also Ehrlichia canis, which attack the dog leukocytes (Davoust, 1993; Simpson et al., 1991). Data from literature describe that R. sanguineus, due to their low specificity, are also potential vectors of the bacteria Francisella tularensis, etiologic agent of tu- laremia to the human being (Walker, 1994). The females reproductive system of R. sanguineus, as for ticks in general, is essential for the development and perpetuation of the species, consisting of a tubular ovary located in the posterior region of the body, with a pair of oviducts, an uterus, a vagina, and a pair of accessory glands ending in the genital opening (Said, 1992; Sonenshine, 1991). This organ contains a wall formed by small epithelial cells with spherical nuclei, where a great number of oocytes attach; undergoing several stages of development until the oviposition phase (Oliveira et al., 2005). Methods for an effective control of ticks have contin- uously been researched, as well as new acaricide *Correspondence to: Dr. Gislaine Cristina Roma, UNESP, Univ. Estadual Paulista, Avenida 24 A, 1515, 13506-900, Rio Claro, Sao Paulo, CP 199, Brazil. E-mail: gislaineroma@yahoo.com.br Received 15 June 2012; accepted in revised form 16 August 2012 Contract grant sponsor: Fundac ¸a ˜o de Amparo a ` Pesquisa do Estado de Sa ˜o Paulo-FAPESP; Contract grant numbers: 2011/07938-9, 2011/10427-6, 2010/ 51942-8, and 2011/06865-8 DOI 10.1002/jemt.22126 Published online in Wiley Online Library (wileyonlinelibrary.com). V V C 2012 WILEY PERIODICALS, INC. MICROSCOPY RESEARCH AND TECHNIQUE 00:000–000 (2012)