Solitary oil-collecting bee in cities: Habitat suitability and lack of population structuring in Centris analis

Abstract

The decline of insect populations worldwide has raised concerns about the negative impact on ecosystem services, particularly pollination. Among the vital pollinators, bees play a central role, with wild and solitary species often receiving less attention compared to commercially managed bees. In this study, we focused on investigating the genetic and morphometric variation found across urban populations of the solitary oil-collecting bee Centris (Heterocentris) analis. We collected and examined 361 individuals (259 males, 102 females) from 26 different locations in Brazil between 2012 and 2018. First, we developed a model to identify potential climatic habitats for this species, which revealed its distribution ranging from Mexico and North America to southern Brazil and other countries in South America. Second, to assess the interpopulational genetic differentiation, we genotyped 266 individuals from 25 locations at 16 species-specific microsatellite loci. Our analysis indicated no genetic structuring. Third, a geometric morphometrics analysis of the wings from 361 individuals showed a clear sexual size dimorphism, with centroid size (CS) of males bigger than CS of females, but low differentiation among samples from four phytogeographical regions (Amazonian Forest, Cerrado, Caatinga, and Atlantic Forest). Intranidal sociogenetic structure was assessed through microsatellite genotyping, confirming a monogyny-monandry mating system. Our findings emphasise the importance of studying both male and female solitary bees in the wild and urban areas to better comprehend the impacts of human-dominated habitats on insect population genetics, a critical step for proposing effective conservation and management strategies to preserve them. Understanding the population genetics of these species is a critical step in developing effective conservation and management strategies to preserve them. Moreover, C. analis is a vital pollinator of various plant families, and identifying the plant species most frequently visited by these pollinators and promoting their cultivation in urban landscapes are valuable initiatives to support conservation efforts.