Tag: foraging

Natural history collections shed light on bumblebees’ modern struggles

Using pollen metabarcoding, researchers analyzed historical and recent bee specimens, revealing significant shifts in foraging patterns.

A new study highlights potential causes for changing foraging habits of bumblebees. Using advanced molecular techniques called pollen metabarcoding, researchers investigated interactions between bumblebees and plants in Cuxhaven, Germany, and how they changed over 60 years. Their findings can help us understand the connections between availability of floral resources and changing landscapes.

The study, led by the Botany Department of the University of Kassel (Germany) in collaboration with the Leibniz Institute for the Analysis of Biodiversity Change (Germany), used bumblebee specimens from historical museum collections dating back to 1968/69 and compared them with bumblebees collected in the field in 2019. By analyzing pollen samples attached to the bodies of the bees, the researchers were able to identify the plant species they had interacted with.

The results revealed significant shifts in the foraging habits of bumblebees between the late 1960s and more recent sampling periods. In particular, there was a noticeable decrease in interactions with Fabaceae plants in 2019 compared to the past. “This suggests that changes in the landscape have led to alterations in the availability of floral resources, which may contribute to the decline of specialized bee species,” the researchers explain.

“The successful application of scalable molecular techniques to analyze historical pollen samples highlights the value of museum collections as a valuable resource for biodiversity research,” they add. “This study, published in the journal Metabarcoding and Metagenomics, serves as a proof of concept for comparative analysis of recent and historical pollination data, providing important insights into the changes in foraging trends of bumblebees over time.”

“In conclusion, this study contributes to our understanding of bumblebee interactions with foraging resources and the impact of landscape changes on their foraging habits,” say the researchers. Their findings underscore the importance of conserving and restoring suitable habitats for pollinators.

“Future research in this field is expected to provide valuable insights for the conservation and management of pollinators and their critical role in maintaining ecosystems,” they conclude.

Original source:

Kolter A, Husemann M, Podsiadlowski L, Gemeinholzer B (2023) Pollen metabarcoding of museum specimens and recently collected bumblebees (Bombus) indicates foraging shifts. Metabarcoding and Metagenomics 7: e86883. https://doi.org/10.3897/mbmg.7.86883

Images by Andreas Kolter

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First Australian night bees recorded foraging under the cover of darkness

Original post by Flinders University, Australia

Australian bees are known for pollinating plants on beautiful sunny days, but a new study has identified two species that have adapted their vision for night-time conditions for the first time.

The study by a team of ecology researchers has observed night time foraging behaviour by a nomiine (Reepenia bituberculata) and masked (Meroglossa gemmata) bee species, with both developing enlarged compound and simple eyes which allow more light to be gathered when compared to their daytime kin.

Published in the Journal of Hymenoptera Research, the researchers explain that this improved low-light ability could potentially also exist in other Australian species secretly active at night, with their image processing ability best observed through high-resolution close-up images. 

Lead author PhD Candidate James Dorey, in the College of Science & Engineering at Flinders University, says the two Australian bee species active at night and during twilight hours are mostly found in Australia’s tropical north, but there could potentially more in arid, subtropical and maybe even temperate conditions across the continent.

“We have confirmed the existence of at least two crepuscular bee species in Australia and there are likely to be many more that can forage both during the day and into the early morning or evening under low light conditions. It’s true that bees aren’t generally known to be very capable when it comes to using their eyes at night, but it turns out that low-light foraging is more common than currently thought,”

says Mr Dorey.

“Before this study, the only way to show that a bee had adapted to low-light was by using difficult-to-obtain behavioural observations, but we have found that you should be able to figure this out by using high-quality images of a specific bee.”

Mr Dorey says bees that forage during dim-light conditions aren’t studied enough with no previously reliable published records for any Australian species.  

“Our study provides a framework to help identify low-light-adapted bees and the data that is needed to determine the behavioural traits of other species. This is important as we need to increase efforts to collect bee species outside of normal hours and publish new observations to better understand the role that they play in maintaining ecosystems.”

The researchers outline why more needs to be understood about the behaviour of bee species to help protect them from the potential impacts of climate change. 

“Global weather patterns are changing and temperatures in many parts of Australia are rising along with the risk of prolonged droughts and fires. So, we have to improve our understanding about insects pollinating at night or in milder parts of the day to avoid potential extinction risks or to mitigate loss of pollination services.” 

“This also means we have to highlight the species that operate in a narrow window of time and could be sensitive to climatic changes, so conservation becomes an important concern. Because quite frankly, we have ignored these species up until now.”

Publication:

Dorey JB, Fagan-Jeffries EP, Stevens MI, Schwarz MP (2020) Morphometric comparisons and novel observations of diurnal and low-light-foraging bees. Journal of Hymenoptera Research 79: 117–144. https://doi.org/10.3897/jhr.79.57308