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• DOI: https://doi.org/10.25849/myrmecol.news_029:125
• Open Access: CC BY 4.0
• Author: Nie, L., Ni, M., Ning, D., Ran, H., Hassan, B. & Xu, Y.
• Year: 2019
• Title: Comparing mechanisms of competition among introduced and resident ants in China: from behavior to trophic position (Hymenoptera: Formicidae)
• Journal: Myrmecological News
• Volume: 29
• Pages: 125-133
• Type of contribution: Original Article
• Supplementary material: Yes, see below
• Abstract: Invasive ant species interact with both native and previously introduced ants in new environments. Their effects on resident species may vary warranting a careful examination of the possible mechanisms that govern these differences. We used individual and group aggression assays and an assay of walking speed to examine behavioral interactions between Solenopsis invicta Buren, 1972 and one native and four previously introduced ant species in China. We also determined the toxicity of S. invicta venom to these resident ants and inferred differences in trophic position for all five ant species using stable isotope (δ15N) data. No differences in walking speed were observed between S. invicta and other species with the exception of the introduced Anoplolepis gracilipes (Smith, 1857), which had a faster walking speed than S. invicta. Maximum aggression scores were observed between S. invicta and the introduced Solenopsis geminata (Fabricius, 1804) (2.83 ± 0.11) as well as the native Pheidole yeensis Forel, 1902 (2.37 ± 0.15), followed by A. gracilipes (2.05 ± 0.15), in the individual aggression assay. In the group aggression assay, workers of S. invicta were very aggressive towards four resident ants and caused high mortality of P. yeensis (98%) and S. geminata (80%), followed by Tapinoma melanocephalum (Fabricius, 1793) (66%). However, one introduced ant, A. gracilipes, was more aggressive and caused high mortality in S. invicta (62%). The application of venom of S. invicta caused high mortality in T. melanocephalum (61.68 ± 8.62%) but did not differ from the mortality of A. gracilipes and S. geminata. In the trophic assay, S. invicta occupied a significantly higher trophic position than the native ant and two introduced species, but occupied a similar trophic position to the introduced species S. geminata and Paratrechina longicornis. These results suggest species differences in behavioral and trophic interactions between invasive and resident ants may promote co-existence for some species and that S. geminata is most likely to be replaced by S. invicta.
• Key words:  Solenopsis invicta, resident ants, aggressive behavior, venom toxicity, trophic position.
• Publisher: The Austrian Society of Entomofaunistics
• ISSN: 1997-3500
• Check out the accompanying blog contribution: https://blog.myrmecologicalnews.org/2019/09/11/competition-mechanism-of-introduced-and-native-ants-in-china/

• Interested in receiving weekly updates on Myrmecol. News & Myrmecol. News Blog? Sign up to Newsletter.
• DOI: https://doi.org/10.25849/myrmecol.news_029:125
• Open Access: CC BY 4.0
• Author: Nie, L., Ni, M., Ning, D., Ran, H., Hassan, B. & Xu, Y.
• Year: 2019
• Title: Comparing mechanisms of competition among introduced and resident ants in China: from behavior to trophic position (Hymenoptera: Formicidae)
• Journal: Myrmecological News
• Volume: 29
• Pages: 125-133
• Type of contribution: Original Article
• Supplementary material: Yes, see below
• Abstract: Invasive ant species interact with both native and previously introduced ants in new environments. Their effects on resident species may vary warranting a careful examination of the possible mechanisms that govern these differences. We used individual and group aggression assays and an assay of walking speed to examine behavioral interactions between Solenopsis invicta Buren, 1972 and one native and four previously introduced ant species in China. We also determined the toxicity of S. invicta venom to these resident ants and inferred differences in trophic position for all five ant species using stable isotope (δ15N) data. No differences in walking speed were observed between S. invicta and other species with the exception of the introduced Anoplolepis gracilipes (Smith, 1857), which had a faster walking speed than S. invicta. Maximum aggression scores were observed between S. invicta and the introduced Solenopsis geminata (Fabricius, 1804) (2.83 ± 0.11) as well as the native Pheidole yeensis Forel, 1902 (2.37 ± 0.15), followed by A. gracilipes (2.05 ± 0.15), in the individual aggression assay. In the group aggression assay, workers of S. invicta were very aggressive towards four resident ants and caused high mortality of P. yeensis (98%) and S. geminata (80%), followed by Tapinoma melanocephalum (Fabricius, 1793) (66%). However, one introduced ant, A. gracilipes, was more aggressive and caused high mortality in S. invicta (62%). The application of venom of S. invicta caused high mortality in T. melanocephalum (61.68 ± 8.62%) but did not differ from the mortality of A. gracilipes and S. geminata. In the trophic assay, S. invicta occupied a significantly higher trophic position than the native ant and two introduced species, but occupied a similar trophic position to the introduced species S. geminata and Paratrechina longicornis. These results suggest species differences in behavioral and trophic interactions between invasive and resident ants may promote co-existence for some species and that S. geminata is most likely to be replaced by S. invicta.
• Key words:  Solenopsis invicta, resident ants, aggressive behavior, venom toxicity, trophic position.
• Publisher: The Austrian Society of Entomofaunistics
• ISSN: 1997-3500
• Check out the accompanying blog contribution: https://blog.myrmecologicalnews.org/2019/09/11/competition-mechanism-of-introduced-and-native-ants-in-china/