EAPSI: Exploring the Causes and Consequences of Extreme Spine Evolution in a Diverse, Widespread, and Ecologically Dominant Group of Spiny Ants

Blanchard Benjamin D, Chicago IL

Investigators

Abstract

Why are some species successful in their environment, while others are rare? Why do some groups of species persist over evolutionary time, while others go extinct? My project will address these questions using a diverse genus of ants called Polyrhachis, which is found throughout tropical Africa, Asia, and the Pacific Islands. This group of species varies greatly in physical structure: some species have many very long spines while others have short spines, or no spines at all. In order to determine how these spines impact the evolutionary and ecological success of this group, the principal investigator will conduct research at the Xishuangbanna Tropical Botanical Gardens (XTBG) in collaboration with Dr. Cao Min and Dr. Akihiro Nakamura. Several species of Polyrhachis will be collected and various measurements taken to determine the association between extreme spine length evolution and the rate of species generation, using a published tree of life for the genus. Competition trials to test the impact of spines on ecological interactions will also be conducted. The results of my project with contribute to our understanding of the success of this widespread and environmentally important group of ants. Morphological traits are often linked due to underlying genetic, developmental, or functional constraints; this phenomenon is called 'integration'. Integration may allow for increased adaptability and specialization or instead constrain the adaptability of a species and limit the rate of speciation, thereby influencing evolutionary dynamics. Here, a highly speciose and morphologically diverse genus of ants, Polyrhachis, is used to determine causal forces driving and potential constraints on morphological evolution and the rate of speciation in the group. In collaboration with Dr. Cao Min and Dr. Akihiro Nakamura, professors at the Xishuangbanna Tropical Botanical Gardens (XTBG), the PI will collect ants in three tropical locations in Yunnan, China, and identify, image, and measure specimens in the lab at XTBG. Furthermore, preliminary interspecific competition trials with live ant specimens will be conducted. The results of my project will inform theories about the ecological causes and evolutionary consequences of morphological specialization. This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the Ministry of Science and Technology of China.