Bioecological aspects of Sepedon maculifemur (Diptera: Sciomyzidae), a predator of mollusc vectors of distomatosis in the Zou department of Benin (West Africa)

Abstract

Sciomyzidae dipterans are attracting growing interest in the context of alternative strategies for controlling mollusc vectors of parasites. In Benin, Sepedon maculifemur, a poorly documented species whose biology and predatory efficiency remain largely unknown, could play a role in mollusc population regulation. The general aim of this study is to characterize the development cycle of S. maculifemur under laboratory conditions and to evaluate its predatory performance on various mollusc prey. To achieve this adults were captured in the field and reared in the laboratory to obtain eggs, larvae and pupae. Morphological observations are made at each developmental stage. Five mollusc species were used as experimental prey to measure larval predatory performance. Data were analyzed using advanced statistical models, including penalized logistic regression (Firth) and LASSO models, with graphical representation in R (version 4.3.2). The results show that S. maculifemur completes its development cycle in laboratory, with a high hatching rate (75.65%) and larval survival dependent on mollusc species. Bulinus globosus is identified as the most favorable prey, serving as a comparative basis in the analyses. Larval survival probabilities were significantly reduced (25 times less) with other species such as Subulina octona (OR = 0.04). Analysis of combined effects of larval stage, species and prey size reveal a significant interaction, highlighting a progressive trophic adaptation during larval development. This study provides new data on the biology of S. maculifemur and confirms its malacophagous potential with regard to molluscs of medical interest. These results lay the foundations for the future development of this species as a biological control agent in bilharzia-endemic areas. Further investigations are required to confirm its ecological significance.