Patterns of differentiation in the life history and demography of four recently described species of the Brachionus calyciflorus cryptic species complex
Steven A. J. Declerck; Kimberley D. Lemmen; Libin Zhou; Spiros Papakostas; Wei Zhang
https://urn.fi/URN:NBN:fi-fe2021042822943
Tiivistelmä
1. Brachionus calyciflorus is arguably the most studied freshwater
monogonont roti‐ fer. Although it has been recognised as a cryptic
species complex for more than a decade, a formal (re‐)description of the
four species known so far (B. calyciflorus, Brachionus dorcas,
Brachionus elevatus, and Brachionus fernandoi) has only recently been
made. Information on the ecology of these species is very scant and
frag‐ mented. The aim of this study was to test for ecological
divergence between these four species, specifically their life history
strategy and population demography. 2. We conducted a life history
experiment using 12–16 genotypes per species. For each species,
genotypes were extracted from at least three different natural pop‐
ulations. In addition, we performed population‐level culture experiments
with the aim to compare population growth rates and demographic
structure of experi‐ mental populations among species. Finally, we
searched the literature for life his‐ tory studies with molecular data
allowing retrospective species identification. 3. We found pronounced
differences in life history traits between B. fernandoi and the other
three species. B. fernandoi had higher egg and juvenile development
times and a lower egg production rate and mictic ratio. We detected no
significant life history differences among B. calyciflorus, B. elevatus,
and B. dorcas. 4. Population growth rates of B. fernandoi and B.
calyciflorus were higher than those of B. elevatus and B. dorcas. Life
history divergence resulted in marked differences in the demographic
structure of populations. Populations of B. fernandoi con‐ tained larger
fractions of pre‐reproductive females and lower fractions of adult
females with sexual eggs than populations of B. calyciflorus, B.
elevatus, and B. dor‐ cas. Mortality was found to be highest in B.
elevatus and lowest in B. calyciflorus populations. 5. Our results show
that a reverse taxonomy approach is powerful in revealing sources of
variation in ecologically relevant traits of cryptic species, such as
life history and demographic structure. Explicit consideration of this
variation is cru‐ cial for future studies of their dynamics in natural
communities. KEYWORDS ecological divergence, integrative taxonomy,
monogonont rotifer, reverse taxonomy, sibling species
Kokoelmat
- Rinnakkaistallenteet [19207]