<em></em>A Striking Diploid Male Frequency in a Less Suitable Environment: The Future of the Orchid Bee <em>Euglossa Annectans</em>

Abstract

Climate change and deforestation have figured among the main causes of the pollinators' decline. Especially for bees, the resulting losses of genetic diversity might cause higher levels of nonviable diploid male production, compromising population survival. Herein we evaluate the impact of both climate change and genetic diversity on the present and future of the orchid bee Euglossa annectans Dressler, 1982. We estimated the frequency of diploid males in 359 individuals using eight microsatellite loci. We also build ecological niche models based on 71 occurrence points to project the environmental suitability over time from the past 21 Ka towards 2050 considering the IPCC -RCP 4.5 scenario. We confirmed a diploid male frequency in E. annectans 10-folds higher than any other report for orchid bee species. The niche models also indicate an average reduction of 45.12% in suitable areas for the last 21 Ka and 36.34% up to 2050. Considering the species trend to diploid male production and the projected reduction of suitable area, we strongly recommend connecting and monitoring relictual populations as a strategy to increase the species potential distribution area.

Revisiting the hymenopteran diploid male vortex: a review of avoidance mechanisms and incidence

“…This can be seen in solitary bees that are highly specialized such as the euglossine orchid bees, a group defined by male behavior of collecting volatiles and in the process pollinating co-associated orchid species, in order to attract female mates (Faria et al, 2016). There is one case of higher DMP for an orchid bee (Euglossa annectans Dressler) due to habitat fragmentation and reduced genetic diversity (Frantine-Silva et al, 2021b), but E. cordata (Boff et al, 2014), E. dilemma, and E. viridissima (Soro et al, 2017) do not experience population declines from the same factors. In fact, there is also at least one case of an orchid bee (E. viridissima) becoming invasive and the primary pollinator of an invasive plant (Solanum torvum Swartz), demonstrating that even the most specialized of hymenopterans can decouple from their host plant and adapt (Liu & Pemberton, 2009).…”