Are invasive hymenopteran species replacing native mud dauber wasp-associated taxa on the Seychelles Archipelago?
Nest aggregations of mud dauber wasps increase substrate heterogeneity and provide suitable sites for colonization by other invertebrate species. The mud dauber wasp Sceliphron fuscum Klug, 1801 (Hymenoptera: Sphecidae) abundantly occurs throughout the Seychelles Archipelago, Republic of Seychelles. Here, we estimated the taxonomic richness of the hymenopteran assemblage associated with S. fuscum's nest aggregations, using material collected from the Inner Seychelles in 2016. Furthermore, we examine available historical survey data in order to assess possible changes in this association over decades. We discovered that from 1936 to 1938, seven hymenopteran species were associated with the nest aggregations of S. fuscum on Mahé and Praslin islands, representing six native taxa and one invasive species. From the material collected in 2016, we found one native and three invasive hymenopteran species associated to S. fuscum nests. Our findings could indicate a replacement of native species associated with the mud dauber wasps' nest aggregations by recently introduced alien taxa on the Seychelles Archipelago.