Urban landscapes tend to increase the presence of pathogenic protozoa, microsporidia and viruses, but likely decrease the abundance of viruses in wild bees and wasps

Abstract

Pathogens are shared between wild bees and wasps but little is known about how urbanization affects their occurrence. Here, the role of temperature and fragmentation of green areas, both associated with urbanization, in modulating pathogen loads was investigated. Twelve pathogens were investigated in the bees Anthophora plumipes Pallas, 1772, Halictus scabiosae (Rossi, 1790), Osmia cornuta (Latreille, 1805), and the wasp Polistes dominula (Christ, 1791) sampled across an urbanization gradient in a metropolitan area of northern Italy. Overall, the relative presence/abundance of the pathogens were found to be species specific, as were the responses to urbanization. Anthophora plumipes and O. cornuta had a higher occurrence probability of the neogregarine protozoan Apicystis bombi in more fragmented urban areas. In the same bee species, both temperature and the fragmentation of green areas reduced the number of copies of the deformed wing virus (DWV). In H. scabiosae and P. dominula, higher temperature increased respectively the likelihood of occurrence of DWV and chronic bee paralysis virus (CBPV). In addition, the viruses were found to be replicative in all samples tested. The results show a consistent presence of pathogens in the four target species, and that urbanization plays a role in modulating the pathogen load. Although transmission pathways could not be considered here, it may be suggested that appropriate management of urban areas may buffer wild insects from potentially harmful pathogens. Whether the presence of such pathogens also results in symptomatic phenotypes remains to be determined in laboratory experiments.

Keywords

Apicystis bombi / DWV / green fragmentation / Nosema ceranae / urban heat island / urbanization

References

[1] Abou-Shaara, H.F., Staron, M. and Owayss, A.A. (2024) A mini-review on temperature-pathogen interactions and honey bee colony losses. Journal of Apicultural Research, 64(3), 991–1000. https://doi.org/10.1080/00218839.2024.2361550.

[2] Altschul, S.F., Gish, W., Miller, W., Myers, E.W. and Lipman, D.J. (1990) Basic local alignment search tool. Journal of Molecular Biology, 215, 403–410.

[3] Becker, D.J., Streicker, D.G. and Altizer, S. (2015) Linking anthropogenic resources to wildlife–pathogen dynamics: a review and meta-analysis. Ecology Letters, 18, 483–495.

[4] Boncristiani, H., Ellis, J.D., Bustamante, T., Graham, J., Jack, C., Kimmel, C.B. et al. (2020) World honey bee health: the global distribution of western honey bee (Apis mellifera L.) pests and pathogens. Bee World, 98, 2–6.

[5] Borchardt, K.E., Holthaus, D., Soto Méndez, P.A. and Toth, A.L. (2024) Debunking wasp pollination: wasps are comparable to bees in terms of plant interactions, body pollen and single-visit pollen deposition. Ecological Entomology, 49, 569–584.

[6] Brock, R.E., Cini, A. and Sumner, S. (2021) Ecosystem services provided by aculeate wasps. Biological Reviews, 96, 1645–1675.

[7] Brooks, M.E., Kristensen, K., van Benthem, K.J., Magnusson, A., Berg, C.W., Nielsen, A. et al. (2017) glmmTMB balances speed and flexibility among packages for zero-inflated generalized linear mixed modeling. The R Journal, 9, 378–400.

[8] Buendía-Abad, M., Martín-Hernández, R. and Higes, M. (2023) Trypanosomatids in honey bee colonies in Spain: A new specific qPCR method for specific quantification of Lotmaria passim, Crithidia mellificae and Crithidia bombi. Journal of Invertebrate Pathology, 201, 108004.

[9] Burnham, P.A., Alger, S.A., Case, B., Boncristiani, H., Hébert-Dufresne, L. and Brody, A.K. (2021) Flowers as dirty doorknobs: deformed wing virus transmitted between Apis mellifera and Bombus impatiens through shared flowers. Journal of Applied Ecology, 58, 2065–2074.

[10] Castelli, L., Branchiccela, B., Garrido, M., Invernizzi, C., Porrini, M., Romero, H. et al. (2020) Impact of nutritional stress on honey bee gut microbiota, immunity, and Nosema ceranae infection. Microbial Ecology, 80, 908–919.

[11] Chantawannakul, P., Ward, L., Boonham, N. and Brown, M. (2006) A scientific note on the detection of honey bee viruses using real-time PCR (TaqMan) in Varroa mites collected from a Thai honey bee (Apis mellifera) apiary. Journal of Invertebrate Pathology, 91, 69–73.

