Bioresource large scale facility project

• Research unit: EU RFP
• Project number: 99.0196-3

Key words (English)

Gene flow; bird fleas; Ceratophyllidae

Alternative project number (English)

EU project number: FMGECT980131

Research programs (English)

EU-programme: 4. Frame Research Programme - 10.1 Stimulation of training and mobility

Short description (English)

See abstract

Partners and International Organizations (English)

Coordinator: Natural History Museum, London (UK)

Abstract (English)

Introduction:
Bird fleas species exhibit extensive variation in their host-range and geographical distribution. Specialization or generalization maybe primarily dependent on the spatial distribution of their potential hosts.
In a preliminary study we showed that generalist fleas mostly parasitize territorial birds which are spread out in the habitat, whilst specialist fleas infest colonial birds. This lends support to the hypothesis that the narrow selection pressures and genetic structuration associated with living on colonial hosts favor specialization and possibly speciation in bird fleas. The aim of the project conducted at the Natural History Museum was to gather data on morphological traits that could correlate with flea mobility. Evidence of adaptations that would tend to reduce flea mobility and their capacity to infest additional host species in fleas from colonial hosts would suggest that specialization correlates with a reduction of gene flow and accelerates speciation processes.
Results:
5 morphological traits were measured 'on screen' from digital pictures of the 58 fleas species for which suficient data on host range is available. There were: 1) the length of the pleural plate (the plate covers the area where the resilin or 'jum protein' is located and were muscles responsible to contract that 'rubber-like' protein before jumps have their upper insertions, 2) the length of the trochanter, 3) femur, and 4) tibia of the hind leg. In addition, we recorded body height, a variable used to correct the previous variables for body size in all analyses.
Next the data was corrected for phylogenetics effects by building a phylogenetic regression based on the existing classifications based on morphology.
We found that the variable defined as the ratio of the pleural plate length over total leg length, and arguably the best correlate of jumping ability, significantly correlated with the fleas' host-range and the mean level of nest aggregation of their hosts. Our data therefore support the hypothesis that specialization correlates with a reduction of gene flow and accelerates speciation processes.

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 99.0196-3