Moquet Laura, Laurent Estelle, Bacchetta Rossana, Jacquemart Anne-Laure
Research Group Genetics, Reproduction, Populations Earth and Life Institute - Université catholique de Louvain Louvain-la-Neuve Belgium.
Present address: Research group Quantitative Conservation Biology Earth and Life Institute - Universite catholique de Louvain Louvain-la-Neuve Belgium.
Insect Conserv Divers. 2018 Jan;11(1):72-87. doi: 10.1111/icad.12245. Epub 2017 Jul 10.
Accumulating evidence shows that landscape fragmentation drives the observed worldwide decline in populations of pollinators, particularly in species of Lepidoptera and Hymenoptera. However, Little is known about the effects of landscape fragmentation on hoverfly (Diptera, Syrphidae) communities. Hoverflies provide varied ecosystem services: larvae contribute to waste decomposition (saprophagous species) and pest control (aphidophagous species), and adults pollinate a wide range of flowers.To determine how the diversity and quantity of resources for larvae and adults affect hoverfly abundance and species richness at three spatial scales, we recorded insect visitors of five target plant species in Belgian heathlands, habitats that have decreased considerably due to human activities.Hoverflies represented the most abundant visitors on two plant species, and the second most abundant visitors (after bumblebees) on the other target plant species. A large proportion of hoverflies observed were aphidophagous species associated with coniferous and deciduous forests. Resources for the larvae and floral resources for the adults influenced interactions among hoverflies and plants, but acted at different scales: larval habitat availability (distance to larval habitat) was relevant at the landscape scale, whereas adult resource availability (floral density) was relevant at the plot scale.Hoverfly abundance and species richness decreased with distance to larval habitat but increased with floral density. Moreover, landscape structure and composition had different effects according to hoverfly ecological traits. Landscape composition influenced aphidophagous but not saprophagous hoverflies, in that their abundance and species richness decreased with distance to forests. Maintenance of the interactions between plants and their hoverfly visitors requires complementary resources at both landscape and local scales.
越来越多的证据表明，景观破碎化导致了全球传粉者种群数量的下降，尤其是鳞翅目和膜翅目物种。然而，关于景观破碎化对食蚜蝇（双翅目，食蚜蝇科）群落的影响却知之甚少。食蚜蝇提供多种生态系统服务：幼虫有助于废物分解（腐食性物种）和害虫控制（食蚜物种），成虫则为多种花卉授粉。为了确定幼虫和成虫的资源多样性和数量如何在三个空间尺度上影响食蚜蝇的丰度和物种丰富度，我们记录了比利时石南荒地中五种目标植物物种的昆虫访客，这些栖息地因人类活动而大幅减少。食蚜蝇是两种植物物种上最丰富的访客，在其他目标植物物种上是第二丰富的访客（仅次于熊蜂）。观察到的大部分食蚜蝇是与针叶林和落叶林相关的食蚜物种。幼虫资源和成虫的花卉资源影响了食蚜蝇与植物之间的相互作用，但作用尺度不同：幼虫栖息地可用性（到幼虫栖息地的距离）在景观尺度上相关，而成虫资源可用性（花卉密度）在地块尺度上相关。食蚜蝇的丰度和物种丰富度随着到幼虫栖息地距离的增加而降低，但随着花卉密度的增加而增加。此外，景观结构和组成根据食蚜蝇的生态特征有不同影响。景观组成影响食蚜但不影响腐食性食蚜蝇，因为它们的丰度和物种丰富度随着到森林距离的增加而降低。维持植物与其食蚜蝇访客之间的相互作用需要在景观和局部尺度上都有互补资源。