[12] Cilia, G., Cabbri, R., Maiorana, G., Cardaio, I., Dall'Olio, R. and Nanetti, A. (2018) A novel TaqMan® assay for Nosema ceranae quantification in honey bee, based on the protein coding gene Hsp70. European Journal of Protistology, 63, 44–50.

[13] Cilia, G., Garrido, C., Bonetto, M., Tesoriero, D. and Nanetti, A. (2020) Effect of Api-Bioxal® and ApiHerb® treatments against Nosema ceranae infection in Apis mellifera investigated by two qPCR methods. Veterinary Sciences, 7, 125.

[14] Cilia, G., Zavatta, L., Ranalli, R., Nanetti, A. and Bortolotti, L. (2021) Replicative Deformed Wing Virus found in the head of adults from symptomatic commercial bumblebee (Bombus terrestris) colonies. Veterinary Sciences, 8, 117.

[15] Cilia, G., Flaminio, S., Zavatta, L., Ranalli, R., Quaranta, M., Bortolotti, L., et al. (2022) Occurrence of honey bee (Apis mellifera L.) pathogens in wild pollinators in northern Italy. Frontiers in Cellular and Infection Microbiology, 12, 907489.

[16] Cilia, G., Flaminio, S., Ranalli, R., Zavatta, L., Nanetti, A., Bortolotti, L., et al. (2023) Presence of Apis mellifera pathogens in different developmental stages of wild Hymenoptera species. Bulletin of Insectology, 76, 147‒154.

[17] Cilia, G., Caringi, V., Zavatta, L. and Bortolotti, L. (2024) Pathogen occurrence in different developmental stages of the invasive Vespa velutina nigrithorax (Buysson, 1905). Pest Management Science, 80(11), 5909–5917. https://doi.org/10.1002/ps.8325.

[18] Cuvillier-Hot, V., Fisogni, A., Doublet, V., Guillot, S., Holl, A.C., Leclercq-Dransart, J. et al. (2024) Urbanization shifts immunometabolism in a common bumblebee. Ecology and Evolution, 14, e70743.

[19] Dalmon, A., Peruzzi, M., Le Conte, Y., Alaux, C. and Pioz, M. (2019) Temperature-driven changes in viral loads in the honey bee Apis mellifera. Journal of Invertebrate Pathology, 160, 87–94.

[20] Desai, S.D. and Currie, R.W. (2016) Effects of wintering environment and parasite–pathogen interactions on honey bee colony loss in north temperate regions. PLoS ONE, 11, e0159615.

[21] Deutsch, K.R., Graham, J.R., Boncristiani, H.F., Bustamante, T., Mortensen, A.N., Schmehl, D.R. et al. (2023) Widespread distribution of honey bee-associated pathogens in native bees and wasps: trends in pathogen prevalence and co-occurrence. Journal of Invertebrate Pathology, 200, 107973.

[22] Durrer, S. and Schmid-Hempel, P. (1994) Shared use of flowers leads to horizontal pathogen transmission. Proceedings of the Royal Society B-Biological Sciences, 258, 299–302.

[23] Elizalde, L., Arbetman, M., Arnan, X., Eggleton, P., Leal, I.R., Lescano, M.N. et al. (2020) The ecosystem services provided by social insects: traits, management tools and knowledge gaps. Biological Reviews, 95, 1418–1441.

[24] Eskov, E.K., Eskova, M.D., Rozhenkov, A.S. and Shestakova, E.V. (2022) Damage to the intestinal medium of honey bees with Nosema. Cell and Tissue Biology, 16, 92–96.

[25] Ferrari, A. and Polidori, C. (2022) How city traits affect taxonomic and functional diversity of urban wild bee communities: insights from a worldwide analysis. Apidologie, 53, 46.

[26] Ferrari, A., Tommasi, N. and Polidori, C. (2024a) Urbanisation reduced body size but potentially improved flight performance in bees and wasps. Basic and Applied Ecology, 74, 57–65.

[27] Ferrari, A., Tacconi, G. and Polidori, C. (2024b) Subtle morphological changes in the visual and antennal sensory system of bees and wasps across an urbanisation gradient. Scientific Reports, 14, 8960.

[28] Ferrari, A. and Polidori, C. (2024) Males of the solitary bee Anthophora plumipes have longer tongue, larger ocelli, and higher fluctuating asymmetry in more urbanised habitats. The European Zoological Journal, 91, 1178–1191.

[29] Ferrari, A. and Polidori, C. (2025) Are cities shaping bee behavior? Female-female interactions in the solitary Megachilid Osmia cornuta in an urban matrix. Journal of Insect Behavior, 38, 3.

