摘要
达尔文雀是种群进化生态学研究的一个模式类群。然而,关于这些鸟类的寄生虫和疾病方面,我们所知甚少。本文对小地雀( Geospiza fuliginosa)的血液和消化道、中地雀( G. fortis)的消化道寄生虫进行了调查。根据对来自3个岛屿127成体血液样本、22个雏鸟血液和消化道样本的检测,我们没有从小地雀的血液里和中地雀的消化道里发现寄生虫。仅仅从1只来自Floreana岛的小地雀雏鸟的消化道里,发现一种寄生虫(Isosporaspp.) [动物学报51 (3) : 507 -512 , 2005]。
The impact of parasites on wild vertebrate populations is receiving increased attention due to findings from numerous studies that document severe parasite-induced fitness costs in hosts (Hart, 1992; Oppliger et al., 1996; Richner, 1998; Milton et al., 2001; Daszak et al., 2003). Avian studies have greatly contributed to our knowledge of parasites in relation to mortality, reduced growth, and lowered reproductive success across taxonomic groups (Oksansen, 1994; Martin et al., 2001; Fessl and Tebbich, 2002; Sanz et al., 2002). Island host-parasite interactions are of considerable interest due to their distribution patterns, which can provide insights into the maintenance of host-parasite associations across variable island environments (van Riper et al.,1986; Apanius et al., 2000). Introduced diseases affecting island bird populations have been identified as strong determinants of population persistence, (e.g., van Riper et al., 2002; Vander Werf, 2001), which is thought to be due to reduced immunological defense against multiple pathogens among insular species (Wikelski et al., 2004). The observation of species-specific and island-specific host-pathogen interactions is important for monitoring the impact of pathogens on host communities at the local level (Apanius et al., 2000). Such specific interactions may occur due to slight differences between island habitats or species compositions (Dobson and Pacala, 1992). Wild birds are commonly infected with coccidia (Phylum Apicomplexa), which are protozoan endoparasites that cause blood parasitism (e.g., Plasmodium, Hemoproteus, Apicomplexa) or intestinal parasitism (e.g., Isospora, Eimeria). Fitness costs induced by avian blood parasites have been reported in relation to breeding success (Siikamaki et al., 1997; Dawson and Bortolotti, 2000), clutch size (Sanz et al., 2002), parental effort (Appleby et al., 1999) and immune function (Navarro et al., 2003). Intestinal protozoan parasites are known to significantly contribute to mortality (Oksansen,1994; Skírnisson,1997), affect nestling growth (Kruszewicz, 1995; Mazgajski and Kdra, 1998), cause dehydration (Todd and Hammond, 1971), weight loss (Callow, 1984), and impair the uptake of nutrients (Augustine and Ruff, 1983). The susceptibility of birds to coccidial infections has been associated with the host’s feeding behavior, ecology, and age (Long, 1970; Skírnisson, 1997; McQuistion, 2000). Both blood parasitism and intestinal coccidiosis are associated with reduced reproductive fitness by interacting with the expression of sexually selected morphological traits and female mate choice (Hillgarth, 1990; Buchholz, 1995; Wiehn et al., 1997; Hill and Brawner, 1998; Freeman-Gallant et al., 2001). Darwin’s finches on the Galapagos Islands are an iconic group of birds that have received much attention within evolutionary biology and behavioral ecology (Grant and Grant, 2003). However, the study of pathogens that may be contributing to their decline has only recently been acknowledged as a priority research area (Wikelski et al., 2004; pers. comm. D. Wiedenfeld, 2004). Introduced pathogens such as the devastating ectoparasite Philornis downsi (see Fessl and Tebbich, 2002), and avian poxvirus (Lindstrm et al., 2004; Kleindorfer and Dudaniec, in press) are receiving increased recognition across the islands. The mangrove finch Cactospiza heliobates has the smallest population of all of the Darwin finches with approximately 200 pairs on Isabela island (a primary reason for this restricted population size is thought to be habitat loss) (Dvorak et al., 2002), while other endemic species including Darwin’s warbler finch Certhidea fusca on Floreana Island are of particular conservation concern, with population fluctuations that may be partially linked with parasitism by P. downsi (Grant et al. 2005). Previous studies have found coccidian infections in Darwin’s finches, with the discovery of six new Isospora species distributed on the islands of Santa Cruz, Isabela, and Daphne Major (McQuistion and Wilson, 1988; McQuistion and Wilson
出处
《动物学报》
SCIE
CAS
CSCD
北大核心
2005年第3期507-512,共6页
ACTA ZOOLOGICA SINICA
