Semester of Graduation

Fall 2026

Degree

Master of Science (MS)

Department

Entomology

Document Type

Thesis

Abstract

The invasive apple snail, Pomacea maculata Perry, has become an important pest in Louisiana rice (Oryza sativa L.) and crawfish (Procambarus clarkii Girard, 1852) aquaculture. Despite populations are increasing, little information is available regarding the abiotic factors and trophic interactions influencing apple snail abundance in Louisiana. This study evaluated seasonal population dynamics of P. maculata, determine the influence of abiotic factors and crop rotation strategies between C3 and C4 forage on apple snail abundance, assess feeding preferences between rice and sorghum plants under controlled conditions and potential attractants preferred by apple snails, and investigate snail and crawfish (Procambarus clarkii) trophic interactions using stable isotope analysis of δ¹³C and δ¹⁵N signatures. Biweekly field surveys were conducted from 2024 to 2026 in rice-crawfish ponds in 5 different regions in southern Louisiana. Apple snail and crawfish abundance were monitored using baited crawfish traps and transects. Water quality parameters, including pH, temperature, salinity, and water depth, were recorded during each sampling week. Comparisons in apple snail abundance were recorded between ponds planted with rice (C3) and sorghum (C4). Apple snail abundance varied in years and locations and was positively associated with water temperature, pH exhibited a negative relationship during one sampling year. Sorghum ponds reflected lower apple snail densities than rice ponds. Apple snails showed no significant preference between C3 and C4 seedlings in laboratory assays. Stable isotope analyses demonstrated that apple snails occupied broader isotopic niches compared to crawfish in different density ponds. Isotopic overlap between both species indicated the potential use of similar food sources and the potential for trophic interactions in rice–crawfish ponds. These findings show that the establishment of P. maculata in Louisiana is influenced by environmental conditions, agricultural management practices, and dietary plasticity. This study provides new ecological information that improves the understanding of apple snail populations in rice–crawfish systems and contributes to the development of integrated management strategies for this invasive species.

Date

8-24-2026

Committee Chair

Wilson, Blake.

LSU Acknowledgement

1

LSU Accessibility Acknowledgment

1

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Available for download on Thursday, August 23, 2029

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