Kudô K, Hasegawa M, Mateus S, Zucchi R, Nascimento F S
Depto de Biologia, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Univ de São Paulo, Ribeirão Preto, SP, 14040-901, Brasil.
Lab of Insect Ecology, Faculty of Education, Niigata Univ, Niigata, Japan.
Neotrop Entomol. 2019 Jun;48(3):368-372. doi: 10.1007/s13744-018-0649-9. Epub 2018 Nov 28.
Social insects face strong selection from parasites because the conditions of group living often favor the transmission of infection among nestmates. However, there is little detailed information on the effects of parasite infection in the host species. Workers of Polybia species, neotropical swarm-founding wasps, are commonly infected by gregarines, protozoans that are exclusively parasitic on invertebrates. Previous studies showed that high rates of gregarine infection in workers of Polybia occidentalis (Olivier) have negative effects on their colony performance. However, the effect of seasonality on infection rates throughout the year or between wet and dry seasons has not been examined. Host-parasite interactions cannot be understood without consideration of the overall population dynamic. We compared rates of gregarine infection in workers of Polybia paulista (Ihering) between wet and dry seasons and among months. The 35% rate was by far the highest of the four wet seasons sampled, but the rates declined in the mid-wet season and were very low during the dry season. Strong seasonal differences in infection rates were also observed between the dry and wet seasons. Several potential factors affecting the seasonal differences are discussed.
群居昆虫面临着来自寄生虫的强大选择压力，因为群体生活的条件往往有利于感染在同巢伙伴之间传播。然而，关于寄生虫感染对宿主物种的影响，目前几乎没有详细信息。新热带地区群居性黄蜂多鞭蚁属的工蚁通常会被簇虫感染，簇虫是一类专门寄生于无脊椎动物的原生动物。先前的研究表明，西方多鞭蚁（Olivier）工蚁的高簇虫感染率对其蚁群表现有负面影响。然而季节性对全年或干湿季节间感染率的影响尚未得到研究。如果不考虑总体种群动态，就无法理解宿主 - 寄生虫之间的相互作用。我们比较了圣保罗多鞭蚁（Ihering）工蚁在干湿季节以及不同月份的簇虫感染率情况：在所采样的四个雨季中，35% 的感染率是迄今为止最高的，但在雨季中期感染率下降，在旱季则非常低。在旱季和雨季之间也观察到了感染率的强烈季节性差异。文中还讨论了影响季节性差异的几个潜在因素。
