Department of Fish, Wildlife and Conservation Ecology, New Mexico State University, Las Cruces, New Mexico 88003.
Present address: Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, Montana 59812.
J Parasitol. 2024 Aug 1;110(4):375-385. doi: 10.1645/23-45.
With the intensity and frequency of wildfires increasing rapidly, the need to study the ecological effects of these wildfires is also growing. An understudied aspect of fire ecology is the effect fires have on parasite-host interactions, including ectoparasites that might be pathogen vectors. Although some studies have examined the impacts of fire on ticks, studies on other ectoparasites, including pathogen vectors, are rare. To help address this knowledge gap, we examined the abiotic and biotic factors that predict the likelihood and extent of parasitism of deer mice (Peromyscus maniculatus) by fleas within a landscape of unburned and recovering burned (>9 yr postfire) mixed conifer forests. We sampled 227 individual deer mice across 27 sites within the Jemez Mountains of northern New Mexico in 2022 and quantified measures of parasitism by fleas (primarily Aetheca wagneri). These sites were distributed in both unburned areas (n = 15) and recovering burned areas (n = 12), with the latter derived from 2 large fires, the Las Conchas fire (2011) and the Thompson Ridge fire (2013). Using these data, we tested for differences in prevalence, mean abundance, and mean intensity of fleas on deer mice, focusing on the predictive importance of host sex and fire history. We also created generalized linear mixed-effects models to investigate the best host and environmental predictors of parasitism by fleas. Approximately a decade postfire, we found minimal evidence to suggest that fire history influenced either the presence or intensity of fleas on deer mice. Rather, at the current forest-regeneration stage, the extent of parasitism by fleas was best predicted by measures of host sex, body condition, and the trapline's ability to accumulate water, as measured through topography. As host body condition increased, the probability of males being parasitized increased, whereas the opposite pattern was seen for females. Male mice also had significantly greater flea loads. Among potential abiotic predictors, the topographic wetness index or compound topographic index (a proxy for soil moisture) was positively related to flea intensity, suggesting larger flea populations in burrows with higher relative humidity. In summary, although fire may potentially have short-term impacts on the likelihood and extent of host parasitism by fleas, in this recovering study system, host characteristics and topographic wetness index are the primary predictors of parasitism by fleas.
随着野火的强度和频率迅速增加，研究这些野火的生态影响的需求也在增长。火生态学中一个研究不足的方面是火灾对寄生虫-宿主相互作用的影响，包括可能是病原体载体的外寄生虫。尽管一些研究已经检查了火灾对蜱的影响，但关于其他外寄生虫（包括病原体载体）的研究很少。为了帮助解决这一知识空白，我们研究了在未燃烧和恢复燃烧（火灾后>9 年）混合针叶林景观中预测鹿鼠（Peromyscus maniculatus）被跳蚤寄生的可能性和程度的非生物和生物因素。我们在 2022 年新墨西哥州杰米兹山脉的 27 个地点对 227 只个体鹿鼠进行了采样，并量化了跳蚤（主要是 Aetheca wagneri）的寄生程度。这些地点分布在未燃烧区（n = 15）和恢复燃烧区（n = 12），后者来自 2 场大火，即拉孔查斯大火（2011 年）和汤普森岭大火（2013 年）。使用这些数据，我们测试了鹿鼠上跳蚤的患病率、平均丰度和平均强度的差异，重点关注宿主性别和火灾历史的预测重要性。我们还创建了广义线性混合效应模型，以研究宿主和环境对跳蚤寄生的最佳预测因素。大约火灾后 10 年，我们几乎没有证据表明火灾历史会影响鹿鼠身上跳蚤的存在或强度。相反，在当前的森林再生阶段，跳蚤寄生的程度最好通过宿主性别、身体状况和陷阱线积累水的能力来预测，这可以通过地形来衡量。随着宿主身体状况的改善，雄性被寄生的可能性增加，而雌性则相反。雄性老鼠的跳蚤负荷也明显更大。在潜在的非生物预测因素中，地形湿度指数或复合地形指数（土壤湿度的代理）与跳蚤强度呈正相关，这表明在相对湿度较高的洞穴中跳蚤数量更多。总之，尽管火灾可能对跳蚤寄生的可能性和程度产生短期影响，但在这个恢复的研究系统中，宿主特征和地形湿度指数是跳蚤寄生的主要预测因素。
