Effects of myrmecochore species abundance, diversity, and fruiting phenology on Aphaenogaster (Hymenoptera: Formicidae) nesting and foraging in southern Appalachian rich cove forests

WCU Author/Contributor (non-WCU co-authors, if there are any, appear on document)
Mary N. Schultz (Creator)
Western Carolina University (WCU )
Web Site: http://library.wcu.edu/
James Costa

Abstract: In forests of the southern Appalachians, myrmecochory, or ant-mediated seed dispersal, is a diffuse mutualism between more than 42 species of plants and ants of the genus Aphaenogaster. Myrmecochores produce lipid-rich appendages on their seeds called elaiosomes, a reward that attracts Aphaenogaster ants and facilitates dispersal. Since myrmecochores set seed from March to September, forests with higher myrmecochore diversity may provide a more continuous source of elaiosomes for Aphaenogaster ants, likely affecting foraging and nesting behavior. I compared myrmecochore abundance and diversity among three forest ages (young, middle-aged and mature) and tested for correlations between herb community dynamics and Aphaenogaster foraging behavior, nest colonization, and elaiosome availability. I paired artificial ant nests with bait stations that I provisioned with tuna in temporal patterns to mimic patterns of theoretical elaiosome availability in communities with low myrmecochore diversity and high myrmecochore diversity.Higher myrmecochore abundance and higher soil temperature marginally correlated with increased Aphaenogaster foraging. Myrmecochore diversity measures among forest ages were not significantly different, and varying availability of resource did not affect foraging or nesting behavior. Higher soil moisture in mature forests may explain why the majority of colonized nests appeared in mature forests. Fruit phenology showed elaiosomes were more consistently available in middle-aged forests; however, this greater availability was not correlated with myrmecochore species diversity or abundance, and did not affect Aphaenogaster nesting or foraging. My results suggest Aphaenogaster dynamics are influenced more by moisture and temperature than by resource availability. The lack of significant differences in diversity among forest ages precludes measuring the effects of diversity on either elaiosome availability or on Aphaenogaster dynamics. However, my results support current research showing elaiosomes provide a supplement to resources preferred by Aphaenogaster ants.

Additional Information

Language: English
Date: 2014
Aphaenogaster, Elaiosome, Herb Diversity, Myrmecochory, Rich Cove Forests, Southern Appalachians
Ants -- Behavior -- Environmental aspects -- North Carolina, Western
Seed dispersal by ants -- North Carolina, Western
Mutualism (Biology) -- North Carolina, Western

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