Local and landscape effects on the reproduction of wild bees and wasps in Mediterranean communities along a gradient of land-use
Data files
Dec 11, 2024 version files 44.03 KB
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DATA_MARRERO_Ecol.Ent_2024.xlsx
39.80 KB
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README.md
4.23 KB
Abstract
The transformation of natural landscapes for agricultural proposes may severely affect wild bee and wasp reproduction. In this study, we located trap-nests on 18 natural Mediterranean communities within agricultural areas to study the effects of landscape (% natural areas and heterogeneity) and local flowering communities (flower abundance and richness) on the total abundance and richness of solitary bees and wasps that nest within cavities. We also estimated several reproductive variables (number of nests, number of cells per nest, sex ratio, parasitoidism and survival) of the two most common species in the study system: the bee Osmia caerulescens and the wasp Ancistrocerus longispinosus. We found that total bee abundance increased with flower richness and landscape heterogeneity, while it decreased with flower abundance. Furthermore, our results indicated local and landscape effects on the focal species’ reproductive success, being overall stronger those at the local than at the landscape scale. Floral richness and abundance influenced the number of cells per nest. However, while the effect of flower abundance was positive in both cases, the effect of flower richness differed, being positive for O. caerulescens and negative for A. longispinosus. The percentage of natural habitats in the landscape had a positive additional effect on the number of cells per nest only in A. longispinosus. Besides, flower richness was positively related to the proportion of females in both species, and increased O. caerulescens survival. Our findings stress the importance of considering different spatial scales for an effective conservation management that takes into account Hymenoptera reproduction.
README: Local and landscape effects on the reproduction of wild bees and wasps in Mediterranean communities along a gradient of land-use
Description of the data and file structure
We conducted a field study in Mallorca, Spain, to investigate the factors influencing the reproduction of wild bees and wasps. We aimed to understand how both landscape-scale factors and local-scale factors, such as the availability of floral resources, affect the reproductive success of wild bees and wasps in Mediterranean environments. We established 18 study sites in natural scrubland areas and collected data on:
Landscape characteristics: The amount and diversity of natural habitats surrounding the study sites.
Flowering community: The abundance and richness of flowering plants within the study sites.
Bee and wasp reproduction: The number and types of nests built by bees and wasps in trap-nests, the number of cells within these nests, the sex ratio of emerging adults, parasitism rates, and larval survival.
Files and variables
File: DATA_MARRERO_Ecol.Ent_2024.xlsx
Description: The “bee.wasp_rich-abu” spreadsheet has data on the total richness and abundance of bees and wasps found at each of the sites and separated by bundle. In addition, there are data on landscape heterogeneity of the percentage (land.hetero); of the surface with patches of natural vegetation (land.natural) in areas of 1km radius; of the total abundance of flowers (ab.flowerTotal) or inflorescences and the richness (r.flowerTotal).
The “nest.abundance” spreadsheet has data on the number of nests for the two most common species of bees (O. caerulescens) and wasps (A. longispinosus) found at each of the sites and separated by bundle. In addition, there are data on landscape heterogeneity of the percentage (land.hetero); and of the surface with patches of natural vegetation (land.natural) in areas of 1km radius. For flower abundance (ab.flower) or inflorescences and richness (r.flower) here, we only analyzed data on two months –May and June–, and flower richness and abundance were estimated by summing up data on the two surveys conducted just prior to the collection of nests.
The “cell.abu-survival-parasitoid” spreadsheet contains data on the number of cells per nest, the number of cells that survived within the nest at the time of nest opening, the abundance of parasitoids, and the species of parasitoids for the two most common species of bees (O. caerulescens) and wasps (A. longispinosus). In addition, there are data on landscape heterogeneity of the percentage (land.hetero); and of the surface with patches of natural vegetation (land.natural) in areas of 1km radius. For flower abundance (ab.flower) or inflorescences and richness (r.flower) here, we only analyzed data on two months –May and June–, and flower richness and abundance were estimated by summing up data on the two surveys conducted just prior to the collection of nests. The 'n/a' data points reflect the absence of parasitism in these nests, resulting in no recorded values for the corresponding variables
The “sex.ratio” spreadsheet contains data on the offspring of each nest that were found to be male or female for the two most common species of bees (O. caerulescens) and wasps (A. longispinosus). The total number of cells may be lower than that recorded in the cell.abu-survival-parasitoid spreadsheet, since many cells were sacrificed for other analyses (pollen, contamination, among others).
Variables
- Bee and wasp abundance and richness: Total number of bees and wasps nests at each site, separated by bundle.
- Landscape characteristics: Percentage of natural vegetation and landscape heterogeneity within a 1km radius of each site.
- Flower abundance and richness: Total number and richness of flowers or inflorescences at each site, analyzed for May and June.
- Nest abundance: Number of nests for O. caerulescens and A. longispinosus at each site and bundle.
- Cell data: Number of cells per nest, survival rates, parasitoid abundance, and species.
- Sex ratio: Proportion of male and female offspring for O. caerulescens and A. longispinosus.
Methods
This study we investigated how landscape and local factors influence wild bee and wasp reproduction on the island of Mallorca, Spain.
Study Sites: We chose 18 natural scrubland areas surrounded by agricultural landscapes. These sites varied in the amount of surrounding natural habitat and overall landscape diversity.
Landscape Characteristics: To assess resource availability at a large scale, we analyzed a 1km radius around each study site, measuring the percentage of natural habitat and landscape diversity within that area.
Flower community: To assess resource availability at a local scale, we placed sampling squares within each study site and counted the number and types of flowering plants throughout the season.
Trap-nest sampling: To assess bee and wasp reproduction, we placed bundles of trap-nests at each site. These nests were collected and examined monthly throughout the breeding season. Then, we counted the number and types of nests built, the number of cells within each nest, sex ratio of emerged adults, parasitoid abundance, and larval survival rate.
Focus species: While data was collected for all bee and wasp species, we focused our analysis on the two most abundant species: the solitary bee Osmia caerulescens and the wasp Ancistocerus longispinosus.