Switching lifestyles using hormones
Vicencio Oostra, who defended his PhD-thesis at the IBL successfully in June 2013, published new insights into the hormonal regulation of butterfly responses to fluctuating environments.
Seasonal variation in ecological threats and opportunities has a major impact on the life of small animals. Especially cold-blooded insects often have to be remarkably flexible. Some species have evolved intriguing behavioural, physiological and morphological responses to survive and reproduce despite large differences in temperature and humidity between seasons.
African butterflies of the species Bicyclus anynana are well-known to switch life styles with seasons: in the dry season they have a cryptic appearance and they invest most energy in body reserves to increase chances of survival. In the dry season, they have brighter eye-patterns and they invest most energy in activities that increase chances of reproduction.
Discovery
But how do butterflies sense what the relevant changes in the environment will be? And how do they convey this information to the various systems in their body that need to be adjusted to upcoming circumstances? Mind you, the developmental decisions have to be made at a pre-adult stage when the butterflies are still immobile pupae…
Earlier work had already shown that seasonal variation in temperature is the trigger for one or the other divergent developmental pathways within the pupae. The new publication reports on the crucial role played by hormones. It was discovered that ecdysteroids have different concentrations in pupae from different seasons. Furthermore, when developing pupae destined to become dry-season adults are injected with these ecdysteroids, they instead become more wet-season–like adults.
Collaboration and support
Vicencio did his research together with former supervisors and collaborators from the IBL Paul Brakefield (now at Cambridge University), Bas Zwaan (now at Wageningen University) and Patricia Beldade (now at Instituto Gulbenkian de Ciência, Oeiras, Portugal).
Links
- Article in The American Naturalist
- The thesis of Vicencio Oostra
- Personal page Vicencio Oostra
- Personal page Paul Brakefield
- Personal page Bas Zwaan
- Personal page Patricia Beldade