Oscherov E B, Damborsky M P, Bar M E, Gorla D E
Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, Corrientes, Argentina.
Med Vet Entomol. 2004 Dec;18(4):323-8. doi: 10.1111/j.0269-283X.2004.00526.x.
Interspecific competition between two species of triatomine bugs (Hemiptera: Reduviidae), vectors of Chagas disease, was assessed for 16 months through comparative fecundity and mortality of experimental populations in chicken nests, maintained indoors with ambient conditions. Triatoma sordida (Stål), the secondary vector in north-eastern Argentina, was compared with Triatoma infestans (Klug) the more widespread domestic vector in the southern cone of South America. Both species populations originated from females collected in 1995 from the community of Empedrado, Corrientes, Argentina. Three population units were monitored: T. infestans alone, T. sordida alone and both species together in equal proportions. Each population started with six male and six female adults, 116 eggs, and nymphal instars I to V numbering 82, 48, 16, 11 and 19, respectively. Numbers and weight of individual bugs were recorded monthly (August 1995 to December 1996). The pure populations of T. infestans and T. sordida showed temporal changes in abundance, rising in summer and falling in winter, similar to the typical trends under normal field conditions. In the mixed population, however, T. sordida fell to extinction after 6 months, whereas T. infestans reached similar abundance to the pure (control) population. For each nymphal instar of T. sordida, the mean body weight was significantly less and mortality rate was higher in the mixed population compared to the pure population, but there were no significant differences of adult longevity or fecundity between the pure and mixed populations of T. sordida. The apparent competitive displacement of T. sordida by T. infestans was attributed to the latter species having better ability to obtain bloodmeals. This might explain the rarity of mixed populations where these two species occur in sympatry.
对两种锥蝽（半翅目：猎蝽科）——恰加斯病的传播媒介进行了16个月的种间竞争评估，评估通过在室内环境条件下鸡窝中实验种群的相对繁殖力和死亡率来进行。将阿根廷东北部的次要传播媒介污色锥蝽（Stål）与南美洲南锥体地区分布更广的家栖传播媒介大劣按蚊（Klug）进行比较。两个物种的种群均源自1995年从阿根廷科连特斯省恩佩德拉多社区采集的雌性个体。监测了三个种群单位：单独的大劣按蚊、单独的污色锥蝽以及两者等量混合的种群。每个种群起始时有6只雄性和6只雌性成虫、116枚卵，以及一至五龄若虫，数量分别为82只、48只、16只、11只和19只。每月记录单个锥蝽的数量和体重（1995年8月至1996年12月）。大劣按蚊和污色锥蝽的纯种种群数量随时间变化，夏季增加，冬季减少，与正常野外条件下的典型趋势相似。然而，在混合种群中，污色锥蝽在6个月后灭绝，而大劣按蚊的数量达到了与纯（对照）种群相似的水平。对于污色锥蝽的每个若虫龄期，混合种群中的平均体重显著低于纯种种群，死亡率也更高，但污色锥蝽纯种种群和混合种群之间的成虫寿命或繁殖力没有显著差异。污色锥蝽被大劣按蚊明显的竞争取代归因于后者获取血餐的能力更强。这可能解释了这两个物种同域分布时混合种群罕见的原因。
