Symbiotic species diversity can explain invasion success and stability
of the host-parasite system: the case of native and invasive gammarids
(Crustacea, Amphipoda)
- Volodimir Sarabeev,
- Juan Antonio Balbuena,
- Mikuláš Oros,
- Valerii Domnich,
- Rosa Ana Sueiro,
- Jose Manuel Leiro,
- Mykola Ovcharenko
Mikuláš Oros
Institute of Parasitology Slovak Academy of Sciences
Author ProfileAbstract
The major current challenge related to alien species is the absence of a
comprehensive theoretical basis to explain the resistance from
bioinvasions. One of the factors conferring resistance to invasion is
the native species diversity of a recipient ecosystem. We aim to examine
patterns of species diversity to understand the mechanisms underlying
host-parasite relationships in alien species. The dataset represents 20
host-locality samples, including over 15,067,600 symbiotic organisms
counted from 612 host individuals belonging to 7 gammarid species, two
native and five invasive, sampled at 16 localities in the Baltic region
of Poland. We asked whether diversity patterns depended on locality,
habitat and host species, and which factors are deterministic in the
variation of diversity. Our results suggest that both locality and host
phylogeny are critical factors in determining the composition and
abundance of symbiotic communities in gammarids. Out of these two
factors, locality appears to be more determinant of the symbiotic
community of gammarids than host species, whereas habitat condition was
a stronger determinant of the symbiotic communities than geographic
distance. The rich and uneven symbiotic communities of native gammarids
keep the host-parasite system in equilibrium. Sharply dominated
symbiotic species with a high load per host individual stabilize the
host population. Simplified symbiotic communities of the invasive hosts
showed a relatively even distribution of species with moderate loads per
individual, with heavily infected gammarids being rare in the
population. The survival rate of invasive gammarids is expected to be
relatively high, facilitating their population growth and further
spread. Complex communities of the native gammarids constructed from
many symbiotic species may prevent host populations from undergoing
explosive growth, while such mechanisms may be completely or partially
reduced in invasive hosts.