Dynamics of colonization and invasion of ladybirds: the Azores islands as a case study.

Objectivo

In the Azores fauna, only small and medium size ladybird species are present (Soares et al., 2003). Regarding the theoretical framework discussed above, the objectives of this project are to test the following hypotheses:

1) Small ladybird species may be better adapted to stable habitats where prey populations are present at low abundance but relatively constant over time. These features are typically found in the habitats of the Azores where large agricultural surfaces are not present and contrast with what is found in continental areas.

2) The sharp topography of the islands, associated to small habitats, gives to the landscape a mosaic of juxtaposing different habitats as pristine and man-altered habitats (including agricultural fields), each of small surface. This fact may increase the probability of co-occurrence of a high number of associated species, as it is predicted by the theory of niches (Kadmon & Allouche, 2007).

3) The hot draught is an important mechanism of dispersion in ladybird species (Hodek, 1996). This mechanism may confer an advantage for small ladybird species to colonize new islands.

Other than the general question (adapted from Whittaker and Fernández-Palacios, 2009) “How fragile and prone to invasion are the Azorean ecosystems towards ladybird beetles?”, the objectives of this project are to study each of the above mentioned hypotheses.

The post-doctoral fellow will mainly focus on the:

• i) characterization of the landscape profile in an island and a continental ecosystem,
• ii) characterization of the ladybird habitat and community structure in an island and European continental ecosystem,
• iii) comparison of the spatial and temporal dynamics of prey and predators and
• iv) evaluation of resource allocation to growth and reproduction of different sized ladybirds relative to different habitat characteristics (large uniform habitats with periodically and extremely abundant crop aphids and small and fragmented habitats harbouring scarce and dispersed small colonies of aphids).
  In parallel, the post-doctoral fellow will collaborate on a phylogeographical study with other partners of the main project: the dispersion rate, across the archipelago, of a medium and a small sized ladybird will be studied. This will allow her to acquire some expertise in molecular biology techniques. This part of the project will be carried out in France under the supervision of Dr. Alexandra Magro (École Nationale de Formation Agronomique, University of Toulouse), the co-supervisor of the project.