NUBENOCEPHALUS SECUNDUS INFECTION IN FIVE SPECIES OF DAMSELFLIES (ODONATA: COENAGRIONIDAE) IN EAST TEXAS

Date

2024-05

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Abstract

Damselfly parasites are diverse and highly susceptible to ectoparasites and endoparasites. Damselflies are commonly parasitized by gregarines (Apicomplexa: Eugregarinida) which inhabit the gut of its host. Gregarines are ubiquitous protozoan parasites that infect aquatic and terrestrial invertebrates all over the world except for Antarctica. More than 1,600 gregarine species have been described, however, only a small percentage of invertebrates have been surveyed for apicomplexan parasites, thus the biodiversity of gregarines is underestimated. Gregarines are highly thought to be host-specific, with some studies suggesting a one-host-to-one gregarine species ratio. However, a survey of damselflies in the genus Argia found Nubenocephalus secundus infecting at least seven species. It has additionally been reported from Ischnura ramburii and an unidentified species of Nubenocephalus was reported from Ischnura hastata and Ischnura posita. The objective of this project was to survey adults of the damselflies Argia sedula, Argia translata, Argia tibialis, Enallagma civile, and Ischnura posita and measure if the Nubenocephalus infecting each of these species is N. secundus. All host species were collected among three sites in Walker County, TX: Harmon Creek and the pond at the Pineywoods Environmental Research Lab and Cook Pond. Adult damselfly populations were dissected and examined for gregarine infection from May 2022 through August 2023. Using a combined approach of observing for morphological characteristics, a multivariate analysis of variance (MANOVA) on gregarine trophozoites and a centroid clustering on sporonts, we observed that the Nubenocephalus species infecting A. sedula and A. translata is N. secundus. However, the gregarine infecting the other three damselfly species was not N. secundus but another gregarine species. Additional data collection, including the collection of oocysts, is necessary to determine which species of gregarine is infecting A. tibialis, E. civile, and I. posita.

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Biology, Parasitology

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