Limiting resources on the reproductive success of a cavity-nesting bee species in a grassland agroecosystem

ROSANIGO, MARINA P.; MARRERO, HUGO J.; TORRETTA, JUAN P.

JOURNAL OF APICULTURAL RESEARCH

INT BEE RESEARCH ASSOC

Año: 2020 vol. 59 p. 583 - 591

0021-8839

Intensiveagricultural land use can impact pollinators mainly through habitat loss and/ormodification. Native bees are negatively affected by agriculturalintensification, isolation from natural habitats, decreases in plant diversity,and reduction in the availability of nesting sites. Despite this, in thePampean region, there are scarce studies about the effect of agriculturalactivities on native bees. We studied the nesting ecology of the nativeleafcutter bee Megachile gomphrenoides (Megachilidae) in eight sites immersedin an agricultural matrix, where land use is a mosaic of agricultural land andsome semi-natural areas. The sampling was developed using paired trap-nests infragments without agricultural management and in soybean crops. We aimed to analysethe effects of floral and nesting resources on the abundance, the reproductivesuccess and the parasitism rate of a population of M. gomphrenoides in aPampean agroecosystem. Floral diversity was significantly correlated withabundance of nests and brood cells, and both parasitism rate and reproductive successof M. gomphrenoides were higher in nests built in fragments withoutagricultural management when compared to crop areas. Additionally, a negativecorrelation was found between reproductive success and flower diversity in cropareas. These results suggest that floral diversity is limiting the abundance ofM. gomphrenoides nests, its reproductive success as well as its parasitismrate.