Premium
Environmental condition related reproductive strategies and sex ratio in hydras
Author(s) -
Kaliszewicz Anita,
Lipińska Agnieszka
Publication year - 2013
Publication title -
acta zoologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.414
H-Index - 37
eISSN - 1463-6395
pISSN - 0001-7272
DOI - 10.1111/j.1463-6395.2011.00536.x
Subject(s) - lernaean hydra , biology , sex ratio , ecology , zoology , parthenogenesis , asexual reproduction , population , fishery , embryo , demography , sociology , microbiology and biotechnology
Kaliszewicz, A. and Lipińska, A. 2011. Environmental condition related reproductive strategies and sex ratio in hydras. — Acta Zoologica (Stockholm) 00 :1–7. Temperature and food supply appeared to affect sex ratio, sex composition and percentage of sexual individuals in three Hydra species: Hydra vulgaris , Hydra circumcincta and Hydra viridissima . We found three sexes present: females, males and hermaphrodites depending on environmental conditions. Hydra vulgaris appeared to be a species with a temperature‐dependent sex determination (TSD). The males and hermaphrodites were present only under rising temperatures, whereas females were observed exclusively at lowering temperatures. Hydras reproduced asexually at constant room temperature. Unlimited food affected sex ratios and induced the presence of males in H. circumcincta at lowering temperatures. Thus, H. circumcincta may be recognised as another Hydra species in which sex is determined by environmental factors (ESD). Under rising temperatures, the number of hermaphroditic individuals was higher when food supply was unlimited in all three species, indicating that hermaphrodites may need more energy to produce both male and female gonads. Both temperature changes and food supply positively affected asexual reproductive strategies in hydras, especially budding rates. Hydra circumcincta appeared to be less agile than other hydras and able to self‐fertilise. It is likely that self‐fertilisation is an adaptation to the low probability of meeting a mate belonging to the other clone.