Intraspecific functional traits and stable isotope signatures of ground-dwelling ants across an elevational gradient

Highlights

● Ant morphological traits (dry mass, head length, body size and leg length) increased with elevation.

● Ant δ¹³C increased with elevation, whereas δ¹⁵N did not.

● Ant δ¹³C values correlated positively with soil C:N ratio.

Abstract

Understanding the responses of species to changing climates is becoming increasingly urgent. Investigating the effects of climate change on the functional traits of species at the intraspecific level is particularly important. We used elevation gradients as proxies for climate change to explore the intraspecific responses of two ground-dwelling ant species, Ectomomyrmex javanus and Odontoponera transversa, from 100 to 700 m.a.s.l. within a subtropical evergreen broadleaf forest. Our study addressed the specific relationships among environmental factors, trait variations, and trophic levels. Key functional traits such as dry mass, head length, body size, and leg length exhibited a general increase with elevation. Using stable isotope signatures (δ¹³C and δ¹⁵N), we quantified shifts in diets and trophic positions along the elevation gradients. Notably, our data revealed a significant elevation-related increase in Ant δ¹³C, whereas δ¹⁵N exhibited no such correlation. Moreover, Ant δ¹³C values of E. javanus demonstrated a negative correlation with mean annual temperature (MAT), and the δ¹³C values of both species correlated positively with soil C:N ratio. Having revealed that the individual traits and δ¹³C signatures of ground-dwelling ants exhibit significant negative correlations with temperature, our findings suggest that climate warming has the potential to cause intraspecific variation in the functional traits and diets of ground-dwelling ants and possibly other insect species.

Graphical abstract

Keywords

altitude / ant / climate change / stable isotope / trophic position

References

[1] Atkinson, D. 1994. Temperature and organism size—A biological law for ectotherms?. Advances in Ecological Research25, 1–58.

[2] Bishop, T.R., Robertson, M.P., Gibb, H., van Rensburg, B.J., Braschler, B., Chown, S.L., Foord, S.H., Munyai, T.C., Okey, I., Tshivhandekano, P.G., Werenkraut, V., Parr, C.L., 2016. Ant assemblages have darker and larger members in cold environments. Global Ecology and Biogeography25, 1489–1499.

[3] Blüthgen, N., Gebauer, G., Fiedler, K., 2003. Disentangling a rainforest food web using stable isotopes: Dietary diversity in a species-rich ant community. Oecologia137, 426–435.

[4] Classen, A., Steffan-Dewenter, I., Kindeketa, W.J., Peters, M.K., 2017. Integrating intraspecific variation in community ecology unifies theories on body size shifts along climatic gradients. Functional Ecology31, 768–777.

[5] Diniz-Reis, T.R., Augusto, F.G., Abdalla Filho, A.L., Araújo, M.G.S., Chaves, S.S.F., Almeida, R.F., Perez, E.B., Simon, C.P., de Souza, J.L., da Costa, C.F.G., Gomes, T.F., Martinez, M.G., Soltangheisi, A., Mariano, E., Vanin, A.S., Andrade, T.R., Boesing, A.L., Costa, F.J.V., Fortuna, M.D.A., Guedes, V.M., Kisaka, T.B., Kruszynski, C., Lara, N.R.F., Lima, R.A.M., Pompermaier, V.T., Rangel, B.S., Ribeiro, J.F., Santi Junior, A., Tassoni Filho, M., Ferreira, A., Marques, T.S., Pereira, A.L., Aguiar, L.M.S., Anjos, M.B., Medeiros, E.S.F., Benedito, E., Calheiros, D.F., Christofoletti, R.A., Cremer, M.J., Duarte-Neto, P.J., Nardoto, G.B., Oliveira, A.C.B., Rezende, C.E., da Silva, M.N.F., Zuanon, J.A.S., Verdade, L.M., Moreira, M.Z., Camargo, P.B., Martinelli, L.A., 2022. SIA-BRA: A database of animal stable carbon and nitrogen isotope ratios of Brazil. Global Ecology and Biogeography31, 611–620.

[6] Feldhaar, H., Gebauer, G., Blúthgen, N., 2009. Stable isotopes: Past and future in exposing secrets of ant nutrition (Hymenoptera: Formicidae). Myrmecological News13, 3–13.

[7] Feng, J., Yang, F., Wu, J., Chen, Q., Zhang, Q., Cheng, X., 2020. Contrasting soil C and N dynamics inferred from δ¹³C and δ¹⁵N values along a climatic gradient in southern China. Plant and Soil452, 217–231.

[8] Gibb, H., Bishop, T.R., Leahy, L., Parr, C.L., Lessard, J.P., Sanders, N.J., Shik, J.Z., Ibarra-Isassi, J., Narendra, A., Dunn, R.R., Wright, I.J., 2023. Ecological strategies of (pl)ants: Towards a world-wide worker economic spectrum for ants. Functional Ecology37, 13–25.

