Age and Body Size Influence Sperm Quantity in Male Aedes albopictus (Diptera: Culicidae) Mosquitoes

Abstract

Aedes albopictus (Skuse) (Diptera: Culicidae) is a vector of several arboviruses impacting human health, including dengue, chikungunya, and potentially Zika. Vector control strategies that deploy modified males into the field are in use or under development and require a solid understanding of male biology; unfortunately, there has been limited effort to understand male Ae. albopictus reproductive biology, including sperm production and capacity. We tested whether body size and age affect spermatogenesis in Ae. albopictus. In general, older and larger males produced more sperm than their younger or smaller counterparts. Large males continued spermatogenesis well after 10-d post-eclosion (dpe), augmenting their reserves by 39%. By contrast, small males stopped producing sperm at 10 dpe. These results contribute to a deeper understanding of Ae. albopictus reproductive physiology. We discuss the usefulness of these findings in the context of Ae. albopictus life history and their utility in optimizing male mosquito release strategies.

Proteins, Transcripts, and Genetic Architecture of Seminal Fluid and Sperm in the Mosquito Aedes aegypti

“…Transcriptome Analysis of Testes and Male Accessory Glands-Testes were harvested from males at 1 dpe and transferred to TRIzol. Because mature sperm are actively produced at this age (47), and spermatogenesis is at its peak (48,49), testes at this age likely contain most transcripts that contribute to the testicular sperm proteome. Male accessory glands (MAG) including the connecting ejaculatory duct were dissected from virgin males aged 6 and 8 dpe, and care was taken to remove as much of the adjoining seminal vesicle as possible with a minutien pin.…”

Glycoprotein Hormone Receptor Knockdown Leads to Reduced Reproductive Success in Male Aedes aegypti

“…Sperm quantitation was performed following a protocol that was previously shown to obtain accurate sperm counts (Ponlawat and Harrington, 2007). Male reproductive organs (testes and seminal vesicle) were isolated in PBS from adult virgin A. aegypti that were fed as larvae with either E. coli expressing control dsRNA (empty L4440) or LGR1 dsRNA.…”

Physiological and Environmental Factors Affecting the Composition of the Ejaculate in Mosquitoes and Other Insects

“…In Ae. albopictus , sperm count increases until at least 20 days post-eclosion in large males, but in small males it increases until ten days post-eclosion and then does not increase beyond that number later in life [77]. These studies suggest that aging has clear effects on the physiology of the male mosquito reproductive tract and on sperm number, but no work has yet tested whether aging influences the composition of the seminal fluid or the abundance of SFPs in male mosquitoes.…”

“…aegypti and Ae. albopictus (Table 1; [75,77]). In these studies, males were experimentally reared to be smaller by placing larvae in crowded and nutritionally limited conditions, and smaller males were found to produce fewer sperm than larger males.…”