Abstract：
We studied the relationship between fleas\' metabolic rate and their ecological traits, using data on standard metabolic rate (SMR), mean abundance, host specificity, and geographic range size in males and females of seven desert flea species. SMR was measured via mass-specific CO2 emission, whereas host specificity was measured as (a) the mean number of host species used by a flea per region in regions where this flea was recorded; (b) the total number of host species a flea exploited across its geographic range; and (c) the phylogenetic diversity of the flea\'s hosts. To control for confounding effects of phylogeny when analysing data on multiple species, we applied the Phylogenetic Generalised Least Squares (PGLS) model. We found that the only ecological trait significantly correlating with flea SMR was the phylogenetic diversity of hosts utilized by a flea across its geographic range. The strength of the association between SMR and host phylogenetic diversity was higher in male than in female fleas. We explain the relationship between flea SMR and their host specificity by the necessity of host-opportunistic species to compensate for the high energetic cost of neutralizing multiple defences from multiple hosts by increased SMR.
摘要：
我们研究了跳蚤的代谢率与其生态特征之间的关系，使用标准代谢率(SMR)的数据，意味着丰富，宿主特异性，以及七个沙漠跳蚤物种的雄性和雌性的地理范围。SMR是通过质量比CO2排放量测量的，而宿主特异性的测量方法是：(a)在记录该跳蚤的地区，每个区域的跳蚤使用的宿主物种的平均数；(b)跳蚤在其地理范围内利用的宿主物种总数；(c)跳蚤宿主的系统发育多样性。在分析多个物种的数据时，为了控制系统发育的混杂效应，我们应用了系统发育广义最小二乘(PGLS)模型。我们发现，与跳蚤SMR显着相关的唯一生态特征是跳蚤在其地理范围内利用的宿主的系统发育多样性。SMR与寄主系统发育多样性之间的关联强度在雄性跳蚤中高于雌性跳蚤。我们通过宿主机会物种的必要性来解释跳蚤SMR与其宿主特异性之间的关系，以补偿通过增加SMR来中和来自多个宿主的多种防御的高能量成本。
