Short-day and low-temperature conditions promote reproductive maturation in the terrestrial slug, Lehmannia valentiana.
Terrestrial slugs (Lehmannia valentiana) collected from a field in Osaka, southwestern Japan, were reared under long-day (16-h light and 8-h darkness, LD 16:8) or short-day conditions (LD 12:12) at 15, 20, or 25 degrees C for 60 days. Slugs reared under short-day conditions were heavier than those reared under long-day conditions; however, slugs reared at 15 degrees C gained more weight regardless of the photoperiodic condition. Gonads were significantly heavier under short-day conditions than under long-day conditions, and oogenesis and spermatogenesis were also induced under short-day conditions. Under short-day conditions, reproductive maturation was suppressed at 25 degrees C as compared with 15 and 20 degrees C, whereas under long-day conditions, lower temperatures induced reproductive maturation. In contrast, slugs reared under short-day conditions at 20 degrees C from the time of hatching gained more weight than those reared under long-day conditions at the same temperature. Moreover, short-day conditions induced reproductive maturation, similar to that observed in the field-collected slugs. In conclusion, short-day and low-temperature conditions promoted growth and reproductive maturation, whereas long-day and high-temperature conditions suppressed them in L. valentiana. Thus, L. valentiana reproduces from late autumn to spring in Osaka.
Udaka
Hiroko
H
Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan.
Numata
Hideharu
H
D000818:Animals; D005260:Female; D049851:Gastropoda / Q000254:growth & development / Q000502:physiology* / Q000528:radiation effects*; D008027:Light; D012741:Sexual Maturation / Q000502:physiology / Q000528:radiation effects*; D013696:Temperature