Species' traits and taxonomic distance can predict the hatching phenology of ostracod (Crustacea) resting eggs from tropical floodplain lakes

Abstract

Freshwater ostracods are commonly found in temporary ponds and lakes, surviving drought periods by producing resting eggs. We investigated the hatching phenology of ostracod resting eggs from the sediments of temporary floodplain lakes, considering both the taxonomic distance between species and their functional traits, such as carapace size (length and height) and shape, valve ornamentation, and reproductive mode. In addition, we tested the hypotheses: (1) that the hatching time is more similar between congeneric ostracod species than between noncongeneric species; (2) that differences in hatching time between congeneric species are often related to differences in functional traits; (3) that both species composition and functional traits composition of hatchlings change over the incubation time, but with a reduction in the variability over time. The experiment was conducted for 98 days in the laboratory, and the microcosms were monitored weekly. The first hatching of an ostracod was recorded during the second week of incubation after hydration of the sediments. A total of 12 ostracod species hatched, belonging to the families Cyprididae and Candonidae. The above three hypotheses were corroborated. The time between inundation and first hatching was mostly similar for congeneric species in the genus Chlamydotheca, but was different between some species of Strandesia, which might be owing to differences in functional traits. The species composition and functional trait composition of the hatched ostracods were significantly different over the 14 weeks of incubation due to the different hatching phenology of different species. Furthermore, our results show that both taxonomic distance and functional traits can influence the hatching time of ostracod resting eggs from temporary floodplain lakes. Thus, future studies addressing the hatching phenology of ostracod resting eggs (and resting stages from other invertebrates) should also emphasize the use of functional traits.

To sleep or not to sleep: Dormancy and life history traits in Eucypris virens (Crustacea, Ostracoda)

“…Nevertheless, the fixation of a particular mutation that affects the phenotypic measured traits is relatively low assuming a low mutation rate, few individuals and only two generations under study (Pfenninger et al, 2022). We cannot exclude that, the duration of dormancy, storage conditions of resting eggs, exposure of the dormant cohorts to anthropogenic chemicals (e.g, fungicides and PFAS compounds) in mineral water for a longer period of time than that of the nondormant cohorts, might affect the hatchling performances (Navis et al, 2015;Rosa et al, 2021;Rossi et al, 1991Rossi et al, , 2015Ślusarczyk et al, 2019). In H. incongruens, we found that age to adulthood, fecundity, size, and developmental time of eggs of females from 40-month-old resting eggs were affected by their hatching asynchrony after a first or a second inundation event (Rossi et al, 2015).…”

“…Freshwater, nonmarine, ostracods are small crustaceans called “seed shrimp” because they are completely enclosed within a small, “seed‐sized,” bivalved carapace commonly found in temporary ponds and lakes (Meisch, 2000). Both amphimictic and parthenogenetic females produce resting eggs and, according to Rosa et al (2021), species' functional traits and taxonomic distance influence their hatching phenology. In previous works, we described genetic, environmental, and maternal control of dormancy and hatching phenology of Eucypris virens (Jurine, 1820) a geographic parthenogenetic species of freshwater ostracods (Otero et al, 1998; Rossi & Menozzi, 2012a).…”

Geodiversity influences limnological conditions and freshwater ostracode species distributions across broad spatial scales in the northern Neotropics

“…Sulfate is an interesting component of some lakes of the YG1 systems (Socki et al, 2002;Pérez-Ceballos et al, 2012). The presence of sulfates in lake waters may be attributed to the K/T anhydrite/gypsum-bearing impact breccia and dissolution of CaSO 4 of evaporites (Rosencrantz, 1990). This suggests that lakes with high sulfate contents receive L. Macario-González et al: Geodiversity influences limnological conditions high ground water input, as evaporites are only present at depths greater than 170 m below surface, or that these lakes developed along sites with past tectonic activity such as faulting and uplift (Perry et al, 2002).…”

“…In addition, sampling was conducted in a single climatic period. Ostracode phenology, such as differences in hatching time and functional traits, varied within species and are mostly influenced by photoperiod, conductivity, and water temperature (Rossi et al, 2013;Rosa et al, 2021). Therefore, the estimated values of biodiversity may partially represent the true diversity in the region.…”