Garden plants for wild bees – laypersons’ assessment of their suitability and opinions on gardening approaches

Nest site availability and quality are important for maintaining robust populations and communities of wild bees. However, for most species, nesting traits and nest site conditions are poorly known, limiting both our understanding of basic ecology for bee species and conservation efforts. Additionally, many of the threats commonly associated with reducing bee populations have effects that can extend into nests but are largely unstudied. In general, threats such as habitat disturbances and climate change likely affect nest site availability and nest site conditions, which in turn affect nest initiation, growth, development, and overwintering success of bees. To facilitate a better understanding of how these and other threats may affect nesting bees, in this review, I quantify key nesting traits and environmental conditions and then consider how these traits may intersect with observed and anticipated changes in nesting conditions experienced by wild bees. These data suggest that the effects of common threats to bees through nesting may strongly influence their survival and persistence but are vastly understudied. Increasing research into nesting biology and incorporating nesting information into conservation efforts may help improve conservation of this declining but critical group.

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Possible Epigenetic Origin of a Recurrent Gynandromorph Pattern in Megachile Wild Bees

Insects ◽

10.3390/insects12050437 ◽

2021 ◽

Vol 12 (5) ◽

pp. 437

Author(s):

Daniele Sommaggio ◽

Giuseppe Fusco ◽

Marco Uliana ◽

Alessandro Minelli

Keyword(s):

Current Knowledge ◽

Sex Differentiation ◽

General Pattern ◽

Body Parts ◽

Wild Bees ◽

Male And Female ◽

Female Phenotype ◽

In The Wild ◽

Gene Transcripts ◽

Individual Body

Gynandromorphs, i.e., individuals with a mix of male and female traits, are common in the wild bees of the genus Megachile (Hymenoptera, Apoidea). We described new transverse gynandromorphs in Megachile pilidens Alfkeen, 1924 and analyze the spatial distribution of body parts with male vs. female phenotype hitherto recorded in the transverse gynandromorphs of the genus Megachile. We identified 10 different arrangements, nine of which are minor variants of a very general pattern, with a combination of male and female traits largely shared by the gynandromorphs recorded in 20 out of 21 Megachile species in our dataset. Based on the recurrence of the same gynandromorph pattern, the current knowledge on sex determination and sex differentiation in the honey bee, and the results of recent gene-knockdown experiments in these insects, we suggest that these composite phenotypes are possibly epigenetic, rather than genetic, mosaics, with individual body parts of either male or female phenotype according to the locally expressed product of the alternative splicing of sex-determining gene transcripts.

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Wild bees of Chile: a database on taxonomy, sociality, and ecology

Ecology ◽

10.1002/ecy.3377 ◽

2021 ◽

Author(s):

Manuel López‐Aliste ◽

Luis Flores‐Prado ◽

Luisa Ruz ◽

Yanet Sepúlveda ◽

Sharon Rodríguez ◽

...

Keyword(s):

Wild Bees

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Identity of mass-flowering crops moderates functional trait composition of pollinator communities

Landscape Ecology ◽

10.1007/s10980-021-01261-3 ◽

2021 ◽

Author(s):

Nicole Beyer ◽

Felix Kirsch ◽

Doreen Gabriel ◽

Catrin Westphal

Keyword(s):

Faba Bean ◽

Management Practices ◽

Functional Trait ◽

Flower Morphology ◽

Landscape Diversity ◽

Floral Resources ◽

Wild Bees ◽

Natural Habitats ◽

Mass Flowering ◽

Wild Bee

Abstract Context Pollinator declines and functional homogenization of farmland insect communities have been reported. Mass-flowering crops (MFC) can support pollinators by providing floral resources. Knowledge about how MFC with dissimilar flower morphology affect functional groups and functional trait compositions of wild bee communities is scarce. Objective We investigated how two morphologically different MFC, land cover and local flower cover of semi-natural habitats (SNH) and landscape diversity affect wild bees and their functional traits (body size, tongue length, sociality, foraging preferences). Methods We conducted landscape-level wild bee surveys in SNH of 30 paired study landscapes covering an oilseed rape (OSR) (Brassica napus L.) gradient. In 15 study landscapes faba beans (Vicia faba L.) were grown, paired with respective control landscapes without grain legumes. Results Faba bean cultivation promoted bumblebees (Bombus spp. Latreille), whereas non-Bombus densities were only driven by the local flower cover of SNH. High landscape diversity enhanced wild bee species richness. Faba bean cultivation enhanced the proportions of social wild bees, bees foraging on Fabaceae and slightly of long-tongued bumblebees. Solitary bee proportions increased with high covers of OSR. High local SNH flower covers mitigated changes of mean bee sizes caused by faba bean cultivation. Conclusions Our results show that MFC support specific functional bee groups adapted to their flower morphology and can alter pollinators` functional trait composition. We conclude that management practices need to target the cultivation of functionally diverse crops, combined with high local flower covers of diverse SNH to create heterogeneous landscapes, which sustain diverse pollinator communities.

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Nesting, Sex Ratio and Natural Enemies of the Giant Resin Bee in Relation to Native Species in Europe

Insects ◽

10.3390/insects12060545 ◽

2021 ◽

Vol 12 (6) ◽

pp. 545

Author(s):

Sara Straffon Díaz ◽

Luca Carisio ◽

Aulo Manino ◽

Paolo Biella ◽

Marco Porporato

Keyword(s):

Sex Ratio ◽

Natural Enemies ◽

Native Species ◽

Wild Bees ◽

Trap Nests ◽

Native Bee ◽

New Locations ◽

Negative Impacts ◽

Set Up ◽

North Western

Megachile sculpturalis (Smith, 1853) is the first exotic bee species in Europe. Its remarkably fast expansion across this continent is leading to a growing concern on the extent of negative impacts to the native fauna. To evaluate the interactions of exotic bees with local wild bees, we set up trap nests for above-ground nesting bees on a semi-urban area of north-western Italy. We aimed to investigate the interaction in artificial traps between the exotic and native wild bees and to assess offspring traits accounting for exotic bee fitness: progeny sex ratio and incidence of natural enemies. We found that the tunnels occupied by exotic bees were already cohabited by O. cornuta, and thus the cells of later nesting alien bees may block the native bee emergence for the next year. The progeny sex ratio of M. sculpturalis was strongly unbalanced toward males, indicating a temporary adverse population trend in the local invaded area. In addition, we documented the presence of three native natural enemies affecting the brood of the exotic bee. Our results bring out new insights on how the M. sculpturalis indirectly competes with native species and on its performance in new locations.

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