[9] He, X., Hou, E., Liu, Y., Wen, D., 2016. Altitudinal patterns and controls of plant and soil nutrient concentrations and stoichiometry in subtropical China. Scientific Reports6, 24261.

[10] Joseph, G.S., Muluvhahothe, M.M., Seymour, C.L., Munyai, T.C., Bishop, T.R., Foord, S.H., 2019. Stability of Afromontane ant diversity decreases across an elevation gradient. Global Ecology and Conservation17, e00596.

[11] Kaspari, M., Weiser, M.D., 1999. The size-grain hypothesis and interspecific scaling in ants. Functional Ecology13, 530–538.

[12] Kjeldgaard, M.K.K., Sword, G.A., Eubanks, M.D., 2022. Sugar is an ant’s best friend? Testing food web theory predictions about trophic position and abundance in an invasive ant (Nylanderia fulva). Biological Invasions24, 67–80.

[13] Liu, C., Guénard, B., Blanchard, B., Peng, Y.Q., Economo, E.P., 2016. Reorganization of taxonomic, functional, and phylogenetic ant biodiversity after conversion to rubber plantation. Ecological Monographs86, 215–227.

[14] Liu, H., Zhang, M., Lin, Z., Xu, X., 2018. Spatial heterogeneity of the relationship between vegetation dynamics and climate change and their driving forces at multiple time scales in Southwest China. Agricultural and Forest Meteorology 256–257, 256–257

[15] Moretti, M., Dias, A.T.C., de Bello, F., Altermatt, F., Chown, S.L., Azcárate, F.M., Bell, J.R., Fournier, B., Hedde, M., Hortal, J., Ibanez, S., Öckinger, E., Sousa, J.P., Ellers, J., Berg, M.P., 2017. Handbook of protocols for standardized measurement of terrestrial invertebrate functional traits. Functional Ecology31, 558–567.

[16] Panek, J.A., Waring, R.H., 1995. Carbon isotope variation in Douglas-fir foliage: Improving the δ¹³C-climate relationship. Tree Physiology15, 657–663.

[17] Penick, C.A., Savage, A.M., Dunn, R.R., 2015. Stable isotopes reveal links between human food inputs and urban ant diets. Proceedings Biological Sciences282, 20142608.

[18] Peterson, B.J., Fry, B., 1987. Stable isotopes in ecosystem studies. Annual Review of Ecology and Systematics18, 293–320.

[19] Pilar, F.C., Loïc, M., Emmanuel, D., Sergio, R., 2020. Seasonal changes in arthropod diversity patterns along an alpine elevation gradient. Ecological Entomology45, 1035–1043.

[20] Reymond, A., Purcell, J., Cherix, D., Guisan, A., Pellissier, L., 2013. Functional diversity decreases with temperature in high elevation ant fauna. Ecological Entomology38, 364–373.

[21] Silva, R.R., Brandão, C.R.F., 2014. Ecosystem-wide morphological structure of leaf-litter ant communities along a tropical latitudinal gradient. PLoS ONE9, e93049.

[22] Tillberg, C.V., McCarthy, D.P., Dolezal, A.G., Suarez, A.V., 2006. Measuring the trophic ecology of ants using stable isotopes. Insectes Sociaux53, 65–69.

[23] Wiescher, P.T., Pearce-Duvet, J.M.C., Feener, D.H., 2012. Assembling an ant community: species functional traits reflect environmental filtering. Oecologia169, 1063–1074.

[24] Yan, C., Han, S., Zhou, Y., Zheng, X., Yu, D., Zheng, J., Dai, G., Li, M.H., 2013. Needle δ¹³C and mobile carbohydrates in Pinus koraiensis in relation to decreased temperature and increased moisture along an elevational gradient in NE China. Trees (Berlin)27, 389–399.

[25] Zhou, Y., Fan, J., Zhang, W., Harris, W., Zhong, H., Hu, Z., Song, L., 2011. Factors influencing altitudinal patterns of C₃ plant foliar carbon isotope composition of grasslands on the Qinghai-Tibet Plateau, China. Alpine Botany121, 79–90.

Acknowledgments

This work was supported by the National Natural Science Foundation of China (NSFC) (Grant No. 41977057), Yunnan Applied Basic Research Projects (Grant No. 202001AW070014), and the EJP Soil ICONICA project.

Electronic supplementary material

Supplementary material is available in the online version of this article at https://doi.org/10.1007/s42832-024-0230-x and is accessible for authorized users.

Compliance with ethics guidelines

All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. This paper does not contain any studies involving human participants performed by any of the authors.

Ethics declarations

The authors declare no competing interests.

RIGHTS & PERMISSIONS

2024 Higher Education Press