Thu, Aug 05, 2021:On Demand
Background/Question/Methods
Global declines of bumble bees are well-documented, with populations of more than 60% of Bombus spp. decreasing and approximately 45% listed as ‘vulnerable’ or a more severe category by the International Union for Conservation of Nature. Local extinctions and range compressions are driven by habitat loss, agrochemicals, disease and climate change, threatening pollination services in both agricultural and natural ecosystems. Given their economic and ecological importance as pollinators, bumble bee declines have stimulated a proliferation of conservation-focused research over the last two decades. However, it is unknown whether the use of lethal sampling, a common entomological practice, has changed over time in response to conservation concern. We reviewed 411 Bombus-related studies spanning from 1970-2019 alongside a dataset of Bombus pinned specimens (>200k) to discern whether lethal sampling has decreased in association with heightened conservation awareness. For each journal article, we assessed whether (1) lethal and/or non-lethal sampling techniques were used, (2) the paper was explicitly written to have conservation relevance, and then (3) associated each paper with its scientific impact using citations and journal impact factors. We hypothesized that lethal sampling would decrease over time with heightened conservation awareness and that publications utilizing lethal collections would have greater scientific impact.
Results/Conclusions We found that the publication of Bombus-focused papers has increased log-linearly over the last fifty years (r2=0.96, p<0.0001) and that lethal and non-lethal sampling rates have not changed in the same time period. Despite growing conservation awareness (r2=0.74, p<0.0001) and availability of non-lethal sampling methods, lethal specimen collection has accelerated with publication volume (r2=0.33, p<0.0001). Remarkably, the highest rates of lethal sampling are associated with papers demonstrating conservation awareness (χ2=8.135, df=1, p=0.004). Furthermore, we found that papers using lethal sampling were likely to have fewer citations on average (r2=0.09, p<0.001) and publication in academic journals with lower impact factors (r2=0.04, p<0.01), highlighting the utility of non-lethal approaches for investigating critical research questions. Facing myriad pressures, vulnerable bumble bee populations may be less resilient to traditional sampling norms than broadly assumed. While non-destructive sampling does not replace the numerous utilities of physical specimens, technological advances allow us to answer important questions about bumble bee colonies, populations and communities without the need for extravagant collection sizes. We highlight non-lethal sampling alternatives and underscore the need to draft proactive, empirically informed sampling guidelines that align with the long-term conservation needs of bumble bee pollinators.
Results/Conclusions We found that the publication of Bombus-focused papers has increased log-linearly over the last fifty years (r2=0.96, p<0.0001) and that lethal and non-lethal sampling rates have not changed in the same time period. Despite growing conservation awareness (r2=0.74, p<0.0001) and availability of non-lethal sampling methods, lethal specimen collection has accelerated with publication volume (r2=0.33, p<0.0001). Remarkably, the highest rates of lethal sampling are associated with papers demonstrating conservation awareness (χ2=8.135, df=1, p=0.004). Furthermore, we found that papers using lethal sampling were likely to have fewer citations on average (r2=0.09, p<0.001) and publication in academic journals with lower impact factors (r2=0.04, p<0.01), highlighting the utility of non-lethal approaches for investigating critical research questions. Facing myriad pressures, vulnerable bumble bee populations may be less resilient to traditional sampling norms than broadly assumed. While non-destructive sampling does not replace the numerous utilities of physical specimens, technological advances allow us to answer important questions about bumble bee colonies, populations and communities without the need for extravagant collection sizes. We highlight non-lethal sampling alternatives and underscore the need to draft proactive, empirically informed sampling guidelines that align with the long-term conservation needs of bumble bee pollinators.