The way pollinators gather resources may play a key role for buffering their population declines. Social pollinators like bumblebees could adjust their foraging after significant workforce reductions to keep provisions to the colony optimal, especially in terms of pollen diversity and quantity. To test what effects a workforce reduction causes on the foraging for pollen, commercially-acquired colonies of the bumblebee Bombus terrestris were allowed to forage in the field and they were experimentally manipulated by removing half the number of workers. For each bumblebee, the pollen pellets were taxonomically identified with DNA metabarcoding of the ITS2 region followed by a statistical filtering based on ROC curves to filter out underrepresented OTUs. Video cameras and network analyses were employed to investigate changes in foraging strategies and behaviour. After filtering out the false-positives, HTS metabarcoding yielded a high plant diversity in the pollen pellets; for plant identity and pollen quantity traits no differences emerged between samples from treated and from control colonies, suggesting that plant choice was influenced mainly by external factors such as the plant phenology. The colonies responded to the removal of 50% of their workers by increasing the foraging activity of the remaining workers, while only negligible changes were found in diet breadth and indices describing the structure of the pollen transport network. Therefore, a consistency in the bumblebees' feeding strategies emerges in the short term despite the lowered workforce.
- MeSH
- biodiverzita MeSH
- fyziologie výživy zvířat MeSH
- opylení fyziologie MeSH
- populační dynamika MeSH
- pyl * genetika MeSH
- rostliny klasifikace genetika MeSH
- stravovací zvyklosti MeSH
- taxonomické DNA čárové kódování MeSH
- včely fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
Species extinctions undermine ecosystem functioning, with the loss of a small subset of functionally important species having a disproportionate impact. However, little is known about the effects of species loss on plant-pollinator interactions. We addressed this issue in a field experiment by removing the plant species with the highest visitation frequency, then measuring the impact of plant removal on flower visitation, pollinator effectiveness and insect foraging in several sites. Our results show that total visitation decreased exponentially after removing 1-4 most visited plants, suggesting that these plants could benefit co-occurring ones by maintaining high flower visitor abundances. Although we found large variation among plant species, the redistribution of the pollinator guild affected mostly the other plants with high visitor richness. Also, the plant traits mediated the effect of removal on flower visitation; while visitation of plants which had smaller inflorescences and more sugar per flower increased after removal, flower visitors did not switch between flower shapes and visitation decreased mostly in plants visited by many morpho-species of flower visitors. Together, these results suggest that the potential adaptive foraging was constrained by flower traits. Moreover, pollinator effectiveness fluctuated but was not directly linked to changes of flower visitation. In conclusion, it seems that the loss of generalist plants alters plant-pollinator interactions by decreasing pollinator abundance with implications for pollination and insect foraging. Therefore, generalist plants have high conservation value because they sustain the complex pattern of plant-pollinator interactions.
- MeSH
- distribuce rostlin MeSH
- druhová specificita MeSH
- extinkce biologická * MeSH
- hmyz fyziologie MeSH
- květy MeSH
- migrace zvířat fyziologie MeSH
- opylení fyziologie MeSH
- pilotní projekty MeSH
- potravní řetězec * MeSH
- stravovací zvyklosti fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
