My general interest is to understand
how organisms interact with their biotic and abiotic environments.
My aim is to reveal the feedback loops between biotic and abiotic
factors through which climate affects organismal physiology. A
comprehensive description of biophysical interaction mechanisms
between biotic and abiotic environment is needed to forecast the
effects of climate changes to come. I have knowledge in physiological
ecology of invertebrates and plants as well as in environmental
biophysics.
During my master's degree in France, I studied
the impact of ambient light heterogeneity in a tropical rain forest
on the efficiency of visual (color) communication in some dung
beetles of French Guiana, including the largest dung/carrion beetle
of South America (Fig. 1). I incorporated physical measurements
of body coloration and ambient light into a physiological model
of color vision. The model allowed me to precisely quantify the
color contrasts of insect body as seen through the eyes of the
dung beetle. I found that body coloration is a signal of body size
for conspecific and that the signal efficiency is maximal in the
light environment actually used while searching for food or mate.
My PhD dealt with the thermal ecology of an intimate
herbivore insect-plant interaction. The larva of the leaf miner
Phyllonorycter blancardella (Lepidoptera: Gracillariidae) feeds
on apple leaf tissues and develops inside a structure called a
mine (Fig. 2). I built a biophysical model to compute the temperature
inside a mine from climatic variables and the physical/physiological
properties of the mine. Micro-measurements indicated that the larva
alters both the optical properties of plant tissues and the physiological
functioning of the stomata while building its mine. These local
modifications in plant tissues induced a large temperature excess
within the mine, up to 10°C above ambient air and 5°C above
leaf temperature at high radiation level. This warm microclimate
allows larvae to develop faster and to decrease the predator/parasitoid
attack rate. The second trophic level manages and partially controls
the first one, even to the point of one trophic partner co-opting
the physiology of the other. This energy budget model is the first
ever built incorporating heat transfers through two different trophic
levels.
The goal of my postdoc in the Helmuth lab is to
forecast the impacts of climate change on the prey-predator relationship
between mussels (strong intertidal competitors) and the sea star
Pisaster ochraceus (keystone intertidal predator). The first step
is to measure the impact of aerial temperatures experienced during
low tide on the physiology of Pisaster, e.g. the predation rate
on mussels. The temperature-dependent physiological parameters
will be incorporated within a biophysical model of Pisaster’s
body temperature, allowing us to predict the predation rate and
the intertidal distribution limits of Pisaster from climatic databases.
The big question is when and where along the US west coast the
prey would likely be eliminated by both direct impact of climate
(heat stress) and indirect impact through the effects of climate
on the predator. I will work at the local (intertidal) scale as
well as at the biogeographic scale. |
|
| Fig 1: The largest
dung/carrion beetle of south america, Coprophanaeus lancifer
(Coleoptera: Scarabaeidae), is up to 8cm in length. It has
a dark blue body coloration and flies only at dusk to search
for food or mate. |
|
 |
| Fig 2: The larva of
the leaf mining moth Phyllonorycter blancardella (Lepidotera:
Gracillariidae) is about 5 mm in length at the end of its
development. This picture shows what one can see when opening
a mine. The larva creates a mozaic of white and green patches
when feeding on leaf tissues. The green patches are the chlorophyll-containing
tissues remaining in the mine. |
|
| Publications: |
Pincebourde S., Sinoquet H., Combes D. & Casas J. (2007).
Regional climatic
conditions modulate the within-tree mosaic of favourable and
risky microclimate
for insects. Journal of Animal Ecology (in press). |
Pincebourde S., Frak E., Sinoquet H., Regnard J.L. & Casas
J. (2006). Herbivory
mitigation through increased water use efficiency in a leaf mining
moth-apple
tree relationship. Plant Cell and Environment 29, 2238-2247. |
| Pincebourde S. & Casas J. (2006). Multitrophic biophysical
budgets: Thermal ecology of an intimate herbivore insect plant
interaction. Ecological Monographs 76, 175-194. |
| Pincebourde S. & Casas J. (2006). Leaf miner-induced changes
in leaf transmittance cause variations in insect respiration
rates. Journal of Insect Physiology 52, 194-201. |
| Casas J., Pincebourde S., Mandon N., Vannier F., Poujol R. & Giron
D. (2005). Lifetime nutrient dynamics reveal simultaneous capital
and income breeding in a parasitoid. Ecology 86, 545-554. |
| Loon J.J.A.v., Casas J. & Pincebourde S. (2005). Nutritional
ecology of insect-plant interactions: persistent handicaps and
the need for innovative approaches. Oikos 108, 194-201. |
| Feer F. & Pincebourde S. (2005). Diel flight activity and
ecological segregation within an assemblage of tropical forest
dung and carrion beetles. Journal of Tropical Ecology 21, 1-10. |
| Giron D., Pincebourde S. & Casas J. (2004). Lifetime gains
of host-feeding in a synovigenic parasitic wasp. Physiological
Entomology 29, 436-442. |
|
|
