CHU Lille, EA 7367-UTML-Unite de Taphonomie Medico-Legale, University of Lille, Lille, 59000, France.
Insect Sci. 2021 Feb;28(1):144-152. doi: 10.1111/1744-7917.12766. Epub 2020 Jun 25.
Necrophagous blowflies (Diptera: Calliphoridae) such as Calliphora vicina, a cold-tolerant species, and Lucilia sericata, a warm-adapted species, are pioneer carrion-breeder. Although these two species have different temperature preferences, larvae aggregate actively and often feed simultaneously on carrion. The hypothesis to be tested was that L. sericata benefits from the association with C. vicina at lower temperatures (i.e., 15 °C) and that C. vicina derives greater benefits from this association at higher temperatures (i.e., 28 °C). Therefore, both species were raised at these two constant temperatures from first instars to adults under three different conditions: monospecific low-density, monospecific high-density, and heterospecific high-density. The time until larval migration, surface area of puparia, and survival rates were determined for each condition. Differences between these fitness-related traits were found between species, temperatures, group densities, and species compositions. At 28 °C, C. vicina larvae bred in heterospecific groups migrated significantly earlier and in higher numbers than that under same density conspecific conditions, with a lower mortality rate. At 15 °C, both species benefited from high-density heterospecific associations, expressed by faster development and larger puparia. In conclusion, necrophagous larvae benefited from heterospecific aggregations at suboptimal temperatures by adapting their migration time to that of the faster species. Since temperature changes throughout the day and over the year, the beneficiary of such a collective association also changes. The costs involved and deviations to the temperature-size rule highlight the complexity of the carrion ecosystem.
嗜尸性麻蝇（双翅目：Calliphoridae），如耐寒物种丽蝇 Calliphora vicina 和适温物种丝光绿蝇 Lucilia sericata，是先锋腐肉生物。尽管这两个物种对温度有不同的偏好，但幼虫会主动聚集，并经常同时在腐肉上进食。要测试的假设是，在较低温度（即 15°C）下，丝光绿蝇从与丽蝇的共生中受益，而丽蝇在较高温度（即 28°C）下从这种共生中获得更大的益处。因此，两种蝇从一龄幼虫到成虫，在三种不同条件下分别在这两个恒定温度下饲养：单种低密度、单种高密度和异种高密度。确定了每种条件下幼虫迁移时间、蛹表面积和存活率。在这些与适应性相关的特征上，在种间、温度、群体密度和种间组成方面存在差异。在 28°C 时，异种群体中饲养的丽蝇幼虫比相同密度同种条件下更早且数量更多地迁移，死亡率更低。在 15°C 时，两种蝇都受益于高密度的异种共生，表现为发育更快和蛹更大。总之，嗜尸性幼虫在亚适温下通过适应迁移时间来受益于异种聚集。由于温度在一天中和一年中会发生变化，因此这种集体共生的受益者也会发生变化。所涉及的成本和对温度-体型规律的偏离突出了腐肉生态系统的复杂性。