[30] Figueroa, L.L., Blinder, M., Grincavitch, C., Jelinek, A., Mann, E.K., Merva, L.A. et al. (2019) Bee pathogen transmission dynamics: deposition, persistence and acquisition on flowers. Proceedings of the Royal Society B, 286, 20190603.

[31] Flaminio, S., Nanetti, A., Bortolotti, L. and Cilia, G. (2023) Replicative DWV type A in Bombus terrestris in Pantelleria island (Sicily, Italy). Journal of Asia-Pacific Entomology, 26, 102123.

[32] Forzan, M., Sagona, S., Mazzei, M. and Felicioli, A. (2017) Detection of deformed wing virus in Vespa crabro. Bulletin of Insectology, 70, 261–265.

[33] Garnier, S., Ross, N., Rudis, R., Camargo, A.P., Sciaini, M. and Scherer, C. (2024) viridis(Lite)—Colorblind-Friendly Color Maps for R.viridis package version 0.6.5.

[34] Genersch, E., Yue, C., Fries, I. and de Miranda, J.R. (2006) Detection of Deformed wing virus, a honey bee viral pathogen, in bumble bees (Bombus terrestris and Bombus pascuorum) with wing deformities. Journal of Invertebrate Pathology, 91, 61–63.

[35] Geppert, C., Cappellari, A., Corcos, D., Caruso, V., Cerretti, P., Mei, M., et al. (2023) Temperature and not landscape composition shapes wild bee communities in an urban environment. Insect Conservation and Diversity, 16, 65–76.

[36] Gil-Tapetado, D., Ferrari, A., Ronchetti, F. and Polidori, C. (2024) Distribution widening of a ground-nesting social bee across Europe favored by climate change and urban setting. Apidologie, 55, 35.

[37] Gisder, S., Horchler, L., Pieper, F., Schüler, V., Šima, P. and Genersch, E. (2020) Rapid gastrointestinal passage may protect Bombus terrestris from becoming a true host for Nosema ceranae. Applied and Environmental Microbiology, 86, e00629–e00620.

[38] Goblirsch, M., Huang, Z.Y. and Spivak, M. (2013) Physiological and behavioral changes in honey bees (Apis mellifera) induced by Nosema ceranae infection. PLoS ONE, 8, e58165.

[39] Goulson, D., Whitehorn, P. and Fowley, M. (2012) Influence of urbanisation on the prevalence of protozoan parasites of bumblebees. Ecological Entomology, 37, 83–89.

[40] Greenleaf, S. S., Williams, N. M., Winfree, R., & Kremen, C. (2007). Bee foraging ranges and their relationship to body size. Oecologia, 153, 589–596.

[41] Graystock, P., Meeus, I., Smagghe, G., Goulson, D. and Hughes, W.O. (2016) The effects of single and mixed infections of Apicystis bombi and deformed wing virus in Bombus terrestris. Parasitology, 143, 358–365.

[42] Graystock, P., Ng, W.H., Parks, K., Tripodi, A.D., Muñiz, P.A., Fersch, A.A. et al. (2020) Dominant bee species and floral abundance drive parasite temporal dynamics in plant-pollinator communities. Nature Ecology & Evolution, 4, 1358–1367.

[43] Hallmann, C.A., Sorg, M., Jongejans, E., Siepel, H., Hofland, N., Schwan, H. et al. (2017) More than 75 percent decline over 27 years in total flying insect biomass in protected areas. PLoS ONE, 12, e0185809.

[44] Hanley, N., Breeze, T.D., Ellis, C. and Goulson, D. (2015) Measuring the economic value of pollination services: principles, evidence and knowledge gaps. Ecosystem Services, 14, 124–132.

[45] Hung, K.L.J., Kingston, J.M., Albrecht, M., Holway, D.A. and Kohn, J.R. (2018) The worldwide importance of honey bees as pollinators in natural habitats. Proceedings of the Royal Society B, 285, 20172140.

[46] Ivers, N.A., Jordan, Z., Cohen, H., Tripodi, A., Brown, M.J., Liere, H. et al. (2022) Parasitism of urban bumble bees influenced by pollinator taxonomic richness, local garden management, and surrounding impervious cover. Urban Ecosystems, 25, 1169–1179.

[47] James, R.R. and Skinner, J.S. (2005) PCR diagnostic methods for Ascosphaera infections in bees. Journal of Invertebrate Pathology, 90, 98–103.

[48] Lange, C.E. and Lord, J.C. (2012) Protistan entomopathogens. In Insect Pathology, 2nd edn. (eds. F.E. Vega & H.K. Kaya), pp. 367–394. San Diego, CA. Academic Press.

