Statistical analysis of frequencies and proportions of cytologically classified spermatogenic cells in the hermaphroditic snailLymnaea stagnalis.1. A study of diurnal variations

Abstract

Diurnal vanattons in spermatogenesis in the hermaphroditic snail Lymnaea stagnalis were studied by counting Sertoli cells classified according to their developmental stage (I-IV). The levels of the frequencies of these stages were studied in a field population of non-copulating snails during a 24 h period. The results were extensively analysed with statistical methods.Non-copulating snails sampled at the same time during a 24 h period appeared to be homogeneous with respect to the frequency distributions of Sertoli cells over the distinguished stages, except for the snails sampled at 5.00 a.m. This inhomogeneity coincided with lowest values or changes of environmental factors measured. The relative frequencies of stage III ('ripe' spermatids) showed a significant fluctuating pattern, whereas those of stage IV (spermiation) remained at a very constant level.

Sublethal heat reduces overall reproductive investment and male allocation in a simultaneously hermaphroditic snail species

“…We chose to examine the effect of continuous heating for 14 days, rather than a brief heat shock, as water is slow to increase or decrease its temperature compared to air. Moreover, this duration is long enough to evaluate the effect of heat on sperm production, since their spermatogenesis takes less than 10 days [ 51 , 52 ]. To achieve these heat treatments, we used six aquariums ( ca 15 l) with heaters.…”

Sublethal heat reduces overall reproductive investment and male allocation in a simultaneously hermaphroditic snail species

“…We chose to examine the effect of continuous heating for 14 days, rather than a brief heat shock, as water is slow to increase or decrease its temperature compared to air. Moreover, this duration is long enough to evaluate the effect of heat on sperm production, since their spermatogenesis takes less than 10 days (De Jong-Brink et al 1985, Nakadera et al 2020). To achieve these heat treatments, we used six aquariums (ca.…”