Abundance of lungworm parasites in invasive cane toads from burned and unburned sites

The frequency and severity of wildfires are increasing due to anthropogenic modifications to habitats and to climate. Post-fire landscapes may advantage invasive species via multiple mechanisms, including changes to host-parasite interactions. We surveyed the incidence of endoparasitic lungworms (Rhabdias pseudosphaerocephala) in invasive cane toads (Rhinella marina) in near-coastal sites of eastern Australia, a year after extensive fires in this region. Both the prevalence of infection, and number of worms in infected toads, increased with toad body size in unburned areas. In contrast, parasite load decreased rather than increased with toad body size in burned areas. By killing moisture-dependent free-living lungworm larvae, the intense fires may have liberated adult cane toads from a parasite that can substantially reduce the viability of its host. Smaller toads, which are restricted to moist environments, did not receive this benefit from fires.

Methods
Toads were collected by community volunteers, humanely euthanased, and dissected to count lungworms.

由于人类对栖息地的改造以及气候变化的影响，野火的发生频率和严重程度正在加剧。火灾后的景观可能通过多种机制，包括宿主-寄生虫相互作用的变化，为入侵物种提供优势。我们在澳大利亚东部沿海地区广泛火灾发生一年后，调查了该地区入侵性甘蔗蟾蜍（Rhinella marina）中内寄生虫肺蠕虫（Rhabdias pseudosphaerocephala）的发病率。感染率以及感染蟾蜍体内虫子数量与蟾蜍体型在未燃烧区域呈正相关。然而，在燃烧区域，寄生虫负荷随蟾蜍体型增大而减少而非增加。通过杀死依赖水分的自由生活肺蠕虫幼虫，强烈的大火可能释放了甘蔗蟾蜍，使其免受一种能显著降低其宿主生存能力的寄生虫的侵害。那些局限于湿润环境的体型较小的蟾蜍没有从火灾中获得这种益处。

方法
通过社区志愿者收集蟾蜍，人道地安乐死并进行解剖，以计数肺蠕虫。