[49] Lanner, J., Yañez, O., Cilia, G., Bortolotti, L., Meimberg, H. and Neumann, P. (2023) Deformed wings in introduced solitary bees, Megachile spp., independent of virus infections. Journal of Apicultural Research, 62, 823–825.

[50] Li, X., Ma, W. and Jiang, Y. (2022) Heat stress affects the expression of antimicrobial peptide genes in adult honey bee (Apis cerana and Apis mellifera). International Journal of Tropical Insect Science, 42, 2465–2471.

[51] Lipa, J.J. and Triggiani, O. (1996) Apicystis gen. nov. and Apicystis bombi (Liu, Macfarlane Pengelly) comb. nov. (Protozoa: Neogregarinida), a cosmopolitan parasite of Bombus and Apis (Hymenoptera: Apidae). Apidologie, 27, 29–34.

[52] Lucia, M., Reynaldi, F.J., Sguazza, G.H. and Abrahamovich, A.H. (2014) First detection of deformed wing virus in Xylocopa augusti larvae (Hymenoptera: Apidae) in Argentina. Journal of Apicultural Research, 53, 466–468.

[53] Lüdecke, D., Ben-Shachar, M.S., Patil, I., Waggoner, P. and Makowski, D. (2021) performance: An R package for assessment, comparison and testing of statistical models. Journal of Open Source Software, 6, 3139.

[54] Martín-Hernández, R., Botías, C., Barrios, L., Martínez-Salvador, A., Meana, A., Mayack, C., et al. (2011) Comparison of the energetic stress associated with experimental Nosema ceranae and Nosema apis infection of honey bees (Apis mellifera). Parasitology Research, 109, 605–612.

[55] Mazzei, M., Carrozza, M.L., Luisi, E., Forzan, M., Giusti, M., Sagona, S. et al. (2014) Infectivity of DWV associated to flower pollen: experimental evidence of a horizontal transmission route. PLoS ONE, 9, e113448.

[56] Mazzei, M., Forzan, M., Cilia, G., Sagona, S., Bortolotti, L. and Felicioli, A. (2018) First detection of replicative deformed wing virus (DWV) in Vespa velutina nigrithorax. Bulletin of Insectology, 71, 211‒216.

[57] Mazzei, M., Cilia, G., Forzan, M., Lavazza, A., Mutinelli, F. and Felicioli, A. (2019) Detection of replicative Kashmir bee virus and Black queen cell virus in Asian hornet Vespa velutina (Lepelieter 1836) in Italy. Scientific Reports, 9, 10091.

[58] Müller, U., McMahon, D.P. and Rolff, J. (2019) Exposure of the wild bee Osmia bicornis to the honey bee pathogen Nosema ceranae. Agricultural and Forest Entomology, 21, 363–371.

[59] Mullins, J.L., Strange, J.P. and Tripodi, A.D. (2020) Why are queens broodless? Failed nest initiation not linked to parasites, mating status, or ovary development in two bumble bee species of Pyrobombus (Hymenoptera: Apidae: Bombus). Journal of Economic Entomology, 113, 575–581.

[60] Nanetti, A., Bortolotti, L. and Cilia, G. (2021a) Pathogens spillover from honey bees to other arthropods. Pathogens, 10, 1044.

[61] Nanetti, A., Ellis, J.D., Cardaio, I. and Cilia, G. (2021b) Detection of Lotmaria passim, Crithidia mellificae and replicative forms of deformed wing virus and Kashmir bee virus in the small hive beetle (Aethina tumida). Pathogens, 10, 372.

[62] Oksanen, J., Simpson, G., Blanchet, F., Kindt, R., Legendre, P., Minchin, P. et al. (2022) vegan: Community Ecology Package. R package version 2.6-4.

[63] Palmer-Young, E.C., Raffel, T.R. and McFrederick, Q.S. (2018) Temperature-mediated inhibition of a bumblebee parasite by an intestinal symbiont. Proceedings of the Royal Society B-Biological Sciences, 285, 20182041.

[64] Palmer-Young, E.C., Ryabov, E.V., Markowitz, L.M., Boncristiani, D.L., Grubbs, K., Pawar, A. et al. (2023) Host-driven temperature dependence of Deformed wing virus infection in honey bee pupae. Communications Biology, 6, 333.

[65] Piot, N., Schweiger, O., Meeus, I., Yañez, O., Straub, L., Villamar-Bouza, L. et al. (2022) Honey bees and climate explain viral prevalence in wild bee communities on a continental scale. Scientific Reports, 12, 1904.

