Annual variation of ovarian structures of Boulengerula taitana (Loveridge 1935), a Kenyan caecilian

Abstract

The Kenyan caecilian, Boulengerula taitanus inhabits a climate characterised by two distinct dry and wet seasons, and a single thermal minimum in June. It is oviparous with direct development and a remarkable dermatophagous maternal care, but the female reproductive cycle until now remains unknown. The purpose of this work was to complete the knowledge about the reproductive modes of this species, using anatomical and histological studies of the ovaries. Quantitative variations of follicle categories showed a continuous folliculogenesis. Yet, young corpora lutea were only detected between November and February during the short rain season and the short dry season, indicating ovulation occurred during these four months during the thermal maximum. Oestrogen and progesterone detection allowed determination of three reproductive periods during the year: preparation in September and October, ovulation from November until February and quiescence from March until August. So, the female reproductive cycle of B. taitanus appears to be annual and synchronised with testicular evolution. Because the ovulation was observed following the second peak of follicle production (beginning of June), temperature is supposed to be the main regulating factor of reproductive pattern in this caecilian.