Simková Andrea, Jarkovský Jirí, Koubková Bozena, Barus Vlastimil, Prokes Miroslav
Department of Zoology and Ecology, Faculty of Science, Masaryk University, Kotlárská 2, 61137, Brno, Czech Republic.
Parasitol Res. 2005 Jan;95(1):65-72. doi: 10.1007/s00436-004-1261-y. Epub 2004 Nov 25.
The parasite fauna of the stone loach (Barbatula barbatula) was investigated monthly from May to December 2001. Four parasite species were recorded: Gyrodactylus spp. (Monogenea), Tylodelphys clavata (Digenea), Proteocephalus sagittus (Cestoda), and Raphidascaris acus (Nematoda). The changes in the seasonal dynamics of parasite infection were investigated throughout the 8 months. The potential effect of the reproductive investment of the host, measured by gonad mass and gonado-somatic index (GSI), on the parasite infection was tested against the prediction that, during periods of high reproductive investment (beginning of the breeding period or forming gonads after breeding), the fish are more susceptible to parasite infection. Differences between parasite loads between genders were also hypothesized. Seasonal differences in infection were observed for all parasite species studied. The values of GSI showed a pattern of energy accumulation in the pre-reproductive period and at the beginning of breeding, a decrease during breeding, and an increase in the post-breeding period. A similar pattern was observed for parasite abundance, a strong or weak increase in spring and/or autumn and a decrease during summer (July and August). Positive correlations between the abundance of Gyrodactylus spp. and R. acus and both gonad mass and GSI were found in females after eliminating the effect of fish weight. Our results suggest that stone loach females are more susceptible to parasite infection in periods of higher reproductive investment. The main factor determining the infection of T. clavata was fish size. The abundance of P. sagittus was positively correlated with GSI in the total fish sample with no detectable effect of sex or fish weight. The increase in cestode infection in spring supports the hypothesis that the parasite life cycle could by synchronized with the beginning of host reproduction, probably induced by increasing fish hormone levels in the spring.
2001年5月至12月，每月对石爬鮡（Barbatula barbatula）的寄生虫区系进行调查。记录了四种寄生虫：三代虫属（Gyrodactylus spp.，单殖吸虫纲）、棒尾囊宫吸虫（Tylodelphys clavata，复殖吸虫纲）、箭形前殖吸虫（Proteocephalus sagittus，绦虫纲）和鲤嗜子宫线虫（Raphidascaris acus，线虫纲）。在这8个月期间研究了寄生虫感染的季节动态变化。通过性腺质量和性腺-体质量指数（GSI）衡量宿主的繁殖投入对寄生虫感染的潜在影响，并根据以下预测进行检验：在繁殖投入高的时期（繁殖期开始或繁殖后形成性腺），鱼类更容易受到寄生虫感染。还假设了不同性别之间寄生虫负荷的差异。在所研究的所有寄生虫种类中均观察到感染的季节差异。GSI值呈现出在繁殖前期和繁殖开始时能量积累、繁殖期间下降以及繁殖后期增加的模式。寄生虫丰度也观察到类似模式，在春季和/或秋季有强烈或微弱增加，夏季（7月和8月）减少。在消除鱼体重的影响后，发现雌性三代虫属和鲤嗜子宫线虫的丰度与性腺质量和GSI均呈正相关。我们的结果表明，石爬鮡雌鱼在繁殖投入较高的时期更容易受到寄生虫感染。决定棒尾囊宫吸虫感染的主要因素是鱼的大小。在整个鱼样本中，箭形前殖吸虫的丰度与GSI呈正相关，未检测到性别或鱼体重的影响。春季绦虫感染的增加支持了这样的假设，即寄生虫的生命周期可能与宿主繁殖的开始同步，可能是由春季鱼激素水平升高诱导的。