[66] Plischuk, S. and Lange, C.E. (2024) On the occurrence of the neogregarine Apicystis bombi (Apicomplexa) in South America: an unassembled puzzle. Biological Invasions, 1–21.

[67] Polidori, C., Ferrari, A., Ronchetti, F., Tommasi, N. and Nalini, E. (2023) Warming up through buildings and roads: What we know and should know about the Urban Heat Island effect on bees. Frontiers in Bee Science, 1, 1269600.

[68] Power, K., Martano, M., Ragusa, E., Altamura, G. and Maiolino, P. (2023) Detection of honey bee viruses in larvae of Vespa orientalis. Frontiers in Cellular and Infection Microbiology, 13, 1207319.

[69] Power, K., Cilia, G., Ragusa, E., Rizzo, R., Bortolotti, L. and Maiolino, P. (2024) Occurrence of Nosema ceranae, Ascosphaera apis and trypanosomatids in Vespa orientalis Linneus 1771. Journal of Invertebrate Pathology, 206, 108168.

[70] Olgun, T., Everhart, S.E., Anderson, T. and Wu-Smart, J. (2020) Comparative analysis of viruses in four bee species collected from agricultural, urban, and natural landscapes. PLoS ONE, 15, e0234431.

[71] R Core Team. (2023) R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria.

[72] Rutrecht, S.T. and Brown, M.J. (2008) The life-history impact and implications of multiple parasites for bumble bee queens. International Journal for Parasitology, 38, 799–808.

[73] Schmid-Hempel, P. (2001) On the evolutionary ecology of host–parasite interactions: addressing the question with regard to bumblebees and their parasites. Die Naturwissenschaften, 88, 147–158.

[74] Schmid-Hempel, P. and Cremer, S. (2021) Parasites and pathogens. In C.K. Starr Encyclopedia of Social Insects, pp. 713–723. Springer, Cham.

[75] Tiritelli, R., Flaminio, S., Zavatta, L., Ranalli, R., Giovanetti, M., Grasso, D.A. et al. (2024) Ecological and social factors influence interspecific pathogens occurrence among bees. Scientific Reports, 14, 5136.

[76] Tiritelli, R., Cilia, G. and Gómez-Moracho, T. (2025) The trypanosomatid (Kinetoplastida: Trypanosomatidae) parasites in bees: a review on their environmental circulation, impacts and implications. Current Research in Insect Science, 7, 100106.

[77] Tommasi, N., Colombo, B., Pioltelli, E., Biella, P., Casiraghi, M. and Galimberti, A. (2023) Urban habitat fragmentation and floral resources shape the occurrence of gut parasites in two bumblebee species. Ecology and Evolution, 13, e10299.

[78] Wei, T., Simko, V., Levy, M., Xie, Y., Jin, Y. and Zemla, J. (2017) Package ‘corrplot’. Statistician, 56, e24.

[79] Wickham, H. (2016) ggplot2: Elegant Graphics for Data Analysis. Springer Verlag, New York.

[80] Wilfert, L., Brown, M.J. and Doublet, V. (2021) OneHealth implications of infectious diseases of wild and managed bees. Journal of Invertebrate Pathology, 186, 107506.

[81] Xu, J. and James, R.R. (2012) Temperature stress affects the expression of immune response genes in the alfalfa leafcutting bee, Megachile rotundata. Insect Molecular Biology, 21, 269–280.

[82] Yang, L.H., Postema, E.G., Hayes, T.E., Lippey, M.K. and MacArthur-Waltz, D.J. (2021) The complexity of global change and its effects on insects. Current Opinion in Insect Science, 47, 90–102.

[83] Youngsteadt, E., Appler, R.H., López-Uribe, M.M., Tarpy, D.R. and Frank, S.D. (2015) Urbanization increases pathogen pressure on feral and managed honey bees. PLoS ONE, 10, e0142031.

[84] Yue, C. and Genersch, E. (2005) RT-PCR analysis of Deformed wing virus in honeybees (Apis mellifera) and mites (Varroa destructor). Journal of General Virology, 86, 3419–3424.

[85] Zavatta, L., Bortolotti, L., Catelan, D., Granato, A., Guerra, I., Medrzycki, P. et al. (2024) Spatiotemporal evolution of the distribution of Chronic bee paralysis virus (CBPV) in honey bee colonies. Virology, 598, 110191.

RIGHTS & PERMISSIONS

2025 The Author(s). Insect Science published by John Wiley & Sons Australia, Ltd on behalf of Institute of Zoology, Chinese Academy of Sciences.